Merge branch

.github/workflows/release.yml

@@ -62,6 +62,10 @@ jobs:
           pip install dist/*.whl
           ./ci/check_installed_data.py
 
+      - name: verify sdist can be installed without npm/yarn
+        run: |
+          docker run --rm -v $PWD/dist:/dist:ro docker.io/library/python:3.9-slim-bullseye bash -c 'pip install /dist/jupyterhub-*.tar.gz'
+
       # ref: https://github.com/actions/upload-artifact#readme
       - uses: actions/upload-artifact@v3
         with:
@@ -104,10 +108,10 @@ jobs:
       # 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
+        uses: docker/setup-qemu-action@e81a89b1732b9c48d79cd809d8d81d79c4647a18 # associated tag: v1.0.2
 
       - name: Set up Docker Buildx (for multi-arch builds)
-        uses: docker/setup-buildx-action@dc7b9719a96d48369863986a06765841d7ea23f6 # associated tag: v1.1.2
+        uses: docker/setup-buildx-action@8c0edbc76e98fa90f69d9a2c020dcb50019dc325
         with:
           # Allows pushing to registry on localhost:5000
           driver-opts: network=host
@@ -145,7 +149,7 @@ jobs:
           branchRegex: ^\w[\w-.]*$
 
       - name: Build and push jupyterhub
-        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
+        uses: docker/build-push-action@c56af957549030174b10d6867f20e78cfd7debc5
         with:
           context: .
           platforms: linux/amd64,linux/arm64
@@ -166,7 +170,7 @@ jobs:
           branchRegex: ^\w[\w-.]*$
 
       - name: Build and push jupyterhub-onbuild
-        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
+        uses: docker/build-push-action@c56af957549030174b10d6867f20e78cfd7debc5
         with:
           build-args: |
             BASE_IMAGE=${{ fromJson(steps.jupyterhubtags.outputs.tags)[0] }}
@@ -187,7 +191,7 @@ jobs:
           branchRegex: ^\w[\w-.]*$
 
       - name: Build and push jupyterhub-demo
-        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
+        uses: docker/build-push-action@c56af957549030174b10d6867f20e78cfd7debc5
         with:
           build-args: |
             BASE_IMAGE=${{ fromJson(steps.onbuildtags.outputs.tags)[0] }}
@@ -211,7 +215,7 @@ jobs:
           branchRegex: ^\w[\w-.]*$
 
       - name: Build and push jupyterhub/singleuser
-        uses: docker/build-push-action@c84f38281176d4c9cdb1626ffafcd6b3911b5d94
+        uses: docker/build-push-action@c56af957549030174b10d6867f20e78cfd7debc5
         with:
           build-args: |
             JUPYTERHUB_VERSION=${{ github.ref_type == 'tag' && github.ref_name || format('git:{0}', github.sha) }}

.github/workflows/test-docs.yml

@@ -41,7 +41,7 @@ jobs:
       - uses: actions/checkout@v3
 
       - name: Validate REST API definition
-        uses: char0n/swagger-editor-validate@v1.3.1
+        uses: char0n/swagger-editor-validate@v1.3.2
         with:
           definition-file: docs/source/_static/rest-api.yml
 

.github/workflows/test.yml

@@ -87,6 +87,8 @@ jobs:
             subdomain: subdomain
           - python: "3.10"
             ssl: ssl
+          - python: "3.10"
+            selenium: selenium
           - python: "3.11.0-rc.1"
           - python: "3.10"
             main_dependencies: main_dependencies
@@ -214,13 +216,25 @@ jobs:
               DB=postgres bash ci/docker-db.sh
               DB=postgres bash ci/init-db.sh
           fi
+      - name: Setup Firefox
+        if: matrix.selenium
+        uses: browser-actions/setup-firefox@latest
+        with:
+          firefox-version: latest
+
+      - name: Setup Geckodriver
+        if: matrix.selenium
+        uses: browser-actions/setup-geckodriver@latest
+
+      - name: Configure selenium tests
+        if: matrix.selenium
+        run: echo "PYTEST_ADDOPTS=$PYTEST_ADDOPTS -m selenium" >> "${GITHUB_ENV}"
 
