Bump to 3.0.0

Update changelog for 3.0.0

.github/dependabot.yml

@@ -0,0 +1,15 @@
+# dependabot.yml reference: https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
+#
+# Notes:
+# - Status and logs from dependabot are provided at
+#   https://github.com/jupyterhub/jupyterhub/network/updates.
+#
+version: 2
+updates:
+  # Maintain dependencies in our GitHub Workflows
+  - package-ecosystem: github-actions
+    directory: "/"
+    schedule:
+      interval: weekly
+      time: "05:00"
+      timezone: "Etc/UTC"

.github/workflows/release.yml

@@ -1,27 +1,49 @@
-# Build releases and (on tags) publish to PyPI
+# This is a GitHub workflow defining a set of jobs with a set of steps.
+# ref: https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions
+#
+# Test build release artifacts (PyPI package, Docker images) and publish them on
+# pushed git tags.
+#
 name: Release
 
-# always build releases (to make sure wheel-building works)
-# but only publish to PyPI on tags
 on:
-  push:
   pull_request:
+    paths-ignore:
+      - "docs/**"
+      - "**.md"
+      - "**.rst"
+      - ".github/workflows/*"
+      - "!.github/workflows/release.yml"
+  push:
+    paths-ignore:
+      - "docs/**"
+      - "**.md"
+      - "**.rst"
+      - ".github/workflows/*"
+      - "!.github/workflows/release.yml"
+    branches-ignore:
+      - "dependabot/**"
+      - "pre-commit-ci-update-config"
+    tags:
+      - "**"
+  workflow_dispatch:
 
 jobs:
   build-release:
     runs-on: ubuntu-20.04
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
         with:
-          python-version: 3.8
+          python-version: "3.9"
 
-      - uses: actions/setup-node@v1
+      - uses: actions/setup-node@v3
         with:
           node-version: "14"
 
-      - name: install build package
+      - name: install build requirements
         run: |
+          npm install -g yarn
           pip install --upgrade pip
           pip install build
           pip freeze
@@ -31,28 +53,17 @@ jobs:
           python -m build --sdist --wheel .
           ls -l dist
 
-      - name: verify wheel
+      - name: verify sdist
         run: |
-          cd dist
-          pip install ./*.whl
-          # verify data-files are installed where they are found
-          cat <<EOF | python
-          import os
-          from jupyterhub._data import DATA_FILES_PATH
-          print(f"DATA_FILES_PATH={DATA_FILES_PATH}")
-          assert os.path.exists(DATA_FILES_PATH), DATA_FILES_PATH
-          for subpath in (
-              "templates/page.html",
-              "static/css/style.min.css",
-              "static/components/jquery/dist/jquery.js",
-          ):
-              path = os.path.join(DATA_FILES_PATH, subpath)
-              assert os.path.exists(path), path
-          print("OK")
-          EOF
+          ./ci/check_sdist.py dist/jupyterhub-*.tar.gz
+
+      - name: verify data-files are installed where they are found
+        run: |
+          pip install dist/*.whl
+          ./ci/check_installed_data.py
 
       # ref: https://github.com/actions/upload-artifact#readme
-      - uses: actions/upload-artifact@v2
+      - uses: actions/upload-artifact@v3
         with:
           name: jupyterhub-${{ github.sha }}
           path: "dist/*"
@@ -80,37 +91,43 @@ jobs:
     steps:
       - name: Should we push this image to a public registry?
         run: |
-          if [ "${{ startsWith(github.ref, 'refs/tags/') || (github.ref == 'refs/heads/master') }}" = "true" ]; then
+          if [ "${{ startsWith(github.ref, 'refs/tags/') || (github.ref == 'refs/heads/main') }}" = "true" ]; then
               # Empty => Docker Hub
               echo "REGISTRY=" >> $GITHUB_ENV
           else
               echo "REGISTRY=localhost:5000/" >> $GITHUB_ENV
           fi
 
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
-      # Setup docker to build for multiple platforms (requires qemu).
-      # See:
-      # https://github.com/docker/build-push-action/tree/v2.3.0#usage
-      # https://github.com/docker/build-push-action/blob/v2.3.0/docs/advanced/multi-platform.md
+      # Setup docker to build for multiple platforms, see:
+      # https://github.com/docker/build-push-action/tree/v2.4.0#usage
+      # https://github.com/docker/build-push-action/blob/v2.4.0/docs/advanced/multi-platform.md
+      - name: Set up QEMU (for docker buildx)
+        uses: docker/setup-qemu-action@8b122486cedac8393e77aa9734c3528886e4a1a8 # associated tag: v1.0.2
 
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v1
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v1
+      - name: Set up Docker Buildx (for multi-arch builds)
+        uses: docker/setup-buildx-action@dc7b9719a96d48369863986a06765841d7ea23f6 # associated tag: v1.1.2
         with:
           # Allows pushing to registry on localhost:5000
           driver-opts: network=host
 
-      # https://github.com/docker/login-action/tree/v1.8.0#docker-hub
-      - name: Login to Docker Hub
-        uses: docker/login-action@v1
+      - name: Setup push rights to Docker Hub
+        # This was setup by...
+        # 1. Creating a Docker Hub service account "jupyterhubbot"
+        # 2. Creating a access token for the service account specific to this
+        #    repository: https://hub.docker.com/settings/security
+        # 3. Making the account part of the "bots" team, and granting that team
+        #    permissions to push to the relevant images:
+        #    https://hub.docker.com/orgs/jupyterhub/teams/bots/permissions
+        # 4. Registering the username and token as a secret for this repo:
+        #    https://github.com/jupyterhub/jupyterhub/settings/secrets/actions
         if: env.REGISTRY != 'localhost:5000/'
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_TOKEN }}
+        run: |
+          docker login -u "${{ secrets.DOCKERHUB_USERNAME }}" -p "${{ secrets.DOCKERHUB_TOKEN }}"
 
+      # image: jupyterhub/jupyterhub
+      #
       # https://github.com/jupyterhub/action-major-minor-tag-calculator
       # If this is a tagged build this will return additional parent tags.
       # E.g. 1.2.3 is expanded to Docker tags
@@ -120,14 +137,15 @@ jobs:
       # If GITHUB_TOKEN isn't available (e.g. in PRs) returns no tags [].
       - name: Get list of jupyterhub tags
         id: jupyterhubtags
-        uses: jupyterhub/action-major-minor-tag-calculator@v1
+        uses: jupyterhub/action-major-minor-tag-calculator@v2
         with:
           githubToken: ${{ secrets.GITHUB_TOKEN }}
           prefix: "${{ env.REGISTRY }}jupyterhub/jupyterhub:"
           defaultTag: "${{ env.REGISTRY }}jupyterhub/jupyterhub:noref"
+          branchRegex: ^\w[\w-.]*$
 
       - name: Build and push jupyterhub
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
         with:
           context: .
           platforms: linux/amd64,linux/arm64
@@ -136,18 +154,19 @@ jobs:
           # array into a comma separated list of tags
           tags: ${{ join(fromJson(steps.jupyterhubtags.outputs.tags)) }}
 
-      # jupyterhub-onbuild
-
+      # image: jupyterhub/jupyterhub-onbuild
+      #
       - name: Get list of jupyterhub-onbuild tags
         id: onbuildtags
-        uses: jupyterhub/action-major-minor-tag-calculator@v1
+        uses: jupyterhub/action-major-minor-tag-calculator@v2
         with:
           githubToken: ${{ secrets.GITHUB_TOKEN }}
           prefix: "${{ env.REGISTRY }}jupyterhub/jupyterhub-onbuild:"
           defaultTag: "${{ env.REGISTRY }}jupyterhub/jupyterhub-onbuild:noref"
+          branchRegex: ^\w[\w-.]*$
 
       - name: Build and push jupyterhub-onbuild
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
         with:
           build-args: |
             BASE_IMAGE=${{ fromJson(steps.jupyterhubtags.outputs.tags)[0] }}
@@ -156,18 +175,19 @@ jobs:
           push: true
           tags: ${{ join(fromJson(steps.onbuildtags.outputs.tags)) }}
 
-      # jupyterhub-demo
-
+      # image: jupyterhub/jupyterhub-demo
+      #
       - name: Get list of jupyterhub-demo tags
         id: demotags
-        uses: jupyterhub/action-major-minor-tag-calculator@v1
+        uses: jupyterhub/action-major-minor-tag-calculator@v2
         with:
           githubToken: ${{ secrets.GITHUB_TOKEN }}
           prefix: "${{ env.REGISTRY }}jupyterhub/jupyterhub-demo:"
           defaultTag: "${{ env.REGISTRY }}jupyterhub/jupyterhub-demo:noref"
+          branchRegex: ^\w[\w-.]*$
 
       - name: Build and push jupyterhub-demo
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
         with:
           build-args: |
             BASE_IMAGE=${{ fromJson(steps.onbuildtags.outputs.tags)[0] }}
@@ -178,3 +198,24 @@ jobs:
           platforms: linux/amd64
           push: true
           tags: ${{ join(fromJson(steps.demotags.outputs.tags)) }}
+
+      # image: jupyterhub/singleuser
+      #
+      - name: Get list of jupyterhub/singleuser tags
+        id: singleusertags
+        uses: jupyterhub/action-major-minor-tag-calculator@v2
+        with:
+          githubToken: ${{ secrets.GITHUB_TOKEN }}
+          prefix: "${{ env.REGISTRY }}jupyterhub/singleuser:"
+          defaultTag: "${{ env.REGISTRY }}jupyterhub/singleuser:noref"
+          branchRegex: ^\w[\w-.]*$
+
+      - name: Build and push jupyterhub/singleuser
+        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
+        with:
+          build-args: |
+            JUPYTERHUB_VERSION=${{ github.ref_type == 'tag' && github.ref_name || format('git:{0}', github.sha) }}
+          context: singleuser
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ join(fromJson(steps.singleusertags.outputs.tags)) }}

.github/workflows/support-bot.yml

@@ -0,0 +1,31 @@
+# https://github.com/dessant/support-requests
+name: "Support Requests"
+
+on:
+  issues:
+    types: [labeled, unlabeled, reopened]
+
+permissions:
+  issues: write
+
+jobs:
+  action:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: dessant/support-requests@v2
+        with:
+          github-token: ${{ github.token }}
+          support-label: "support"
+          issue-comment: |
+            Hi there @{issue-author} :wave:!
+
+            I closed this issue because it was labelled as a support question.
+
+            Please help us organize discussion by posting this on the http://discourse.jupyter.org/ forum.
+
+            Our goal is to sustain a positive experience for both users and developers. We use GitHub issues for specific discussions related to changing a repository's content, and let the forum be where we can more generally help and inspire each other.
+
+            Thanks you for being an active member of our community! :heart:
+          close-issue: true
+          lock-issue: false
+          issue-lock-reason: "off-topic"

.github/workflows/test-docs.yml

@@ -0,0 +1,62 @@
+# This is a GitHub workflow defining a set of jobs with a set of steps.
+# ref: https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions
+#
+# This workflow validates the REST API definition and runs the pytest tests in
+# the docs/ folder. This workflow does not build the documentation. That is
+# instead tested via ReadTheDocs (https://readthedocs.org/projects/jupyterhub/).
+#
+name: Test docs
+
+# The tests defined in docs/ are currently influenced by changes to _version.py
+# and scopes.py.
+on:
+  pull_request:
+    paths:
+      - "docs/**"
+      - "jupyterhub/_version.py"
+      - "jupyterhub/scopes.py"
+      - ".github/workflows/test-docs.yml"
+  push:
+    paths:
+      - "docs/**"
+      - "jupyterhub/_version.py"
+      - "jupyterhub/scopes.py"
+      - ".github/workflows/test-docs.yml"
+    branches-ignore:
+      - "dependabot/**"
+      - "pre-commit-ci-update-config"
+    tags:
+      - "**"
+  workflow_dispatch:
+
+env:
+  # UTF-8 content may be interpreted as ascii and causes errors without this.
+  LANG: C.UTF-8
+  PYTEST_ADDOPTS: "--verbose --color=yes"
+
+jobs:
+  validate-rest-api-definition:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Validate REST API definition
+        uses: char0n/swagger-editor-validate@v1.3.1
+        with:
+          definition-file: docs/source/_static/rest-api.yml
+
+  test-docs:
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: "3.9"
+
+      - name: Install requirements
+        run: |
+          pip install -r docs/requirements.txt pytest -e .
+
+      - name: pytest docs/
+        run: |
+          pytest docs/

.github/workflows/test-jsx.yml

@@ -0,0 +1,52 @@
+# This is a GitHub workflow defining a set of jobs with a set of steps.
+# ref: https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions
+#
+name: Test jsx (admin-react.js)
+
+on:
+  pull_request:
+    paths:
+      - "jsx/**"
+      - ".github/workflows/test-jsx.yml"
+  push:
+    paths:
+      - "jsx/**"
+      - ".github/workflows/test-jsx.yml"
+    branches-ignore:
+      - "dependabot/**"
+      - "pre-commit-ci-update-config"
+    tags:
+      - "**"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  # The ./jsx folder contains React based source code files that are to compile
+  # to share/jupyterhub/static/js/admin-react.js. The ./jsx folder includes
+  # tests also has tests that this job is meant to run with `yarn test`
+  # according to the documentation in jsx/README.md.
+  test-jsx-admin-react:
+    runs-on: ubuntu-20.04
+    timeout-minutes: 5
+
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+        with:
+          node-version: "14"
+
+      - name: Install yarn
+        run: |
+          npm install -g yarn
+
+      - name: yarn
+        run: |
+          cd jsx
+          yarn
+
+      - name: yarn test
+        run: |
+          cd jsx
+          yarn test

.github/workflows/test.yml

@@ -1,60 +1,43 @@
 # This is a GitHub workflow defining a set of jobs with a set of steps.
-# ref: https://docs.github.com/en/free-pro-team@latest/actions/reference/workflow-syntax-for-github-actions
+# ref: https://docs.github.com/en/actions/learn-github-actions/workflow-syntax-for-github-actions
 #
 name: Test
 
-# Trigger the workflow's on all PRs but only on pushed tags or commits to
-# main/master branch to avoid PRs developed in a GitHub fork's dedicated branch
-# to trigger.
 on:
   pull_request:
+    paths-ignore:
+      - "docs/**"
+      - "**.md"
+      - "**.rst"
+      - ".github/workflows/*"
+      - "!.github/workflows/test.yml"
   push:
+    paths-ignore:
+      - "docs/**"
+      - "**.md"
+      - "**.rst"
+      - ".github/workflows/*"
+      - "!.github/workflows/test.yml"
+    branches-ignore:
+      - "dependabot/**"
+      - "pre-commit-ci-update-config"
+    tags:
+      - "**"
   workflow_dispatch:
 
-defaults:
-  run:
-    # Declare bash be used by default in this workflow's "run" steps.
-    #
-    # NOTE: bash will by default run with:
-    #   --noprofile: Ignore ~/.profile etc.
-    #   --norc:      Ignore ~/.bashrc etc.
-    #   -e:          Exit directly on errors
-    #   -o pipefail: Don't mask errors from a command piped into another command
-    shell: bash
-
 env:
   # UTF-8 content may be interpreted as ascii and causes errors without this.
   LANG: C.UTF-8
+  PYTEST_ADDOPTS: "--verbose --color=yes"
+
+permissions:
+  contents: read
 
 jobs:
-  # Run "pre-commit run --all-files"
-  pre-commit:
-    runs-on: ubuntu-20.04
-    timeout-minutes: 2
-
-    steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
-        with:
-          python-version: 3.8
-
-      # ref: https://github.com/pre-commit/action
-      - uses: pre-commit/action@v2.0.0
-      - name: Help message if pre-commit fail
-        if: ${{ failure() }}
-        run: |
-          echo "You can install pre-commit hooks to automatically run formatting"
-          echo "on each commit with:"
-          echo "    pre-commit install"
-          echo "or you can run by hand on staged files with"
-          echo "    pre-commit run"
-          echo "or after-the-fact on already committed files with"
-          echo "    pre-commit run --all-files"
-
   # Run "pytest jupyterhub/tests" in various configurations
   pytest:
     runs-on: ubuntu-20.04
-    timeout-minutes: 10
+    timeout-minutes: 15
 
     strategy:
       # Keep running even if one variation of the job fail
@@ -73,9 +56,9 @@ jobs:
         #   Tests everything when JupyterHub works against a dedicated mysql or
         #   postgresql server.
         #
-        # jupyter_server:
+        # legacy_notebook:
         #   Tests everything when the user instances are started with
-        #   jupyter_server instead of notebook.
+        #   the legacy notebook server instead of jupyter_server.
         #
         # ssl:
         #   Tests everything using internal SSL connections instead of
@@ -83,25 +66,29 @@ jobs:
         #
         # main_dependencies:
         #   Tests everything when the we use the latest available dependencies
-        #   from: ipytraitlets.
+        #   from: traitlets.
         #
         # NOTE: Since only the value of these parameters are presented in the
         #       GitHub UI when the workflow run, we avoid using true/false as
         #       values by instead duplicating the name to signal true.
+        # Python versions available at:
+        #   https://github.com/actions/python-versions/blob/HEAD/versions-manifest.json
         include:
-          - python: "3.6"
+          - python: "3.7"
             oldest_dependencies: oldest_dependencies
-          - python: "3.6"
-            subdomain: subdomain
-          - python: "3.7"
-            db: mysql
-          - python: "3.7"
-            ssl: ssl
+            legacy_notebook: legacy_notebook
           - python: "3.8"
-            db: postgres
-          - python: "3.8"
-            jupyter_server: jupyter_server
+            legacy_notebook: legacy_notebook
           - python: "3.9"
+            db: mysql
+          - python: "3.10"
+            db: postgres
+          - python: "3.10"
+            subdomain: subdomain
+          - python: "3.10"
+            ssl: ssl
+          - python: "3.11.0-rc.1"
+          - python: "3.10"
             main_dependencies: main_dependencies
 
     steps:
@@ -129,28 +116,38 @@ jobs:
           if [ "${{ matrix.jupyter_server }}" != "" ]; then
               echo "JUPYTERHUB_SINGLEUSER_APP=jupyterhub.tests.mockserverapp.MockServerApp" >> $GITHUB_ENV
           fi
-      - uses: actions/checkout@v2
-      # NOTE: actions/setup-node@v1 make use of a cache within the GitHub base
+      - uses: actions/checkout@v3
+      # NOTE: actions/setup-node@v3 make use of a cache within the GitHub base
       #       environment and setup in a fraction of a second.
       - name: Install Node v14
-        uses: actions/setup-node@v1
+        uses: actions/setup-node@v3
         with:
           node-version: "14"
-      - name: Install Node dependencies
+      - name: Install Javascript dependencies
         run: |
           npm install
-          npm install -g configurable-http-proxy
+          npm install -g configurable-http-proxy yarn
           npm list
 
-      # NOTE: actions/setup-python@v2 make use of a cache within the GitHub base
+      # NOTE: actions/setup-python@v4 make use of a cache within the GitHub base
       #       environment and setup in a fraction of a second.
       - name: Install Python ${{ matrix.python }}
-        uses: actions/setup-python@v2
+        uses: actions/setup-python@v4
         with:
-          python-version: ${{ matrix.python }}
+          python-version: "${{ matrix.python }}"
+
       - name: Install Python dependencies
         run: |
           pip install --upgrade pip
+
+          if [[ "${{ matrix.python }}" == "3.11"* ]]; then
+            # greenlet is not actually required,
+            # but is an install dependency of sqlalchemy.
+            # It does not yet install on 3.11
+            # see: see https://github.com/gevent/gevent/issues/1867
+            pip install ./ci/mock-greenlet
+          fi
+
           pip install --upgrade . -r dev-requirements.txt
 
           if [ "${{ matrix.oldest_dependencies }}" != "" ]; then
@@ -164,9 +161,9 @@ jobs:
           if [ "${{ matrix.main_dependencies }}" != "" ]; then
               pip install git+https://github.com/ipython/traitlets#egg=traitlets --force
           fi
-          if [ "${{ matrix.jupyter_server }}" != "" ]; then
-              pip uninstall notebook --yes
-              pip install jupyter_server
+          if [ "${{ matrix.legacy_notebook }}" != "" ]; then
+              pip uninstall jupyter_server --yes
+              pip install 'notebook<7'
           fi
           if [ "${{ matrix.db }}" == "mysql" ]; then
               pip install mysql-connector-python
@@ -202,33 +199,35 @@ jobs:
         if: ${{ matrix.db }}
         run: |
           if [ "${{ matrix.db }}" == "mysql" ]; then
+            if [[ -z "$(which mysql)" ]]; then
               sudo apt-get update
               sudo apt-get install -y mysql-client
+            fi
               DB=mysql bash ci/docker-db.sh
               DB=mysql bash ci/init-db.sh
           fi
           if [ "${{ matrix.db }}" == "postgres" ]; then
+            if [[ -z "$(which psql)" ]]; then
               sudo apt-get update
               sudo apt-get install -y postgresql-client
+            fi
               DB=postgres bash ci/docker-db.sh
               DB=postgres bash ci/init-db.sh
           fi
 
       - name: Run pytest
-        # FIXME: --color=yes explicitly set because:
-        #        https://github.com/actions/runner/issues/241
         run: |
-          pytest -v --maxfail=2 --color=yes --cov=jupyterhub jupyterhub/tests
+          pytest --maxfail=2 --cov=jupyterhub jupyterhub/tests
       - name: Submit codecov report
         run: |
           codecov
 
   docker-build:
     runs-on: ubuntu-20.04
-    timeout-minutes: 10
+    timeout-minutes: 20
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: build images
         run: |

.gitignore

@@ -8,7 +8,9 @@ dist
 docs/_build
 docs/build
 docs/source/_static/rest-api
+docs/source/rbac/scope-table.md
 .ipynb_checkpoints
+jsx/build/
 # ignore config file at the top-level of the repo
 # but not sub-dirs
 /jupyterhub_config.py
@@ -18,6 +20,7 @@ package-lock.json
 share/jupyterhub/static/components
 share/jupyterhub/static/css/style.min.css
 share/jupyterhub/static/css/style.min.css.map
+share/jupyterhub/static/js/admin-react.js*
 *.egg-info
 MANIFEST
 .coverage
@@ -29,3 +32,5 @@ htmlcov
 pip-wheel-metadata
 docs/source/reference/metrics.rst
 oldest-requirements.txt
+jupyterhub-proxy.pid
+examples/server-api/service-token

.pre-commit-config.yaml

@@ -1,24 +1,52 @@
+# pre-commit is a tool to perform a predefined set of tasks manually and/or
+# automatically before git commits are made.
+#
+# Config reference: https://pre-commit.com/#pre-commit-configyaml---top-level
+#
+# Common tasks
+#
+# - Run on all files:   pre-commit run --all-files
+# - Register git hooks: pre-commit install --install-hooks
+#
 repos:
-  - repo: https://github.com/asottile/reorder_python_imports
-    rev: v1.9.0
+  # Autoformat: Python code, syntax patterns are modernized
+  - repo: https://github.com/asottile/pyupgrade
+    rev: v2.37.3
     hooks:
-      - id: reorder-python-imports
+      - id: pyupgrade
+        args:
+          - --py36-plus
+
+  # Autoformat: Python code
+  - repo: https://github.com/pycqa/isort
+    rev: 5.10.1
+    hooks:
+      - id: isort
+
+  # Autoformat: Python code
   - repo: https://github.com/psf/black
-    rev: 20.8b1
+    rev: 22.6.0
     hooks:
       - id: black
+
+  # Autoformat: markdown, yaml, javascript (see the file .prettierignore)
   - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v2.2.1
+    rev: v2.7.1
     hooks:
       - id: prettier
-  - repo: https://gitlab.com/pycqa/flake8
-    rev: "3.8.4"
-    hooks:
-      - id: flake8
+
+  # Autoformat and linting, misc. details
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v3.4.0
+    rev: v4.3.0
     hooks:
       - id: end-of-file-fixer
+        exclude: share/jupyterhub/static/js/admin-react.js
+      - id: requirements-txt-fixer
       - id: check-case-conflict
       - id: check-executables-have-shebangs
-      - id: requirements-txt-fixer
+
+  # Linting: Python code (see the file .flake8)
+  - repo: https://github.com/PyCQA/flake8
+    rev: "5.0.4"
+    hooks:
+      - id: flake8

.prettierignore

@@ -1 +1,2 @@
 share/jupyterhub/templates/
+share/jupyterhub/static/js/admin-react.js

.readthedocs.yaml

@@ -4,10 +4,12 @@ sphinx:
   configuration: docs/source/conf.py
 
 build:
-  image: latest
+  os: ubuntu-20.04
+  tools:
+    nodejs: "16"
+    python: "3.9"
 
 python:
-  version: 3.7
   install:
     - method: pip
       path: .

CHECKLIST-Release.md

@@ -1,26 +0,0 @@
-# Release checklist
-
-- [ ] Upgrade Docs prior to Release
-
-  - [ ] Change log
-  - [ ] New features documented
-  - [ ] Update the contributor list - thank you page
-
-- [ ] Upgrade and test Reference Deployments
-
-- [ ] Release software
-
-  - [ ] Make sure 0 issues in milestone
-  - [ ] Follow release process steps
-  - [ ] Send builds to PyPI (Warehouse) and Conda Forge
-
-- [ ] Blog post and/or release note
-
-- [ ] Notify users of release
-
-  - [ ] Email Jupyter and Jupyter In Education mailing lists
-  - [ ] Tweet (optional)
-
-- [ ] Increment the version number for the next release
-
-- [ ] Update roadmap

CODE_OF_CONDUCT.md

@@ -1 +1 @@
-Please refer to [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md).
+Please refer to [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md).

CONTRIBUTING.md

@@ -3,137 +3,12 @@
 Welcome! As a [Jupyter](https://jupyter.org) project,
 you can follow the [Jupyter contributor guide](https://jupyter.readthedocs.io/en/latest/contributing/content-contributor.html).
 
-Make sure to also follow [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md)
+Make sure to also follow [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md)
 for a friendly and welcoming collaborative environment.
 
-## Setting up a development environment
+Please see our documentation on
 
-<!--
-https://jupyterhub.readthedocs.io/en/stable/contributing/setup.html
-contains a lot of the same information. Should we merge the docs and
-just have this page link to that one?
--->
+- [Setting up a development install](https://jupyterhub.readthedocs.io/en/latest/contributing/setup.html)
+- [Testing JupyterHub and linting code](https://jupyterhub.readthedocs.io/en/latest/contributing/tests.html)
 
-JupyterHub requires Python >= 3.5 and nodejs.
-
-As a Python project, a development install of JupyterHub follows standard practices for the basics (steps 1-2).
-
-1. clone the repo
-   ```bash
-   git clone https://github.com/jupyterhub/jupyterhub
-   ```
-2. do a development install with pip
-
-   ```bash
-   cd jupyterhub
-   python3 -m pip install --editable .
-   ```
-
-3. install the development requirements,
-   which include things like testing tools
-
-   ```bash
-   python3 -m pip install -r dev-requirements.txt
-   ```
-
-4. install configurable-http-proxy with npm:
-
-   ```bash
-   npm install -g configurable-http-proxy
-   ```
-
-5. set up pre-commit hooks for automatic code formatting, etc.
-
-   ```bash
-   pre-commit install
-   ```
-
-   You can also invoke the pre-commit hook manually at any time with
-
-   ```bash
-   pre-commit run
-   ```
-
-## Contributing
-
-JupyterHub has adopted automatic code formatting so you shouldn't
-need to worry too much about your code style.
-As long as your code is valid,
-the pre-commit hook should take care of how it should look.
-You can invoke the pre-commit hook by hand at any time with:
-
-```bash
-pre-commit run
-```
-
-which should run any autoformatting on your code
-and tell you about any errors it couldn't fix automatically.
-You may also install [black integration](https://github.com/psf/black#editor-integration)
-into your text editor to format code automatically.
-
-If you have already committed files before setting up the pre-commit
-hook with `pre-commit install`, you can fix everything up using
-`pre-commit run --all-files`. You need to make the fixing commit
-yourself after that.
-
-## Testing
-
-It's a good idea to write tests to exercise any new features,
-or that trigger any bugs that you have fixed to catch regressions.
-
-You can run the tests with:
-
-```bash
-pytest -v
-```
-
-in the repo directory. If you want to just run certain tests,
-check out the [pytest docs](https://pytest.readthedocs.io/en/latest/usage.html)
-for how pytest can be called.
-For instance, to test only spawner-related things in the REST API:
-
-```bash
-pytest -v -k spawn jupyterhub/tests/test_api.py
-```
-
-The tests live in `jupyterhub/tests` and are organized roughly into:
-
-1. `test_api.py` tests the REST API
-2. `test_pages.py` tests loading the HTML pages
-
-and other collections of tests for different components.
-When writing a new test, there should usually be a test of
-similar functionality already written and related tests should
-be added nearby.
-
-The fixtures live in `jupyterhub/tests/conftest.py`. There are
-fixtures that can be used for JupyterHub components, such as:
-
-- `app`: an instance of JupyterHub with mocked parts
-- `auth_state_enabled`: enables persisting auth_state (like authentication tokens)
-- `db`: a sqlite in-memory DB session
-- `io_loop`: a Tornado event loop
-- `event_loop`: a new asyncio event loop
-- `user`: creates a new temporary user
-- `admin_user`: creates a new temporary admin user
-- single user servers
-  - `cleanup_after`: allows cleanup of single user servers between tests
-- mocked service
-  - `MockServiceSpawner`: a spawner that mocks services for testing with a short poll interval
-  - `mockservice`: mocked service with no external service url
-  - `mockservice_url`: mocked service with a url to test external services
-
-And fixtures to add functionality or spawning behavior:
-
-- `admin_access`: grants admin access
-- `no_patience`: sets slow-spawning timeouts to zero
-- `slow_spawn`: enables the SlowSpawner (a spawner that takes a few seconds to start)
-- `never_spawn`: enables the NeverSpawner (a spawner that will never start)
-- `bad_spawn`: enables the BadSpawner (a spawner that fails immediately)
-- `slow_bad_spawn`: enables the SlowBadSpawner (a spawner that fails after a short delay)
-
-To read more about fixtures check out the
-[pytest docs](https://docs.pytest.org/en/latest/fixture.html)
-for how to use the existing fixtures, and how to create new ones.
-
-When in doubt, feel free to [ask](https://gitter.im/jupyterhub/jupyterhub).
+If you need some help, feel free to ask on [Gitter](https://gitter.im/jupyterhub/jupyterhub) or [Discourse](https://discourse.jupyter.org/).

Dockerfile

@@ -21,7 +21,7 @@
 # your jupyterhub_config.py will be added automatically
 # from your docker directory.
 