       - name: Run pytest
         run: |
           pytest --maxfail=2 --cov=jupyterhub jupyterhub/tests
-      - name: Submit codecov report
-        run: |
-          codecov
+
+      - uses: codecov/codecov-action@v3
 
   docker-build:
     runs-on: ubuntu-20.04

.pre-commit-config.yaml

@@ -11,7 +11,7 @@
 repos:
   # Autoformat: Python code, syntax patterns are modernized
   - repo: https://github.com/asottile/pyupgrade
-    rev: v2.37.3
+    rev: v3.2.0
     hooks:
       - id: pyupgrade
         args:
@@ -25,13 +25,13 @@ repos:
 
   # Autoformat: Python code
   - repo: https://github.com/psf/black
-    rev: 22.6.0
+    rev: 22.10.0
     hooks:
       - id: black
 
   # Autoformat: markdown, yaml, javascript (see the file .prettierignore)
   - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v2.7.1
+    rev: v3.0.0-alpha.4
     hooks:
       - id: prettier
 

dev-requirements.txt

@@ -3,7 +3,6 @@
 # seems to be a pip bug
 attrs>=17.4.0
 beautifulsoup4
-codecov
 coverage
 cryptography
 html5lib  # needed for beautifulsoup
@@ -18,6 +17,7 @@ pytest>=3.3
 pytest-asyncio>=0.17
 pytest-cov
 requests-mock
+selenium
 tbump
 # blacklist urllib3 releases affected by https://github.com/urllib3/urllib3/issues/1683
 # I *think* this should only affect testing, not production

docs/source/admin/log-messages.md

@@ -1,33 +1,33 @@
 # 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.
+JupyterHub is very helpful. This document intends to describe some common
+log messages, what they mean and what are the most common causes that generated them, as well as some possible ways to fix them.
 
 ## Failing suspected API request to not-running server
 
 ### Example
 
-Your logs might be littered with lines that might look slightly scary
+Your logs might be littered with lines that look 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
+### Cause
+
+This likely means 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 you shut
+the server down via one.
+Another possible reason could be that you closed your laptop and the server was culled for inactivity, then reopened the laptop!
+However, the client-side code (JupyterLab, Classic Notebook, etc) doesn't interpret the shut-down server and continues to make some API requests.
 
-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.
+inform the user that the server is not running anymore, and provide an option
+to 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).
@@ -47,9 +47,9 @@ This log message is benign, and there is usually no action for you to take.
 ### 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
+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
+the same as the JupyterHub server's version 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
@@ -67,6 +67,6 @@ 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
+so that 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

@@ -5,35 +5,36 @@ Upgrading JupyterHub
 JupyterHub offers easy upgrade pathways between minor versions. This
 document describes how to do these upgrades.
 
-If you are using :ref:`a JupyterHub distribution <index/distributions>`, you
+If you use :ref:`a JupyterHub distribution <index/distributions>`, you
 should consult the distribution's documentation on how to upgrade. This
-document is if you have set up your own JupyterHub without using a
+document is applicable if you have set up your own JupyterHub without using a
 distribution.
 
-It is long because is pretty detailed! Most likely, upgrading
+This documentation is lengthy because it is quite detailed. Most likely, upgrading
 JupyterHub is painless, quick and with minimal user interruption.
 
+The steps are discussed in detail, so if you get stuck at any step you can always refer to this guide. 
+
 Read the Changelog
 ==================
 
-The `changelog <../changelog.html>`_ contains information on what has
-changed with the new JupyterHub release, and any deprecation warnings.
+The `changelog <../changelog.md>`_ contains information on what has
+changed with the new JupyterHub release and any deprecation warnings.
 Read these notes to familiarize yourself with the coming changes. There
-might be new releases of authenticators & spawners you are using, so
+might be new releases of the authenticators & spawners you use, so
 read the changelogs for those too!
 
 Notify your users
 =================
 
-If you are using the default configuration where ``configurable-http-proxy``
+If you use the default configuration where ``configurable-http-proxy``
 is managed by JupyterHub, your users will see service disruption during
 the upgrade process. You should notify them, and pick a time to do the
 upgrade where they will be least disrupted.
 
-If you are using a different proxy, or running ``configurable-http-proxy``
+If you use a different proxy or run ``configurable-http-proxy``
 independent of JupyterHub, your users will be able to continue using notebook
-servers they had already launched, but will not be able to launch new servers
-nor sign in.
+servers they had already launched, but will not be able to launch new servers or sign in.
 