-ARG BASE_IMAGE=ubuntu:focal-20200729
+ARG BASE_IMAGE=ubuntu:22.04
 FROM $BASE_IMAGE AS builder
 
 USER root
@@ -37,6 +37,7 @@ RUN apt-get update \
     python3-pycurl \
     nodejs \
     npm \
+    yarn \
  && apt-get clean \
  && rm -rf /var/lib/apt/lists/*
 

MANIFEST.in

@@ -8,6 +8,7 @@ include *requirements.txt
 include Dockerfile
 
 graft onbuild
+graft jsx
 graft jupyterhub
 graft scripts
 graft share
@@ -18,6 +19,10 @@ graft ci
 graft docs
 prune docs/node_modules
 
+# Intermediate javascript files
+prune jsx/node_modules
+prune jsx/build
+
 # prune some large unused files from components
 prune share/jupyterhub/static/components/bootstrap/dist/css
 exclude share/jupyterhub/static/components/bootstrap/dist/fonts/*.svg

README.md

@@ -6,27 +6,37 @@
 **[License](#license)** |
 **[Help and Resources](#help-and-resources)**
 
+---
+
+Please note that this repository is participating in a study into the sustainability of open source projects. Data will be gathered about this repository for approximately the next 12 months, starting from 2021-06-11.
+
+Data collected will include the number of contributors, number of PRs, time taken to close/merge these PRs, and issues closed.
+
+For more information, please visit
+[our informational page](https://sustainable-open-science-and-software.github.io/) or download our [participant information sheet](https://sustainable-open-science-and-software.github.io/assets/PIS_sustainable_software.pdf).
+
+---
+
 # [JupyterHub](https://github.com/jupyterhub/jupyterhub)
 
 [![Latest PyPI version](https://img.shields.io/pypi/v/jupyterhub?logo=pypi)](https://pypi.python.org/pypi/jupyterhub)
-[![Latest conda-forge version](https://img.shields.io/conda/vn/conda-forge/jupyterhub?logo=conda-forge)](https://www.npmjs.com/package/jupyterhub)
+[![Latest conda-forge version](https://img.shields.io/conda/vn/conda-forge/jupyterhub?logo=conda-forge)](https://anaconda.org/conda-forge/jupyterhub)
 [![Documentation build status](https://img.shields.io/readthedocs/jupyterhub?logo=read-the-docs)](https://jupyterhub.readthedocs.org/en/latest/)
 [![GitHub Workflow Status - Test](https://img.shields.io/github/workflow/status/jupyterhub/jupyterhub/Test?logo=github&label=tests)](https://github.com/jupyterhub/jupyterhub/actions)
 [![DockerHub build status](https://img.shields.io/docker/build/jupyterhub/jupyterhub?logo=docker&label=build)](https://hub.docker.com/r/jupyterhub/jupyterhub/tags)
-[![CircleCI build status](https://img.shields.io/circleci/build/github/jupyterhub/jupyterhub?logo=circleci)](https://circleci.com/gh/jupyterhub/jupyterhub)<!-- CircleCI Token: b5b65862eb2617b9a8d39e79340b0a6b816da8cc -->
-[![Test coverage of code](https://codecov.io/gh/jupyterhub/jupyterhub/branch/master/graph/badge.svg)](https://codecov.io/gh/jupyterhub/jupyterhub)
+[![Test coverage of code](https://codecov.io/gh/jupyterhub/jupyterhub/branch/main/graph/badge.svg)](https://codecov.io/gh/jupyterhub/jupyterhub)
 [![GitHub](https://img.shields.io/badge/issue_tracking-github-blue?logo=github)](https://github.com/jupyterhub/jupyterhub/issues)
 [![Discourse](https://img.shields.io/badge/help_forum-discourse-blue?logo=discourse)](https://discourse.jupyter.org/c/jupyterhub)
 [![Gitter](https://img.shields.io/badge/social_chat-gitter-blue?logo=gitter)](https://gitter.im/jupyterhub/jupyterhub)
 
 With [JupyterHub](https://jupyterhub.readthedocs.io) you can create a
-**multi-user Hub** which spawns, manages, and proxies multiple instances of the
+**multi-user Hub** that spawns, manages, and proxies multiple instances of the
 single-user [Jupyter notebook](https://jupyter-notebook.readthedocs.io)
 server.
 
 [Project Jupyter](https://jupyter.org) created JupyterHub to support many
 users. The Hub can offer notebook servers to a class of students, a corporate
-data science workgroup, a scientific research project, or a high performance
+data science workgroup, a scientific research project, or a high-performance
 computing group.
 
 ## Technical overview
@@ -40,36 +50,30 @@ Three main actors make up JupyterHub:
 Basic principles for operation are:
 
 - Hub launches a proxy.
-- Proxy forwards all requests to Hub by default.
-- Hub handles login, and spawns single-user servers on demand.
-- Hub configures proxy to forward url prefixes to the single-user notebook
+- The Proxy forwards all requests to Hub by default.
+- Hub handles login and spawns single-user servers on demand.
+- Hub configures proxy to forward URL prefixes to the single-user notebook
   servers.
 
 JupyterHub also provides a
-[REST API](http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/jupyterhub/master/docs/rest-api.yml#/default)
+[REST API][]
 for administration of the Hub and its users.
 
+[rest api]: https://jupyterhub.readthedocs.io/en/latest/reference/rest-api.html
+
 ## Installation
 
 ### Check prerequisites
 
 - A Linux/Unix based system
-- [Python](https://www.python.org/downloads/) 3.5 or greater
+- [Python](https://www.python.org/downloads/) 3.6 or greater
 - [nodejs/npm](https://www.npmjs.com/)
 
   - If you are using **`conda`**, the nodejs and npm dependencies will be installed for
     you by conda.
 
-  - If you are using **`pip`**, install a recent version of
+  - If you are using **`pip`**, install a recent version (at least 12.0) of
     [nodejs/npm](https://docs.npmjs.com/getting-started/installing-node).
-    For example, install it on Linux (Debian/Ubuntu) using:
-
-    ```
-    sudo apt-get install npm nodejs-legacy
-    ```
-
-    The `nodejs-legacy` package installs the `node` executable and is currently
-    required for npm to work on Debian/Ubuntu.
 
 - If using the default PAM Authenticator, a [pluggable authentication module (PAM)](https://en.wikipedia.org/wiki/Pluggable_authentication_module).
 - TLS certificate and key for HTTPS communication
@@ -85,12 +89,11 @@ To install JupyterHub along with its dependencies including nodejs/npm:
 conda install -c conda-forge jupyterhub
 ```
 
-If you plan to run notebook servers locally, install the Jupyter notebook
-or JupyterLab:
+If you plan to run notebook servers locally, install JupyterLab or Jupyter notebook:
 
 ```bash
-conda install notebook
 conda install jupyterlab
+conda install notebook
 ```
 
 #### Using `pip`
@@ -102,10 +105,10 @@ npm install -g configurable-http-proxy
 python3 -m pip install jupyterhub
 ```
 
-If you plan to run notebook servers locally, you will need to install the
-[Jupyter notebook](https://jupyter.readthedocs.io/en/latest/install.html)
-package:
+If you plan to run notebook servers locally, you will need to install
+[JupyterLab or Jupyter notebook](https://jupyter.readthedocs.io/en/latest/install.html):
 
+    python3 -m pip install --upgrade jupyterlab
     python3 -m pip install --upgrade notebook
 
 ### Run the Hub server
@@ -114,10 +117,9 @@ To start the Hub server, run the command:
 
     jupyterhub
 
-Visit `https://localhost:8000` in your browser, and sign in with your unix
-PAM credentials.
+Visit `http://localhost:8000` in your browser, and sign in with your system username and password.
 
-_Note_: To allow multiple users to sign into the server, you will need to
+_Note_: To allow multiple users to sign in to the server, you will need to
 run the `jupyterhub` command as a _privileged user_, such as root.
 The [wiki](https://github.com/jupyterhub/jupyterhub/wiki/Using-sudo-to-run-JupyterHub-without-root-privileges)
 describes how to run the server as a _less privileged user_, which requires
@@ -201,7 +203,7 @@ These accounts will be used for authentication in JupyterHub's default configura
 ## Contributing
 
 If you would like to contribute to the project, please read our
-[contributor documentation](http://jupyter.readthedocs.io/en/latest/contributor/content-contributor.html)
+[contributor documentation](https://jupyter.readthedocs.io/en/latest/contributing/content-contributor.html)
 and the [`CONTRIBUTING.md`](CONTRIBUTING.md). The `CONTRIBUTING.md` file
 explains how to set up a development installation, how to run the test suite,
 and how to contribute to documentation.
@@ -228,18 +230,17 @@ docker container or Linux VM.
 We use a shared copyright model that enables all contributors to maintain the
 copyright on their contributions.
 
-All code is licensed under the terms of the revised BSD license.
+All code is licensed under the terms of the [revised BSD license](./COPYING.md).
 
 ## Help and resources
 
-We encourage you to ask questions on the [Jupyter mailing list](https://groups.google.com/forum/#!forum/jupyter).
-To participate in development discussions or get help, talk with us on
-our JupyterHub [Gitter](https://gitter.im/jupyterhub/jupyterhub) channel.
+We encourage you to ask questions and share ideas on the [Jupyter community forum](https://discourse.jupyter.org/).
+You can also talk with us on our JupyterHub [Gitter](https://gitter.im/jupyterhub/jupyterhub) channel.
 
 - [Reporting Issues](https://github.com/jupyterhub/jupyterhub/issues)
 - [JupyterHub tutorial](https://github.com/jupyterhub/jupyterhub-tutorial)
 - [Documentation for JupyterHub](https://jupyterhub.readthedocs.io/en/latest/) | [PDF (latest)](https://media.readthedocs.org/pdf/jupyterhub/latest/jupyterhub.pdf) | [PDF (stable)](https://media.readthedocs.org/pdf/jupyterhub/stable/jupyterhub.pdf)
-- [Documentation for JupyterHub's REST API](http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/jupyterhub/master/docs/rest-api.yml#/default)
+- [Documentation for JupyterHub's REST API][rest api]
 - [Documentation for Project Jupyter](http://jupyter.readthedocs.io/en/latest/index.html) | [PDF](https://media.readthedocs.org/pdf/jupyter/latest/jupyter.pdf)
 - [Project Jupyter website](https://jupyter.org)
 - [Project Jupyter community](https://jupyter.org/community)

RELEASE.md

@@ -0,0 +1,50 @@
+# How to make a release
+
+`jupyterhub` is a package [available on
+PyPI](https://pypi.org/project/jupyterhub/) and
+[conda-forge](https://conda-forge.org/).
+These are instructions on how to make a release on PyPI.
+The PyPI release is done automatically by CI when a tag is pushed.
+
+For you to follow along according to these instructions, you need:
+
+- To have push rights to the [jupyterhub GitHub
+  repository](https://github.com/jupyterhub/jupyterhub).
+
+## Steps to make a release
+
+1. Checkout main and make sure it is up to date.
+
+   ```shell
+   ORIGIN=${ORIGIN:-origin} # set to the canonical remote, e.g. 'upstream' if 'origin' is not the official repo
+   git checkout main
+   git fetch $ORIGIN main
+   git reset --hard $ORIGIN/main
+   ```
+
+1. Make sure `docs/source/changelog.md` is up-to-date.
+   [github-activity][] can help with this.
+
+1. Update the version with `tbump`.
+   You can see what will happen without making any changes with `tbump --dry-run ${VERSION}`
+
+   ```shell
+   tbump ${VERSION}
+   ```
+
+   This will tag and publish a release,
+   which will be finished on CI.
+
+1. Reset the version back to dev, e.g. `2.1.0.dev` after releasing `2.0.0`
+
+   ```shell
+   tbump --no-tag ${NEXT_VERSION}.dev
+   ```
+
+1. Following the release to PyPI, an automated PR should arrive to
+   [conda-forge/jupyterhub-feedstock][],
+   check for the tests to succeed on this PR and then merge it to successfully
+   update the package for `conda` on the conda-forge channel.
+
+[github-activity]: https://github.com/choldgraf/github-activity
+[conda-forge/jupyterhub-feedstock]: https://github.com/conda-forge/jupyterhub-feedstock

SECURITY.md

@@ -0,0 +1,5 @@
+# Reporting a Vulnerability
+
+If you believe you’ve found a security vulnerability in a Jupyter
+project, please report it to security@ipython.org. If you prefer to
+encrypt your security reports, you can use [this PGP public key](https://jupyter-notebook.readthedocs.io/en/stable/_downloads/1d303a645f2505a8fd283826fafc9908/ipython_security.asc).

bower-lite

@@ -29,5 +29,5 @@ dependencies = package_json['dependencies']
 for dep in dependencies:
     src = join(node_modules, dep)
     dest = join(components, dep)
-    print("%s -> %s" % (src, dest))
+    print(f"{src} -> {dest}")
     shutil.copytree(src, dest)

ci/check_installed_data.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+# Check that installed package contains everything we expect
+
+
+import os
+
+from jupyterhub._data import DATA_FILES_PATH
+
+print("Checking jupyterhub._data")
+print(f"DATA_FILES_PATH={DATA_FILES_PATH}")
+assert os.path.exists(DATA_FILES_PATH), DATA_FILES_PATH
+for subpath in (
+    "templates/page.html",
+    "static/css/style.min.css",
+    "static/components/jquery/dist/jquery.js",
+    "static/js/admin-react.js",
+):
+    path = os.path.join(DATA_FILES_PATH, subpath)
+    assert os.path.exists(path), path
+print("OK")

ci/check_sdist.py

@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+# Check that sdist contains everything we expect
+
+import sys
+import tarfile
+from tarfile import TarFile
+
+expected_files = [
+    "docs/requirements.txt",
+    "jsx/package.json",
+    "package.json",
+    "README.md",
+]
+
+assert len(sys.argv) == 2, "Expected one file"
+print(f"Checking {sys.argv[1]}")
+
+tar = tarfile.open(name=sys.argv[1], mode="r:gz")
+try:
+    # Remove leading jupyterhub-VERSION/
+    filelist = {f.partition('/')[2] for f in tar.getnames()}
+finally:
+    tar.close()
+
+for e in expected_files:
+    assert e in filelist, f"{e} not found"
+
+print("OK")

ci/init-db.sh

@@ -20,7 +20,7 @@ fi
 
 # Configure a set of databases in the database server for upgrade tests
 set -x
-for SUFFIX in '' _upgrade_072 _upgrade_081 _upgrade_094; do
+for SUFFIX in '' _upgrade_100 _upgrade_122 _upgrade_130 _upgrade_150 _upgrade_211; do
     $SQL_CLIENT "DROP DATABASE jupyterhub${SUFFIX};" 2>/dev/null || true
     $SQL_CLIENT "CREATE DATABASE jupyterhub${SUFFIX} ${EXTRA_CREATE_DATABASE_ARGS:-};"
 done

ci/mock-greenlet/greenlet.py

@@ -0,0 +1,3 @@
+__version__ = "22.0.0.dev0"
+
+raise ImportError("Don't actually have greenlet")

ci/mock-greenlet/pyproject.toml

@@ -0,0 +1,13 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "greenlet"
+description = 'Mock greenlet to allow install on 3.11'
+requires-python = ">=3.7"
+dynamic = ["version"]
+
+
+[tool.hatch.version]
+path = "greenlet.py"

dev-requirements.txt

@@ -7,13 +7,18 @@ codecov
 coverage
 cryptography
 html5lib  # needed for beautifulsoup
+jupyterlab >=3
 mock
-notebook
+# nbclassic provides the '/tree/' handler, which we use in tests
+# it is a transitive dependency via jupyterlab,
+# but depend on it directly
+nbclassic
 pre-commit
 pytest>=3.3
-pytest-asyncio
+pytest-asyncio>=0.17
 pytest-cov
 requests-mock
+tbump
 # blacklist urllib3 releases affected by https://github.com/urllib3/urllib3/issues/1683
 # I *think* this should only affect testing, not production
 urllib3!=1.25.4,!=1.25.5

docs/Makefile

@@ -53,20 +53,17 @@ help:
 clean:
 	rm -rf $(BUILDDIR)/*
 
-node_modules: package.json
-	npm install && touch node_modules
-
-rest-api: source/_static/rest-api/index.html
-
-source/_static/rest-api/index.html: rest-api.yml node_modules
-	npm run rest-api
-
 metrics: source/reference/metrics.rst
 
 source/reference/metrics.rst: generate-metrics.py
 	python3 generate-metrics.py
 
-html: rest-api metrics
+scopes: source/rbac/scope-table.md
+
+source/rbac/scope-table.md: source/rbac/generate-scope-table.py
+	python3 source/rbac/generate-scope-table.py
+
+html: metrics scopes
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
 	@echo
 	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."

docs/package.json

@@ -1,14 +0,0 @@
-{
-  "name": "jupyterhub-docs-build",
-  "version": "0.8.0",
-  "description": "build JupyterHub swagger docs",
-  "scripts": {
-    "rest-api": "bootprint openapi ./rest-api.yml source/_static/rest-api"
-  },
-  "author": "",
-  "license": "BSD-3-Clause",
-  "devDependencies": {
-    "bootprint": "^1.0.0",
-    "bootprint-openapi": "^1.0.0"
-  }
-}

docs/requirements.txt

@@ -1,12 +1,12 @@
 -r ../requirements.txt
 
 alabaster_jupyterhub
-# Temporary fix of #3021. Revert back to released autodoc-traits when
-# 0.1.0 released.
-https://github.com/jupyterhub/autodoc-traits/archive/75885ee24636efbfebfceed1043459715049cd84.zip
+autodoc-traits
+myst-parser
+pre-commit
 pydata-sphinx-theme
 pytablewriter>=0.56
-recommonmark>=0.6
+ruamel.yaml
 sphinx>=1.7
 sphinx-copybutton
 sphinx-jsonschema

docs/rest-api.yml

@@ -1,893 +0,0 @@
-# see me at: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#/default
-swagger: "2.0"
-info:
-  title: JupyterHub
-  description: The REST API for JupyterHub
-  version: 1.4.0
-  license:
-    name: BSD-3-Clause
-schemes: [http, https]
-securityDefinitions:
-  token:
-    type: apiKey
-    name: Authorization
-    in: header
-security:
-  - token: []
-basePath: /hub/api
-produces:
-  - application/json
-consumes:
-  - application/json
-paths:
-  /:
-    get:
-      summary: Get JupyterHub version
-      description: |
-        This endpoint is not authenticated for the purpose of clients and user
-        to identify the JupyterHub version before setting up authentication.
-      responses:
-        "200":
-          description: The JupyterHub version
-          schema:
-            type: object
-            properties:
-              version:
-                type: string
-                description: The version of JupyterHub itself
-  /info:
-    get:
-      summary: Get detailed info about JupyterHub
-      description: |
-        Detailed JupyterHub information, including Python version,
-        JupyterHub's version and executable path,
-        and which Authenticator and Spawner are active.
-      responses:
-        "200":
-          description: Detailed JupyterHub info
-          schema:
-            type: object
-            properties:
-              version:
-                type: string
-                description: The version of JupyterHub itself
-              python:
-                type: string
-                description: The Python version, as returned by sys.version
-              sys_executable:
-                type: string
-                description: The path to sys.executable running JupyterHub
-              authenticator:
-                type: object
-                properties:
-                  class:
-                    type: string
-                    description: The Python class currently active for JupyterHub Authentication
-                  version:
-                    type: string
-                    description: The version of the currently active Authenticator
-              spawner:
-                type: object
-                properties:
-                  class:
-                    type: string
-                    description: The Python class currently active for spawning single-user notebook servers
-                  version:
-                    type: string
-                    description: The version of the currently active Spawner
-  /users:
-    get:
-      summary: List users
-      parameters:
-        - name: state
-          in: query
-          required: false
-          type: string
-          enum: ["inactive", "active", "ready"]
-          description: |
-            Return only users who have servers in the given state.
-            If unspecified, return all users.
-
-            active: all users with any active servers (ready OR pending)
-            ready: all users who have any ready servers (running, not pending)
-            inactive: all users who have *no* active servers (complement of active)
-
-            Added in JupyterHub 1.3
-      responses:
-        "200":
-          description: The Hub's user list
-          schema:
-            type: array
-            items:
-              $ref: "#/definitions/User"
-    post:
-      summary: Create multiple users
-      parameters:
-        - name: body
-          in: body
-          required: true
-          schema:
-            type: object
-            properties:
-              usernames:
-                type: array
-                description: list of usernames to create on the Hub
-                items:
-                  type: string
-              admin:
-                description: whether the created users should be admins
-                type: boolean
-      responses:
-        "201":
-          description: The users have been created
-          schema:
-            type: array
-            description: The created users
-            items:
-              $ref: "#/definitions/User"
-  /users/{name}:
-    get:
-      summary: Get a user by name
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-      responses:
-        "200":
-          description: The User model
-          schema:
-            $ref: "#/definitions/User"
-    post:
-      summary: Create a single user
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-      responses:
-        "201":
-          description: The user has been created
-          schema:
-            $ref: "#/definitions/User"
-    patch:
-      summary: Modify a user
-      description: Change a user's name or admin status
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-        - name: body
-          in: body
-          required: true
-          description: Updated user info. At least one key to be updated (name or admin) is required.
-          schema:
-            type: object
-            properties:
-              name:
-                type: string
-                description: the new name (optional, if another key is updated i.e. admin)
-              admin:
-                type: boolean
-                description: update admin (optional, if another key is updated i.e. name)
-      responses:
-        "200":
-          description: The updated user info
-          schema:
-            $ref: "#/definitions/User"
-    delete:
-      summary: Delete a user
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-      responses:
-        "204":
-          description: The user has been deleted
-  /users/{name}/activity:
-    post:
-      summary: Notify Hub of activity for a given user.
-      description: Notify the Hub of activity by the user,
-        e.g. accessing a service or (more likely)
-        actively using a server.
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-        - name: body
-          in: body
-          schema:
-            type: object
-            properties:
-              last_activity:
-                type: string
-                format: date-time
-                description: |
-                  Timestamp of last-seen activity for this user.
-                  Only needed if this is not activity associated
-                  with using a given server.
-              servers:
-                description: |
-                  Register activity for specific servers by name.
-                  The keys of this dict are the names of servers.
-                  The default server has an empty name ('').
-                type: object
-                properties:
-                  "<server name>":
-                    description: |
-                      Activity for a single server.
-                    type: object
-                    required:
-                      - last_activity
-                    properties:
-                      last_activity:
-                        type: string
-                        format: date-time
-                        description: |
-                          Timestamp of last-seen activity on this server.
-            example:
-              last_activity: "2019-02-06T12:54:14Z"
-              servers:
-                "":
-                  last_activity: "2019-02-06T12:54:14Z"
-                gpu:
-                  last_activity: "2019-02-06T12:54:14Z"
-      responses:
-        "401":
-          $ref: "#/responses/Unauthorized"
-        "404":
-          description: No such user
-  /users/{name}/server:
-    post:
-      summary: Start a user's single-user notebook server
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-        - name: options
-          description: |
-            Spawn options can be passed as a JSON body
-            when spawning via the API instead of spawn form.
-            The structure of the options
-            will depend on the Spawner's configuration.
-            The body itself will be available as `user_options` for the
-            Spawner.
-          in: body
-          required: false
-          schema:
-            type: object
-
-      responses:
-        "201":
-          description: The user's notebook server has started
-        "202":
-          description: The user's notebook server has not yet started, but has been requested
-    delete:
-      summary: Stop a user's server
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-      responses:
-        "204":
-          description: The user's notebook server has stopped
-        "202":
-          description: The user's notebook server has not yet stopped as it is taking a while to stop
-  /users/{name}/servers/{server_name}:
-    post:
-      summary: Start a user's single-user named-server notebook server
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-        - name: server_name
-          description: |
-            name given to a named-server. 
-
-            Note that depending on your JupyterHub infrastructure there are chracterter size limitation to `server_name`. Default spawner with K8s pod will not allow Jupyter Notebooks to be spawned with a name that contains more than 253 characters (keep in mind that the pod will be spawned with extra characters to identify the user and hub).
-          in: path
-          required: true
-          type: string
-        - name: options
-          description: |
-            Spawn options can be passed as a JSON body
-            when spawning via the API instead of spawn form.
-            The structure of the options
-            will depend on the Spawner's configuration.
-          in: body
-          required: false
-          schema:
-            type: object
-      responses:
-        "201":
-          description: The user's notebook named-server has started
-        "202":
-          description: The user's notebook named-server has not yet started, but has been requested
-    delete:
-      summary: Stop a user's named-server
-      parameters:
-        - name: name
-          description: username
-          in: path
-          required: true
-          type: string
-        - name: server_name
-          description: name given to a named-server
-          in: path
-          required: true
-          type: string
-        - name: body
-          in: body
-          required: false
-          schema:
-            type: object
-            properties:
-              remove:
-                type: boolean
-                description: |
-                  Whether to fully remove the server, rather than just stop it.
-                  Removing a server deletes things like the state of the stopped server.
-                  Default: false.
-      responses:
-        "204":
-          description: The user's notebook named-server has stopped
-        "202":
-          description: The user's notebook named-server has not yet stopped as it is taking a while to stop
-  /users/{name}/tokens:
-    parameters:
-      - name: name
-        description: username
-        in: path
-        required: true
-        type: string
-    get:
-      summary: List tokens for the user
-      responses:
-        "200":
-          description: The list of tokens
-          schema:
-            type: array
-            items:
-              $ref: "#/definitions/Token"
-        "401":
-          $ref: "#/responses/Unauthorized"
-        "404":
-          description: No such user
-    post:
-      summary: Create a new token for the user
-      parameters:
-        - name: token_params
-          in: body
-          required: false
-          schema:
-            type: object
-            properties:
-              expires_in:
-                type: number
-                description: lifetime (in seconds) after which the requested token will expire.
-              note:
-                type: string
-                description: A note attached to the token for future bookkeeping
-      responses:
-        "201":
-          description: The newly created token
-          schema:
-            $ref: "#/definitions/Token"
-        "400":
-          description: Body must be a JSON dict or empty
-  /users/{name}/tokens/{token_id}:
-    parameters:
-      - name: name
-        description: username
-        in: path
-        required: true
-        type: string
-      - name: token_id
-        in: path
-        required: true
-        type: string
-    get:
-      summary: Get the model for a token by id
-      responses:
-        "200":
-          description: The info for the new token
-          schema:
-            $ref: "#/definitions/Token"
-    delete:
-      summary: Delete (revoke) a token by id
-      responses:
-        "204":
-          description: The token has been deleted
-  /user:
-    get:
-      summary: Return authenticated user's model
-      responses:
-        "200":
-          description: The authenticated user's model is returned.
-          schema:
-            $ref: "#/definitions/User"
-  /groups:
-    get:
-      summary: List groups
-      responses:
-        "200":
-          description: The list of groups
-          schema:
-            type: array
-            items:
-              $ref: "#/definitions/Group"
-  /groups/{name}:
-    get:
-      summary: Get a group by name
-      parameters:
-        - name: name
-          description: group name
-          in: path
-          required: true
-          type: string
-      responses:
-        "200":
-          description: The group model
-          schema:
-            $ref: "#/definitions/Group"
-    post:
-      summary: Create a group
-      parameters:
-        - name: name
-          description: group name
-          in: path
-          required: true
-          type: string
-      responses:
-        "201":
-          description: The group has been created
-          schema:
-            $ref: "#/definitions/Group"
-    delete:
-      summary: Delete a group
-      parameters:
-        - name: name
-          description: group name
-          in: path
-          required: true
-          type: string
-      responses:
-        "204":
-          description: The group has been deleted
-  /groups/{name}/users:
-    post:
-      summary: Add users to a group
-      parameters:
-        - name: name
-          description: group name
-          in: path
-          required: true
-          type: string
-        - name: body
-          in: body
-          required: true
-          description: The users to add to the group
-          schema:
-            type: object
-            properties:
-              users:
-                type: array
-                description: List of usernames to add to the group
-                items:
-                  type: string
-      responses:
-        "200":
-          description: The users have been added to the group
-          schema:
-            $ref: "#/definitions/Group"
-    delete:
-      summary: Remove users from a group
-      parameters:
-        - name: name
-          description: group name
-          in: path
-          required: true
-          type: string
-        - name: body
-          in: body
-          required: true
-          description: The users to remove from the group
-          schema:
-            type: object
-            properties:
-              users:
-                type: array
-                description: List of usernames to remove from the group
-                items:
-                  type: string
-      responses:
-        "200":
-          description: The users have been removed from the group
-  /services:
-    get:
-      summary: List services
-      responses:
-        "200":
-          description: The service list
-          schema:
-            type: array
-            items:
-              $ref: "#/definitions/Service"
-  /services/{name}:
-    get:
-      summary: Get a service by name
-      parameters:
-        - name: name
-          description: service name
-          in: path
-          required: true
-          type: string
-      responses:
-        "200":
-          description: The Service model
-          schema:
-            $ref: "#/definitions/Service"
-  /proxy:
-    get:
-      summary: Get the proxy's routing table
-      description: A convenience alias for getting the routing table directly from the proxy
-      responses:
-        "200":
-          description: Routing table
-          schema:
-            type: object
-            description: configurable-http-proxy routing table (see configurable-http-proxy docs for details)
-    post:
-      summary: Force the Hub to sync with the proxy
-      responses:
-        "200":
-          description: Success
-    patch:
-      summary: Notify the Hub about a new proxy
-      description: Notifies the Hub of a new proxy to use.
-      parameters:
-        - name: body
-          in: body
-          required: true
-          description: Any values that have changed for the new proxy. All keys are optional.
-          schema:
-            type: object
-            properties:
-              ip:
-                type: string
-                description: IP address of the new proxy
-              port:
-                type: string
-                description: Port of the new proxy
-              protocol:
-                type: string
-                description: Protocol of new proxy, if changed
-              auth_token:
-                type: string
-                description: CONFIGPROXY_AUTH_TOKEN for the new proxy
-      responses:
-        "200":
-          description: Success
-  /authorizations/token:
-    post:
-      summary: Request a new API token
-      description: |
-        Request a new API token to use with the JupyterHub REST API.
-        If not already authenticated, username and password can be sent
-        in the JSON request body.
-        Logging in via this method is only available when the active Authenticator
-        accepts passwords (e.g. not OAuth).
-      parameters:
-        - name: credentials
-          in: body
-          schema:
-            type: object
-            properties:
-              username:
-                type: string
-              password:
-                type: string
-      responses:
-        "200":
-          description: The new API token
-          schema:
-            type: object
-            properties:
-              token:
-                type: string
-                description: The new API token.
-        "403":
-          description: The user can not be authenticated.
-  /authorizations/token/{token}:
-    get:
-      summary: Identify a user or service from an API token
-      parameters:
-        - name: token
-          in: path
-          required: true
-          type: string
-      responses:
-        "200":
-          description: The user or service identified by the API token
-        "404":
-          description: A user or service is not found.
-  /authorizations/cookie/{cookie_name}/{cookie_value}:
-    get:
-      summary: Identify a user from a cookie
-      description: Used by single-user notebook servers to hand off cookie authentication to the Hub
-      parameters:
-        - name: cookie_name
-          in: path
-          required: true
-          type: string
-        - name: cookie_value
-          in: path
-          required: true
-          type: string
-      responses:
-        "200":
-          description: The user identified by the cookie
-          schema:
-            $ref: "#/definitions/User"
-        "404":
-          description: A user is not found.
-  /oauth2/authorize:
-    get:
-      summary: "OAuth 2.0 authorize endpoint"
-      description: |
-        Redirect users to this URL to begin the OAuth process.
-        It is not an API endpoint.
-      parameters:
-        - name: client_id
-          description: The client id
-          in: query
-          required: true
-          type: string
-        - name: response_type
-          description: The response type (always 'code')
-          in: query
-          required: true
-          type: string
-        - name: state
-          description: A state string
-          in: query
-          required: false
-          type: string
-        - name: redirect_uri
-          description: The redirect url
-          in: query
-          required: true
-          type: string
-      responses:
-        "200":
-          description: Success
-        "400":
-          description: OAuth2Error
-  /oauth2/token:
-    post:
-      summary: Request an OAuth2 token
-      description: |
-        Request an OAuth2 token from an authorization code.
-        This request completes the OAuth process.
-      consumes:
-        - application/x-www-form-urlencoded
-      parameters:
-        - name: client_id
-          description: The client id
-          in: formData
-          required: true
-          type: string
-        - name: client_secret
-          description: The client secret
-          in: formData
-          required: true
-          type: string
-        - name: grant_type
-          description: The grant type (always 'authorization_code')
-          in: formData
-          required: true
-          type: string
-        - name: code
-          description: The code provided by the authorization redirect
-          in: formData
-          required: true
-          type: string
-        - name: redirect_uri
-          description: The redirect url
-          in: formData
-          required: true
-          type: string
-      responses:
-        "200":
-          description: JSON response including the token
-          schema:
-            type: object
-            properties:
-              access_token:
-                type: string
-                description: The new API token for the user
-              token_type:
-                type: string
-                description: Will always be 'Bearer'
-  /shutdown:
-    post:
-      summary: Shutdown the Hub
-      parameters:
-        - name: body
-          in: body
-          schema:
-            type: object
-            properties:
-              proxy:
-                type: boolean
-                description: Whether the proxy should be shutdown as well (default from Hub config)
-              servers:
-                type: boolean
-                description: Whether users' notebook servers should be shutdown as well (default from Hub config)
-      responses:
-        "202":
-          description: Shutdown successful
-        "400":
-          description: Unexpeced value for proxy or servers
-# Descriptions of common responses
-responses:
-  NotFound:
-    description: The specified resource was not found
-  Unauthorized:
-    description: Authentication/Authorization error
-definitions:
-  User:
-    type: object
-    properties:
-      name:
-        type: string
-        description: The user's name
-      admin:
-        type: boolean
-        description: Whether the user is an admin
-      groups:
-        type: array
-        description: The names of groups where this user is a member
-        items:
-          type: string
-      server:
-        type: string
-        description: The user's notebook server's base URL, if running; null if not.
-      pending:
-        type: string
-        enum: ["spawn", "stop", null]
-        description: The currently pending action, if any
-      last_activity:
-        type: string
-        format: date-time
-        description: Timestamp of last-seen activity from the user
-      servers:
-        type: array
-        description: The active servers for this user.
-        items:
-          $ref: "#/definitions/Server"
-  Server:
-    type: object
-    properties:
-      name:
-        type: string
-        description: The server's name. The user's default server has an empty name ('')
-      ready:
-        type: boolean
-        description: |
-          Whether the server is ready for traffic.
-          Will always be false when any transition is pending.
-      pending:
-        type: string
-        enum: ["spawn", "stop", null]
-        description: |
-          The currently pending action, if any.
-          A server is not ready if an action is pending.
-      url:
-        type: string
-        description: |
-          The URL where the server can be accessed
-          (typically /user/:name/:server.name/).
-      progress_url:
-        type: string
-        description: |
-          The URL for an event-stream to retrieve events during a spawn.
-      started:
-        type: string
-        format: date-time
-        description: UTC timestamp when the server was last started.
-      last_activity:
-        type: string
-        format: date-time
-        description: UTC timestamp last-seen activity on this server.
-      state:
-        type: object
-        description: Arbitrary internal state from this server's spawner.  Only available on the hub's users list or get-user-by-name method, and only if a hub admin.  None otherwise.
-      user_options:
-        type: object
-        description: User specified options for the user's spawned instance of a single-user server.
-  Group:
-    type: object
-    properties:
-      name:
-        type: string
-        description: The group's name
-      users:
-        type: array
-        description: The names of users who are members of this group
-        items:
-          type: string
-  Service:
-    type: object
-    properties:
-      name:
-        type: string
-        description: The service's name
-      admin:
-        type: boolean
-        description: Whether the service is an admin
-      url:
-        type: string
-        description: The internal url where the service is running
-      prefix:
-        type: string
-        description: The proxied URL prefix to the service's url
-      pid:
-        type: number
-        description: The PID of the service process (if managed)
-      command:
-        type: array
-        description: The command used to start the service (if managed)
-        items:
-          type: string
-      info:
-        type: object
-        description: |
-          Additional information a deployment can attach to a service.
-          JupyterHub does not use this field.
-  Token:
-    type: object
-    properties:
-      token:
-        type: string
-        description: The token itself. Only present in responses to requests for a new token.
-      id:
-        type: string
-        description: The id of the API token. Used for modifying or deleting the token.
-      user:
-        type: string
-        description: The user that owns a token (undefined if owned by a service)
-      service:
-        type: string
-        description: The service that owns the token (undefined of owned by a user)
-      note:
-        type: string
-        description: A note about the token, typically describing what it was created for.
-      created:
-        type: string
-        format: date-time
-        description: Timestamp when this token was created
-      expires_at:
-        type: string
-        format: date-time
-        description: Timestamp when this token expires. Null if there is no expiry.
-      last_activity:
-        type: string
-        format: date-time
-        description: |
-          Timestamp of last-seen activity using this token.
-          Can be null if token has never been used.

docs/source/_static/custom.css

@@ -2,3 +2,9 @@
 .navbar-brand {
   height: 4rem !important;
 }
+
+/* hide redundant funky-formatted swagger-ui version */
+
+.swagger-ui .info .title small {
+  display: none !important;
+}

docs/source/admin/log-messages.md

@@ -0,0 +1,72 @@
+# Interpreting common log messages
+
+When debugging errors and outages, looking at the logs emitted by
+JupyterHub is very helpful. This document tries to document some common
+log messages, and what they mean.
+
+## Failing suspected API request to not-running server
+
+### Example
+
+Your logs might be littered with lines that might look slightly scary
+
+```
+[W 2022-03-10 17:25:19.774 JupyterHub base:1349] Failing suspected API request to not-running server: /hub/user/<user-name>/api/metrics/v1
+```
+
+### Most likely cause
+
+This likely means is that the user's server has stopped running but they
+still have a browser tab open. For example, you might have 3 tabs open, and shut
+your server down via one. Or you closed your laptop, your server was
+culled for inactivity, and then you reopen your laptop again! The
+client side code (JupyterLab, Classic Notebook, etc) does not know
+yet that the server is dead, and continues to make some API requests.
+JupyterHub's architecture means that the proxy routes all requests that
+don't go to a running user server to the hub process itself. The hub
+process then explicitly returns a failure response, so the client knows
+that the server is not running anymore. This is used by JupyterLab to
+tell you your server is not running anymore, and offer you the option
+to let you restart it.
+
+Most commonly, you'll see this in reference to the `/api/metrics/v1`
+URL, used by [jupyter-resource-usage](https://github.com/jupyter-server/jupyter-resource-usage).
+
+### Actions you can take
+
+This log message is benign, and there is usually no action for you to take.
+
+## JupyterHub Singleuser Version mismatch
+
+### Example
+
+```
+ jupyterhub version 1.5.0 != jupyterhub-singleuser version 1.3.0. This could cause failure to authenticate and result in redirect loops!
+```
+
+### Cause
+
+JupyterHub requires the `jupyterhub` python package installed inside the image or
+environment the user server starts in. This message indicates that the version of
+the `jupyterhub` package installed inside the user image or environment is not
+the same version as the JupyterHub server itself. This is not necessarily always a
+problem - some version drift is mostly acceptable, and the only two known cases of
+breakage are across the 0.7 and 2.0 version releases. In those cases, issues pop
+up immediately after upgrading your version of JupyterHub, so **always check the JupyterHub
+changelog before upgrading!**. The primary problems this _could_ cause are:
+
+1. Infinite redirect loops after the user server starts
+2. Missing expected environment variables in the user server once it starts
+3. Failure for the started user server to authenticate with the JupyterHub server -
+   note that this is _not_ the same as _user authentication_ failing!
+
+However, for the most part, unless you are seeing these specific issues, the log
+message should be counted as a warning to get the `jupyterhub` package versions
+aligned, rather than as an indicator of an existing problem.
+
+### Actions you can take
+
+Upgrade the version of the `jupyterhub` package in your user environment or image
+so it matches the version of JupyterHub running your JupyterHub server! If you
+are using the [zero-to-jupyterhub](https://z2jh.jupyter.org) helm chart, you can find the appropriate
+version of the `jupyterhub` package to install in your user image [here](https://jupyterhub.github.io/helm-chart/)

docs/source/admin/upgrading.rst

@@ -1,5 +1,3 @@
-.. _admin/upgrading:
-
 ====================
 Upgrading JupyterHub
 ====================

docs/source/api/index.rst

@@ -17,11 +17,6 @@ information on:
 - making an API request programmatically using the requests library
 - learning more about JupyterHub's API
 
-The same JupyterHub API spec, as found here, is available in an interactive form
-`here (on swagger's petstore) <http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default>`__.
-The `OpenAPI Initiative`_ (fka Swagger™) is a project used to describe
-and document RESTful APIs.
-
 JupyterHub API Reference:
 
 .. toctree::

docs/source/conf.py

@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #
 import os
 import sys
@@ -19,16 +18,21 @@ extensions = [
     'autodoc_traits',
     'sphinx_copybutton',
     'sphinx-jsonschema',
-    'recommonmark',
+    'myst_parser',
 ]
 
+myst_heading_anchors = 2
+myst_enable_extensions = [
+    'colon_fence',
+    'deflist',
+]
 # The master toctree document.
 master_doc = 'index'
 
 # General information about the project.
-project = u'JupyterHub'
-copyright = u'2016, Project Jupyter team'
-author = u'Project Jupyter team'
+project = 'JupyterHub'
+copyright = '2016, Project Jupyter team'
+author = 'Project Jupyter team'
 
 # Autopopulate version
 from os.path import dirname
@@ -44,7 +48,7 @@ version = '%i.%i' % jupyterhub.version_info[:2]
 # The full version, including alpha/beta/rc tags.
 release = jupyterhub.__version__
 
-language = None
+language = "en"
 exclude_patterns = []
 pygments_style = 'sphinx'
 todo_include_todos = False
@@ -52,17 +56,14 @@ todo_include_todos = False
 # Set the default role so we can use `foo` instead of ``foo``
 default_role = 'literal'
 
-# -- Source -------------------------------------------------------------
+from contextlib import redirect_stdout
+from io import StringIO
 
-import recommonmark
-from recommonmark.transform import AutoStructify
+from docutils import nodes
+from sphinx.directives.other import SphinxDirective
 
 # -- Config -------------------------------------------------------------
 from jupyterhub.app import JupyterHub
-from docutils import nodes
-from sphinx.directives.other import SphinxDirective
-from contextlib import redirect_stdout
-from io import StringIO
 
 # create a temp instance of JupyterHub just to get the output of the generate-config
 # and help --all commands.
@@ -111,9 +112,7 @@ class HelpAllDirective(SphinxDirective):
 
 
 def setup(app):
-    app.add_config_value('recommonmark_config', {'enable_eval_rst': True}, True)
     app.add_css_file('custom.css')
-    app.add_transform(AutoStructify)
     app.add_directive('jupyterhub-generate-config', ConfigDirective)
     app.add_directive('jupyterhub-help-all', HelpAllDirective)
 
@@ -134,6 +133,30 @@ html_static_path = ['_static']
 
 htmlhelp_basename = 'JupyterHubdoc'
 
+html_theme_options = {
+    "icon_links": [
+        {
+            "name": "GitHub",
+            "url": "https://github.com/jupyterhub/jupyterhub",
+            "icon": "fab fa-github-square",
+        },
+        {
+            "name": "Discourse",
+            "url": "https://discourse.jupyter.org/c/jupyterhub/10",
+            "icon": "fab fa-discourse",
+        },
+    ],
+    "use_edit_page_button": True,
+    "navbar_align": "left",
+}
+
+html_context = {
+    "github_user": "jupyterhub",
+    "github_repo": "jupyterhub",
+    "github_version": "main",
+    "doc_path": "docs",
+}
+
 # -- Options for LaTeX output ---------------------------------------------
 
 latex_elements = {
@@ -150,8 +173,8 @@ latex_documents = [
     (
         master_doc,
         'JupyterHub.tex',
-        u'JupyterHub Documentation',
-        u'Project Jupyter team',
+        'JupyterHub Documentation',
+        'Project Jupyter team',
         'manual',
     )
 ]
@@ -168,7 +191,7 @@ latex_documents = [
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [(master_doc, 'jupyterhub', u'JupyterHub Documentation', [author], 1)]
+man_pages = [(master_doc, 'jupyterhub', 'JupyterHub Documentation', [author], 1)]
 
 # man_show_urls = False
 
@@ -182,7 +205,7 @@ texinfo_documents = [
     (
         master_doc,
         'JupyterHub',
-        u'JupyterHub Documentation',
+        'JupyterHub Documentation',
         author,
         'JupyterHub',
         'One line description of project.',
@@ -209,7 +232,10 @@ epub_exclude_files = ['search.html']
 
 # -- Intersphinx ----------------------------------------------------------
 
-intersphinx_mapping = {'https://docs.python.org/3/': None}
+intersphinx_mapping = {
+    'python': ('https://docs.python.org/3/', None),
+    'tornado': ('https://www.tornadoweb.org/en/stable/', None),
+}
 
 # -- Read The Docs --------------------------------------------------------
 
@@ -219,7 +245,7 @@ if on_rtd:
     # build both metrics and rest-api, since RTD doesn't run make
     from subprocess import check_call as sh
 
-    sh(['make', 'metrics', 'rest-api'], cwd=docs)
+    sh(['make', 'metrics', 'scopes'], cwd=docs)
 
 # -- Spell checking -------------------------------------------------------
 

docs/source/contributing/docs.rst

@@ -13,7 +13,7 @@ Building documentation locally
 We use `sphinx <http://sphinx-doc.org>`_ to build our documentation. It takes
 our documentation source files (written in `markdown
 <https://daringfireball.net/projects/markdown/>`_ or `reStructuredText
-<http://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ &
+<https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ &
 stored under the ``docs/source`` directory) and converts it into various
 formats for people to read. To make sure the documentation you write or
 change renders correctly, it is good practice to test it locally.
@@ -39,8 +39,8 @@ change renders correctly, it is good practice to test it locally.
    along with the filename / line number in which they occurred. Fix them,
    and re-run the ``make html`` command to re-render the documentation.
 
-#. View the rendered documentation by opening ``build/html/index.html`` in 
-   a web browser. 
+#. View the rendered documentation by opening ``build/html/index.html`` in
+   a web browser.
 
    .. tip::
 

docs/source/contributing/index.rst

@@ -6,8 +6,8 @@ We want you to contribute to JupyterHub in ways that are most exciting
 & useful to you. We value documentation, testing, bug reporting & code equally,
 and are glad to have your contributions in whatever form you wish :)
 
-Our `Code of Conduct <https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md>`_
-(`reporting guidelines <https://github.com/jupyter/governance/blob/master/conduct/reporting_online.md>`_)
+Our `Code of Conduct <https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md>`_
+(`reporting guidelines <https://github.com/jupyter/governance/blob/HEAD/conduct/reporting_online.md>`_)
 helps keep our community welcoming to as many people as possible.
 
 .. toctree::

docs/source/contributing/setup.rst

@@ -16,7 +16,7 @@ Install Python
 --------------
 
 JupyterHub is written in the `Python <https://python.org>`_ programming language, and
-requires you have at least version 3.5 installed locally. If you haven’t
+requires you have at least version 3.6 installed locally. If you haven’t
 installed Python before, the recommended way to install it is to use
 `miniconda <https://conda.io/miniconda.html>`_. Remember to get the ‘Python 3’ version,
 and **not** the ‘Python 2’ version!
@@ -24,11 +24,10 @@ and **not** the ‘Python 2’ version!
 Install nodejs
 --------------
 
-``configurable-http-proxy``, the default proxy implementation for
-JupyterHub, is written in Javascript to run on `NodeJS
-<https://nodejs.org/en/>`_. If you have not installed nodejs before, we
-recommend installing it in the ``miniconda`` environment you set up for
-Python. You can do so with ``conda install nodejs``.
+`NodeJS 12+ <https://nodejs.org/en/>`_ is required for building some JavaScript components.
+``configurable-http-proxy``, the default proxy implementation for JupyterHub, is written in Javascript.
+If you have not installed nodejs before, we recommend installing it in the ``miniconda`` environment you set up for Python.
+You can do so with ``conda install nodejs``.
 
 Install git
 -----------
@@ -46,7 +45,7 @@ their effects quickly. You need to do a developer install to make that
 happen.
 
 .. note:: This guide does not attempt to dictate *how* development
-   environements should be isolated since that is a personal preference and can
+   environments should be isolated since that is a personal preference and can
    be achieved in many ways, for example `tox`, `conda`, `docker`, etc. See this
    `forum thread <https://discourse.jupyter.org/t/thoughts-on-using-tox/3497>`_ for
    a more detailed discussion.
@@ -66,7 +65,7 @@ happen.
 
       python -V
 
-   This should return a version number greater than or equal to 3.5.
+   This should return a version number greater than or equal to 3.6.
 
    .. code:: bash
 
@@ -74,12 +73,11 @@ happen.
 
    This should return a version number greater than or equal to 5.0.
 
-3. Install ``configurable-http-proxy``. This is required to run
-   JupyterHub.
+3. Install ``configurable-http-proxy`` (required to run and test the default JupyterHub configuration) and ``yarn`` (required to build some components):
 
    .. code:: bash
 
-      npm install -g configurable-http-proxy
+      npm install -g configurable-http-proxy yarn
 
    If you get an error that says ``Error: EACCES: permission denied``,
    you might need to prefix the command with ``sudo``. If you do not
@@ -87,11 +85,17 @@ happen.
 
    .. code:: bash
 
-      npm install configurable-http-proxy
+      npm install configurable-http-proxy yarn
       export PATH=$PATH:$(pwd)/node_modules/.bin
 
    The second line needs to be run every time you open a new terminal.
 
+   If you are using conda you can instead run:
+
+   .. code:: bash
+
+      conda install configurable-http-proxy yarn
+
 4. Install the python packages required for JupyterHub development.
 
    .. code:: bash
@@ -186,3 +190,4 @@ development updates, with:
 
    python3 setup.py js    # fetch updated client-side js
    python3 setup.py css   # recompile CSS from LESS sources
+   python3 setup.py jsx   # build React admin app

docs/source/contributing/tests.rst

@@ -1,8 +1,8 @@
 .. _contributing/tests:
 
-==================
-Testing JupyterHub
-==================
+===================================
+Testing JupyterHub and linting code
+===================================
 
 Unit test help validate that JupyterHub works the way we think it does,
 and continues to do so when changes occur. They also help communicate
@@ -57,6 +57,50 @@ Running the tests
       
       pytest -v jupyterhub/tests/test_api.py::test_shutdown
 
+   See the `pytest usage documentation <https://pytest.readthedocs.io/en/latest/usage.html>`_ for more details.
+
+Test organisation
+=================
+
+The tests live in ``jupyterhub/tests`` and are organized roughly into:
+
+#. ``test_api.py`` tests the REST API
+#. ``test_pages.py`` tests loading the HTML pages
+
+and other collections of tests for different components.
+When writing a new test, there should usually be a test of
+similar functionality already written and related tests should
+be added nearby.
+
+The fixtures live in ``jupyterhub/tests/conftest.py``. There are
+fixtures that can be used for JupyterHub components, such as:
+
+- ``app``: an instance of JupyterHub with mocked parts
+- ``auth_state_enabled``: enables persisting auth_state (like authentication tokens)
+- ``db``: a sqlite in-memory DB session
+- ``io_loop```: a Tornado event loop
+- ``event_loop``: a new asyncio event loop
+- ``user``: creates a new temporary user
+- ``admin_user``: creates a new temporary admin user
+- single user servers
+  - ``cleanup_after``: allows cleanup of single user servers between tests
+- mocked service
+  - ``MockServiceSpawner``: a spawner that mocks services for testing with a short poll interval
+  - ``mockservice```: mocked service with no external service url
+  - ``mockservice_url``: mocked service with a url to test external services
+
+And fixtures to add functionality or spawning behavior:
+
+- ``admin_access``: grants admin access
+- ``no_patience```: sets slow-spawning timeouts to zero
+- ``slow_spawn``: enables the SlowSpawner (a spawner that takes a few seconds to start)
+- ``never_spawn``: enables the NeverSpawner (a spawner that will never start)
+- ``bad_spawn``: enables the BadSpawner (a spawner that fails immediately)
+- ``slow_bad_spawn``: enables the SlowBadSpawner (a spawner that fails after a short delay)
+
+See the `pytest fixtures documentation <https://pytest.readthedocs.io/en/latest/fixture.html>`_
+for how to use the existing fixtures, and how to create new ones.
+
 
 Troubleshooting Test Failures
 =============================
@@ -66,3 +110,27 @@ All the tests are failing
 
 Make sure you have completed all the steps in :ref:`contributing/setup` successfully, and
 can launch ``jupyterhub`` from the terminal.
+
+
+Code formatting and linting
+===========================
+
+JupyterHub has adopted automatic code formatting and linting.
+As long as your code is valid, the pre-commit hook should take care of how it should look.
+You can invoke the pre-commit hook by hand at any time with:
+
+.. code:: bash
+
+   pre-commit run
+
+which should run any autoformatting on your code and tell you about any errors it couldn't fix automatically.
+You may also install `black integration <https://github.com/psf/black#editor-integration>`_
+into your text editor to format code automatically.
+
+If you have already committed files before running pre-commit you can fix everything using:
+
+.. code:: bash
+
+   pre-commit run --all-files
+
+And committing the changes.

docs/source/gallery-jhub-deployments.md

@@ -30,7 +30,7 @@ Please submit pull requests to update information or to add new institutions or
 
 ### University of California Davis
 
-- [Spinning up multiple Jupyter Notebooks on AWS for a tutorial](https://github.com/mblmicdiv/course2017/blob/master/exercises/sourmash-setup.md)
+- [Spinning up multiple Jupyter Notebooks on AWS for a tutorial](https://github.com/mblmicdiv/course2017/blob/HEAD/exercises/sourmash-setup.md)
 
 Although not technically a JupyterHub deployment, this tutorial setup
 may be helpful to others in the Jupyter community.
@@ -61,6 +61,13 @@ easy to do with RStudio too.
 
 - [jupyterhub-deploy-teaching](https://github.com/jupyterhub/jupyterhub-deploy-teaching) based on work by Brian Granger for Cal Poly's Data Science 301 Course
 
+### Chameleon
+
+[Chameleon](https://www.chameleoncloud.org) is a NSF-funded configurable experimental environment for large-scale computer science systems research with [bare metal reconfigurability](https://chameleoncloud.readthedocs.io/en/latest/technical/baremetal.html). Chameleon users utilize JupyterHub to document and reproduce their complex CISE and networking experiments.
+
+- [Shared JupyterHub](https://jupyter.chameleoncloud.org): provides a common "workbench" environment for any Chameleon user.
+- [Trovi](https://www.chameleoncloud.org/experiment/share): a sharing portal of experiments, tutorials, and examples, which users can launch as a dedicated isolated environments on Chameleon's JupyterHub.
+
 ### Clemson University
 
 - Advanced Computing

docs/source/getting-started/authenticators-users-basics.md

@@ -16,13 +16,24 @@ c.Authenticator.allowed_users = {'mal', 'zoe', 'inara', 'kaylee'}
 Users in the `allowed_users` set are added to the Hub database when the Hub is
 started.
 
+```{warning}
+If this configuration value is not set, then **all authenticated users will be allowed into your hub**.
+```
+
 ## Configure admins (`admin_users`)
 
+```{note}
+As of JupyterHub 2.0, the full permissions of `admin_users`
+should not be required.
+Instead, you can assign [roles][] to users or groups
+with only the scopes they require.
+```
+
 Admin users of JupyterHub, `admin_users`, can add and remove users from
 the user `allowed_users` set. `admin_users` can take actions on other users'
 behalf, such as stopping and restarting their servers.
 
-A set of initial admin users, `admin_users` can configured be as follows:
+A set of initial admin users, `admin_users` can be configured as follows:
 
 ```python
 c.Authenticator.admin_users = {'mal', 'zoe'}
@@ -32,9 +43,9 @@ Users in the admin set are automatically added to the user `allowed_users` set,
 if they are not already present.
 
 Each authenticator may have different ways of determining whether a user is an
-administrator. By default JupyterHub use the PAMAuthenticator which provide the
-`admin_groups` option and can determine administrator status base on a user
-groups. For example we can let any users in the `wheel` group be admin:
+administrator. By default JupyterHub uses the PAMAuthenticator which provides the
+`admin_groups` option and can set administrator status based on a user
+group. For example we can let any user in the `wheel` group be admin:
 
 ```python
 c.PAMAuthenticator.admin_groups = {'wheel'}
@@ -42,9 +53,9 @@ c.PAMAuthenticator.admin_groups = {'wheel'}
 
 ## Give admin access to other users' notebook servers (`admin_access`)
 
-Since the default `JupyterHub.admin_access` setting is False, the admins
+Since the default `JupyterHub.admin_access` setting is `False`, the admins
 do not have permission to log in to the single user notebook servers
-owned by _other users_. If `JupyterHub.admin_access` is set to True,
+owned by _other users_. If `JupyterHub.admin_access` is set to `True`,
 then admins have permission to log in _as other users_ on their
 respective machines, for debugging. **As a courtesy, you should make
 sure your users know if admin_access is enabled.**
@@ -53,8 +64,8 @@ sure your users know if admin_access is enabled.**
 
 Users can be added to and removed from the Hub via either the admin
 panel or the REST API. When a user is **added**, the user will be
-automatically added to the allowed users set and database. Restarting the Hub
-will not require manually updating the allowed users set in your config file,
+automatically added to the `allowed_users` set and database. Restarting the Hub
+will not require manually updating the `allowed_users` set in your config file,
 as the users will be loaded from the database.
 
 After starting the Hub once, it is not sufficient to **remove** a user
@@ -107,8 +118,8 @@ with any provider, is also available.
 
 ## Use DummyAuthenticator for testing
 
-The :class:`~jupyterhub.auth.DummyAuthenticator` is a simple authenticator that
-allows for any username/password unless if a global password has been set. If
+The `DummyAuthenticator` is a simple authenticator that
+allows for any username/password unless a global password has been set. If
 set, it will allow for any username as long as the correct password is provided.
 To set a global password, add this to the config file:
 

docs/source/getting-started/config-basics.md

@@ -44,7 +44,7 @@ jupyterhub -f /etc/jupyterhub/jupyterhub_config.py
 ```
 
 The IPython documentation provides additional information on the
-[config system](http://ipython.readthedocs.io/en/stable/development/config)
+[config system](http://ipython.readthedocs.io/en/stable/development/config.html)
 that Jupyter uses.
 
 ## Configure using command line options
@@ -63,11 +63,11 @@ would enter:
     jupyterhub --ip 10.0.1.2 --port 443 --ssl-key my_ssl.key --ssl-cert my_ssl.cert
 ```
 