 
 Backup database & config
@@ -41,37 +42,35 @@ Backup database & config
 
 Before doing an upgrade, it is critical to back up:
 
-#. Your JupyterHub database (sqlite by default, or MySQL / Postgres
-   if you used those). If you are using sqlite (the default), you
-   should backup the ``jupyterhub.sqlite`` file.
+#. Your JupyterHub database (SQLite by default, or MySQL / Postgres if you used those). 
+If you use SQLite (the default), you should backup the ``jupyterhub.sqlite`` file.
 #. Your ``jupyterhub_config.py`` file.
-#. Your user's home directories. This is unlikely to be affected directly by
-   a JupyterHub upgrade, but we recommend a backup since user data is very
-   critical.
+#. Your users' home directories. This is unlikely to be affected directly by
+   a JupyterHub upgrade, but we recommend a backup since user data is critical.
 
 
-Shutdown JupyterHub
-===================
+Shut down JupyterHub
+====================
 
-Shutdown the JupyterHub process. This would vary depending on how you
-have set up JupyterHub to run. Most likely, it is using a process
+Shut down the JupyterHub process. This would vary depending on how you
+have set up JupyterHub to run. It is most likely using a process
 supervisor of some sort (``systemd`` or ``supervisord`` or even ``docker``).
-Use the supervisor specific command to stop the JupyterHub process.
+Use the supervisor-specific command to stop the JupyterHub process.
 
 Upgrade JupyterHub packages
 ===========================
 
 There are two environments where the ``jupyterhub`` package is installed:
 
-#. The *hub environment*, which is where the JupyterHub server process
+#. The *hub environment*: where the JupyterHub server process
    runs. This is started with the ``jupyterhub`` command, and is what
    people generally think of as JupyterHub.
 
-#. The *notebook user environments*. This is where the user notebook
+#. The *notebook user environments*: where the user notebook
    servers are launched from, and is probably custom to your own
    installation. This could be just one environment (different from the
    hub environment) that is shared by all users, one environment
-   per user, or same environment as the hub environment. The hub
+   per user, or the same environment as the hub environment. The hub
    launched the ``jupyterhub-singleuser`` command in this environment,
    which in turn starts the notebook server.
 
@@ -92,10 +91,8 @@ with:
 
    conda install -c conda-forge jupyterhub==<version>
 
-Where ``<version>`` is the version of JupyterHub you are upgrading to.
-
 You should also check for new releases of the authenticator & spawner you
-are using. You might wish to upgrade those packages too along with JupyterHub,
+are using. You might wish to upgrade those packages, too, along with JupyterHub
 or upgrade them separately.
 
 Upgrade JupyterHub database
@@ -109,7 +106,7 @@ database. From the hub environment, in the same directory as your
 
    jupyterhub upgrade-db
 
-This should find the location of your database, and run necessary upgrades
+This should find the location of your database, and run the necessary upgrades
 for it.
 
 SQLite database disadvantages
@@ -118,11 +115,11 @@ SQLite database disadvantages
 SQLite has some disadvantages when it comes to upgrading JupyterHub. These
 are:
 
--  ``upgrade-db`` may not work, and you may need delete your database
+-  ``upgrade-db`` may not work, and you may need to delete your database
    and start with a fresh one.
 -  ``downgrade-db`` **will not** work if you want to rollback to an
    earlier version, so backup the ``jupyterhub.sqlite`` file before
-   upgrading
+   upgrading.
 
 What happens if I delete my database?
 -------------------------------------
@@ -137,10 +134,10 @@ resides only in the Hub database includes:
 If the following conditions are true, you should be fine clearing the
 Hub database and starting over:
 
--  users specified in config file, or login using an external
+-  users specified in the config file, or login using an external
    authentication provider (Google, GitHub, LDAP, etc)
--  user servers are stopped during upgrade
--  don't mind causing users to login again after upgrade
+-  user servers are stopped during the upgrade
+-  don't mind causing users to log in again after the upgrade
 
 Start JupyterHub
 ================
@@ -148,7 +145,7 @@ Start JupyterHub
 Once the database upgrade is completed, start the ``jupyterhub``
 process again.
 
-#. Log-in and start the server to make sure things work as
+#. Log in and start the server to make sure things work as
    expected.
 #. Check the logs for any errors or deprecation warnings. You
    might have to update your ``jupyterhub_config.py`` file to

docs/source/contributing/community.md

@@ -0,0 +1,27 @@
+# Community communication channels
+
+We use different channels of communication for different purposes. Whichever one you use will depend on what kind of communication you want to engage in.
+
+## Discourse (recommended)
+
+We use [Discourse](https://discourse.jupyter.org) for online discussions and support questions.
+You can ask questions here if you are a first-time contributor to the JupyterHub project.
+Everyone in the Jupyter community is welcome to bring ideas and questions there.
+
+We recommend that you first use our Discourse as all past and current discussions on it are archived and searchable. Thus, all discussions remain useful and accessible to the whole community.
+
+## Gitter
+
+We use [our Gitter channel](https://gitter.im/jupyterhub/jupyterhub) for online, real-time text chat; a place for more ephemeral discussions. When you're not on Discourse, you can stop here to have other discussions on the fly.
+
+## Github Issues
+
+[Github issues](https://docs.github.com/en/issues/tracking-your-work-with-issues/about-issues) are used for most long-form project discussions, bug reports and feature requests.
+
+- Issues related to a specific authenticator or spawner should be opened in the appropriate repository for the authenticator or spawner.
+- If you are using a specific JupyterHub distribution (such as [Zero to JupyterHub on Kubernetes](http://github.com/jupyterhub/zero-to-jupyterhub-k8s) or [The Littlest JupyterHub](http://github.com/jupyterhub/the-littlest-jupyterhub/)), you should open issues directly in their repository.
+- If you cannot find a repository to open your issue in, do not worry! Open the issue in the [main JupyterHub repository](https://github.com/jupyterhub/jupyterhub/) and our community will help you figure it out.
+
+```{note}
+Our community is distributed across the world in various timezones, so please be patient if you do not get a response immediately!
+```

docs/source/contributing/community.rst

@@ -1,30 +0,0 @@
-.. _contributing/community:
-
-================================
-Community communication channels
-================================
-
-We use `Discourse <https://discourse.jupyter.org>` for online discussion.
-Everyone in the Jupyter community is welcome to bring ideas and questions there.
-In addition, we use `Gitter <https://gitter.im>`_ for online, real-time text chat,
-a place for more ephemeral discussions.
-The primary Gitter channel for JupyterHub is `jupyterhub/jupyterhub <https://gitter.im/jupyterhub/jupyterhub>`_.
-Gitter isn't archived or searchable, so we recommend going to discourse first
-to make sure that discussions are most useful and accessible to the community.
-Remember that our community is distributed across the world in various
-timezones, so be patient if you do not get an answer immediately!
-
-GitHub issues are used for most long-form project discussions, bug reports
-and feature requests. Issues related to a specific authenticator or
-spawner should be directed to the appropriate repository for the
-authenticator or spawner. If you are using a specific JupyterHub
-distribution (such as `Zero to JupyterHub on Kubernetes <http://github.com/jupyterhub/zero-to-jupyterhub-k8s>`_
-or `The Littlest JupyterHub <http://github.com/jupyterhub/the-littlest-jupyterhub/>`_),
-you should open issues directly in their repository. If you can not
-find a repository to open your issue in, do not worry! Create it in the `main
-JupyterHub repository <https://github.com/jupyterhub/jupyterhub/>`_ and our
-community will help you figure it out.
-
-A `mailing list <https://groups.google.com/forum/#!forum/jupyter>`_ for all
-of Project Jupyter exists, along with one for `teaching with Jupyter
-<https://groups.google.com/forum/#!forum/jupyter-education>`_. 

docs/source/contributing/docs.rst

@@ -18,7 +18,7 @@ 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.
 
-#. Make sure you have successfuly completed :ref:`contributing/setup`.
+#. Make sure you have successfully completed :ref:`contributing/setup`.
 
 #. Install the packages required to build the docs.
 
@@ -44,7 +44,8 @@ change renders correctly, it is good practice to test it locally.
 
    .. tip::
 
-      On macOS, you can open a file from the terminal with ``open <path-to-file>``.
+      On Windows, you can open a file from the terminal with ``start <path-to-file>``.
+      On macOS, you can do the same with ``open <path-to-file>``.
       On Linux, you can do the same with ``xdg-open <path-to-file>``.
 