-All configurable options may technically be set on the command-line,
+All configurable options may technically be set on the command line,
 though some are inconvenient to type. To set a particular configuration
 parameter, `c.Class.trait`, you would use the command line option,
 `--Class.trait`, when starting JupyterHub. For example, to configure the
-`c.Spawner.notebook_dir` trait from the command-line, use the
+`c.Spawner.notebook_dir` trait from the command line, use the
 `--Spawner.notebook_dir` option:
 
 ```bash
@@ -89,11 +89,11 @@ meant as illustration, are:
 ## Run the proxy separately
 
 This is _not_ strictly necessary, but useful in many cases. If you
-use a custom proxy (e.g. Traefik), this also not needed.
+use a custom proxy (e.g. Traefik), this is also not needed.
 
 Connections to user servers go through the proxy, and _not_ the hub
 itself. If the proxy stays running when the hub restarts (for
-maintenance, re-configuration, etc.), then use connections are not
+maintenance, re-configuration, etc.), then user connections are not
 interrupted. For simplicity, by default the hub starts the proxy
 automatically, so if the hub restarts, the proxy restarts, and user
 connections are interrupted. It is easy to run the proxy separately,

docs/source/getting-started/faq.md

@@ -1,6 +1,6 @@
 # Frequently asked questions
 
-### How do I share links to notebooks?
+## How do I share links to notebooks?
 
 In short, where you see `/user/name/notebooks/foo.ipynb` use `/hub/user-redirect/notebooks/foo.ipynb` (replace `/user/name` with `/hub/user-redirect`).
 
@@ -26,7 +26,7 @@ so Breq would open `/user/breq/notebooks/foo.ipynb` and
 Seivarden would open `/user/seivarden/notebooks/foo.ipynb`, etc.
 
 JupyterHub has a special URL that does exactly this!
-It's called `/hub/user-redirect/...` and after the visitor logs in,
+It's called `/hub/user-redirect/...`.
 So if you replace `/user/yourname` in your URL bar
 with `/hub/user-redirect` any visitor should get the same
 URL on their own server, rather than visiting yours.

docs/source/getting-started/institutional-faq.md

@@ -11,7 +11,7 @@ Yes! JupyterHub has been used at-scale for large pools of users, as well
 as complex and high-performance computing. For example, UC Berkeley uses
 JupyterHub for its Data Science Education Program courses (serving over
 3,000 students). The Pangeo project uses JupyterHub to provide access
-to scalable cloud computing with Dask. JupyterHub is stable customizable
+to scalable cloud computing with Dask. JupyterHub is stable and customizable
 to the use-cases of large organizations.
 
 ### I keep hearing about Jupyter Notebook, JupyterLab, and now JupyterHub. What’s the difference?
@@ -27,14 +27,14 @@ Here is a quick breakdown of these three tools:
   for other parts of the data science stack.
 - **JupyterHub** is an application that manages interactive computing sessions for **multiple users**.
   It also connects them with infrastructure those users wish to access. It can provide
-  remote access to Jupyter Notebooks and Jupyter Lab for many people.
+  remote access to Jupyter Notebooks and JupyterLab for many people.
 
 ## For management
 
 ### Briefly, what problem does JupyterHub solve for us?
 
 JupyterHub provides a shared platform for data science and collaboration.
-It allows users to utilize familiar data science workflows (such as the scientific python stack,
+It allows users to utilize familiar data science workflows (such as the scientific Python stack,
 the R tidyverse, and Jupyter Notebooks) on institutional infrastructure. It also allows administrators
 some control over access to resources, security, environments, and authentication.
 
@@ -55,7 +55,7 @@ industry, and government research labs. It is most-commonly used by two kinds of
 - Large teams (e.g., a department, a large class, or a large group of remote users) to provide
   access to organizational hardware, data, and analytics environments at scale.
 
-Here are a sample of organizations that use JupyterHub:
+Here is a sample of organizations that use JupyterHub:
 
 - **Universities and colleges**: UC Berkeley, UC San Diego, Cal Poly SLO, Harvard University, University of Chicago,
   University of Oslo, University of Sheffield, Université Paris Sud, University of Versailles
@@ -99,7 +99,7 @@ that we currently suggest are:
   guide that runs on Kubernetes. Better for larger or dynamic user groups (50-10,000) or more complex
   compute/data needs.
 - [The Littlest JupyterHub](https://tljh.jupyter.org) is a lightweight JupyterHub that runs on a single
-  single machine (in the cloud or under your desk). Better for smaller usergroups (4-80) or more
+  single machine (in the cloud or under your desk). Better for smaller user groups (4-80) or more
   lightweight computational resources.
 
 ### Does JupyterHub run well in the cloud?
@@ -123,7 +123,7 @@ level for several years, and makes a number of "default" security decisions that
 users.
 
 - For security considerations in the base JupyterHub application,
-  [see the JupyterHub security page](https://jupyterhub.readthedocs.io/en/stable/reference/websecurity.html)
+  [see the JupyterHub security page](https://jupyterhub.readthedocs.io/en/stable/reference/websecurity.html).
 - For security considerations when deploying JupyterHub on Kubernetes, see the
   [JupyterHub on Kubernetes security page](https://zero-to-jupyterhub.readthedocs.io/en/latest/security.html).
 
@@ -183,7 +183,7 @@ how those resources are controlled is taken care of by the non-JupyterHub applic
 
 Yes - JupyterHub can provide access to many kinds of computing infrastructure.
 Especially when combined with other open-source schedulers such as Dask, you can manage fairly
-complex computing infrastructure from the interactive sessions of a JupyterHub. For example
+complex computing infrastructures from the interactive sessions of a JupyterHub. For example
 [see the Dask HPC page](https://docs.dask.org/en/latest/setup/hpc.html).
 
 ### How much resources do user sessions take?
@@ -192,7 +192,7 @@ This is highly configurable by the administrator. If you wish for your users to
 data analytics environments for prototyping and light data exploring, you can restrict their
 memory and CPU based on the resources that you have available. If you'd like your JupyterHub
 to serve as a gateway to high-performance compute or data resources, you may increase the
-resources available on user machines, or connect them with computing infrastructure elsewhere.
+resources available on user machines, or connect them with computing infrastructures elsewhere.
 
 ### Can I customize the look and feel of a JupyterHub?
 
@@ -217,7 +217,7 @@ your JupyterHub with the various services and tools that you wish to provide to
 ### How well does JupyterHub scale? What are JupyterHub's limitations?
 
 JupyterHub works well at both a small scale (e.g., a single VM or machine) as well as a
-high scale (e.g., a scalable Kubernetes cluster). It can be used for teams as small a 2, and
+high scale (e.g., a scalable Kubernetes cluster). It can be used for teams as small as 2, and
 for user bases as large as 10,000. The scalability of JupyterHub largely depends on the
 infrastructure on which it is deployed. JupyterHub has been designed to be lightweight and
 flexible, so you can tailor your JupyterHub deployment to your needs.
@@ -249,7 +249,7 @@ share their results with one another.
 
 JupyterHub also provides a computational framework to share computational narratives between
 different levels of an organization. For example, data scientists can share Jupyter Notebooks
-rendered as [voila dashboards](https://voila.readthedocs.io/en/stable/) with those who are not
+rendered as [Voilà dashboards](https://voila.readthedocs.io/en/stable/) with those who are not
 familiar with programming, or create publicly-available interactive analyses to allow others to
 interact with your work.
 

docs/source/getting-started/networking-basics.md

@@ -43,7 +43,7 @@ port.
 
 By default, this REST API listens on port 8001 of `localhost` only.
 The Hub service talks to the proxy via a REST API on a secondary port. The
-API URL can be configured separately and override the default settings.
+API URL can be configured separately to override the default settings.
 
 ### Set api_url
 
@@ -82,13 +82,13 @@ c.JupyterHub.hub_ip = '10.0.1.4'
 c.JupyterHub.hub_port = 54321
 ```
 
-**Added in 0.8:** The `c.JupyterHub.hub_connect_ip` setting is the ip address or
+**Added in 0.8:** The `c.JupyterHub.hub_connect_ip` setting is the IP address or
 hostname that other services should use to connect to the Hub. A common
 configuration for, e.g. docker, is:
 
 ```python
 c.JupyterHub.hub_ip = '0.0.0.0'  # listen on all interfaces
-c.JupyterHub.hub_connect_ip = '10.0.1.4'  # ip as seen on the docker network. Can also be a hostname.
+c.JupyterHub.hub_connect_ip = '10.0.1.4'  # IP as seen on the docker network. Can also be a hostname.
 ```
 
 ## Adjusting the hub's URL

docs/source/getting-started/security-basics.rst

@@ -183,12 +183,6 @@ itself, ``jupyterhub_config.py``, as a binary string:
 
     c.JupyterHub.cookie_secret = bytes.fromhex('64 CHAR HEX STRING')
 
-
-.. important::
-
-   If the cookie secret value changes for the Hub, all single-user notebook
-   servers must also be restarted.
-
 .. _cookies:
 
 Cookies used by JupyterHub authentication

docs/source/getting-started/services-basics.md

@@ -2,7 +2,7 @@
 
 When working with JupyterHub, a **Service** is defined as a process
 that interacts with the Hub's REST API. A Service may perform a specific
-or action or task. For example, shutting down individuals' single user
+action or task. For example, shutting down individuals' single user
 notebook servers that have been idle for some time is a good example of
 a task that could be automated by a Service. Let's look at how the
 [jupyterhub_idle_culler][] script can be used as a Service.
@@ -93,18 +93,40 @@ In `jupyterhub_config.py`, add the following dictionary for the
 c.JupyterHub.services = [
     {
         'name': 'idle-culler',
-        'admin': True,
         'command': [sys.executable, '-m', 'jupyterhub_idle_culler', '--timeout=3600'],
     }
 ]
+
+c.JupyterHub.load_roles = [
+    {
+        "name": "list-and-cull", # name the role
+        "services": [
+            "idle-culler", # assign the service to this role
+        ],
+        "scopes": [
+            # declare what permissions the service should have
+            "list:users", # list users
+            "read:users:activity", # read user last-activity
+            "admin:servers", # start/stop servers
+        ],
+    }
+]
 ```
 
 where:
 
-- `'admin': True` indicates that the Service has 'admin' permissions, and
-- `'command'` indicates that the Service will be launched as a
+- `command` indicates that the Service will be launched as a
   subprocess, managed by the Hub.
 
+```{versionchanged} 2.0
+Prior to 2.0, the idle-culler required 'admin' permissions.
+It now needs the scopes:
+
+- `list:users` to access the user list endpoint
+- `read:users:activity` to read activity info
+- `admin:servers` to start/stop servers
+```
+
 ## Run `cull-idle` manually as a standalone script
 
 Now you can run your script by providing it
@@ -114,7 +136,8 @@ interact with it.
 This will run the idle culler service manually. It can be run as a standalone
 script anywhere with access to the Hub, and will periodically check for idle
 servers and shut them down via the Hub's REST API. In order to shutdown the
-servers, the token given to cull-idle must have admin privileges.
+servers, the token given to `cull-idle` must have permission to list users
+and admin their servers.
 
 Generate an API token and store it in the `JUPYTERHUB_API_TOKEN` environment
 variable. Run `jupyterhub_idle_culler` manually.

docs/source/getting-started/spawners-basics.md

@@ -1,8 +1,8 @@
 # Spawners and single-user notebook servers
 
 Since the single-user server is an instance of `jupyter notebook`, an entire separate
-multi-process application, there are many aspect of that server can configure, and a lot of ways
-to express that configuration.
+multi-process application, there are many aspects of that server that can be configured, and a lot
+of ways to express that configuration.
 
 At the JupyterHub level, you can set some values on the Spawner. The simplest of these is
 `Spawner.notebook_dir`, which lets you set the root directory for a user's server. This root
@@ -14,7 +14,7 @@ expanded to the user's home directory.
 c.Spawner.notebook_dir = '~/notebooks'
 ```
 
-You can also specify extra command-line arguments to the notebook server with:
+You can also specify extra command line arguments to the notebook server with:
 
 ```python
 c.Spawner.args = ['--debug', '--profile=PHYS131']

docs/source/index-admin.rst

@@ -10,4 +10,5 @@ well as other information relevant to running your own JupyterHub over time.
 
    troubleshooting
    admin/upgrading
+   admin/log-messages
    changelog

docs/source/index.rst

@@ -43,7 +43,7 @@ JupyterHub performs the following functions:
   notebook servers
 
 For convenient administration of the Hub, its users, and services,
-JupyterHub also provides a `REST API`_.
+JupyterHub also provides a :doc:`REST API <reference/rest-api>`.
 
 The JupyterHub team and Project Jupyter value our community, and JupyterHub
 follows the Jupyter `Community Guides <https://jupyter.readthedocs.io/en/latest/community/content-community.html>`_.
@@ -108,6 +108,14 @@ API Reference
 
    api/index
 
+RBAC Reference
+--------------
+
+.. toctree::
+   :maxdepth: 2
+
+   rbac/index
+
 Contributing
 ------------
 
@@ -115,8 +123,8 @@ We want you to contribute to JupyterHub in ways that are most exciting
 & useful to you. We value documentation, testing, bug reporting & code equally,
 and are glad to have your contributions in whatever form you wish :)
 
-Our `Code of Conduct <https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md>`_
-(`reporting guidelines <https://github.com/jupyter/governance/blob/master/conduct/reporting_online.md>`_)
+Our `Code of Conduct <https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md>`_
+(`reporting guidelines <https://github.com/jupyter/governance/blob/HEAD/conduct/reporting_online.md>`_)
 helps keep our community welcoming to as many people as possible.
 
 .. toctree::
@@ -147,4 +155,3 @@ Questions? Suggestions?
 
 .. _JupyterHub: https://github.com/jupyterhub/jupyterhub
 .. _Jupyter notebook: https://jupyter-notebook.readthedocs.io/en/latest/
-.. _REST API: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default

docs/source/installation-guide-hard.rst

@@ -3,4 +3,4 @@
 JupyterHub the hard way
 =======================
 
-This guide has moved to https://github.com/jupyterhub/jupyterhub-the-hard-way/blob/master/docs/installation-guide-hard.md
+This guide has moved to https://github.com/jupyterhub/jupyterhub-the-hard-way/blob/HEAD/docs/installation-guide-hard.md

docs/source/quickstart.md

@@ -5,8 +5,8 @@
 Before installing JupyterHub, you will need:
 
 - a Linux/Unix based system
-- [Python](https://www.python.org/downloads/) 3.5 or greater. An understanding
-  of using [`pip`](https://pip.pypa.io/en/stable/) or
+- [Python](https://www.python.org/downloads/) 3.6 or greater. An understanding
+  of using [`pip`](https://pip.pypa.io) or
   [`conda`](https://conda.io/docs/get-started.html) for
   installing Python packages is helpful.
 - [nodejs/npm](https://www.npmjs.com/). [Install nodejs/npm](https://docs.npmjs.com/getting-started/installing-node),
@@ -20,11 +20,11 @@ Before installing JupyterHub, you will need:
     For example, install it on Linux (Debian/Ubuntu) using:
 
     ```
-    sudo apt-get install npm nodejs-legacy
+    sudo apt-get install nodejs npm
     ```
 
-    The `nodejs-legacy` package installs the `node` executable and is currently
-    required for npm to work on Debian/Ubuntu.
+    [nodesource][] is a great resource to get more recent versions of the nodejs runtime,
+    if your system package manager only has an old version of Node.js (e.g. 10 or older).
 
 - A [pluggable authentication module (PAM)](https://en.wikipedia.org/wiki/Pluggable_authentication_module)
   to use the [default Authenticator](./getting-started/authenticators-users-basics.md).
@@ -33,11 +33,17 @@ Before installing JupyterHub, you will need:
 - TLS certificate and key for HTTPS communication
 - Domain name
 
+[nodesource]: https://github.com/nodesource/distributions#table-of-contents
+
 Before running the single-user notebook servers (which may be on the same
 system as the Hub or not), you will need:
 
-- [Jupyter Notebook](https://jupyter.readthedocs.io/en/latest/install.html)
-  version 4 or greater
+- [JupyterLab][] version 3 or greater,
+  or [Jupyter Notebook][]
+  4 or greater.
+
+[jupyterlab]: https://jupyterlab.readthedocs.io
+[jupyter notebook]: https://jupyter.readthedocs.io/en/latest/install.html
 
 ## Installation
 
@@ -48,14 +54,14 @@ JupyterHub can be installed with `pip` (and the proxy with `npm`) or `conda`:
 ```bash
 python3 -m pip install jupyterhub
 npm install -g configurable-http-proxy
-python3 -m pip install notebook  # needed if running the notebook servers locally
+python3 -m pip install jupyterlab notebook  # needed if running the notebook servers in the same environment
 ```
 
 **conda** (one command installs jupyterhub and proxy):
 
 ```bash
 conda install -c conda-forge jupyterhub  # installs jupyterhub and proxy
-conda install notebook  # needed if running the notebook servers locally
+conda install jupyterlab notebook  # needed if running the notebook servers in the same environment
 ```
 
 Test your installation. If installed, these commands should return the packages'
@@ -74,7 +80,7 @@ To start the Hub server, run the command:
 jupyterhub
 ```
 
-Visit `https://localhost:8000` in your browser, and sign in with your unix
+Visit `http://localhost:8000` in your browser, and sign in with your unix
 credentials.
 
 To **allow multiple users to sign in** to the Hub server, you must start

docs/source/rbac/generate-scope-table.py

@@ -0,0 +1,161 @@
+"""
+This script updates two files with the RBAC scope descriptions found in
+`scopes.py`.
+
+The files are:
+
+    1. scope-table.md
+
+       This file is git ignored and referenced by the documentation.
+
+    2. rest-api.yml
+
+       This file is JupyterHub's REST API schema. Both a version and the RBAC
+       scopes descriptions are updated in it.
+"""
+import os
+from collections import defaultdict
+from pathlib import Path
+from subprocess import run
+
+from pytablewriter import MarkdownTableWriter
+from ruamel.yaml import YAML
+
+from jupyterhub import __version__
+from jupyterhub.scopes import scope_definitions
+
+HERE = os.path.abspath(os.path.dirname(__file__))
+DOCS = Path(HERE).parent.parent.absolute()
+REST_API_YAML = DOCS.joinpath("source", "_static", "rest-api.yml")
+SCOPE_TABLE_MD = Path(HERE).joinpath("scope-table.md")
+
+
+class ScopeTableGenerator:
+    def __init__(self):
+        self.scopes = scope_definitions
+
+    @classmethod
+    def create_writer(cls, table_name, headers, values):
+        writer = MarkdownTableWriter()
+        writer.table_name = table_name
+        writer.headers = headers
+        writer.value_matrix = values
+        writer.margin = 1
+        return writer
+
+    def _get_scope_relationships(self):
+        """Returns a tuple of dictionary of all scope-subscope pairs and a list of just subscopes:
+
+        ({scope: subscope}, [subscopes])
+
+        used for creating hierarchical scope table in _parse_scopes()
+        """
+        pairs = []
+        for scope, data in self.scopes.items():
+            subscopes = data.get('subscopes')
+            if subscopes is not None:
+                for subscope in subscopes:
+                    pairs.append((scope, subscope))
+            else:
+                pairs.append((scope, None))
+        subscopes = [pair[1] for pair in pairs]
+        pairs_dict = defaultdict(list)
+        for scope, subscope in pairs:
+            pairs_dict[scope].append(subscope)
+        return pairs_dict, subscopes
+
+    def _get_top_scopes(self, subscopes):
+        """Returns a list of highest level scopes
+        (not a subscope of any other scopes)"""
+        top_scopes = []
+        for scope in self.scopes.keys():
+            if scope not in subscopes:
+                top_scopes.append(scope)
+        return top_scopes
+
+    def _parse_scopes(self):
+        """Returns a list of table rows where row:
+        [indented scopename string, scope description string]"""
+        scope_pairs, subscopes = self._get_scope_relationships()
+        top_scopes = self._get_top_scopes(subscopes)
+
+        table_rows = []
+        md_indent = "   "
+
+        def _add_subscopes(table_rows, scopename, depth=0):
+            description = self.scopes[scopename]['description']
+            doc_description = self.scopes[scopename].get('doc_description', '')
+            if doc_description:
+                description = doc_description
+            table_row = [f"{md_indent * depth}`{scopename}`", description]
+            table_rows.append(table_row)
+            for subscope in scope_pairs[scopename]:
+                if subscope:
+                    _add_subscopes(table_rows, subscope, depth + 1)
+
+        for scope in top_scopes:
+            _add_subscopes(table_rows, scope)
+
+        return table_rows
+
+    def write_table(self):
+        """Generates the RBAC scopes reference documentation as a markdown table
+        and writes it to the .gitignored `scope-table.md`."""
+        filename = SCOPE_TABLE_MD
+        table_name = ""
+        headers = ["Scope", "Grants permission to:"]
+        values = self._parse_scopes()
+        writer = self.create_writer(table_name, headers, values)
+
+        title = "Table 1. Available scopes and their hierarchy"
+        content = f"{title}\n{writer.dumps()}"
+        with open(filename, 'w') as f:
+            f.write(content)
+        print(f"Generated {filename}.")
+        print(
+            "Run 'make clean' before 'make html' to ensure the built scopes.html contains latest scope table changes."
+        )
+
+    def write_api(self):
+        """Loads `rest-api.yml` and writes it back with a dynamically set
+        JupyterHub version field and list of RBAC scopes descriptions from
+        `scopes.py`."""
+        filename = REST_API_YAML
+
+        yaml = YAML(typ="rt")
+        yaml.preserve_quotes = True
+        yaml.indent(mapping=2, offset=2, sequence=4)
+
+        scope_dict = {}
+        with open(filename) as f:
+            content = yaml.load(f.read())
+
+        content["info"]["version"] = __version__
+        for scope in self.scopes:
+            description = self.scopes[scope]['description']
+            doc_description = self.scopes[scope].get('doc_description', '')
+            if doc_description:
+                description = doc_description
+            scope_dict[scope] = description
+        content['components']['securitySchemes']['oauth2']['flows'][
+            'authorizationCode'
+        ]['scopes'] = scope_dict
+
+        with open(filename, 'w') as f:
+            yaml.dump(content, f)
+
+        run(
+            ['pre-commit', 'run', 'prettier', '--files', filename],
+            cwd=HERE,
+            check=False,
+        )
+
+
+def main():
+    table_generator = ScopeTableGenerator()
+    table_generator.write_table()
+    table_generator.write_api()
+
+
+if __name__ == "__main__":
+    main()

docs/source/rbac/index.md

@@ -0,0 +1,39 @@
+(RBAC)=
+
+# JupyterHub RBAC
+
+Role Based Access Control (RBAC) in JupyterHub serves to provide fine grained control of access to Jupyterhub's API resources.
+
+RBAC is new in JupyterHub 2.0.
+
+## Motivation
+
+The JupyterHub API requires authorization to access its APIs.
+This ensures that an arbitrary user, or even an unauthenticated third party, are not allowed to perform such actions.
+For instance, the behaviour prior to adoption of RBAC is that creating or deleting users requires _admin rights_.
+
+The prior system is functional, but lacks flexibility. If your Hub serves a number of users in different groups, you might want to delegate permissions to other users or automate certain processes.
+Prior to RBAC, appointing a 'group-only admin' or a bot that culls idle servers, requires granting full admin rights to all actions. This poses a risk of the user or service intentionally or unintentionally accessing and modifying any data within the Hub and violates the [principle of least privilege](https://en.wikipedia.org/wiki/Principle_of_least_privilege).
+
+To remedy situations like this, JupyterHub is transitioning to an RBAC system. By equipping users, groups and services with _roles_ that supply them with a collection of permissions (_scopes_), administrators are able to fine-tune which parties are granted access to which resources.
+
+## Definitions
+
+**Scopes** are specific permissions used to evaluate API requests. For example: the API endpoint `users/servers`, which enables starting or stopping user servers, is guarded by the scope `servers`.
+
+Scopes are not directly assigned to requesters. Rather, when a client performs an API call, their access will be evaluated based on their assigned roles.
+
+**Roles** are collections of scopes that specify the level of what a client is allowed to do. For example, a group administrator may be granted permission to control the servers of group members, but not to create, modify or delete group members themselves.
+Within the RBAC framework, this is achieved by assigning a role to the administrator that covers exactly those privileges.
+
+## Technical Overview
+
+```{toctree}
+:maxdepth: 2
+
+roles
+scopes
+use-cases
+tech-implementation
+upgrade
+```

docs/source/rbac/roles.md

@@ -0,0 +1,161 @@
+(roles)=
+
+# Roles
+
+JupyterHub provides four roles that are available by default:
+
+```{admonition} **Default roles**
+- `user` role provides a {ref}`default user scope <default-user-scope-target>` `self` that grants access to the user's own resources.
+- `admin` role contains all available scopes and grants full rights to all actions. This role **cannot be edited**.
+- `token` role provides a {ref}`default token scope <default-token-scope-target>` `inherit` that resolves to the same permissions as the owner of the token has.
+- `server` role allows for posting activity of "itself" only.
+
+**These roles cannot be deleted.**
+```
+
+These default roles have a default collection of scopes,
+but you can define the scopes associated with each role (excluding admin) to suit your needs,
+as seen [below](overriding-default-roles).
+
+The `user`, `admin`, and `token` roles by default all preserve the permissions prior to RBAC.
+Only the `server` role is changed from pre-2.0, to reduce its permissions to activity-only
+instead of the default of a full access token.
+
+Additional custom roles can also be defined (see {ref}`define-role-target`).
+Roles can be assigned to the following entities:
+
+- Users
+- Services
+- Groups
+
+An entity can have zero, one, or multiple roles, and there are no restrictions on which roles can be assigned to which entity. Roles can be added to or removed from entities at any time.
+
+**Users** \
+When a new user gets created, they are assigned their default role `user`. Additionaly, if the user is created with admin privileges (via `c.Authenticator.admin_users` in `jupyterhub_config.py` or `admin: true` via API), they will be also granted `admin` role. If existing user's admin status changes via API or `jupyterhub_config.py`, their default role will be updated accordingly (after next startup for the latter).
+
+**Services** \
+Services do not have a default role. Services without roles have no access to the guarded API end-points, so most services will require assignment of a role in order to function.
+
+**Groups** \
+A group does not require any role, and has no roles by default. If a user is a member of a group, they automatically inherit any of the group's permissions (see {ref}`resolving-roles-scopes-target` for more details). This is useful for assigning a set of common permissions to several users.
+
+**Tokens** \
+A token’s permissions are evaluated based on their owning entity. Since a token is always issued for a user or service, it can never have more permissions than its owner. If no specific scopes are requested for a new token, the token is assigned the scopes of the `token` role.
+
+(define-role-target)=
+
+## Defining Roles
+
+Roles can be defined or modified in the configuration file as a list of dictionaries. An example:
+
+% TODO: think about loading users into roles if membership has been changed via API.
+% What should be the result?
+
+```python
+# in jupyterhub_config.py
+
+c.JupyterHub.load_roles = [
+ {
+   'name': 'server-rights',
+   'description': 'Allows parties to start and stop user servers',
+   'scopes': ['servers'],
+   'users': ['alice', 'bob'],
+   'services': ['idle-culler'],
+   'groups': ['admin-group'],
+ }
+]
+```
+
+The role `server-rights` now allows the starting and stopping of servers by any of the following:
+
+- users `alice` and `bob`
+- the service `idle-culler`
+- any member of the `admin-group`.
+
+```{attention}
+Tokens cannot be assigned roles through role definition but may be assigned specific roles when requested via API (see {ref}`requesting-api-token-target`).
+```
+
+Another example:
+
+```python
+# in jupyterhub_config.py
+
+c.JupyterHub.load_roles = [
+ {
+   'description': 'Read-only user models',
+   'name': 'reader',
+   'scopes': ['read:users'],
+   'services': ['external'],
+   'users': ['maria', 'joe']
+ }
+]
+```
+
+The role `reader` allows users `maria` and `joe` and service `external` to read (but not modify) any user’s model.
+
+```{admonition} Requirements
+:class: warning
+In a role definition, the `name` field is required, while all other fields are optional.\
+**Role names must:**
+- be 3 - 255 characters
+- use ascii lowercase, numbers, 'unreserved' URL punctuation `-_.~`
+- start with a letter
+- end with letter or number.
+
+`users`, `services`, and `groups` only accept objects that already exist in the database or are defined previously in the file.
+It is not possible to implicitly add a new user to the database by defining a new role.
+```
+
+If no scopes are defined for _new role_, JupyterHub will raise a warning. Providing non-existing scopes will result in an error.
+
+In case the role with a certain name already exists in the database, its definition and scopes will be overwritten. This holds true for all roles except the `admin` role, which cannot be overwritten; an error will be raised if trying to do so. All the role bearers permissions present in the definition will change accordingly.
+
+(overriding-default-roles)=
+
+### Overriding default roles
+
+Role definitions can include those of the "default" roles listed above (admin excluded),
+if the default scopes associated with those roles do not suit your deployment.
+For example, to specify what permissions the $JUPYTERHUB_API_TOKEN issued to all single-user servers
+has,
+define the `server` role.
+
+To restore the JupyterHub 1.x behavior of servers being able to do anything their owners can do,
+use the scope `inherit` (for 'inheriting' the owner's permissions):
+
+```python
+c.JupyterHub.load_roles = [
+ {
+   'name': 'server',
+   'scopes': ['inherit'],
+ }
+]
+```
+
+or, better yet, identify the specific [scopes][] you want server environments to have access to.
+
+[scopes]: available-scopes-target
+
+If you don't want to get too detailed,
+one option is the `self` scope,
+which will have no effect on non-admin users,
+but will restrict the token issued to admin user servers to only have access to their own resources,
+instead of being able to take actions on behalf of all other users.
+
+```python
+c.JupyterHub.load_roles = [
+ {
+   'name': 'server',
+   'scopes': ['self'],
+ }
+]
+```
+
+(removing-roles-target)=
+
+## Removing roles
+
+Only the entities present in the role definition in the `jupyterhub_config.py` remain the role bearers. If a user, service or group is removed from the role definition, they will lose the role on the next startup.
+
+Once a role is loaded, it remains in the database until removing it from the `jupyterhub_config.py` and restarting the Hub. All previously defined role bearers will lose the role and associated permissions. Default roles, even if previously redefined through the config file and removed, will not be deleted from the database.