 

docs/source/contributing/roadmap.md

@@ -4,7 +4,7 @@ This roadmap collects "next steps" for JupyterHub. It is about creating a
 shared understanding of the project's vision and direction amongst
 the community of users, contributors, and maintainers.
 The goal is to communicate priorities and upcoming release plans.
-It is not a aimed at limiting contributions to what is listed here.
+It is not aimed at limiting contributions to what is listed here.
 
 ## Using the roadmap
 

docs/source/contributing/setup.rst

@@ -7,7 +7,7 @@ Setting up a development install
 System requirements
 ===================
 
-JupyterHub can only run on MacOS or Linux operating systems. If you are
+JupyterHub can only run on macOS or Linux operating systems. If you are
 using Windows, we recommend using `VirtualBox <https://virtualbox.org>`_
 or a similar system to run `Ubuntu Linux <https://ubuntu.com>`_ for
 development.
@@ -15,10 +15,10 @@ development.
 Install Python
 --------------
 
-JupyterHub is written in the `Python <https://python.org>`_ programming language, and
+JupyterHub is written in the `Python <https://python.org>`_ programming language and
 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,
+`Miniconda <https://conda.io/miniconda.html>`_. Remember to get the ‘Python 3’ version,
 and **not** the ‘Python 2’ version!
 
 Install nodejs
@@ -26,13 +26,13 @@ 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.
+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
 -----------
 
-JupyterHub uses `git <https://git-scm.com>`_ & `GitHub <https://github.com>`_
+JupyterHub uses `Git <https://git-scm.com>`_ & `GitHub <https://github.com>`_
 for development & collaboration. You need to `install git
 <https://git-scm.com/book/en/v2/Getting-Started-Installing-Git>`_ to work on
 JupyterHub. We also recommend getting a free account on GitHub.com.
@@ -40,13 +40,11 @@ JupyterHub. We also recommend getting a free account on GitHub.com.
 Setting up a development install
 ================================
 
-When developing JupyterHub, you need to make changes to the code & see
-their effects quickly. You need to do a developer install to make that
-happen.
+When developing JupyterHub, you would need to make changes and be able to instantly view the results of the changes. To achieve that, a developer install is required.
 
 .. note:: This guide does not attempt to dictate *how* development
    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
+   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.
 
@@ -103,11 +101,11 @@ happen.
       python3 -m pip install -r dev-requirements.txt
       python3 -m pip install -r requirements.txt
 
-5. Setup a database.
+5. Set up a database.
 
    The default database engine is ``sqlite`` so if you are just trying
    to get up and running quickly for local development that should be
-   available via `python <https://docs.python.org/3.5/library/sqlite3.html>`__.
+   available via `Python <https://docs.python.org/3.5/library/sqlite3.html>`__.
    See :doc:`/reference/database` for details on other supported databases.
 
 6. Install the development version of JupyterHub. This lets you edit
@@ -137,7 +135,7 @@ To simplify testing of JupyterHub, it’s helpful to use
 authenticator and SimpleLocalProcessSpawner instead of the default spawner.
 
 There is a sample configuration file that does this in
-``testing/jupyterhub_config.py``. To launch jupyterhub with this
+``testing/jupyterhub_config.py``. To launch JupyterHub with this
 configuration:
 
 .. code:: bash
@@ -153,14 +151,14 @@ JupyterHub as.
 
 DummyAuthenticator allows you to log in with any username & password,
 while SimpleLocalProcessSpawner allows you to start servers without having to
-create a unix user for each JupyterHub user. Together, these make it
+create a Unix user for each JupyterHub user. Together, these make it
 much easier to test JupyterHub.
 
 Tip: If you are working on parts of JupyterHub that are common to all
 authenticators & spawners, we recommend using both DummyAuthenticator &
-SimpleLocalProcessSpawner. If you are working on just authenticator related
+SimpleLocalProcessSpawner. If you are working on just authenticator-related
 parts, use only SimpleLocalProcessSpawner. Similarly, if you are working on
-just spawner related parts, use only DummyAuthenticator.
+just spawner-related parts, use only DummyAuthenticator.
 
 Troubleshooting
 ===============

docs/source/contributing/tests.rst

@@ -4,19 +4,16 @@
 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
-precisely what we expect our code to do. 
+Unit tests help confirm that JupyterHub works as intended, including after modifications are made. Additionally, they help in clarifying our expectations for our code.
 
-JupyterHub uses `pytest <https://pytest.org>`_ for all our tests. You
-can find them under ``jupyterhub/tests`` directory in the git repository.
+JupyterHub uses `pytest <https://pytest.org>`_ for all the tests. You
+can find them under the `jupyterhub/tests <https://github.com/jupyterhub/jupyterhub/tree/main/jupyterhub/tests>`_ directory in the git repository.
 
 Running the tests
 ==================
 
-#. Make sure you have completed :ref:`contributing/setup`. You should be able
-   to start ``jupyterhub`` from the commandline & access it from your
-   web browser. This ensures that the dev environment is properly set
+#. Make sure you have completed :ref:`contributing/setup`. Once completed, you should be able
+   to run ``jupyterhub`` on your command line and access JupyterHub from your browser at http://localhost:8000. Being able to run and access `jupyterhub` should mean that the dev environment is properly set
    up for tests to run.
 
 #. You can run all tests in JupyterHub 
@@ -57,7 +54,7 @@ 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.
+   For more information, refer to the `pytest usage documentation <https://pytest.readthedocs.io/en/latest/usage.html>`_.
 
 Test organisation
 =================
@@ -98,8 +95,7 @@ And fixtures to add functionality or spawning behavior:
 - ``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.
+For information on using the existing fixtures and creating new ones, refer to the `pytest fixtures documentation <https://pytest.readthedocs.io/en/latest/fixture.html>`_
 
 
 Troubleshooting Test Failures
@@ -108,8 +104,7 @@ Troubleshooting Test Failures
 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.
+Make sure you have completed all the steps in :ref:`contributing/setup` successfully, and are able to access JupyterHub from your browser at http://localhost:8000 after starting ``jupyterhub`` in your command line.
 
 
 Code formatting and linting
@@ -117,13 +112,13 @@ 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:
+You can invoke the pre-commit hook manually 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.
+This should run any auto formatting 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.
 

docs/source/contributor-list.md

@@ -120,3 +120,4 @@ contribution on JupyterHub:
 - yuvipanda
 - zoltan-fedor
 - zonca
+- Neeraj Natu

docs/source/events/index.rst

@@ -1,5 +1,5 @@
-Eventlogging and Telemetry
-==========================
+Event logging and telemetry
+===========================
 
 JupyterHub can be configured to record structured events from a running server using Jupyter's `Telemetry System`_. The types of events that JupyterHub emits are defined by `JSON schemas`_ listed at the bottom of this page_.
 
@@ -15,7 +15,7 @@ Event logging is handled by its ``Eventlog`` object. This leverages Python's sta
 
 To begin recording events, you'll need to set two configurations:
 
-    1. ``handlers``: tells the EventLog *where* to route your events. This trait is a list of Python logging handlers that route events to 
+    1. ``handlers``: tells the EventLog *where* to route your events. This trait is a list of Python logging handlers that route events to the event log file.  
     2. ``allows_schemas``: tells the EventLog *which* events should be recorded. No events are emitted by default; all recorded events must be listed here.
 
 Here's a basic example:

docs/source/gallery-jhub-deployments.md

@@ -97,7 +97,7 @@ easy to do with RStudio too.
 
 ### University of Illinois
 
-- https://datascience.business.illinois.edu (currently down; checked 04/26/19)
+- https://datascience.business.illinois.edu (currently down; checked 10/26/22)
 
 ### IllustrisTNG Simulation Project
 
@@ -126,7 +126,7 @@ easy to do with RStudio too.
 
 ### Penn State University
 
-- [Press release](https://news.psu.edu/story/523093/2018/05/24/new-open-source-web-apps-available-students-and-faculty): "New open-source web apps available for students and faculty" (but Hub is currently down; checked 04/26/19)
+- [Press release](https://news.psu.edu/story/523093/2018/05/24/new-open-source-web-apps-available-students-and-faculty): "New open-source web apps available for students and faculty"
 
 ### University of Rochester CIRC
 
@@ -156,13 +156,13 @@ easy to do with RStudio too.
 ### Elucidata
 
 - What's new in Jupyter Notebooks @[Elucidata](https://elucidata.io/):
-  - Using Jupyter Notebooks with Jupyterhub on GCP, managed by GKE - https://medium.com/elucidata/why-you-should-be-using-a-jupyter-notebook-8385a4ccd93d
+  - [Using Jupyter Notebooks with Jupyterhub on GCP, managed by GKE](https://medium.com/elucidata/why-you-should-be-using-a-jupyter-notebook-8385a4ccd93d)
 