docs/source/rbac/scopes.md

@@ -0,0 +1,303 @@
+# Scopes in JupyterHub
+
+A scope has a syntax-based design that reveals which resources it provides access to. Resources are objects with a type, associated data, relationships to other resources, and a set of methods that operate on them (see [RESTful API](https://restful-api-design.readthedocs.io/en/latest/resources.html) documentation for more information).
+
+`<resource>` in the RBAC scope design refers to the resource name in the [JupyterHub's API](../reference/rest-api.rst) endpoints in most cases. For instance, `<resource>` equal to `users` corresponds to JupyterHub's API endpoints beginning with _/users_.
+
+(scope-conventions-target)=
+
+## Scope conventions
+
+- `<resource>` \
+  The top-level `<resource>` scopes, such as `users` or `groups`, grant read, write, and list permissions to the resource itself as well as its sub-resources. For example, the scope `users:activity` is included in the scope `users`.
+
+- `read:<resource>` \
+  Limits permissions to read-only operations on single resources.
+
+- `list:<resource>` \
+  Read-only access to listing endpoints.
+  Use `read:<resource>:<subresource>` to control what fields are returned.
+
+- `admin:<resource>` \
+  Grants additional permissions such as create/delete on the corresponding resource in addition to read and write permissions.
+
+- `access:<resource>` \
+  Grants access permissions to the `<resource>` via API or browser.
+
+- `<resource>:<subresource>` \
+  The {ref}`vertically filtered <vertical-filtering-target>` scopes provide access to a subset of the information granted by the `<resource>` scope. E.g., the scope `users:activity` only provides permission to post user activity.
+
+- `<resource>!<object>=<objectname>` \
+  {ref}`horizontal-filtering-target` is implemented by the `!<object>=<objectname>`scope structure. A resource (or sub-resource) can be filtered based on `user`, `server`, `group` or `service` name. For instance, `<resource>!user=charlie` limits access to only return resources of user `charlie`. \
+  Only one filter per scope is allowed, but filters for the same scope have an additive effect; a larger filter can be used by supplying the scope multiple times with different filters.
+
+By adding a scope to an existing role, all role bearers will gain the associated permissions.
+
+## Metascopes
+
+Metascopes do not follow the general scope syntax. Instead, a metascope resolves to a set of scopes, which can refer to different resources, based on their owning entity. In JupyterHub, there are currently two metascopes:
+
+1. default user scope `self`, and
+2. default token scope `inherit`.
+
+(default-user-scope-target)=
+
+### Default user scope
+
+Access to the user's own resources and subresources is covered by metascope `self`. This metascope includes the user's model, activity, servers and tokens. For example, `self` for a user named "gerard" includes:
+
+- `users!user=gerard` where the `users` scope provides access to the full user model and activity. The filter restricts this access to the user's own resources.
+- `servers!user=gerard` which grants the user access to their own servers without being able to create/delete any.
+- `tokens!user=gerard` which allows the user to access, request and delete their own tokens.
+- `access:servers!user=gerard` which allows the user to access their own servers via API or browser.
+
+The `self` scope is only valid for user entities. In other cases (e.g., for services) it resolves to an empty set of scopes.
+
+(default-token-scope-target)=
+
+### Default token scope
+
+The token metascope `inherit` causes the token to have the same permissions as the token's owner. For example, if a token owner has roles containing the scopes `read:groups` and `read:users`, the `inherit` scope resolves to the set of scopes `{read:groups, read:users}`.
+
+If the token owner has default `user` role, the `inherit` scope resolves to `self`, which will subsequently be expanded to include all the user-specific scopes (or empty set in the case of services).
+
+If the token owner is a member of any group with roles, the group scopes will also be included in resolving the `inherit` scope.
+
+(horizontal-filtering-target)=
+
+## Horizontal filtering
+
+Horizontal filtering, also called _resource filtering_, is the concept of reducing the payload of an API call to cover only the subset of the _resources_ that the scopes of the client provides them access to.
+Requested resources are filtered based on the filter of the corresponding scope. For instance, if a service requests a user list (guarded with scope `read:users`) with a role that only contains scopes `read:users!user=hannah` and `read:users!user=ivan`, the returned list of user models will be an intersection of all users and the collection `{hannah, ivan}`. In case this intersection is empty, the API call returns an HTTP 404 error, regardless if any users exist outside of the clients scope filter collection.
+
+In case a user resource is being accessed, any scopes with _group_ filters will be expanded to filters for each _user_ in those groups.
+
+(self-referencing-filters)=
+
+### Self-referencing filters
+
+There are some 'shortcut' filters,
+which can be applied to all scopes,
+that filter based on the entities associated with the request.
+
+The `!user` filter is a special horizontal filter that strictly refers to the **"owner only"** scopes, where _owner_ is a user entity. The filter resolves internally into `!user=<ownerusername>` ensuring that only the owner's resources may be accessed through the associated scopes.
+
+For example, the `server` role assigned by default to server tokens contains `access:servers!user` and `users:activity!user` scopes. This allows the token to access and post activity of only the servers owned by the token owner.
+
+:::{versionadded} 3.0
+`!service` and `!server` filters.
+:::
+
+In addition to `!user`, _tokens_ may have filters `!service`
+or `!server`, which expand similarly to `!service=servicename`
+and `!server=servername`.
+This only applies to tokens issued via the OAuth flow.
+In these cases, the name is the _issuing_ entity (a service or single-user server),
+so that access can be restricted to the issuing service,
+e.g. `access:servers!server` would grant access only to the server that requested the token.
+
+These filters can be applied to any scope.
+
+(vertical-filtering-target)=
+
+## Vertical filtering
+
+Vertical filtering, also called _attribute filtering_, is the concept of reducing the payload of an API call to cover only the _attributes_ of the resources that the scopes of the client provides them access to. This occurs when the client scopes are subscopes of the API endpoint that is called.
+For instance, if a client requests a user list with the only scope being `read:users:groups`, the returned list of user models will contain only a list of groups per user.
+In case the client has multiple subscopes, the call returns the union of the data the client has access to.
+
+The payload of an API call can be filtered both horizontally and vertically simultaneously. For instance, performing an API call to the endpoint `/users/` with the scope `users:name!user=juliette` returns a payload of `[{name: 'juliette'}]` (provided that this name is present in the database).
+
+(available-scopes-target)=
+
+## Available scopes
+
+Table below lists all available scopes and illustrates their hierarchy. Indented scopes indicate subscopes of the scope(s) above them.
+
+There are four exceptions to the general {ref}`scope conventions <scope-conventions-target>`:
+
+- `read:users:name` is a subscope of both `read:users` and `read:servers`. \
+  The `read:servers` scope requires access to the user name (server owner) due to named servers distinguished internally in the form `!server=username/servername`.
+
+- `read:users:activity` is a subscope of both `read:users` and `users:activity`. \
+  Posting activity via the `users:activity`, which is not included in `users` scope, needs to check the last valid activity of the user.
+
+- `read:roles:users` is a subscope of both `read:roles` and `admin:users`. \
+  Admin privileges to the _users_ resource include the information about user roles.
+
+- `read:roles:groups` is a subscope of both `read:roles` and `admin:groups`. \
+  Similar to the `read:roles:users` above.
+
+```{include} scope-table.md
+
+```
+
+:::{versionadded} 3.0
+The `admin-ui` scope is added to explicitly grant access to the admin page,
+rather than combining `admin:users` and `admin:servers` permissions.
+This means a deployment can enable the admin page with only a subset of functionality enabled.
+
+Note that this means actions to take _via_ the admin UI
+and access _to_ the admin UI are separated.
+For example, it generally doesn't make sense to grant
+`admin-ui` without at least `list:users` for at least some subset of users.
+
+For example:
+
+```python
+c.JupyterHub.load_roles = [
+  {
+    "name": "instructor-data8",
+    "scopes": [
+      # access to the admin page
+      "admin-ui",
+      # list users in the class group
+      "list:users!group=students-data8",
+      # start/stop servers for users in the class
+      "admin:servers!group=students-data8",
+      # access servers for users in the class
+      "access:servers!group=students-data8",
+    ],
+    "group": ["instructors-data8"],
+  }
+]
+```
+
+will grant instructors in the data8 course permission to:
+
+1. view the admin UI
+2. see students in the class (but not all users)
+3. start/stop/access servers for users in the class
+4. but _not_ permission to administer the users themselves (e.g. change their permissions, etc.)
+   :::
+
+```{Caution}
+Note that only the {ref}`horizontal filtering <horizontal-filtering-target>` can be added to scopes to customize them. \
+Metascopes `self` and `all`, `<resource>`, `<resource>:<subresource>`, `read:<resource>`, `admin:<resource>`, and `access:<resource>` scopes are predefined and cannot be changed otherwise.
+```
+
+(custom-scopes)=
+
+### Custom scopes
+
+:::{versionadded} 3.0
+:::
+
+JupyterHub 3.0 introduces support for custom scopes.
+Services that use JupyterHub for authentication and want to implement their own granular access may define additional _custom_ scopes and assign them to users with JupyterHub roles.
+
+% Note: keep in sync with pattern/description in jupyterhub/scopes.py
+
+Custom scope names must start with `custom:`
+and contain only lowercase ascii letters, numbers, hyphen, underscore, colon, and asterisk (`-_:*`).
+The part after `custom:` must start with a letter or number.
+Scopes may not end with a hyphen or colon.
+
+The only strict requirement is that a custom scope definition must have a `description`.
+It _may_ also have `subscopes` if you are defining multiple scopes that have a natural hierarchy,
+
+For example:
+
+```python
+c.JupyterHub.custom_scopes = {
+    "custom:myservice:read": {
+        "description": "read-only access to myservice",
+    },
+    "custom:myservice:write": {
+        "description": "write access to myservice",
+        # write permission implies read permission
+        "subscopes": [
+            "custom:myservice:read",
+        ],
+    },
+}
+
+c.JupyterHub.load_roles = [
+    # graders have read-only access to the service
+    {
+        "name": "service-user",
+        "groups": ["graders"],
+        "scopes": [
+            "custom:myservice:read",
+            "access:service!service=myservice",
+        ],
+    },
+    # instructors have read and write access to the service
+    {
+        "name": "service-admin",
+        "groups": ["instructors"],
+        "scopes": [
+            "custom:myservice:write",
+            "access:service!service=myservice",
+        ],
+    },
+]
+```
+
+In the above configuration, two scopes are defined:
+
+- `custom:myservice:read` grants read-only access to the service, and
+- `custom:myservice:write` grants write access to the service
+- write access _implies_ read access via the `subscope`
+
+These custom scopes are assigned to two groups via `roles`:
+
+- users in the group `graders` are granted read access to the service
+- users in the group `instructors` are
+- both are granted _access_ to the service via `access:service!service=myservice`
+
+When the service completes OAuth, it will retrieve the user model from `/hub/api/user`.
+This model includes a `scopes` field which is a list of authorized scope for the request,
+which can be used.
+
+```python
+def require_scope(scope):
+    """decorator to require a scope to perform an action"""
+    def wrapper(func):
+        @functools.wraps(func)
+        def wrapped_func(request):
+            user = fetch_hub_api_user(request.token)
+            if scope not in user["scopes"]:
+                raise HTTP403(f"Requires scope {scope}")
+            else:
+                return func()
+    return wrapper
+
+@require_scope("custom:myservice:read")
+async def read_something(request):
+    ...
+
+@require_scope("custom:myservice:write")
+async def write_something(request):
+    ...
+```
+
+If you use {class}`~.HubOAuthenticated`, this check is performed automatically
+against the `.hub_scopes` attribute of each Handler
+(the default is populated from `$JUPYTERHUB_OAUTH_ACCESS_SCOPES` and usually `access:services!service=myservice`).
+
+:::{versionchanged} 3.0
+The JUPYTERHUB_OAUTH_SCOPES environment variable is deprecated and renamed to JUPYTERHUB_OAUTH_ACCESS_SCOPES,
+to avoid ambiguity with JUPYTERHUB_OAUTH_CLIENT_ALLOWED_SCOPES
+:::
+
+```python
+from tornado import web
+from jupyterhub.services.auth import HubOAuthenticated
+
+class MyHandler(HubOAuthenticated, BaseHandler):
+    hub_scopes = ["custom:myservice:read"]
+
+    @web.authenticated
+    def get(self):
+        ...
+```
+
+Existing scope filters (`!user=`, etc.) may be applied to custom scopes.
+Custom scope _filters_ are NOT supported.
+
+### Scopes and APIs
+
+The scopes are also listed in the [](../reference/rest-api.rst) documentation. Each API endpoint has a list of scopes which can be used to access the API; if no scopes are listed, the API is not authenticated and can be accessed without any permissions (i.e., no scopes).
+
+Listed scopes by each API endpoint reflect the "lowest" permissions required to gain any access to the corresponding API. For example, posting user's activity (_POST /users/:name/activity_) needs `users:activity` scope. If scope `users` is passed during the request, the access will be granted as the required scope is a subscope of the `users` scope. If, on the other hand, `read:users:activity` scope is passed, the access will be denied.

docs/source/rbac/tech-implementation.md

@@ -0,0 +1,100 @@
+# Technical Implementation
+
+Roles are stored in the database, where they are associated with users, services, etc., and can be added or modified as explained in {ref}`define-role-target` section. Users, services, groups, and tokens can gain, change, and lose roles. This is currently achieved via `jupyterhub_config.py` (see {ref}`define-role-target`) and will be made available via API in future. The latter will allow for changing a token's role, and thereby its permissions, without the need to issue a new token.
+
+Roles and scopes utilities can be found in `roles.py` and `scopes.py` modules. Scope variables take on five different formats which is reflected throughout the utilities via specific nomenclature:
+
+```{admonition} **Scope variable nomenclature**
+:class: tip
+- _scopes_ \
+  List of scopes that may contain abbreviations (used in role definitions). E.g., `["users:activity!user", "self"]`.
+- _expanded scopes_ \
+  Set of fully expanded scopes without abbreviations (i.e., resolved metascopes, filters, and subscopes). E.g., `{"users:activity!user=charlie", "read:users:activity!user=charlie"}`.
+- _parsed scopes_ \
+  Dictionary represenation of expanded scopes. E.g., `{"users:activity": {"user": ["charlie"]}, "read:users:activity": {"users": ["charlie"]}}`.
+- _intersection_ \
+  Set of expanded scopes as intersection of 2 expanded scope sets.
+- _identify scopes_ \
+  Set of expanded scopes needed for identify (whoami) endpoints.
+```
+
+(resolving-roles-scopes-target)=
+
+## Resolving roles and scopes
+
+**Resolving roles** refers to determining which roles a user, service, or group has, extracting the list of scopes from each role and combining them into a single set of scopes.
+
+**Resolving scopes** involves expanding scopes into all their possible subscopes (_expanded scopes_), parsing them into format used for access evaluation (_parsed scopes_) and, if applicable, comparing two sets of scopes (_intersection_). All procedures take into account the scope hierarchy, {ref}`vertical <vertical-filtering-target>` and {ref}`horizontal filtering <horizontal-filtering-target>`, limiting or elevated permissions (`read:<resource>` or `admin:<resource>`, respectively), and metascopes.
+
+Roles and scopes are resolved on several occasions, for example when requesting an API token with specific scopes or making an API request. The following sections provide more details.
+
+(requesting-api-token-target)=
+
+### Requesting API token with specific scopes
+
+:::{versionchanged} 3.0
+API tokens have _scopes_ instead of roles,
+so that their permissions cannot be updated.
+
+You may still request roles for a token,
+but those roles will be evaluated to the corresponding _scopes_ immediately.
+
+Prior to 3.0, tokens stored _roles_,
+which meant their scopes were resolved on each request.
+:::
+
+API tokens grant access to JupyterHub's APIs. The RBAC framework allows for requesting tokens with specific permissions.
+
+RBAC is involved in several stages of the OAuth token flow.
+
+When requesting a token via the tokens API (`/users/:name/tokens`), or the token page (`/hub/token`),
+if no scopes are requested, the token is issued with the permissions stored on the default `token` role
+(providing the requester is allowed to create the token).
+
+OAuth tokens are also requested via OAuth flow
+
+If the token is requested with any scopes, the permissions of requesting entity are checked against the requested permissions to ensure the token would not grant its owner additional privileges.
+
+If, due to modifications of permissions of the token or token owner,
+at API request time a token has any scopes that its owner does not,
+those scopes are removed.
+The API request is resolved without additional errors using the scope _intersection_;
+the Hub logs a warning in this case (see {ref}`Figure 2 <api-request-chart>`).
+
+Resolving a token's scope (yellow box in {ref}`Figure 1 <token-request-chart>`) corresponds to resolving all the token's owner roles (including the roles associated with their groups) and the token's own scopes into a set of scopes. The two sets are compared (Resolve the scopes box in orange in {ref}`Figure 1 <token-request-chart>`), taking into account the scope hierarchy.
+If the token's scopes are a subset of the token owner's scopes, the token is issued with the requested scopes; if not, JupyterHub will raise an error.
+
+{ref}`Figure 1 <token-request-chart>` below illustrates the steps involved. The orange rectangles highlight where in the process the roles and scopes are resolved.
+
+```{figure} ../images/rbac-token-request-chart.png
+:align: center
+:name: token-request-chart
+
+Figure 1. Resolving roles and scopes during API token request
+```
+
+### Making an API request
+
+With the RBAC framework, each authenticated JupyterHub API request is guarded by a scope decorator that specifies which scopes are required to gain the access to the API.
+
+When an API request is performed, the requesting API token's scopes are again intersected with its owner's (yellow box in {ref}`Figure 2 <api-request-chart>`) to ensure the token does not grant more permissions than its owner has at the request time (e.g., due to changing/losing roles).
+If the owner's roles do not include some scopes of the token's scopes, only the _intersection_ of the token's and owner's scopes will be used. For example, using a token with scope `users` whose owner's role scope is `read:users:name` will result in only the `read:users:name` scope being passed on. In the case of no _intersection_, an empty set of scopes will be used.
+
+The passed scopes are compared to the scopes required to access the API as follows:
+
+- if the API scopes are present within the set of passed scopes, the access is granted and the API returns its "full" response
+
+- if that is not the case, another check is utilized to determine if subscopes of the required API scopes can be found in the passed scope set:
+
+  - if found, the RBAC framework employs the {ref}`filtering <vertical-filtering-target>` procedures to refine the API response to access only resource attributes corresponding to the passed scopes. For example, providing a scope `read:users:activity!group=class-C` for the _GET /users_ API will return a list of user models from group `class-C` containing only the `last_activity` attribute for each user model
+
+  - if not found, the access to API is denied
+
+{ref}`Figure 2 <api-request-chart>` illustrates this process highlighting the steps where the role and scope resolutions as well as filtering occur in orange.
+
+```{figure} ../images/rbac-api-request-chart.png
+:align: center
+:name: api-request-chart
+
+Figure 2. Resolving roles and scopes when an API request is made
+```

docs/source/rbac/upgrade.md

@@ -0,0 +1,54 @@
+# Upgrading JupyterHub with RBAC framework
+
+RBAC framework requires different database setup than any previous JupyterHub versions due to eliminating the distinction between OAuth and API tokens (see {ref}`oauth-vs-api-tokens-target` for more details). This requires merging the previously two different database tables into one. By doing so, all existing tokens created before the upgrade no longer comply with the new database version and must be replaced.
+
+This is achieved by the Hub deleting all existing tokens during the database upgrade and recreating the tokens loaded via the `jupyterhub_config.py` file with updated structure. However, any manually issued or stored tokens are not recreated automatically and must be manually re-issued after the upgrade.
+
+No other database records are affected.
+
+(rbac-upgrade-steps-target)=
+
+## Upgrade steps
+
+1. All running **servers must be stopped** before proceeding with the upgrade.
+2. To upgrade the Hub, follow the [Upgrading JupyterHub](../admin/upgrading.rst) instructions.
+   ```{attention}
+   We advise against defining any new roles in the `jupyterhub.config.py` file right after the upgrade is completed and JupyterHub restarted for the first time. This preserves the 'current' state of the Hub. You can define and assign new roles on any other following startup.
+   ```
+3. After restarting the Hub **re-issue all tokens that were previously issued manually** (i.e., not through the `jupyterhub_config.py` file).
+
+When the JupyterHub is restarted for the first time after the upgrade, all users, services and tokens stored in the database or re-loaded through the configuration file will be assigned their default role. Any newly added entities after that will be assigned their default role only if no other specific role is requested for them.
+
+## Changing the permissions after the upgrade
+
+Once all the {ref}`upgrade steps <rbac-upgrade-steps-target>` above are completed, the RBAC framework will be available for utilization. You can define new roles, modify default roles (apart from `admin`) and assign them to entities as described in the {ref}`define-role-target` section.
+
+We recommended the following procedure to start with RBAC:
+
+1. Identify which admin users and services you would like to grant only the permissions they need through the new roles.
+2. Strip these users and services of their admin status via API or UI. This will change their roles from `admin` to `user`.
+   ```{note}
+   Stripping entities of their roles is currently available only via `jupyterhub_config.py` (see {ref}`removing-roles-target`).
+   ```
+3. Define new roles that you would like to start using with appropriate scopes and assign them to these entities in `jupyterhub_config.py`.
+4. Restart the JupyterHub for the new roles to take effect.
+
+(oauth-vs-api-tokens-target)=
+
+## OAuth vs API tokens
+
+### Before RBAC
+
+Previous JupyterHub versions utilize two types of tokens, OAuth token and API token.
+
+OAuth token is issued by the Hub to a single-user server when the user logs in. The token is stored in the browser cookie and is used to identify the user who owns the server during the OAuth flow. This token by default expires when the cookie reaches its expiry time of 2 weeks (or after 1 hour in JupyterHub versions < 1.3.0).
+
+API token is issued by the Hub to a single-user server when launched and is used to communicate with the Hub's APIs such as posting activity or completing the OAuth flow. This token has no expiry by default.
+
+API tokens can also be issued to users via API ([_/hub/token_](../reference/urls.md) or [_POST /users/:username/tokens_](../reference/rest-api.rst)) and services via `jupyterhub_config.py` to perform API requests.
+
+### With RBAC
+
+The RBAC framework allows for granting tokens different levels of permissions via scopes attached to roles. The 'only identify' purpose of the separate OAuth tokens is no longer required. API tokens can be used for every action, including the login and authentication, for which an API token with no role (i.e., no scope in {ref}`available-scopes-target`) is used.
+
+OAuth tokens are therefore dropped from the Hub upgraded with the RBAC framework.

docs/source/rbac/use-cases.md

@@ -0,0 +1,130 @@
+# Use Cases
+
+To determine which scopes a role should have, one can follow these steps:
+
+1. Determine what actions the role holder should have/have not access to
+2. Match the actions against the [JupyterHub's APIs](../reference/rest-api.rst)
+3. Check which scopes are required to access the APIs
+4. Combine scopes and subscopes if applicable
+5. Customize the scopes with filters if needed
+6. Define the role with required scopes and assign to users/services/groups/tokens
+
+Below, different use cases are presented on how to use the RBAC framework.
+
+## Service to cull idle servers
+
+Finding and shutting down idle servers can save a lot of computational resources.
+We can make use of [jupyterhub-idle-culler](https://github.com/jupyterhub/jupyterhub-idle-culler) to manage this for us.
+Below follows a short tutorial on how to add a cull-idle service in the RBAC system.
+
+1. Install the cull-idle server script with `pip install jupyterhub-idle-culler`.
+2. Define a new service `idle-culler` and a new role for this service:
+
+   ```python
+   # in jupyterhub_config.py
+
+   c.JupyterHub.services = [
+       {
+           "name": "idle-culler",
+           "command": [
+               sys.executable, "-m",
+               "jupyterhub_idle_culler",
+               "--timeout=3600"
+           ],
+       }
+   ]
+
+   c.JupyterHub.load_roles = [
+       {
+           "name": "idle-culler",
+           "description": "Culls idle servers",
+           "scopes": ["read:users:name", "read:users:activity", "servers"],
+           "services": ["idle-culler"],
+       }
+   ]
+   ```
+
+   ```{important}
+   Note that in the RBAC system the `admin` field in the `idle-culler` service definition is omitted. Instead, the `idle-culler` role provides the service with only the permissions it needs.
+
+   If the optional actions of deleting the idle servers and/or removing inactive users are desired, **change the following scopes** in the `idle-culler` role definition:
+   - `servers` to `admin:servers` for deleting servers
+   - `read:users:name`, `read:users:activity` to `admin:users` for deleting users.
+   ```
+
+3. Restart JupyterHub to complete the process.
+
+## API launcher
+
+A service capable of creating/removing users and launching multiple servers should have access to:
+
+1. _POST_ and _DELETE /users_
+2. _POST_ and _DELETE /users/:name/server_ or _/users/:name/servers/:server_name_
+3. Creating/deleting servers
+
+The scopes required to access the API enpoints:
+
+1. `admin:users`
+2. `servers`
+3. `admin:servers`
+
+From the above, the role definition is:
+
+```python
+# in jupyterhub_config.py
+
+c.JupyterHub.load_roles = [
+    {
+        "name": "api-launcher",
+        "description": "Manages servers",
+        "scopes": ["admin:users", "admin:servers"],
+        "services": [<service_name>]
+    }
+]
+```
+
+If needed, the scopes can be modified to limit the permissions to e.g. a particular group with `!group=groupname` filter.
+
+## Group admin roles
+
+Roles can be used to specify different group member privileges.
+
+For example, a group of students `class-A` may have a role allowing all group members to access information about their group. Teacher `johan`, who is a student of `class-A` but a teacher of another group of students `class-B`, can have additional role permitting him to access information about `class-B` students as well as start/stop their servers.
+
+The roles can then be defined as follows:
+
+```python
+# in jupyterhub_config.py
+
+c.JupyterHub.load_groups = {
+    'class-A': ['johan', 'student1', 'student2'],
+    'class-B': ['student3', 'student4']
+}
+
+c.JupyterHub.load_roles = [
+    {
+        'name': 'class-A-student',
+        'description': 'Grants access to information about the group',
+        'scopes': ['read:groups!group=class-A'],
+        'groups': ['class-A']
+    },
+    {
+        'name': 'class-B-student',
+        'description': 'Grants access to information about the group',
+        'scopes': ['read:groups!group=class-B'],
+        'groups': ['class-B']
+    },
+    {
+        'name': 'teacher',
+        'description': 'Allows for accessing information about teacher group members and starting/stopping their servers',
+        'scopes': [ 'read:users!group=class-B', 'servers!group=class-B'],
+        'users': ['johan']
+    }
+]
+```
+
+In the above example, `johan` has privileges inherited from `class-A-student` role and the `teacher` role on top of those.
+
+```{note}
+The scope filters (`!group=`) limit the privileges only to the particular groups. `johan` can access the servers and information of `class-B` group members only.
+```

docs/source/reference/api-only.md

@@ -0,0 +1,128 @@
+(api-only)=
+
+# Deploying JupyterHub in "API only mode"
+
+As a service for deploying and managing Jupyter servers for users, JupyterHub
+exposes this functionality _primarily_ via a [REST API](rest).
+For convenience, JupyterHub also ships with a _basic_ web UI built using that REST API.
+The basic web UI enables users to click a button to quickly start and stop their servers,
+and it lets admins perform some basic user and server management tasks.
+
+The REST API has always provided additional functionality beyond what is available in the basic web UI.
+Similarly, we avoid implementing UI functionality that is also not available via the API.
+With JupyterHub 2.0, the basic web UI will **always** be composed using the REST API.
+In other words, no UI pages should rely on information not available via the REST API.
+Previously, some admin UI functionality could only be achieved via admin pages,
+such as paginated requests.
+
+## Limited UI customization via templates
+
+The JupyterHub UI is customizable via extensible HTML [templates](templates),
+but this has some limited scope to what can be customized.
+Adding some content and messages to existing pages is well supported,
+but changing the page flow and what pages are available are beyond the scope of what is customizable.
+
+## Rich UI customization with REST API based apps
+
+Increasingly, JupyterHub is used purely as an API for managing Jupyter servers
+for other Jupyter-based applications that might want to present a different user experience.
+If you want a fully customized user experience,
+you can now disable the Hub UI and use your own pages together with the JupyterHub REST API
+to build your own web application to serve your users,
+relying on the Hub only as an API for managing users and servers.
+
+One example of such an application is [BinderHub][], which powers https://mybinder.org,
+and motivates many of these changes.
+
+BinderHub is distinct from a traditional JupyterHub deployment
+because it uses temporary users created for each launch.
+Instead of presenting a login page,
+users are presented with a form to specify what environment they would like to launch:
+
+![Binder launch form](../images/binderhub-form.png)
+
+When a launch is requested:
+
+1. an image is built, if necessary
+2. a temporary user is created,
+3. a server is launched for that user, and
+4. when running, users are redirected to an already running server with an auth token in the URL
+5. after the session is over, the user is deleted
+
+This means that a lot of JupyterHub's UI flow doesn't make sense:
+
+- there is no way for users to login
+- the human user doesn't map onto a JupyterHub `User` in a meaningful way
+- when a server isn't running, there isn't a 'restart your server' action available because the user has been deleted
+- users do not have any access to any Hub functionality, so presenting pages for those features would be confusing
+
+BinderHub is one of the motivating use cases for JupyterHub supporting being used _only_ via its API.
+We'll use BinderHub here as an example of various configuration options.
+
+[binderhub]: https://binderhub.readthedocs.io
+
+## Disabling Hub UI
+
+`c.JupyterHub.hub_routespec` is a configuration option to specify which URL prefix should be routed to the Hub.
+The default is `/` which means that the Hub will receive all requests not already specified to be routed somewhere else.
+
+There are three values that are most logical for `hub_routespec`:
+
+- `/` - this is the default, and used in most deployments.
+  It is also the only option prior to JupyterHub 1.4.
+- `/hub/` - this serves only Hub pages, both UI and API
+- `/hub/api` - this serves _only the Hub API_, so all Hub UI is disabled,
+  aside from the OAuth confirmation page, if used.
+
+If you choose a hub routespec other than `/`,
+the main JupyterHub feature you will lose is the automatic handling of requests for `/user/:username`
+when the requested server is not running.
+
+JupyterHub's handling of this request shows this page,
+telling you that the server is not running,
+with a button to launch it again:
+
+![screenshot of hub page for server not running](../images/server-not-running.png)
+
+If you set `hub_routespec` to something other than `/`,
+it is likely that you also want to register another destination for `/` to handle requests to not-running servers.
+If you don't, you will see a default 404 page from the proxy:
+
+![screenshot of CHP default 404](../images/chp-404.png)
+
+For mybinder.org, the default "start my server" page doesn't make sense,
+because when a server is gone, there is no restart action.
+Instead, we provide hints about how to get back to a link to start a _new_ server:
+
+![screenshot of mybinder.org 404](../images/binder-404.png)
+
+To achieve this, mybinder.org registers a route for `/` that goes to a custom endpoint
+that runs nginx and only serves this static HTML error page.
+This is set with
+
+```python
+c.Proxy.extra_routes = {
+    "/": "http://custom-404-entpoint/",
+}
+```
+
+You may want to use an alternate behavior, such as redirecting to a landing page,
+or taking some other action based on the requested page.
+
+If you use `c.JupyterHub.hub_routespec = "/hub/"`,
+then all the Hub pages will be available,
+and only this default-page-404 issue will come up.
+
+If you use `c.JupyterHub.hub_routespec = "/hub/api/"`,
+then only the Hub _API_ will be available,
+and all UI will be up to you.
+mybinder.org takes this last option,
+because none of the Hub UI pages really make sense.
+Binder users don't have any reason to know or care that JupyterHub happens
+to be an implementation detail of how their environment is managed.
+Seeing Hub error pages and messages in that situation is more likely to be confusing than helpful.
+
+:::{versionadded} 1.4
+
+`c.JupyterHub.hub_routespec` and `c.Proxy.extra_routes` are new in JupyterHub 1.4.
+:::

docs/source/reference/authenticators.md

@@ -1,6 +1,6 @@
 # Authenticators
 
-The [Authenticator][] is the mechanism for authorizing users to use the
+The {class}`.Authenticator` is the mechanism for authorizing users to use the
 Hub and single user notebook servers.
 
 ## The default PAM Authenticator
@@ -37,7 +37,7 @@ with any provider, is also available.
 ## The Dummy Authenticator
 
 When testing, it may be helpful to use the
-:class:`~jupyterhub.auth.DummyAuthenticator`. This allows for any username and
+{class}`jupyterhub.auth.DummyAuthenticator`. This allows for any username and
 password unless if a global password has been set. Once set, any username will
 still be accepted but the correct password will need to be provided.
 
@@ -137,8 +137,8 @@ via other mechanisms. One such example is using [GitHub OAuth][].
 
 Because the username is passed from the Authenticator to the Spawner,
 a custom Authenticator and Spawner are often used together.
-For example, the Authenticator methods, [pre_spawn_start(user, spawner)][]
-and [post_spawn_stop(user, spawner)][], are hooks that can be used to do
+For example, the Authenticator methods, {meth}`.Authenticator.pre_spawn_start`
+and {meth}`.Authenticator.post_spawn_stop`, are hooks that can be used to do
 auth-related startup (e.g. opening PAM sessions) and cleanup
 (e.g. closing PAM sessions).
 
@@ -223,7 +223,7 @@ If there are multiple keys present, the **first** key is always used to persist
 
 Typically, if `auth_state` is persisted it is desirable to affect the Spawner environment in some way.
 This may mean defining environment variables, placing certificate in the user's home directory, etc.
-The `Authenticator.pre_spawn_start` method can be used to pass information from authenticator state
+The {meth}`Authenticator.pre_spawn_start` method can be used to pass information from authenticator state
 to Spawner environment:
 
 ```python
@@ -247,10 +247,42 @@ class MyAuthenticator(Authenticator):
         spawner.environment['UPSTREAM_TOKEN'] = auth_state['upstream_token']
 ```
 
+(authenticator-groups)=
+
+## Authenticator-managed group membership
+
+:::{versionadded} 2.2
+:::
+
+Some identity providers may have their own concept of group membership that you would like to preserve in JupyterHub.
+This is now possible with `Authenticator.managed_groups`.
+
+You can set the config:
+
+```python
+c.Authenticator.manage_groups = True
+```
+
+to enable this behavior.
+The default is False for Authenticators that ship with JupyterHub,
+but may be True for custom Authenticators.
+Check your Authenticator's documentation for manage_groups support.
+
+If True, {meth}`.Authenticator.authenticate` and {meth}`.Authenticator.refresh_user` may include a field `groups`
+which is a list of group names the user should be a member of:
+
+- Membership will be added for any group in the list
+- Membership in any groups not in the list will be revoked
+- Any groups not already present in the database will be created
+- If `None` is returned, no changes are made to the user's group membership
+
+If authenticator-managed groups are enabled,
+all group-management via the API is disabled.
+
 ## pre_spawn_start and post_spawn_stop hooks
 
-Authenticators uses two hooks, [pre_spawn_start(user, spawner)][] and
-[post_spawn_stop(user, spawner)][] to add pass additional state information
+Authenticators uses two hooks, {meth}`.Authenticator.pre_spawn_start` and
+{meth}`.Authenticator.post_spawn_stop(user, spawner)` to add pass additional state information
 between the authenticator and a spawner. These hooks are typically used auth-related
 startup, i.e. opening a PAM session, and auth-related cleanup, i.e. closing a
 PAM session.
@@ -259,10 +291,7 @@ PAM session.
 
 Beginning with version 0.8, JupyterHub is an OAuth provider.
 
-[authenticator]: https://github.com/jupyterhub/jupyterhub/blob/master/jupyterhub/auth.py
 [pam]: https://en.wikipedia.org/wiki/Pluggable_authentication_module
 [oauth]: https://en.wikipedia.org/wiki/OAuth
 [github oauth]: https://developer.github.com/v3/oauth/
 [oauthenticator]: https://github.com/jupyterhub/oauthenticator
-[pre_spawn_start(user, spawner)]: https://jupyterhub.readthedocs.io/en/latest/api/auth.html#jupyterhub.auth.Authenticator.pre_spawn_start
-[post_spawn_stop(user, spawner)]: https://jupyterhub.readthedocs.io/en/latest/api/auth.html#jupyterhub.auth.Authenticator.post_spawn_stop

docs/source/reference/config-proxy.md

@@ -165,7 +165,7 @@ As with nginx above, you can use [Apache](https://httpd.apache.org) as the rever
 First, we will need to enable the apache modules that we are going to need:
 
 ```bash
-a2enmod ssl rewrite proxy proxy_http proxy_wstunnel
+a2enmod ssl rewrite proxy headers proxy_http proxy_wstunnel
 ```
 
 Our Apache configuration is equivalent to the nginx configuration above:
@@ -188,13 +188,24 @@ Listen 443
 
   ServerName HUB.DOMAIN.TLD
 
+  # enable HTTP/2, if available
+  Protocols h2 http/1.1
+
+  # HTTP Strict Transport Security (mod_headers is required) (63072000 seconds)
+  Header always set Strict-Transport-Security "max-age=63072000"
+
   # configure SSL
   SSLEngine on
   SSLCertificateFile /etc/letsencrypt/live/HUB.DOMAIN.TLD/fullchain.pem
   SSLCertificateKeyFile /etc/letsencrypt/live/HUB.DOMAIN.TLD/privkey.pem
-  SSLProtocol All -SSLv2 -SSLv3
   SSLOpenSSLConfCmd DHParameters /etc/ssl/certs/dhparam.pem
-  SSLCipherSuite EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH
+
+  # intermediate configuration from ssl-config.mozilla.org (2022-03-03)
+  # Please note, that this configuration might be out-dated - please update it accordingly using https://ssl-config.mozilla.org/
+  SSLProtocol             all -SSLv3 -TLSv1 -TLSv1.1
+  SSLCipherSuite          ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
+  SSLHonorCipherOrder     off
+  SSLSessionTickets       off
 
   # Use RewriteEngine to handle websocket connection upgrades
   RewriteEngine On
@@ -208,6 +219,7 @@ Listen 443
     # proxy to JupyterHub
     ProxyPass         http://127.0.0.1:8000/
     ProxyPassReverse  http://127.0.0.1:8000/
+    RequestHeader     set "X-Forwarded-Proto" expr=%{REQUEST_SCHEME}
   </Location>
 </VirtualHost>
 ```
@@ -219,8 +231,8 @@ In case of the need to run the jupyterhub under /jhub/ or other location please
 httpd.conf amendments:
 
 ```bash
- RewriteRule /jhub/(.*) ws://127.0.0.1:8000/jhub/$1 [NE.P,L]
- RewriteRule /jhub/(.*) http://127.0.0.1:8000/jhub/$1 [NE,P,L]
+ RewriteRule /jhub/(.*) ws://127.0.0.1:8000/jhub/$1 [P,L]
+ RewriteRule /jhub/(.*) http://127.0.0.1:8000/jhub/$1 [P,L]
 
  ProxyPass /jhub/ http://127.0.0.1:8000/jhub/
  ProxyPassReverse /jhub/  http://127.0.0.1:8000/jhub/

docs/source/reference/config-user-env.md

@@ -76,13 +76,26 @@ c.InteractiveShellApp.extensions.append("cython")
 
 ### Example: Enable a Jupyter notebook configuration setting for all users
 
+:::{note}
+These examples configure the Jupyter ServerApp,
+which is used by JupyterLab, the default in JupyterHub 2.0.
+
+If you are using the classing Jupyter Notebook server,
+the same things should work,
+with the following substitutions:
+
+- Where you see `jupyter_server_config`, use `jupyter_notebook_config`
+- Where you see `NotebookApp`, use `ServerApp`
+
+:::
+
 To enable Jupyter notebook's internal idle-shutdown behavior (requires
-notebook ≥ 5.4), set the following in the `/etc/jupyter/jupyter_notebook_config.py`
+notebook ≥ 5.4), set the following in the `/etc/jupyter/jupyter_server_config.py`
 file:
 
 ```python
 # shutdown the server after no activity for an hour
-c.NotebookApp.shutdown_no_activity_timeout = 60 * 60
+c.ServerApp.shutdown_no_activity_timeout = 60 * 60
 # shutdown kernels after no activity for 20 minutes
 c.MappingKernelManager.cull_idle_timeout = 20 * 60
 # check for idle kernels every two minutes
@@ -112,8 +125,8 @@ Assuming I have a Python 2 and Python 3 environment that I want to make
 sure are available, I can install their specs system-wide (in /usr/local) with:
 
 ```bash
-/path/to/python3 -m IPython kernel install --prefix=/usr/local
-/path/to/python2 -m IPython kernel install --prefix=/usr/local
+/path/to/python3 -m ipykernel install --prefix=/usr/local
+/path/to/python2 -m ipykernel install --prefix=/usr/local
 ```
 
 ## Multi-user hosts vs. Containers
@@ -176,12 +189,40 @@ The number of named servers per user can be limited by setting
 c.JupyterHub.named_server_limit_per_user = 5
 ```
 
-## Switching to Jupyter Server
+(classic-notebook-ui)=
 
-[Jupyter Server](https://jupyter-server.readthedocs.io/en/latest/) is a new Tornado Server backend for Jupyter web applications (e.g. JupyterLab 3.0 uses this package as its default backend).
+## Switching back to classic notebook
 
-By default, the single-user notebook server uses the (old) `NotebookApp` from the [notebook](https://github.com/jupyter/notebook) package. You can switch to using Jupyter Server's `ServerApp` backend (this will likely become the default in future releases) by setting the `JUPYTERHUB_SINGLEUSER_APP` environment variable to:
+By default the single-user server launches JupyterLab,
+which is based on [Jupyter Server][].
+This is the default server when running JupyterHub ≥ 2.0.
+You can switch to using the legacy Jupyter Notebook server by setting the `JUPYTERHUB_SINGLEUSER_APP` environment variable
+(in the single-user environment) to:
+
+```bash
+export JUPYTERHUB_SINGLEUSER_APP='notebook.notebookapp.NotebookApp'
+```
+
+[jupyter server]: https://jupyter-server.readthedocs.io
+[jupyter notebook]: https://jupyter-notebook.readthedocs.io
+
+:::{versionchanged} 2.0
+JupyterLab is now the default singleuser UI, if available,
+which is based on the [Jupyter Server][],
+no longer the legacy [Jupyter Notebook][] server.
+JupyterHub prior to 2.0 launched the legacy notebook server (`jupyter notebook`),
+and Jupyter server could be selected by specifying
+
+```python
+# jupyterhub_config.py
+c.Spawner.cmd = ["jupyter-labhub"]
+```
+
+or for an otherwise customized Jupyter Server app,
+set the environment variable:
 
 ```bash
 export JUPYTERHUB_SINGLEUSER_APP='jupyter_server.serverapp.ServerApp'
 ```
+
+:::

docs/source/reference/index.rst

@@ -16,9 +16,12 @@ what happens under-the-hood when you deploy and configure your JupyterHub.
    proxy
    separate-proxy
    rest
+   rest-api
+   server-api
    monitoring
    database
    templates
+   api-only
    ../events/index
    config-user-env
    config-examples
@@ -26,3 +29,4 @@ what happens under-the-hood when you deploy and configure your JupyterHub.
    config-proxy
    config-sudo
    config-reference
+   oauth

docs/source/reference/oauth.md

@@ -0,0 +1,373 @@
+# JupyterHub and OAuth
+
+JupyterHub uses OAuth 2 internally as a mechanism for authenticating users.
+As such, JupyterHub itself always functions as an OAuth **provider**.
+More on what that means [below](oauth-terms).
+
+Additionally, JupyterHub is _often_ deployed with [oauthenticator](https://oauthenticator.readthedocs.io),
+where an external identity provider, such as GitHub or KeyCloak, is used to authenticate users.
+When this is the case, there are _two_ nested oauth flows:
+an _internal_ oauth flow where JupyterHub is the **provider**,
+and and _external_ oauth flow, where JupyterHub is a **client**.
+
+This means that when you are using JupyterHub, there is always _at least one_ and often two layers of OAuth involved in a user logging in and accessing their server.
+
+Some relevant points:
+
+- Single-user servers _never_ need to communicate with or be aware of the upstream provider configured in your Authenticator.
+  As far as they are concerned, only JupyterHub is an OAuth provider,
+  and how users authenticate with the Hub itself is irrelevant.
+- When talking to a single-user server,
+  there are ~always two tokens:
+  a token issued to the server itself to communicate with the Hub API,
+  and a second per-user token in the browser to represent the completed login process and authorized permissions.
+  More on this [later](two-tokens).
+
+(oauth-terms)=
+
+## Key OAuth terms
+
+Here are some key definitions to keep in mind when we are talking about OAuth.
+You can also read more detail [here](https://www.oauth.com/oauth2-servers/definitions/).
+
+- **provider** the entity responsible for managing identity and authorization,
+  always a web server.
+  JupyterHub is _always_ an oauth provider for JupyterHub's components.
+  When OAuthenticator is used, an external service, such as GitHub or KeyCloak, is also an oauth provider.
+- **client** An entity that requests OAuth **tokens** on a user's behalf,
+  generally a web server of some kind.
+  OAuth **clients** are services that _delegate_ authentication and/or authorization
+  to an OAuth **provider**.
+  JupyterHub _services_ or single-user _servers_ are OAuth **clients** of the JupyterHub **provider**.
+  When OAuthenticator is used, JupyterHub is itself _also_ an OAuth **client** for the external oauth **provider**, e.g. GitHub.
+- **browser** A user's web browser, which makes requests and stores things like cookies
+- **token** The secret value used to represent a user's authorization. This is the final product of the OAuth process.
+- **code** A short-lived temporary secret that the **client** exchanges
+  for a **token** at the conclusion of oauth,
+  in what's generally called the "oauth callback handler."
+
+## One oauth flow
+
+OAuth **flow** is what we call the sequence of HTTP requests involved in authenticating a user and issuing a token, ultimately used for authorized access to a service or single-user server.
+
+A single oauth flow generally goes like this:
+
+### OAuth request and redirect
+
+1. A **browser** makes an HTTP request to an oauth **client**.
+2. There are no credentials, so the client _redirects_ the browser to an "authorize" page on the oauth **provider** with some extra information:
+   - the oauth **client id** of the client itself
+   - the **redirect uri** to be redirected back to after completion
+   - the **scopes** requested, which the user should be presented with to confirm.
+     This is the "X would like to be able to Y on your behalf. Allow this?" page you see on all the "Login with ..." pages around the Internet.
+3. During this authorize step,
+   the browser must be _authenticated_ with the provider.
+   This is often already stored in a cookie,
+   but if not the provider webapp must begin its _own_ authentication process before serving the authorization page.
+   This _may_ even begin another oauth flow!
+4. After the user tells the provider that they want to proceed with the authorization,
+   the provider records this authorization in a short-lived record called an **oauth code**.
+5. Finally, the oauth provider redirects the browser _back_ to the oauth client's "redirect uri"
+   (or "oauth callback uri"),
+   with the oauth code in a url parameter.
+
+That's the end of the requests made between the **browser** and the **provider**.
+
+### State after redirect
+
+At this point:
+
+- The browser is authenticated with the _provider_
+- The user's authorized permissions are recorded in an _oauth code_
+- The _provider_ knows that the given oauth client's requested permissions have been granted, but the client doesn't know this yet.
+- All requests so far have been made directly by the browser.
+  No requests have originated at the client or provider.
+
+### OAuth Client Handles Callback Request
+
+Now we get to finish the OAuth process.
+Let's dig into what the oauth client does when it handles
+the oauth callback request with the
+
+- The OAuth client receives the _code_ and makes an API request to the _provider_ to exchange the code for a real _token_.
+  This is the first direct request between the OAuth _client_ and the _provider_.
+- Once the token is retrieved, the client _usually_
+  makes a second API request to the _provider_
+  to retrieve information about the owner of the token (the user).
+  This is the step where behavior diverges for different OAuth providers.
+  Up to this point, all oauth providers are the same, following the oauth specification.
+  However, oauth does not define a standard for exchanging tokens for information about their owner or permissions ([OpenID Connect](https://openid.net/connect/) does that),
+  so this step may be different for each OAuth provider.
+- Finally, the oauth client stores its own record that the user is authorized in a cookie.
+  This could be the token itself, or any other appropriate representation of successful authentication.
+- Last of all, now that credentials have been established,
+  the browser can be redirected to the _original_ URL where it started,
+  to try the request again.
+  If the client wasn't able to keep track of the original URL all this time
+  (not always easy!),
+  you might end up back at a default landing page instead of where you started the login process. This is frustrating!
+
+😮‍💨 _phew_.
+
+So that's _one_ OAuth process.
+
+## Full sequence of OAuth in JupyterHub
+
+Let's go through the above oauth process in JupyterHub,
+with specific examples of each HTTP request and what information is contained.
+For bonus points, we are using the double-oauth example of JupyterHub configured with GitHubOAuthenticator.
+
+To disambiguate, we will call the OAuth process where JupyterHub is the **provider** "internal oauth,"
+and the one with JupyterHub as a **client** "external oauth."
+
+Our starting point:
+
+- a user's single-user server is running. Let's call them `danez`
+- jupyterhub is running with GitHub as an oauth provider (this means two full instances of oauth),
+- Danez has a fresh browser session with no cookies yet
+
+First request:
+
+- browser->single-user server running JupyterLab or Jupyter Classic
+- `GET /user/danez/notebooks/mynotebook.ipynb`
+- no credentials, so single-user server (as an oauth **client**) starts internal oauth process with JupyterHub (the **provider**)
+- response: 302 redirect -> `/hub/api/oauth2/authorize`
+  with:
+  - client-id=`jupyterhub-user-danez`
+  - redirect-uri=`/user/danez/oauth_callback` (we'll come back later!)
+
+Second request, following redirect:
+
+- browser->jupyterhub
+- `GET /hub/api/oauth2/authorize`
+- no credentials, so jupyterhub starts external oauth process _with GitHub_
+- response: 302 redirect -> `https://github.com/login/oauth/authorize`
+  with:
+  - client-id=`jupyterhub-client-uuid`
+  - redirect-uri=`/hub/oauth_callback` (we'll come back later!)
+
+_pause_ This is where JupyterHub configuration comes into play.
+Recall, in this case JupyterHub is using:
+
+```python
+c.JupyterHub.authenticator_class = 'github'
+```
+
+That means authenticating a request to the Hub itself starts
+a _second_, external oauth process with GitHub as a provider.
+This external oauth process is optional, though.
+If you were using the default username+password PAMAuthenticator,
+this redirect would have been to `/hub/login` instead, to present the user
+with a login form.
+
+Third request, following redirect:
+
+- browser->GitHub
+- `GET https://github.com/login/oauth/authorize`
+
+Here, GitHub prompts for login and asks for confirmation of authorization
+(more redirects if you aren't logged in to GitHub yet, but ultimately back to this `/authorize` URL).
+
+After successful authorization
+(either by looking up a pre-existing authorization,
+or recording it via form submission)
+GitHub issues an **oauth code** and redirects to `/hub/oauth_callback?code=github-code`
+
+Next request:
+
+- browser->JupyterHub
+- `GET /hub/oauth_callback?code=github-code`
+
+Inside the callback handler, JupyterHub makes two API requests:
+
+The first:
+
+- JupyterHub->GitHub
+- `POST https://github.com/login/oauth/access_token`
+- request made with oauth **code** from url parameter
+- response includes an access **token**
+
+The second:
+
+- JupyterHub->GitHub
+- `GET https://api.github.com/user`
+- request made with access **token** in the `Authorization` header
+- response is the user model, including username, email, etc.
+
+Now the external oauth callback request completes with:
+
+- set cookie on `/hub/` path, recording jupyterhub authentication so we don't need to do external oauth with GitHub again for a while
+- redirect -> `/hub/api/oauth2/authorize`
+
+🎉 At this point, we have completed our first OAuth flow! 🎉
+
+Now, we get our first repeated request:
+
+- browser->jupyterhub
+- `GET /hub/api/oauth2/authorize`
+- this time with credentials,
+  so jupyterhub either
+  1. serves the internal authorization confirmation page, or
+  2. automatically accepts authorization (shortcut taken when a user is visiting their own server)
+- redirect -> `/user/danez/oauth_callback?code=jupyterhub-code`
+
+Here, we start the same oauth callback process as before, but at Danez's single-user server for the _internal_ oauth
+
+- browser->single-user server
+- `GET /user/danez/oauth_callback`
+
+(in handler)
+
+Inside the internal oauth callback handler,
+Danez's server makes two API requests to JupyterHub:
+
+The first:
+
+- single-user server->JupyterHub
+- `POST /hub/api/oauth2/token`
+- request made with oauth code from url parameter
+- response includes an API token
+
+The second:
+
+- single-user server->JupyterHub
+- `GET /hub/api/user`
+- request made with token in the `Authorization` header
+- response is the user model, including username, groups, etc.
+
+Finally completing `GET /user/danez/oauth_callback`:
+
+- response sets cookie, storing encrypted access token
+- _finally_ redirects back to the original `/user/danez/notebooks/mynotebook.ipynb`
+
+Final request:
+
+- browser -> single-user server
+- `GET /user/danez/notebooks/mynotebook.ipynb`
+- encrypted jupyterhub token in cookie
+
+To authenticate this request, the single token stored in the encrypted cookie is passed to the Hub for verification:
+
+- single-user server -> Hub
+- `GET /hub/api/user`
+- browser's token in Authorization header
+- response: user model with name, groups, etc.
+
+If the user model matches who should be allowed (e.g. Danez),
+then the request is allowed.
+See {doc}`../rbac/scopes` for how JupyterHub uses scopes to determine authorized access to servers and services.
+
+_the end_
+
+## Token caches and expiry
+
+Because tokens represent information from an external source,
+they can become 'stale,'
+or the information they represent may no longer be accurate.
+For example: a user's GitHub account may no longer be authorized to use JupyterHub,
+that should ultimately propagate to revoking access and force logging in again.
+
+To handle this, OAuth tokens and the various places they are stored can _expire_,
+which should have the same effect as no credentials,
+and trigger the authorization process again.
+
+In JupyterHub's internal oauth, we have these layers of information that can go stale:
+
+- The oauth client has a **cache** of Hub responses for tokens,
+  so it doesn't need to make API requests to the Hub for every request it receives.
+  This cache has an expiry of five minutes by default,
+  and is governed by the configuration `HubAuth.cache_max_age` in the single-user server.
+- The internal oauth token is stored in a cookie, which has its own expiry (default: 14 days),
+  governed by `JupyterHub.cookie_max_age_days`.
+- The internal oauth token can also itself expire,
+  which is by default the same as the cookie expiry,
+  since it makes sense for the token itself and the place it is stored to expire at the same time.
+  This is governed by `JupyterHub.cookie_max_age_days` first,
+  or can overridden by `JupyterHub.oauth_token_expires_in`.
+
+That's all for _internal_ auth storage,
+but the information from the _external_ authentication provider
+(could be PAM or GitHub OAuth, etc.) can also expire.
+Authenticator configuration governs when JupyterHub needs to ask again,
+triggering the external login process anew before letting a user proceed.
+
+- `jupyterhub-hub-login` cookie stores that a browser is authenticated with the Hub.
+  This expires according to `JupyterHub.cookie_max_age_days` configuration,
+  with a default of 14 days.
+  The `jupyterhub-hub-login` cookie is encrypted with `JupyterHub.cookie_secret`
+  configuration.
+- {meth}`.Authenticator.refresh_user` is a method to refresh a user's auth info.
+  By default, it does nothing, but it can return an updated user model if a user's information has changed,
+  or force a full login process again if needed.
+- {attr}`.Authenticator.auth_refresh_age` configuration governs how often
+  `refresh_user()` will be called to check if a user must login again (default: 300 seconds).
+- {attr}`.Authenticator.refresh_pre_spawn` configuration governs whether
+  `refresh_user()` should be called prior to spawning a server,
+  to force fresh auth info when a server is launched (default: False).
+  This can be useful when Authenticators pass access tokens to spawner environments, to ensure they aren't getting a stale token that's about to expire.
+
+**So what happens when these things expire or get stale?**
+
+- If the HubAuth **token response cache** expires,
+  when a request is made with a token,
+  the Hub is asked for the latest information about the token.
+  This usually has no visible effect, since it is just refreshing a cache.
+  If it turns out that the token itself has expired or been revoked,
+  the request will be denied.
+- If the token has expired, but is still in the cookie:
+  when the token response cache expires,
+  the next time the server asks the hub about the token,
+  no user will be identified and the internal oauth process begins again.
+- If the token _cookie_ expires, the next browser request will be made with no credentials,
+  and the internal oauth process will begin again.
+  This will usually have the form of a transparent redirect browsers won't notice.
+  However, if this occurs on an API request in a long-lived page visit
+  such as a JupyterLab session, the API request may fail and require
+  a page refresh to get renewed credentials.
+- If the _JupyterHub_ cookie expires, the next time the browser makes a request to the Hub,
+  the Hub's authorization process must begin again (e.g. login with GitHub).
+  Hub cookie expiry on its own **does not** mean that a user can no longer access their single-user server!
+- If credentials from the upstream provider (e.g. GitHub) become stale or outdated,
+  these will not be refreshed until/unless `refresh_user` is called
+  _and_ `refresh_user()` on the given Authenticator is implemented to perform such a check.
+  At this point, few Authenticators implement `refresh_user` to support this feature.
+  If your Authenticator does not or cannot implement `refresh_user`,
+  the only way to force a check is to reset the `JupyterHub.cookie_secret` encryption key,
+  which invalidates the `jupyterhub-hub-login` cookie for all users.
+
+### Logging out
+
+Logging out of JupyterHub means clearing and revoking many of these credentials:
+
+- The `jupyterhub-hub-login` cookie is revoked, meaning the next request to the Hub itself will require a new login.
+- The token stored in the `jupyterhub-user-username` cookie for the single-user server
+  will be revoked, based on its associaton with `jupyterhub-session-id`, but the _cookie itself cannot be cleared at this point_
+- The shared `jupyterhub-session-id` is cleared, which ensures that the HubAuth **token response cache** will not be used,
+  and the next request with the expired token will ask the Hub, which will inform the single-user server that the token has expired
+
+## Extra bits
+
+(two-tokens)=
+
+### A tale of two tokens
+
+**TODO**: discuss API token issued to server at startup ($JUPYTERHUB_API_TOKEN)
+and oauth-issued token in the cookie,
+and some details of how JupyterLab currently deals with that.
+They are different, and JupyterLab should be making requests using the token from the cookie,
+not the token from the server,
+but that is not currently the case.
+
+### Redirect loops
+
+In general, an authenticated web endpoint has this behavior,
+based on the authentication/authorization state of the browser:
+
+- If authorized, allow the request to happen
+- If authenticated (I know who you are) but not authorized (you are not allowed), fail with a 403 permission denied error
+- If not authenticated, start a redirect process to establish authorization,
+  which should end in a redirect back to the original URL to try again.
+  **This is why problems in authentication result in redirect loops!**
+  If the second request fails to detect the authentication that should have been established during the redirect,
+  it will start the authentication redirect process over again,
+  and keep redirecting in a loop until the browser balks.

docs/source/reference/proxy.md

@@ -220,3 +220,11 @@ previously required.
 Additionally, configurable attributes for your proxy will
 appear in jupyterhub help output and auto-generated configuration files
 via `jupyterhub --generate-config`.
+
+### Index of proxies
+
+A list of the proxies that are currently available for JupyterHub (that we know about).
+
+1. [`jupyterhub/configurable-http-proxy`](https://github.com/jupyterhub/configurable-http-proxy) The default proxy which uses node-http-proxy
+2. [`jupyterhub/traefik-proxy`](https://github.com/jupyterhub/traefik-proxy) The proxy which configures traefik proxy server for jupyterhub
+3. [`AbdealiJK/configurable-http-proxy`](https://github.com/AbdealiJK/configurable-http-proxy) A pure python implementation of the configurable-http-proxy

docs/source/reference/rest-api.md

@@ -0,0 +1,27 @@
+# JupyterHub REST API
+
+Below is an interactive view of JupyterHub's OpenAPI specification.
+
+<!-- client-rendered openapi UI copied from FastAPI -->
+
+<link type="text/css" rel="stylesheet" href="https://cdn.jsdelivr.net/npm/swagger-ui-dist@3/swagger-ui.css">
+<script src="https://cdn.jsdelivr.net/npm/swagger-ui-dist@4.1/swagger-ui-bundle.js"></script>
+<!-- `SwaggerUIBundle` is now available on the page -->
+
+<!-- render the ui here -->
+<div id="openapi-ui"></div>
+
+<script>
+const ui = SwaggerUIBundle({
+  url: '../_static/rest-api.yml',
+  dom_id: '#openapi-ui',
+  presets: [
+    SwaggerUIBundle.presets.apis,
+    SwaggerUIBundle.SwaggerUIStandalonePreset
+  ],
+  layout: "BaseLayout",
+  deepLinking: true,
+  showExtensions: true,
+  showCommonExtensions: true,
+});
+</script>

docs/source/reference/rest-api.rst

@@ -1,14 +0,0 @@
-:orphan:
-
-===================
-JupyterHub REST API
-===================
-
-.. this doc exists as a resolvable link target
-.. which _static files are not
-
-.. meta::
-    :http-equiv=refresh: 0;url=../_static/rest-api/index.html
-
-The rest API docs are `here <../_static/rest-api/index.html>`_
-if you are not redirected automatically.

docs/source/reference/rest.md

@@ -1,3 +1,5 @@
+(rest-api)=
+
 # Using JupyterHub's REST API
 
 This section will give you information on:
@@ -17,6 +19,7 @@ such as:
 - adding or removing users
 - stopping or starting single user notebook servers
 - authenticating services
+- communicating with an individual Jupyter server's REST API
 
 A [REST](https://en.wikipedia.org/wiki/Representational_state_transfer)
 API provides a standard way for users to get and send information to the
@@ -27,8 +30,7 @@ Hub.
 To send requests using JupyterHub API, you must pass an API token with
 the request.
 
-As of [version 0.6.0](../changelog.md), the preferred way of
-generating an API token is:
+The preferred way of generating an API token is:
 
 ```bash
 openssl rand -hex 32
@@ -48,33 +50,34 @@ jupyterhub token <username>
 This command generates a random string to use as a token and registers
 it for the given user with the Hub's database.
 
-In [version 0.8.0](../changelog.md), a TOKEN request page for
+In [version 0.8.0](../changelog.md), a token request page for
 generating an API token is available from the JupyterHub user interface:
 
-![Request API TOKEN page](../images/token-request.png)
+![Request API token page](../images/token-request.png)
 
-![API TOKEN success page](../images/token-request-success.png)
+![API token success page](../images/token-request-success.png)
 
-## Add API tokens to the config file
+## Assigning permissions to a token
 
-**This is deprecated. We are in no rush to remove this feature,
-but please consider if service tokens are right for you.**
+Prior to JupyterHub 2.0, there were two levels of permissions:
 
-You may also add a dictionary of API tokens and usernames to the hub's
-configuration file, `jupyterhub_config.py` (note that
-the **key** is the 'secret-token' while the **value** is the 'username'):
+1. user, and
+2. admin
 
-```python
-c.JupyterHub.api_tokens = {
-    'secret-token': 'username',
-}
-```
+where a token would always have full permissions to do whatever its owner could do.
+
+In JupyterHub 2.0,
+specific permissions are now defined as 'scopes',
+and can be assigned both at the user/service level,
+and at the individual token level.
+
+This allows e.g. a user with full admin permissions to request a token with limited permissions.
 
 ### Updating to admin services
 
 The `api_tokens` configuration has been softly deprecated since the introduction of services.
 We have no plans to remove it,
-but users are encouraged to use service configuration instead.
+but deployments are encouraged to use service configuration instead.
 
 If you have been using `api_tokens` to create an admin user
 and a token for that user to perform some automations,
@@ -88,19 +91,39 @@ c.JupyterHub.api_tokens = {
 }
 ```
 
-This can be updated to create an admin service, with the following configuration:
+This can be updated to create a service, with the following configuration:
 
 ```python
 c.JupyterHub.services = [
     {
-        "name": "service-token",
-        "admin": True,
+        # give the token a name
+        "name": "service-admin",
         "api_token": "secret-token",
+        # "admin": True, # if using JupyterHub 1.x
     },
 ]
+
+# roles are new in JupyterHub 2.0
+# prior to 2.0, only 'admin': True or False
+# was available
+
+c.JupyterHub.load_roles = [
+    {
+        "name": "service-role",
+        "scopes": [
+            # specify the permissions the token should have
+            "admin:users",
+        ],
+        "services": [
+            # assign the service the above permissions
+            "service-admin",
+        ],
+    }
+]
 ```
 
-The token will have the same admin permissions,
+The token will have the permissions listed in the role
+(see [scopes][] for a list of available permissions),
 but there will no longer be a user account created to house it.
 The main noticeable difference is that there will be no notebook server associated with the account
 and the service will not show up in the various user list pages and APIs.
@@ -112,7 +135,7 @@ Authorization header.
 