 ## Service Providers
 
 ### AWS
 
-- [running-jupyter-notebook-and-jupyterhub-on-amazon-emr](https://aws.amazon.com/blogs/big-data/running-jupyter-notebook-and-jupyterhub-on-amazon-emr/)
+- [Run Jupyter Notebook and JupyterHub on Amazon EMR](https://aws.amazon.com/blogs/big-data/running-jupyter-notebook-and-jupyterhub-on-amazon-emr/)
 
 ### Google Cloud Platform
 
@@ -175,12 +175,12 @@ easy to do with RStudio too.
 
 ### Microsoft Azure
 
-- https://docs.microsoft.com/en-us/azure/machine-learning/machine-learning-data-science-linux-dsvm-intro
+- [Azure Data Science Virtual Machine release notes](https://docs.microsoft.com/en-us/azure/machine-learning/machine-learning-data-science-linux-dsvm-intro)
 
 ### Rackspace Carina
 
 - https://getcarina.com/blog/learning-how-to-whale/
-- http://carolynvanslyck.com/talk/carina/jupyterhub/#/
+- http://carolynvanslyck.com/talk/carina/jupyterhub/#/ (but carolynvanslyck is currently down; checked 10/26/22)
 
 ### Hadoop
 
@@ -189,13 +189,14 @@ easy to do with RStudio too.
 ## Miscellaneous
 
 - https://medium.com/@ybarraud/setting-up-jupyterhub-with-sudospawner-and-anaconda-844628c0dbee#.rm3yt87e1
-- https://groups.google.com/forum/#!topic/jupyter/nkPSEeMr8c0 Mailing list UT deployment
-- JupyterHub setup on Centos https://gist.github.com/johnrc/604971f7d41ebf12370bf5729bf3e0a4
-- Deploy JupyterHub to Docker Swarm https://jupyterhub.surge.sh/#/welcome
+- [Mailing list UT deployment](https://groups.google.com/forum/#!topic/jupyter/nkPSEeMr8c0)
+- [JupyterHub setup on Centos](https://gist.github.com/johnrc/604971f7d41ebf12370bf5729bf3e0a4)
+- [Deploy JupyterHub to Docker Swarm](https://jupyterhub.surge.sh/#/welcome)
 - http://www.laketide.com/building-your-lab-part-3/
 - http://estrellita.hatenablog.com/entry/2015/07/31/083202
 - http://www.walkingrandomly.com/?p=5734
 - https://wrdrd.com/docs/consulting/education-technology
 - https://bitbucket.org/jackhale/fenics-jupyter
 - [LinuxCluster blog](https://linuxcluster.wordpress.com/category/application/jupyterhub/)
-- [Network Technology](https://arnesund.com/tag/jupyterhub/) [Spark Cluster on OpenStack with Multi-User Jupyter Notebook](https://arnesund.com/2015/09/21/spark-cluster-on-openstack-with-multi-user-jupyter-notebook/)
+- [Network Technology](https://arnesund.com/tag/jupyterhub/)
+- [Spark Cluster on OpenStack with Multi-User Jupyter Notebook](https://arnesund.com/2015/09/21/spark-cluster-on-openstack-with-multi-user-jupyter-notebook/)

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

@@ -1,10 +1,10 @@
 # Authentication and User Basics
 
-The default Authenticator uses [PAM][] to authenticate system users with
+The default Authenticator uses [PAM][] (Pluggable Authentication Module) to authenticate system users with
 their username and password. With the default Authenticator, any user
 with an account and password on the system will be allowed to login.
 