 ### Use requests
 
-Using the popular Python [requests](http://docs.python-requests.org/en/master/)
+Using the popular Python [requests](https://docs.python-requests.org)
 library, here's example code to make an API request for the users of a JupyterHub
 deployment. An API GET request is made, and the request sends an API token for
 authorization. The response contains information about the users:
@@ -124,9 +147,9 @@ api_url = 'http://127.0.0.1:8081/hub/api'
 
 r = requests.get(api_url + '/users',
     headers={
-             'Authorization': 'token %s' % token,
-            }
-    )
+        'Authorization': f'token {token}',
+    }
+)
 
 r.raise_for_status()
 users = r.json()
@@ -144,19 +167,95 @@ data = {'name': 'mygroup', 'users': ['user1', 'user2']}
 
 r = requests.post(api_url + '/groups/formgrade-data301/users',
     headers={
-             'Authorization': 'token %s' % token,
-            },
-    json=data
+        'Authorization': f'token {token}',
+    },
+    json=data,
 )
 r.raise_for_status()
 r.json()
 ```
 
 The same API token can also authorize access to the [Jupyter Notebook REST API][]
-provided by notebook servers managed by JupyterHub if one of the following is true:
+provided by notebook servers managed by JupyterHub if it has the necessary `access:users:servers` scope:
 
-1. The token is for the same user as the owner of the notebook
-2. The token is tied to an admin user or service **and** `c.JupyterHub.admin_access` is set to `True`
+(api-pagination)=
+
+## Paginating API requests
+
+```{versionadded} 2.0
+
+```
+
+Pagination is available through the `offset` and `limit` query parameters on
+list endpoints, which can be used to return ideally sized windows of results.
+Here's example code demonstrating pagination on the `GET /users`
+endpoint to fetch the first 20 records.
+
+```python
+import os
+import requests
+
+api_url = 'http://127.0.0.1:8081/hub/api'
+
+r = requests.get(
+    api_url + '/users?offset=0&limit=20',
+    headers={
+        "Accept": "application/jupyterhub-pagination+json",
+        "Authorization": f"token {token}",
+    },
+)
+r.raise_for_status()
+r.json()
+```
+
+For backward-compatibility, the default structure of list responses is unchanged.
+However, this lacks pagination information (e.g. is there a next page),
+so if you have enough users that they won't fit in the first response,
+it is a good idea to opt-in to the new paginated list format.
+There is a new schema for list responses which include pagination information.
+You can request this by including the header:
+
+```
+Accept: application/jupyterhub-pagination+json
+```
+
+with your request, in which case a response will look like:
+
+```python
+{
+  "items": [
+    {
+      "name": "username",
+      "kind": "user",
+      ...
+    },
+  ],
+  "_pagination": {
+    "offset": 0,
+    "limit": 20,
+    "total": 50,
+    "next": {
+      "offset": 20,
+      "limit": 20,
+      "url": "http://127.0.0.1:8081/hub/api/users?limit=20&offset=20"
+    }
+  }
+}
+```
+
+where the list results (same as pre-2.0) will be in `items`,
+and pagination info will be in `_pagination`.
+The `next` field will include the offset, limit, and URL for requesting the next page.
+`next` will be `null` if there is no next page.
+
+Pagination is governed by two configuration options:
+
+- `JupyterHub.api_page_default_limit` - the page size, if `limit` is unspecified in the request
+  and the new pagination API is requested
+  (default: 50)
+- `JupyterHub.api_page_max_limit` - the maximum page size a request can ask for (default: 200)
+
+Pagination is enabled on the `GET /users`, `GET /groups`, and `GET /proxy` REST endpoints.
 
 ## Enabling users to spawn multiple named-servers via the API
 
@@ -204,12 +303,8 @@ or kubernetes pods.
 
 ## Learn more about the API
 
-You can see the full [JupyterHub REST API][] for details. This REST API Spec can
-be viewed in a more [interactive style on swagger's petstore][].
-Both resources contain the same information and differ only in its display.
-Note: The Swagger specification is being renamed the [OpenAPI Initiative][].
+You can see the full [JupyterHub REST API][] for details.
 
-[interactive style on swagger's petstore]: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default
 [openapi initiative]: https://www.openapis.org/
 [jupyterhub rest api]: ./rest-api
-[jupyter notebook rest api]: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/notebook/master/notebook/services/api/api.yaml
+[jupyter notebook rest api]: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyter/notebook/HEAD/notebook/services/api/api.yaml

docs/source/reference/server-api.md

@@ -0,0 +1,369 @@
+# Starting servers with the JupyterHub API
+
+JupyterHub's [REST API][] allows launching servers on behalf of users
+without ever interacting with the JupyterHub UI.
+This allows you to build services launching Jupyter-based services for users
+without relying on the JupyterHub UI at all,
+enabling a variety of user/launch/lifecycle patterns not natively supported by JupyterHub,
+without needing to develop all the server management features of JupyterHub Spawners and/or Authenticators.
+[BinderHub][] is an example of such an application.
+
+[binderhub]: https://binderhub.readthedocs.io
+[rest api]: ../reference/rest.md
+
+This document provides an example of working with the JupyterHub API to
+manage servers for users.
+In particular, we will cover how to:
+
+1. [check status of servers](checking)
+2. [start servers](starting)
+3. [wait for servers to be ready](waiting)
+4. [communicate with servers](communicating)
+5. [stop servers](stopping)
+
+(checking)=
+
+## Checking server status
+
+Requesting information about a user includes a `servers` field,
+which is a dictionary.
+
+```
+GET /hub/api/users/:username
+```
+
+**Required scope: `read:servers`**
+
+```json
+{
+  "admin": false,
+  "groups": [],
+  "pending": null,
+  "server": null,
+  "name": "test-1",
+  "kind": "user",
+  "last_activity": "2021-08-03T18:12:46.026411Z",
+  "created": "2021-08-03T18:09:59.767600Z",
+  "roles": ["user"],
+  "servers": {}
+}
+```
+
+If the `servers` dict is empty, the user has no running servers.
+The keys of the `servers` dict are server names as strings.
+Many JupyterHub deployments only use the 'default' server,
+which has the empty string `''` for a name.
+In this case, the servers dict will always have either zero or one elements.
+
+This is the servers dict when the user's default server is fully running and ready:
+
+```json
+  "servers": {
+    "": {
+      "name": "",
+      "last_activity": "2021-08-03T18:48:35.934000Z",
+      "started": "2021-08-03T18:48:29.093885Z",
+      "pending": null,
+      "ready": true,
+      "url": "/user/test-1/",
+      "user_options": {},
+      "progress_url": "/hub/api/users/test-1/server/progress"
+    }
+  }
+```
+
+Key properties of a server:
+
+name
+: the server's name. Always the same as the key in `servers`
+
+ready
+: boolean. If true, the server can be expected to respond to requests at `url`.
+
+pending
+: `null` or a string indicating a transitional state (such as `start` or `stop`).
+Will always be `null` if `ready` is true,
+and will always be a string if `ready` is false.
+
+url
+: The server's url (just the path, e.g. `/users/:name/:servername/`)
+where the server can be accessed if `ready` is true.
+
+progress_url
+: The API url path (starting with `/hub/api`)
+where the progress API can be used to wait for the server to be ready.
+See below for more details on the progress API.
+
+last_activity
+: ISO8601 timestamp indicating when activity was last observed on the server
+
+started
+: ISO801 timestamp indicating when the server was last started
+
+We've seen the `servers` model with no servers and with one `ready` server.
+Here is what it looks like immediately after requesting a server launch,
+while the server is not ready yet:
+
+```json
+  "servers": {
+    "": {
+      "name": "",
+      "last_activity": "2021-08-03T18:48:29.093885Z",
+      "started": "2021-08-03T18:48:29.093885Z",
+      "pending": "spawn",
+      "ready": false,
+      "url": "/user/test-1/",
+      "user_options": {},
+      "progress_url": "/hub/api/users/test-1/server/progress"
+    }
+  }
+```
+
+Note that `ready` is false and `pending` is `spawn`.
+This means that the server is not ready
+(attempting to access it may not work)
+because it isn't finished spawning yet.
+We'll get more into that below in [waiting for a server][].
+
+[waiting for a server]: waiting
+
+(starting)=
+
+## Starting servers
+
+To start a server, make the request
+
+```
+POST /hub/api/users/:username/servers/[:servername]
+```
+
+**Required scope: `servers`**
+
+(omit servername for the default server)
+
+Assuming the request was valid,
+there are two possible responses:
+
+201 Created
+: This status code means the launch completed and the server is ready.
+It should be available at the server's URL immediately.
+
+202 Accepted
+: This is the more likely response,
+and means that the server has begun launching,
+but isn't immediately ready.
+The server has `pending: 'spawn'` at this point.
+
+_Aside: how quickly JupyterHub responds with `202 Accepted` is governed by the `slow_spawn_timeout` tornado setting._
+
+(waiting)=
+
+## Waiting for a server
+
+If you are starting a server via the API,
+there's a good change you want to know when it's ready.
+There are two ways to do with:
+
+1. {ref}`Polling the server model <polling>`
+2. the {ref}`progress API <progress>`
+
+(polling)=
+
+### Polling the server model
+
+The simplest way to check if a server is ready
+is to request the user model.
+
+If:
+
+1. the server name is in the user's `servers` model, and
+2. `servers['servername']['ready']` is true
+
+A Python example, checking if a server is ready:
+
+```python
+def server_ready(hub_url, user, server_name="", token):
+    r = requests.get(
+        f"{hub_url}/hub/api/users/{user}/servers/{server_name}",
+        headers={"Authorization": f"token {token}"},
+    )
+    r.raise_for_status()
+    user_model = r.json()
+    servers = user_model.get("servers", {})
+    if server_name not in servers:
+        return False
+
+    server = servers[server_name]
+    if server['ready']:
+        print(f"Server {user}/{server_name} ready at {server['url']}")
+        return True
+    else:
+        print(f"Server {user}/{server_name} not ready, pending {server['pending']}")
+        return False
+```
+
+You can keep making this check until `ready` is true.
+
+(progress)=
+
+### Progress API
+
+The most _efficient_ way to wait for a server to start is the progress API.
+
+The progress URL is available in the server model under `progress_url`,
+and has the form `/hub/api/users/:user/servers/:servername/progress`.
+
+_the default server progress can be accessed at `:user/servers//progress` or `:user/server/progress`_
+
+```
+GET /hub/api/users/:user/servers/:servername/progress
+```
+
+**Required scope: `read:servers`**
+
+This is an [EventStream][] API.
+In an event stream, messages are _streamed_ and delivered on lines of the form:
+
+```
+data: {"progress": 10, "message": "...", ...}
+```
+
+where the line after `data:` contains a JSON-serialized dictionary.
+Lines that do not start with `data:` should be ignored.
+
+[eventstream]: https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events#examples
+
+progress events have the form:
+
+```python
+{
+    "progress": 0-100,
+    "message": "",
+    "ready": True, # or False
+
+}
+```
+
+progress
+: integer, 0-100
+
+message
+: string message describing progress stages
+
+ready
+: present and true only for the last event when the server is ready
+
+url
+: only present if `ready` is true; will be the server's url
+
+the progress API can be used even with fully ready servers.
+If the server is ready,
+there will only be one event that looks like:
+
+```json
+{
+  "progress": 100,
+  "ready": true,
+  "message": "Server ready at /user/test-1/",
+  "html_message": "Server ready at <a href=\"/user/test-1/\">/user/test-1/</a>",
+  "url": "/user/test-1/"
+}
+```
+
+where `ready` and `url` are the same as in the server model (`ready` will always be true).
+
+A typical complete stream from the event-stream API:
+
+```
+
+data: {"progress": 0, "message": "Server requested"}
+
+data: {"progress": 50, "message": "Spawning server..."}
+
+data: {"progress": 100, "ready": true, "message": "Server ready at /user/test-user/", "html_message": "Server ready at <a href=\"/user/test-user/\">/user/test-user/</a>", "url": "/user/test-user/"}
+```
+
+Here is a Python example for consuming an event stream:
+
+```{literalinclude} ../../../examples/server-api/start-stop-server.py
+:language: python
+:pyobject: event_stream
+```
+
+(stopping)=
+
+## Stopping servers
+
+Servers can be stopped with a DELETE request:
+
+```
+DELETE /hub/api/users/:user/servers/[:servername]
+```
+
+**Required scope: `servers`**
+
+Like start, delete may not complete immediately.
+The DELETE request has two possible response codes:
+
+204 Deleted
+: This status code means the delete completed and the server is fully stopped.
+It will now be absent from the user `servers` model.
+
+202 Accepted
+: Like start, `202` means your request was accepted,
+but is not yet complete.
+The server has `pending: 'stop'` at this point.
+
+Unlike start, there is no progress API for stop.
+To wait for stop to finish, you must poll the user model
+and wait for the server to disappear from the user `servers` model.
+
+```{literalinclude} ../../../examples/server-api/start-stop-server.py
+:language: python
+:pyobject: stop_server
+```
+
+(communicating)=
+
+## Communicating with servers
+
+JupyterHub tokens with the the `access:servers` scope
+can be used to communicate with servers themselves.
+This can be the same token you used to launch your service.
+
+```{note}
+Access scopes are new in JupyterHub 2.0.
+To access servers in JupyterHub 1.x,
+a token must be owned by the same user as the server,
+*or* be an admin token if admin_access is enabled.
+```
+
+The URL returned from a server model is the url path suffix,
+e.g. `/user/:name/` to append to the jupyterhub base URL.
+
+For instance, `{hub_url}{server_url}`,
+where `hub_url` would be e.g. `http://127.0.0.1:8000` by default,
+and `server_url` `/user/myname`,
+for a full url of `http://127.0.0.1:8000/user/myname`.
+
+## Python example
+
+The JupyterHub repo includes a complete example in {file}`examples/server-api`
+tying all this together.
+
+To summarize the steps:
+
+1. get user info from `/user/:name`
+2. the server model includes a `ready` state to tell you if it's ready
+3. if it's not ready, you can follow up with `progress_url` to wait for it
+4. if it is ready, you can use the `url` field to link directly to the running server
+
+The example demonstrates starting and stopping servers via the JupyterHub API,
+including waiting for them to start via the progress API,
+as well as waiting for them to stop via polling the user model.
+
+```{literalinclude} ../../../examples/server-api/start-stop-server.py
+:language: python
+:start-at: def event_stream
+:end-before: def main
+```

docs/source/reference/services.md

@@ -1,17 +1,5 @@
 # Services
 
-With version 0.7, JupyterHub adds support for **Services**.
-
-This section provides the following information about Services:
-
-- [Definition of a Service](#definition-of-a-service)
-- [Properties of a Service](#properties-of-a-service)
-- [Hub-Managed Services](#hub-managed-services)
-- [Launching a Hub-Managed Service](#launching-a-hub-managed-service)
-- [Externally-Managed Services](#externally-managed-services)
-- [Writing your own Services](#writing-your-own-services)
-- [Hub Authentication and Services](#hub-authentication-and-services)
-
 ## Definition of a Service
 
 When working with JupyterHub, a **Service** is defined as a process that interacts
@@ -47,6 +35,17 @@ A Service may have the following properties:
   the service will be added to the proxy at `/services/:name`
 - `api_token: str (default - None)` - For Externally-Managed Services you need to specify
   an API token to perform API requests to the Hub
+- `display: bool (default - True)` - When set to true, display a link to the
+  service's URL under the 'Services' dropdown in user's hub home page.
+
+- `oauth_no_confirm: bool (default - False)` - When set to true,
+  skip the OAuth confirmation page when users access this service.
+
+  By default, when users authenticate with a service using JupyterHub,
+  they are prompted to confirm that they want to grant that service
+  access to their credentials.
+  Skipping the confirmation page is useful for admin-managed services that are considered part of the Hub
+  and shouldn't need extra prompts for login.
 
 If a service is also to be managed by the Hub, it has a few extra options:
 
@@ -86,10 +85,20 @@ Hub-Managed Service would include:
 This example would be configured as follows in `jupyterhub_config.py`:
 
 ```python
+c.JupyterHub.load_roles = [
+    {
+        "name": "idle-culler",
+        "scopes": [
+            "read:users:activity", # read user last_activity
+            "servers", # start and stop servers
+            # 'admin:users' # needed if culling idle users as well
+        ]
+    }
+]
+
 c.JupyterHub.services = [
     {
         'name': 'idle-culler',
-        'admin': True,
         'command': [sys.executable, '-m', 'jupyterhub_idle_culler', '--timeout=3600']
     }
 ]
@@ -106,6 +115,8 @@ parameters, which describe the environment needed to start the Service process:
 
 The Hub will pass the following environment variables to launch the Service:
 
+(service-env)=
+
 ```bash
 JUPYTERHUB_SERVICE_NAME:   The name of the service
 JUPYTERHUB_API_TOKEN:      API token assigned to the service
@@ -114,6 +125,10 @@ JUPYTERHUB_BASE_URL:       Base URL of the Hub (https://mydomain[:port]/)
 JUPYTERHUB_SERVICE_PREFIX: URL path prefix of this service (/services/:service-name/)
 JUPYTERHUB_SERVICE_URL:    Local URL where the service is expected to be listening.
                            Only for proxied web services.
+JUPYTERHUB_OAUTH_SCOPES:   JSON-serialized list of scopes to use for allowing access to the service
+                           (deprecated in 3.0, use JUPYTERHUB_OAUTH_ACCESS_SCOPES).
+JUPYTERHUB_OAUTH_ACCESS_SCOPES: JSON-serialized list of scopes to use for allowing access to the service (new in 3.0).
+JUPYTERHUB_OAUTH_CLIENT_ALLOWED_SCOPES: JSON-serialized list of scopes that can be requested by the oauth client on behalf of users (new in 3.0).
 ```
 
 For the previous 'cull idle' Service example, these environment variables
@@ -186,27 +201,45 @@ extra slash you might get unexpected behavior. For example if your service has a
 
 ## Hub Authentication and Services
 
-JupyterHub 0.7 introduces some utilities for using the Hub's authentication
-mechanism to govern access to your service. When a user logs into JupyterHub,
-the Hub sets a **cookie (`jupyterhub-services`)**. The service can use this
-cookie to authenticate requests.
+JupyterHub provides some utilities for using the Hub's authentication
+mechanism to govern access to your service.
 
-JupyterHub ships with a reference implementation of Hub authentication that
+Requests to all JupyterHub services are made with OAuth tokens.
+These can either be requests with a token in the `Authorization` header,
+or url parameter `?token=...`,
+or browser requests which must complete the OAuth authorization code flow,
+which results in a token that should be persisted for future requests
+(persistence is up to the service,
+but an encrypted cookie confined to the service path is appropriate,
+and provided by default).
+
+:::{versionchanged} 2.0
+The shared `jupyterhub-services` cookie is removed.
+OAuth must be used to authenticate browser requests with services.
+:::
+
+JupyterHub includes a reference implementation of Hub authentication that
 can be used by services. You may go beyond this reference implementation and
 create custom hub-authenticating clients and services. We describe the process
 below.
 
-The reference, or base, implementation is the [`HubAuth`][hubauth] class,
-which implements the requests to the Hub.
+The reference, or base, implementation is the {class}`.HubAuth` class,
+which implements the API requests to the Hub that resolve a token to a User model.
+
+There are two levels of authentication with the Hub:
+
+- {class}`.HubAuth` - the most basic authentication,
+  for services that should only accept API requests authorized with a token.
+
+- {class}`.HubOAuth` - For services that should use oauth to authenticate with the Hub.
+  This should be used for any service that serves pages that should be visited with a browser.
 
 To use HubAuth, you must set the `.api_token`, either programmatically when constructing the class,
 or via the `JUPYTERHUB_API_TOKEN` environment variable.
 
 Most of the logic for authentication implementation is found in the
-[`HubAuth.user_for_cookie`][hubauth.user_for_cookie]
-and in the
-[`HubAuth.user_for_token`][hubauth.user_for_token]
-methods, which makes a request of the Hub, and returns:
+{meth}`.HubAuth.user_for_token` methods,
+which makes a request of the Hub, and returns:
 
 - None, if no user could be identified, or
 - a dict of the following form:
@@ -215,7 +248,9 @@ methods, which makes a request of the Hub, and returns:
   {
     "name": "username",
     "groups": ["list", "of", "groups"],
-    "admin": False, # or True
+    "scopes": [
+        "access:users:servers!server=username/",
+    ],
   }
   ```
 
@@ -225,78 +260,45 @@ action.
 HubAuth also caches the Hub's response for a number of seconds,
 configurable by the `cookie_cache_max_age` setting (default: five minutes).
 
+If your service would like to make further requests _on behalf of users_,
+it should use the token issued by this OAuth process.
+If you are using tornado,
+you can access the token authenticating the current request with {meth}`.HubAuth.get_token`.
+
+:::{versionchanged} 2.2
+
+{meth}`.HubAuth.get_token` adds support for retrieving
+tokens stored in tornado cookies after completion of OAuth.
+Previously, it only retrieved tokens from URL parameters or the Authorization header.
+Passing `get_token(handler, in_cookie=False)` preserves this behavior.
+:::
+
 ### Flask Example
 
 For example, you have a Flask service that returns information about a user.
 JupyterHub's HubAuth class can be used to authenticate requests to the Flask
 service. See the `service-whoami-flask` example in the
-[JupyterHub GitHub repo](https://github.com/jupyterhub/jupyterhub/tree/master/examples/service-whoami-flask)
+[JupyterHub GitHub repo](https://github.com/jupyterhub/jupyterhub/tree/HEAD/examples/service-whoami-flask)
 for more details.
 
-```python
-from functools import wraps
-import json
-import os
-from urllib.parse import quote
-
-from flask import Flask, redirect, request, Response
-
-from jupyterhub.services.auth import HubAuth
-
-prefix = os.environ.get('JUPYTERHUB_SERVICE_PREFIX', '/')
-
-auth = HubAuth(
-    api_token=os.environ['JUPYTERHUB_API_TOKEN'],
-    cache_max_age=60,
-)
-
-app = Flask(__name__)
-
-
-def authenticated(f):
-    """Decorator for authenticating with the Hub"""
-    @wraps(f)
-    def decorated(*args, **kwargs):
-        cookie = request.cookies.get(auth.cookie_name)
-        token = request.headers.get(auth.auth_header_name)
-        if cookie:
-            user = auth.user_for_cookie(cookie)
-        elif token:
-            user = auth.user_for_token(token)
-        else:
-            user = None
-        if user:
-            return f(user, *args, **kwargs)
-        else:
-            # redirect to login url on failed auth
-            return redirect(auth.login_url + '?next=%s' % quote(request.path))
-    return decorated
-
-
-@app.route(prefix)
-@authenticated
-def whoami(user):
-    return Response(
-        json.dumps(user, indent=1, sort_keys=True),
-        mimetype='application/json',
-        )
+```{literalinclude} ../../../examples/service-whoami-flask/whoami-flask.py
+:language: python
 ```
 
 ### Authenticating tornado services with JupyterHub
 
 Since most Jupyter services are written with tornado,
-we include a mixin class, [`HubAuthenticated`][hubauthenticated],
+we include a mixin class, [`HubOAuthenticated`][huboauthenticated],
 for quickly authenticating your own tornado services with JupyterHub.
 
-Tornado's `@web.authenticated` method calls a Handler's `.get_current_user`
-method to identify the user. Mixing in `HubAuthenticated` defines
-`get_current_user` to use HubAuth. If you want to configure the HubAuth
-instance beyond the default, you'll want to define an `initialize` method,
+Tornado's {py:func}`~.tornado.web.authenticated` decorator calls a Handler's {py:meth}`~.tornado.web.RequestHandler.get_current_user`
+method to identify the user. Mixing in {class}`.HubAuthenticated` defines
+{meth}`~.HubAuthenticated.get_current_user` to use HubAuth. If you want to configure the HubAuth
+instance beyond the default, you'll want to define an {py:meth}`~.tornado.web.RequestHandler.initialize` method,
 such as:
 
 ```python
-class MyHandler(HubAuthenticated, web.RequestHandler):
-    hub_users = {'inara', 'mal'}
+class MyHandler(HubOAuthenticated, web.RequestHandler):
 
     def initialize(self, hub_auth):
         self.hub_auth = hub_auth
@@ -306,39 +308,59 @@ class MyHandler(HubAuthenticated, web.RequestHandler):
         ...
 ```
 
-The HubAuth will automatically load the desired configuration from the Service
-environment variables.
+The HubAuth class will automatically load the desired configuration from the Service
+[environment variables](service-env).
 
-If you want to limit user access, you can specify allowed users through either the
-`.hub_users` attribute or `.hub_groups`. These are sets that check against the
-username and user group list, respectively. If a user matches neither the user
-list nor the group list, they will not be allowed access. If both are left
-undefined, then any user will be allowed.
+:::{versionchanged} 2.0
+
+Access scopes are used to govern access to services.
+Prior to 2.0,
+sets of users and groups could be used to grant access
+by defining `.hub_groups` or `.hub_users` on the authenticated handler.
+These are ignored if the 2.0 `.hub_scopes` is defined.
+:::
+
+:::{seealso}
+{meth}`.HubAuth.check_scopes`
+:::
 
 ### Implementing your own Authentication with JupyterHub
 
 If you don't want to use the reference implementation
 (e.g. you find the implementation a poor fit for your Flask app),
 you can implement authentication via the Hub yourself.
-We recommend looking at the [`HubAuth`][hubauth] class implementation for reference,
+JupyterHub is a standard OAuth2 provider,
+so you can use any OAuth 2 client implementation appropriate for your toolkit.
+See the [FastAPI example][] for an example of using JupyterHub as an OAuth provider with [FastAPI][],
+without using any code imported from JupyterHub.
+
+On completion of OAuth, you will have an access token for JupyterHub,
+which can be used to identify the user and the permissions (scopes)
+the user has authorized for your service.
+
+You will only get to this stage if the user has the required `access:services!service=$service-name` scope.
+
+To retrieve the user model for the token, make a request to `GET /hub/api/user` with the token in the Authorization header.
+For example, using flask:
+
+```{literalinclude} ../../../examples/service-whoami-flask/whoami-flask.py
+:language: python
+```
+
+We recommend looking at the [`HubOAuth`][huboauth] class implementation for reference,
 and taking note of the following process:
 
-1. retrieve the cookie `jupyterhub-services` from the request.
-2. Make an API request `GET /hub/api/authorizations/cookie/jupyterhub-services/cookie-value`,
-   where cookie-value is the url-encoded value of the `jupyterhub-services` cookie.
-   This request must be authenticated with a Hub API token in the `Authorization` header,
-   for example using the `api_token` from your [external service's configuration](#externally-managed-services).
+1. retrieve the token from the request.
+2. Make an API request `GET /hub/api/user`,
+   with the token in the `Authorization` header.
 
    For example, with [requests][]:
 
    ```python
    r = requests.get(
-       '/'.join(["http://127.0.0.1:8081/hub/api",
-                  "authorizations/cookie/jupyterhub-services",
-                  quote(encrypted_cookie, safe=''),
-       ]),
+       "http://127.0.0.1:8081/hub/api/user",
        headers = {
-           'Authorization' : 'token %s' % api_token,
+           'Authorization' : f'token {api_token}',
        },
    )
    r.raise_for_status()
@@ -347,13 +369,27 @@ and taking note of the following process:
 
 3. On success, the reply will be a JSON model describing the user:
 
-   ```json
+   ```python
    {
      "name": "inara",
-     "groups": ["serenity", "guild"]
+     # groups may be omitted, depending on permissions
+     "groups": ["serenity", "guild"],
+     # scopes is new in JupyterHub 2.0
+     "scopes": [
+       "access:services",
+       "read:users:name",
+       "read:users!user=inara",
+       "..."
+     ]
    }
    ```
 
+The `scopes` field can be used to manage access.
+Note: a user will have access to a service to complete oauth access to the service for the first time.
+Individual permissions may be revoked at any later point without revoking the token,
+in which case the `scopes` field in this model should be checked on each access.
+The default required scopes for access are available from `hub_auth.oauth_scopes` or `$JUPYTERHUB_OAUTH_ACCESS_SCOPES`.
+
 An example of using an Externally-Managed Service and authentication is
 in [nbviewer README][nbviewer example] section on securing the notebook viewer,
 and an example of its configuration is found [here](https://github.com/jupyter/nbviewer/blob/ed942b10a52b6259099e2dd687930871dc8aac22/nbviewer/providers/base.py#L95).
@@ -362,9 +398,7 @@ section on securing the notebook viewer.
 
 [requests]: http://docs.python-requests.org/en/master/
 [services_auth]: ../api/services.auth.html
-[hubauth]: ../api/services.auth.html#jupyterhub.services.auth.HubAuth
-[hubauth.user_for_cookie]: ../api/services.auth.html#jupyterhub.services.auth.HubAuth.user_for_cookie
-[hubauth.user_for_token]: ../api/services.auth.html#jupyterhub.services.auth.HubAuth.user_for_token
-[hubauthenticated]: ../api/services.auth.html#jupyterhub.services.auth.HubAuthenticated
 [nbviewer example]: https://github.com/jupyter/nbviewer#securing-the-notebook-viewer
+[fastapi example]: https://github.com/jupyterhub/jupyterhub/tree/HEAD/examples/service-fastapi
+[fastapi]: https://fastapi.tiangolo.com
 [jupyterhub_idle_culler]: https://github.com/jupyterhub/jupyterhub-idle-culler

docs/source/reference/spawners.md

@@ -37,14 +37,13 @@ Some examples include:
 Information about the user can be retrieved from `self.user`,
 an object encapsulating the user's name, authentication, and server info.
 
-The return value of `Spawner.start` should be the (ip, port) of the running server.
-
-**NOTE:** When writing coroutines, _never_ `yield` in between a database change and a commit.
+The return value of `Spawner.start` should be the `(ip, port)` of the running server,
+or a full URL as a string.
 
 Most `Spawner.start` functions will look similar to this example:
 
 ```python
-def start(self):
+async def start(self):
     self.ip = '127.0.0.1'
     self.port = random_port()
     # get environment variables,
@@ -56,8 +55,10 @@ def start(self):
     cmd.extend(self.cmd)
     cmd.extend(self.get_args())
 
-    yield self._actually_start_server_somehow(cmd, env)
-    return (self.ip, self.port)
+    await self._actually_start_server_somehow(cmd, env)
+    # url may not match self.ip:self.port, but it could!
+    url = self._get_connectable_url()
+    return url
 ```
 
 When `Spawner.start` returns, the single-user server process should actually be running,
@@ -65,6 +66,58 @@ not just requested. JupyterHub can handle `Spawner.start` being very slow
 (such as PBS-style batch queues, or instantiating whole AWS instances)
 via relaxing the `Spawner.start_timeout` config value.
 
+#### Note on IPs and ports
+
+`Spawner.ip` and `Spawner.port` attributes set the _bind_ url,
+which the single-user server should listen on
+(passed to the single-user process via the `JUPYTERHUB_SERVICE_URL` environment variable).
+The _return_ value is the ip and port (or full url) the Hub should _connect to_.
+These are not necessarily the same, and usually won't be in any Spawner that works with remote resources or containers.
+
+The default for Spawner.ip, and Spawner.port is `127.0.0.1:{random}`,
+which is appropriate for Spawners that launch local processes,
+where everything is on localhost and each server needs its own port.
+For remote or container Spawners, it will often make sense to use a different value,
+such as `ip = '0.0.0.0'` and a fixed port, e.g. `8888`.
+The defaults can be changed in the class,
+preserving configuration with traitlets:
+
+```python
+from traitlets import default
+from jupyterhub.spawner import Spawner
+
+class MySpawner(Spawner):
+    @default("ip")
+    def _default_ip(self):
+        return '0.0.0.0'
+
+    @default("port")
+    def _default_port(self):
+        return 8888
+
+    async def start(self):
+        env = self.get_env()
+        cmd = []
+        # get jupyterhub command to run,
+        # typically ['jupyterhub-singleuser']
+        cmd.extend(self.cmd)
+        cmd.extend(self.get_args())
+
+        remote_server_info = await self._actually_start_server_somehow(cmd, env)
+        url = self.get_public_url_from(remote_server_info)
+        return url
+```
+
+#### Exception handling
+
+When `Spawner.start` raises an Exception, a message can be passed on to the user via the exception via a `.jupyterhub_html_message` or `.jupyterhub_message` attribute.
+
+When the Exception has a `.jupyterhub_html_message` attribute, it will be rendered as HTML to the user.
+
+Alternatively `.jupyterhub_message` is rendered as unformatted text.
+
+If both attributes are not present, the Exception will be shown to the user as unformatted text.
+
 ### Spawner.poll
 
 `Spawner.poll` should check if the spawner is still running.
@@ -125,7 +178,7 @@ If the `Spawner.options_form` is defined, when a user tries to start their serve
 
 If `Spawner.options_form` is undefined, the user's server is spawned directly, and no spawn page is rendered.
 
-See [this example](https://github.com/jupyterhub/jupyterhub/blob/master/examples/spawn-form/jupyterhub_config.py) for a form that allows custom CLI args for the local spawner.
+See [this example](https://github.com/jupyterhub/jupyterhub/blob/HEAD/examples/spawn-form/jupyterhub_config.py) for a form that allows custom CLI args for the local spawner.
 
 ### `Spawner.options_from_form`
 
@@ -166,7 +219,7 @@ which would return:
 
 When `Spawner.start` is called, this dictionary is accessible as `self.user_options`.
 
-[spawner]: https://github.com/jupyterhub/jupyterhub/blob/master/jupyterhub/spawner.py
+[spawner]: https://github.com/jupyterhub/jupyterhub/blob/HEAD/jupyterhub/spawner.py
 
 ## Writing a custom spawner
 
@@ -207,6 +260,76 @@ Additionally, configurable attributes for your spawner will
 appear in jupyterhub help output and auto-generated configuration files
 via `jupyterhub --generate-config`.
 
+## Environment variables and command-line arguments
+
+Spawners mainly do one thing: launch a command in an environment.
+
+The command-line is constructed from user configuration:
+
+- Spawner.cmd (default: `['jupterhub-singleuser']`)
+- Spawner.args (cli args to pass to the cmd, default: empty)
+
+where the configuration:
+
+```python
+c.Spawner.cmd = ["my-singleuser-wrapper"]
+c.Spawner.args = ["--debug", "--flag"]
+```
+
+would result in spawning the command:
+
+```bash
+my-singleuser-wrapper --debug --flag
+```
+
+The `Spawner.get_args()` method is how Spawner.args is accessed,
+and can be used by Spawners to customize/extend user-provided arguments.
+
+Prior to 2.0, JupyterHub unconditionally added certain options _if specified_ to the command-line,
+such as `--ip={Spawner.ip}` and `--port={Spawner.port}`.
+These have now all been moved to environment variables,
+and from JupyterHub 2.0,
+the command-line launched by JupyterHub is fully specified by overridable configuration `Spawner.cmd + Spawner.args`.
+
+Most process configuration is passed via environment variables.
+Additional variables can be specified via the `Spawner.environment` configuration.
+
+The process environment is returned by `Spawner.get_env`, which specifies the following environment variables:
+
+- JUPYTERHUB*SERVICE_URL - the \_bind* url where the server should launch its http server (`http://127.0.0.1:12345`).
+  This includes Spawner.ip and Spawner.port; _new in 2.0, prior to 2.0 ip,port were on the command-line and only if specified_
+- JUPYTERHUB_SERVICE_PREFIX - the URL prefix the service will run on (e.g. `/user/name/`)
+- JUPYTERHUB_USER - the JupyterHub user's username
+- JUPYTERHUB_SERVER_NAME - the server's name, if using named servers (default server has an empty name)
+- JUPYTERHUB_API_URL - the full url for the JupyterHub API (http://17.0.0.1:8001/hub/api)
+- JUPYTERHUB_BASE_URL - the base url of the whole jupyterhub deployment, i.e. the bit before `hub/` or `user/`,
+  as set by c.JupyterHub.base_url (default: `/`)
+- JUPYTERHUB_API_TOKEN - the API token the server can use to make requests to the Hub.
+  This is also the OAuth client secret.
+- JUPYTERHUB_CLIENT_ID - the OAuth client ID for authenticating visitors.
+- JUPYTERHUB_OAUTH_CALLBACK_URL - the callback URL to use in oauth, typically `/user/:name/oauth_callback`
+- JUPYTERHUB_OAUTH_ACCESS_SCOPES - the scopes required to access the server (called JUPYTERHUB_OAUTH_SCOPES prior to 3.0)
+- JUPYTERHUB_OAUTH_CLIENT_ALLOWED_SCOPES - the scopes the service is allowed to request.
+  If no scopes are requested explicitly, these scopes will be requested.
+
+Optional environment variables, depending on configuration:
+
+- JUPYTERHUB*SSL*[KEYFILE|CERTFILE|CLIENT_CI] - SSL configuration, when internal_ssl is enabled
+- JUPYTERHUB_ROOT_DIR - the root directory of the server (notebook directory), when Spawner.notebook_dir is defined (new in 2.0)
+- JUPYTERHUB_DEFAULT_URL - the default URL for the server (for redirects from /user/:name/),
+  if Spawner.default_url is defined
+  (new in 2.0, previously passed via cli)
+- JUPYTERHUB_DEBUG=1 - generic debug flag, sets maximum log level when Spawner.debug is True
+  (new in 2.0, previously passed via cli)
+- JUPYTERHUB_DISABLE_USER_CONFIG=1 - disable loading user config,
+  sets maximum log level when Spawner.debug is True (new in 2.0,
+  previously passed via cli)
+
+- JUPYTERHUB*[MEM|CPU]*[LIMIT_GUARANTEE] - the values of cpu and memory limits and guarantees.
+  These are not expected to be enforced by the process,
+  but are made available as a hint,
+  e.g. for resource monitoring extensions.
+
 ## Spawners, resource limits, and guarantees (Optional)
 
 Some spawners of the single-user notebook servers allow setting limits or

docs/source/reference/templates.md

@@ -10,7 +10,7 @@ appearance.
 
 JupyterHub will look for custom templates in all of the paths in the
 `JupyterHub.template_paths` configuration option, falling back on the
-[default templates](https://github.com/jupyterhub/jupyterhub/tree/master/share/jupyterhub/templates)
+[default templates](https://github.com/jupyterhub/jupyterhub/tree/HEAD/share/jupyterhub/templates)
 if no custom template with that name is found. This fallback
 behavior is new in version 0.9; previous versions searched only those paths
 explicitly included in `template_paths`. You may override as many
@@ -21,7 +21,7 @@ or as few templates as you desire.
 Jinja provides a mechanism to [extend templates](http://jinja.pocoo.org/docs/2.10/templates/#template-inheritance).
 A base template can define a `block`, and child templates can replace or
 supplement the material in the block. The
-[JupyterHub templates](https://github.com/jupyterhub/jupyterhub/tree/master/share/jupyterhub/templates)
+[JupyterHub templates](https://github.com/jupyterhub/jupyterhub/tree/HEAD/share/jupyterhub/templates)
 make extensive use of blocks, which allows you to customize parts of the
 interface easily.
 

docs/source/reference/websecurity.md

@@ -131,6 +131,6 @@ A handy website for testing your deployment is
 
 If you believe you’ve found a security vulnerability in JupyterHub, or any
 Jupyter project, please report it to
-[security@ipython.org](mailto:security@iypthon.org). If you prefer to encrypt
+[security@ipython.org](mailto:security@ipython.org). If you prefer to encrypt
 your security reports, you can use [this PGP public
 key](https://jupyter-notebook.readthedocs.io/en/stable/_downloads/ipython_security.asc).

docs/source/troubleshooting.md

@@ -234,7 +234,7 @@ With a docker container, pass in the environment variable with the run command:
       -e JUPYTERHUB_API_TOKEN=my_secret_token \
       jupyter/datascience-notebook:latest
 
-[This example](https://github.com/jupyterhub/jupyterhub/tree/master/examples/service-notebook/external) demonstrates how to combine the use of the `jupyterhub-singleuser` environment variables when launching a Notebook as an externally managed service.
+[This example](https://github.com/jupyterhub/jupyterhub/tree/HEAD/examples/service-notebook/external) demonstrates how to combine the use of the `jupyterhub-singleuser` environment variables when launching a Notebook as an externally managed service.
 
 ## How do I...?
 
@@ -275,7 +275,7 @@ where `ssl_cert` is example-chained.crt and ssl_key to your private key.
 
 Then restart JupyterHub.
 
-See also [JupyterHub SSL encryption](./getting-started/security-basics.html#ssl-encryption).
+See also {ref}`ssl-encryption`.
 
 ### Install JupyterHub without a network connection
 
@@ -371,7 +371,7 @@ a JupyterHub deployment. The commands are:
 - System and deployment information
 
 ```bash
-jupyter troubleshooting
+jupyter troubleshoot
 ```
 
 - Kernel information

docs/test_docs.py

@@ -0,0 +1,46 @@
+import sys
+from pathlib import Path
+from subprocess import run
+
+from ruamel.yaml import YAML
+
+yaml = YAML(typ="safe")
+
+here = Path(__file__).absolute().parent
+root = here.parent
+
+
+def test_rest_api_version_is_updated():
+    """Checks that the version in JupyterHub's REST API definition file
+    (rest-api.yml) is matching the JupyterHub version."""
+    version_py = root.joinpath("jupyterhub", "_version.py")
+    rest_api_yaml = root.joinpath("docs", "source", "_static", "rest-api.yml")
+    ns = {}
+    with version_py.open() as f:
+        exec(f.read(), {}, ns)
+    jupyterhub_version = ns["__version__"]
+
+    with rest_api_yaml.open() as f:
+        rest_api = yaml.load(f)
+        rest_api_version = rest_api["info"]["version"]
+
+    assert jupyterhub_version == rest_api_version
+
+
+def test_rest_api_rbac_scope_descriptions_are_updated():
+    """Checks that the RBAC scope descriptions in JupyterHub's REST API
+    definition file (rest-api.yml) as can be updated by generate-scope-table.py
+    matches what is committed."""
+    run([sys.executable, "source/rbac/generate-scope-table.py"], cwd=here, check=True)
+    run(
+        [
+            "git",
+            "--no-pager",
+            "diff",
+            "--color=always",
+            "--exit-code",
+            str(here.joinpath("source", "_static", "rest-api.yml")),
+        ],
+        cwd=here,
+        check=True,
+    )

examples/azuread-with-group-management/jupyterhub_config.py

@@ -0,0 +1,31 @@
+"""sample jupyterhub config file for testing
+
+configures jupyterhub with dummyauthenticator and simplespawner
+to enable testing without administrative privileges.
+"""
+
+c = get_config()  # noqa
+c.Application.log_level = 'DEBUG'
+
+import os
+
+from oauthenticator.azuread import AzureAdOAuthenticator
+
+c.JupyterHub.authenticator_class = AzureAdOAuthenticator
+
+c.AzureAdOAuthenticator.client_id = os.getenv("AAD_CLIENT_ID")
+c.AzureAdOAuthenticator.client_secret = os.getenv("AAD_CLIENT_SECRET")
+c.AzureAdOAuthenticator.oauth_callback_url = os.getenv("AAD_CALLBACK_URL")
+c.AzureAdOAuthenticator.tenant_id = os.getenv("AAD_TENANT_ID")
+c.AzureAdOAuthenticator.username_claim = "email"
+c.AzureAdOAuthenticator.authorize_url = os.getenv("AAD_AUTHORIZE_URL")
+c.AzureAdOAuthenticator.token_url = os.getenv("AAD_TOKEN_URL")
+c.Authenticator.manage_groups = True
+c.Authenticator.refresh_pre_spawn = True
+
+# Optionally set a global password that all users must use
+# c.DummyAuthenticator.password = "your_password"
+
+from jupyterhub.spawner import SimpleLocalProcessSpawner
+
+c.JupyterHub.spawner_class = SimpleLocalProcessSpawner

examples/azuread-with-group-management/requirements.txt

@@ -0,0 +1,2 @@
+oauthenticator
+pyjwt

examples/bootstrap-script/README.md

@@ -148,9 +148,9 @@ else
     echo "...initial content loading for user ..."
     mkdir $USER_DIRECTORY/tutorials
     cd $USER_DIRECTORY/tutorials
-    wget https://github.com/jakevdp/PythonDataScienceHandbook/archive/master.zip
-    unzip -o master.zip
-    rm master.zip
+    wget https://github.com/jakevdp/PythonDataScienceHandbook/archive/HEAD.zip
+    unzip -o HEAD.zip
+    rm HEAD.zip
 fi
 
 exit 0

examples/bootstrap-script/bootstrap.sh

@@ -40,9 +40,9 @@ else
     echo "...initial content loading for user ..."
     mkdir $USER_DIRECTORY/tutorials
     cd $USER_DIRECTORY/tutorials
-    wget https://github.com/jakevdp/PythonDataScienceHandbook/archive/master.zip
-    unzip -o master.zip
-    rm master.zip
+    wget https://github.com/jakevdp/PythonDataScienceHandbook/archive/HEAD.zip
+    unzip -o HEAD.zip
+    rm HEAD.zip
 fi
 
 exit 0

examples/bootstrap-script/jupyterhub_config.py

@@ -10,7 +10,7 @@ from jupyter_client.localinterfaces import public_ips
 
 
 def create_dir_hook(spawner):
-    """ Create directory """
+    """Create directory"""
     username = spawner.user.name  # get the username
     volume_path = os.path.join('/volumes/jupyterhub', username)
     if not os.path.exists(volume_path):
@@ -20,7 +20,7 @@ def create_dir_hook(spawner):
 
 
 def clean_dir_hook(spawner):
-    """ Delete directory """
+    """Delete directory"""
     username = spawner.user.name  # get the username
     temp_path = os.path.join('/volumes/jupyterhub', username, 'temp')
     if os.path.exists(temp_path) and os.path.isdir(temp_path):

examples/custom-scopes/grades.py

@@ -0,0 +1,132 @@
+import os
+from functools import wraps
+from html import escape
+from urllib.parse import urlparse
+
+from tornado.httpserver import HTTPServer
+from tornado.ioloop import IOLoop
+from tornado.web import Application, RequestHandler, authenticated
+
+from jupyterhub.services.auth import HubOAuthCallbackHandler, HubOAuthenticated
+from jupyterhub.utils import url_path_join
+
+SCOPE_PREFIX = "custom:grades"
+READ_SCOPE = f"{SCOPE_PREFIX}:read"
+WRITE_SCOPE = f"{SCOPE_PREFIX}:write"
+
+
+def require_scope(scopes):
+    """Decorator to require scopes
+
+    For use if multiple methods on one Handler
+    may want different scopes,
+    so class-level .hub_scopes is insufficient
+    (e.g. read for GET, write for POST).
+    """
+    if isinstance(scopes, str):
+        scopes = [scopes]
+
+    def wrap(method):
+        """The actual decorator"""
+
+        @wraps(method)
+        @authenticated
+        def wrapped(self, *args, **kwargs):
+            self.hub_scopes = scopes
+            return method(self, *args, **kwargs)
+
+        return wrapped
+
+    return wrap
+
+
+class MyGradesHandler(HubOAuthenticated, RequestHandler):
+    # no hub_scopes, anyone with access to this service
+    # will be able to visit this URL
+
+    @authenticated
+    def get(self):
+        self.write("<h1>My grade</h1>")
+        name = self.current_user["name"]
+        grades = self.settings["grades"]
+        self.write(f"<p>My name is: {escape(name)}</p>")
+        if name in grades:
+            self.write(f"<p>My grade is: {escape(str(grades[name]))}</p>")
+        else:
+            self.write("<p>No grade entered</p>")
+        if READ_SCOPE in self.current_user["scopes"]:
+            self.write('<a href="grades/">enter grades</a>')
+
+
+class GradesHandler(HubOAuthenticated, RequestHandler):
+    # default scope for this Handler: read-only
+    hub_scopes = [READ_SCOPE]
+
+    def _render(self):
+        grades = self.settings["grades"]
+        self.write("<h1>All grades</h1>")
+        self.write("<table>")
+        self.write("<tr><th>Student</th><th>Grade</th></tr>")
+        for student, grade in grades.items():
+            qstudent = escape(student)
+            qgrade = escape(str(grade))
+            self.write(
+                f"""
+                <tr>
+                 <td class="student">{qstudent}</td>
+                 <td class="grade">{qgrade}</td>
+                </tr>
+                """
+            )
+        if WRITE_SCOPE in self.current_user["scopes"]:
+            self.write("Enter grade:")
+            self.write(
+                """
+                <form action=. method=POST>
+                    <input name=student placeholder=student></input>
+                    <input kind=number name=grade placeholder=grade></input>
+                    <input type="submit" value="Submit">
+                """
+            )
+
+    @require_scope([READ_SCOPE])
+    async def get(self):
+        self._render()
+
+    # POST requires WRITE_SCOPE instead of READ_SCOPE
+    @require_scope([WRITE_SCOPE])
+    async def post(self):
+        name = self.get_argument("student")
+        grade = self.get_argument("grade")
+        self.settings["grades"][name] = grade
+        self._render()
+
+
+def main():
+    base_url = os.environ['JUPYTERHUB_SERVICE_PREFIX']
+
+    app = Application(
+        [
+            (base_url, MyGradesHandler),
+            (url_path_join(base_url, 'grades/'), GradesHandler),
+            (
+                url_path_join(base_url, 'oauth_callback'),
+                HubOAuthCallbackHandler,
+            ),
+        ],
+        cookie_secret=os.urandom(32),
+        grades={"student": 53},
+    )
+
+    http_server = HTTPServer(app)
+    url = urlparse(os.environ['JUPYTERHUB_SERVICE_URL'])
+
+    http_server.listen(url.port, url.hostname)
+    try:
+        IOLoop.current().start()
+    except KeyboardInterrupt:
+        pass
+
+
+if __name__ == '__main__':
+    main()

examples/custom-scopes/jupyterhub_config.py

@@ -0,0 +1,52 @@
+import sys
+
+c = get_config()  # noqa
+
+c.JupyterHub.services = [
+    {
+        'name': 'grades',
+        'url': 'http://127.0.0.1:10101',
+        'command': [sys.executable, './grades.py'],
+        'oauth_client_allowed_scopes': [
+            'custom:grades:write',
+            'custom:grades:read',
+        ],
+    },
+]
+
+c.JupyterHub.custom_scopes = {
+    "custom:grades:read": {
+        "description": "read-access to all grades",
+    },
+    "custom:grades:write": {
+        "description": "Enter new grades",
+        "subscopes": ["custom:grades:read"],
+    },
+}
+
+c.JupyterHub.load_roles = [
+    {
+        "name": "user",
+        # grant all users access to services
+        "scopes": ["access:services", "self"],
+    },
+    {
+        "name": "grader",
+        # grant graders access to write grades
+        "scopes": ["custom:grades:write"],
+        "users": ["grader"],
+    },
+    {
+        "name": "instructor",
+        # grant instructors access to read, but not write grades
+        "scopes": ["custom:grades:read"],
+        "users": ["instructor"],
+    },
+]
+
+c.JupyterHub.allowed_users = {"instructor", "grader", "student"}
+# dummy spawner and authenticator for testing, don't actually use these!
+c.JupyterHub.authenticator_class = 'dummy'
+c.JupyterHub.spawner_class = 'simple'
+c.JupyterHub.ip = '127.0.0.1'  # let's just run on localhost while dummy auth is enabled
+c.JupyterHub.log_level = 10

examples/external-oauth/jupyterhub_config.py

@@ -13,7 +13,7 @@ if not api_token:
 c.JupyterHub.services = [
     {
         'name': 'external-oauth',
-        'oauth_client_id': "whoami-oauth-client-test",
+        'oauth_client_id': "service-oauth-client-test",
         'api_token': api_token,
         'oauth_redirect_uri': 'http://127.0.0.1:5555/oauth_callback',
     }

examples/external-oauth/launch-service-basic.sh

@@ -9,7 +9,7 @@ if [[ -z "${JUPYTERHUB_API_TOKEN}" ]]; then
 fi
 
 # 2. oauth client ID
-export JUPYTERHUB_CLIENT_ID='whoami-oauth-client-test'
+export JUPYTERHUB_CLIENT_ID='service-oauth-client-test'
 # 3. where the Hub is
 export JUPYTERHUB_URL='http://127.0.0.1:8000'
 

examples/external-oauth/launch-service.sh

@@ -9,7 +9,7 @@ if [[ -z "${JUPYTERHUB_API_TOKEN}" ]]; then
 fi
 
 # 2. oauth client ID
-export JUPYTERHUB_CLIENT_ID="whoami-oauth-client-test"
+export JUPYTERHUB_CLIENT_ID="service-oauth-client-test"
 # 3. what URL to run on
 export JUPYTERHUB_SERVICE_PREFIX='/'
 export JUPYTERHUB_SERVICE_URL='http://127.0.0.1:5555'

examples/external-oauth/whoami-oauth-basic.py

@@ -5,13 +5,10 @@ so all URLs and requests necessary for OAuth with JupyterHub should be in one pl
 """
 import json
 import os
-from urllib.parse import urlencode
-from urllib.parse import urlparse
+from urllib.parse import urlencode, urlparse
 
-from tornado import log
-from tornado import web
-from tornado.httpclient import AsyncHTTPClient
-from tornado.httpclient import HTTPRequest
+from tornado import log, web
+from tornado.httpclient import AsyncHTTPClient, HTTPRequest
 from tornado.httputil import url_concat
 from tornado.ioloop import IOLoop
 

examples/postgres/hub/jupyterhub_config.py

@@ -1,10 +1,23 @@
 # Configuration file for jupyterhub (postgres example).
 
-c = get_config()
+c = get_config()  # noqa
 
-# Add some users.
-c.JupyterHub.admin_users = {'rhea'}
-c.Authenticator.whitelist = {'ganymede', 'io', 'rhea'}
+# Add some users
+c.Authenticator.allowed_users = {'ganymede', 'io', 'rhea'}
+
+c.JupyterHub.load_roles = [
+    {
+        "name": "user-admin",
+        "scopes": [
+            "admin:groups",
+            "admin:users",
+            "admin:servers",
+        ],
+        "users": [
+            "rhea",
+        ],
+    }
+]
 
 # These environment variables are automatically supplied by the linked postgres
 # container.

examples/server-api/jupyterhub_config.py

@@ -0,0 +1,57 @@
+# create a role with permissions to:
+# 1. start/stop servers, and
+# 2. access the server API
+
+c = get_config()  # noqa
+
+c.JupyterHub.load_roles = [
+    {
+        "name": "launcher",
+        "scopes": [
+            "servers",  # manage servers
+            "access:servers",  # access servers themselves
+        ],
+        # assign role to our 'launcher' service
+        "services": ["launcher"],
+    }
+]
+
+
+# persist token to a file, to share it with the launch-server.py script
+import pathlib
+import secrets
+
+here = pathlib.Path(__file__).parent
+token_file = here.joinpath("service-token")
+if token_file.exists():
+    with token_file.open("r") as f:
+        token = f.read()
+else:
+    token = secrets.token_hex(16)
+    with token_file.open("w") as f:
+        f.write(token)
+
+# define our service
+c.JupyterHub.services = [
+    {
+        "name": "launcher",
+        "api_token": token,
+    }
+]
+
+# ensure spawn requests return immediately,
+# rather than waiting up to 10 seconds for spawn to complete
+# this ensures that we use the progress API
+
+c.JupyterHub.tornado_settings = {"slow_spawn_timeout": 0}
+
+# create our test-user
+c.Authenticator.allowed_users = {
+    'test-user',
+}
+
+
+# testing boilerplate: fake auth/spawner, localhost. Don't use this for real!
+c.JupyterHub.authenticator_class = 'dummy'
+c.JupyterHub.spawner_class = 'simple'
+c.JupyterHub.ip = '127.0.0.1'

examples/server-api/start-stop-server.py

@@ -0,0 +1,172 @@
+#!/usr/bin/env python3
+"""
+Example of starting/stopping a server via the JupyterHub API
+
+1. get user status
+2. start server
+3. wait for server to be ready via progress api
+4. make a request to the server itself
+5. stop server via API
+6. wait for server to finish stopping
+"""
+import json
+import logging
+import pathlib
+import time
+
+import requests
+
+log = logging.getLogger(__name__)
+
+
+def get_token():
+    """boilerplate: get token from share file.
+
+    Make sure to start jupyterhub in this directory first
+    """
+    here = pathlib.Path(__file__).parent
+    token_file = here.joinpath("service-token")
+    log.info(f"Loading token from {token_file}")
+    with token_file.open("r") as f:
+        token = f.read().strip()
+    return token
+
+
+def make_session(token):
+    """Create a requests.Session with our service token in the Authorization header"""
+    session = requests.Session()
+    session.headers = {"Authorization": f"token {token}"}
+    return session
+
+
+def event_stream(session, url):
+    """Generator yielding events from a JSON event stream
+
+    For use with the server progress API
+    """
+    r = session.get(url, stream=True)
+    r.raise_for_status()
+    for line in r.iter_lines():
+        line = line.decode('utf8', 'replace')
+        # event lines all start with `data:`
+        # all other lines should be ignored (they will be empty)
+        if line.startswith('data:'):
+            yield json.loads(line.split(':', 1)[1])
+
+
+def start_server(session, hub_url, user, server_name=""):
+    """Start a server for a jupyterhub user
+
+    Returns the full URL for accessing the server
+    """
+    user_url = f"{hub_url}/hub/api/users/{user}"
+    log_name = f"{user}/{server_name}".rstrip("/")
+
+    # step 1: get user status
+    r = session.get(user_url)
+    r.raise_for_status()
+    user_model = r.json()
+
+    # if server is not 'active', request launch
+    if server_name not in user_model.get('servers', {}):
+        log.info(f"Starting server {log_name}")
+        r = session.post(f"{user_url}/servers/{server_name}")
+        r.raise_for_status()
+        if r.status_code == 201:
+            log.info(f"Server {log_name} is launched and ready")
+        elif r.status_code == 202:
+            log.info(f"Server {log_name} is launching...")
+        else:
+            log.warning(f"Unexpected status: {r.status_code}")
+        r = session.get(user_url)
+        r.raise_for_status()
+        user_model = r.json()
+
+    # report server status
+    server = user_model['servers'][server_name]
+    if server['pending']:
+        status = f"pending {server['pending']}"
+    elif server['ready']:
+        status = "ready"
+    else:
+        # shouldn't be possible!
+        raise ValueError(f"Unexpected server state: {server}")
+
+    log.info(f"Server {log_name} is {status}")
+
+    # wait for server to be ready using progress API
+    progress_url = user_model['servers'][server_name]['progress_url']
+    for event in event_stream(session, f"{hub_url}{progress_url}"):
+        log.info(f"Progress {event['progress']}%: {event['message']}")
+        if event.get("ready"):
+            server_url = event['url']
+            break
+    else:
+        # server never ready
+        raise ValueError(f"{log_name} never started!")
+
+    # at this point, we know the server is ready and waiting to receive requests
+    # return the full URL where the server can be accessed
+    return f"{hub_url}{server_url}"
+
+
+def stop_server(session, hub_url, user, server_name=""):
+    """Stop a server via the JupyterHub API
+
+    Returns when the server has finished stopping
+    """
+    # step 1: get user status
+    user_url = f"{hub_url}/hub/api/users/{user}"
+    server_url = f"{user_url}/servers/{server_name}"
+    log_name = f"{user}/{server_name}".rstrip("/")
+
+    log.info(f"Stopping server {log_name}")
+    r = session.delete(server_url)
+    if r.status_code == 404:
+        log.info(f"Server {log_name} already stopped")
+
+    r.raise_for_status()
+    if r.status_code == 204:
+        log.info(f"Server {log_name} stopped")
+        return
+
+    # else: 202, stop requested, but not complete
+    # wait for stop to finish
+    log.info(f"Server {log_name} stopping...")
+
+    # wait for server to be done stopping
+    while True:
+        r = session.get(user_url)
+        r.raise_for_status()
+        user_model = r.json()
+        if server_name not in user_model.get("servers", {}):
+            log.info(f"Server {log_name} stopped")
+            return
+        server = user_model["servers"][server_name]
+        if not server['pending']:
+            raise ValueError(f"Waiting for {log_name}, but no longer pending.")
+        log.info(f"Server {log_name} pending: {server['pending']}")
+        # wait to poll again
+        time.sleep(1)
+
+
+def main():
+    """Start and stop one server
+
+    Uses test-user and hub from jupyterhub_config.py in this directory
+    """
+    user = "test-user"
+    hub_url = "http://127.0.0.1:8000"
+
+    session = make_session(get_token())
+    server_url = start_server(session, hub_url, user)
+    r = session.get(f"{server_url}/api/status")
+    r.raise_for_status()
+    log.info(f"Server status: {r.text}")
+
+    stop_server(session, hub_url, user)
+
+
+if __name__ == "__main__":
+    logging.basicConfig(level=logging.INFO)
+    main()

examples/service-announcement/README.md

@@ -6,15 +6,17 @@ that appear when JupyterHub renders pages.
 To run the service as a hub-managed service simply include in your JupyterHub
 configuration file something like:
 
-    c.JupyterHub.services = [
-            {
-                'name': 'announcement',
-                'url': 'http://127.0.0.1:8888',
-                'command': [sys.executable, "-m", "announcement"],
-            }
-    ]
+```python
+c.JupyterHub.services = [
+        {
+            'name': 'announcement',
+            'url': 'http://127.0.0.1:8888',
+            'command': [sys.executable, "-m", "announcement", "--port", "8888"],
+        }
+]
+```
 
-This starts the announcements service up at `/services/announcement` when
+This starts the announcements service up at `/services/announcement/` when
 JupyterHub launches. By default the announcement text is empty.
 
 The `announcement` module has a configurable port (default 8888) and an API
@@ -23,15 +25,28 @@ that environment variable is set or `/` if it is not.
 
 ## Managing the Announcement
 
-Admin users can set the announcement text with an API token:
+Users with permission can set the announcement text with an API token:
 
     $ curl -X POST -H "Authorization: token <token>"                        \
         -d '{"announcement":"JupyterHub will be upgraded on August 14!"}'   \
-        https://.../services/announcement
+        https://.../services/announcement/
+
+To grant permission, add a role (JupyterHub 2.0) with access to the announcement service:
+
+```python
+# grant the 'announcer' permission to access the announcement service
+c.JupyterHub.load_roles = [
+    {
+        "name": "announcers",
+        "users": ["announcer"], # or groups
+        "scopes": ["access:services!service=announcement"],
+    }
+]
+```
 
 Anyone can read the announcement:
 
-    $ curl https://.../services/announcement | python -m json.tool
+    $ curl https://.../services/announcement/ | python -m json.tool
     {
         announcement: "JupyterHub will be upgraded on August 14!",
         timestamp: "...",
@@ -41,10 +56,11 @@ Anyone can read the announcement:
 The time the announcement was posted is recorded in the `timestamp` field and
 the user who posted the announcement is recorded in the `user` field.
 
-To clear the announcement text, just DELETE. Only admin users can do this.
+To clear the announcement text, send a DELETE request.
+This has the same permission requirement.
 
-    $ curl -X POST -H "Authorization: token <token>"                        \
-        https://.../services/announcement
+    $ curl -X DELETE -H "Authorization: token <token>"                        \
+        https://.../services/announcement/
 
 ## Seeing the Announcement in JupyterHub
 

examples/service-announcement/announcement.py

@@ -3,9 +3,7 @@ import datetime
 import json
 import os
 
-from tornado import escape
-from tornado import ioloop
-from tornado import web
+from tornado import escape, ioloop, web
 
 from jupyterhub.services.auth import HubAuthenticated
 
@@ -13,9 +11,6 @@ from jupyterhub.services.auth import HubAuthenticated
 class AnnouncementRequestHandler(HubAuthenticated, web.RequestHandler):
     """Dynamically manage page announcements"""
 
-    hub_users = []
-    allow_admin = True
-
     def initialize(self, storage):
         """Create storage for announcement text"""
         self.storage = storage