-## Create a set of allowed users
+## Create a set of allowed users (`allowed_users`)
 
 You can restrict which users are allowed to login with a set,
 `Authenticator.allowed_users`:
@@ -25,7 +25,7 @@ If this configuration value is not set, then **all authenticated users will be a
 ```{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
+Instead, you can assign [roles](define-role-target) to users or groups
 with only the scopes they require.
 ```
 
@@ -42,10 +42,10 @@ c.Authenticator.admin_users = {'mal', 'zoe'}
 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 uses the PAMAuthenticator which provides the
+Each Authenticator may have different ways of determining whether a user is an
+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:
+group. For example, we can let any user in the `wheel` group be an admin:
 
 ```python
 c.PAMAuthenticator.admin_groups = {'wheel'}
@@ -57,12 +57,12 @@ 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`,
 then admins have permission to log in _as other users_ on their
-respective machines, for debugging. **As a courtesy, you should make
+respective machines for debugging. **As a courtesy, you should make
 sure your users know if admin_access is enabled.**
 
 ## Add or remove users from the Hub
 
-Users can be added to and removed from the Hub via either the admin
+Users can be added to and removed from the Hub via 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,
@@ -76,12 +76,12 @@ fresh.
 
 ## Use LocalAuthenticator to create system users
 
-The `LocalAuthenticator` is a special kind of authenticator that has
+The `LocalAuthenticator` is a special kind of Authenticator that has
 the ability to manage users on the local system. When you try to add a
 new user to the Hub, a `LocalAuthenticator` will check if the user
 already exists. If you set the configuration value, `create_system_users`,
 to `True` in the configuration file, the `LocalAuthenticator` has
-the privileges to add users to the system. The setting in the config
+the ability to add users to the system. The setting in the config
 file is:
 
 ```python
@@ -91,7 +91,7 @@ c.LocalAuthenticator.create_system_users = True
 Adding a user to the Hub that doesn't already exist on the system will
 result in the Hub creating that user via the system `adduser` command
 line tool. This option is typically used on hosted deployments of
-JupyterHub, to avoid the need to manually create all your users before
+JupyterHub to avoid the need to manually create all your users before
 launching the service. This approach is not recommended when running
 JupyterHub in situations where JupyterHub users map directly onto the
 system's UNIX users.
@@ -101,25 +101,25 @@ system's UNIX users.
 JupyterHub's [OAuthenticator][] currently supports the following
 popular services:
 
-- Auth0
-- Azure AD
-- Bitbucket
-- CILogon
-- GitHub
-- GitLab
-- Globus
-- Google
-- MediaWiki
-- Okpy
-- OpenShift
+- [Auth0](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.auth0.html#module-oauthenticator.auth0)
+- [Azure AD](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.azuread.html#module-oauthenticator.azuread)
+- [Bitbucket](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.bitbucket.html#module-oauthenticator.bitbucket)
+- [CILogon](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.cilogon.html#module-oauthenticator.cilogon)
+- [GitHub](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.github.html#module-oauthenticator.github)
+- [GitLab](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.gitlab.html#module-oauthenticator.gitlab)
+- [Globus](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.globus.html#module-oauthenticator.globus)
+- [Google](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.google.html#module-oauthenticator.google)
+- [MediaWiki](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.mediawiki.html#module-oauthenticator.mediawiki)
+- [Okpy](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.okpy.html#module-oauthenticator.okpy)
+- [OpenShift](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.openshift.html#module-oauthenticator.openshift)
 
-A generic implementation, which you can use for OAuth authentication
+A [generic implementation](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.generic.html#module-oauthenticator.generic), which you can use for OAuth authentication
 with any provider, is also available.
 
 ## Use DummyAuthenticator for testing
 
-The `DummyAuthenticator` is a simple authenticator that
-allows for any username/password unless a global password has been set. If
+The `DummyAuthenticator` is a simple Authenticator that
+allows for any username or 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

@@ -1,6 +1,6 @@
 # Configuration Basics
 
-The section contains basic information about configuring settings for a JupyterHub
+This section contains basic information about configuring settings for a JupyterHub
 deployment. The [Technical Reference](../reference/index)
 documentation provides additional details.
 
@@ -49,7 +49,7 @@ that Jupyter uses.
 
 ## Configure using command line options
 
-To display all command line options that are available for configuration:
+To display all command line options that are available for configuration run the following command:
 
 ```bash
     jupyterhub --help-all
@@ -81,7 +81,7 @@ specific [authenticators](./authenticators-users-basics) and
 [spawners](./spawners-basics) can be set in the configuration file.
 This enables JupyterHub to be used with a variety of authentication methods or
 process control and deployment environments. [Some examples](../reference/config-examples),
-meant as illustration, are:
+meant as illustrations, are:
 
 - Using GitHub OAuth instead of PAM with [OAuthenticator](https://github.com/jupyterhub/oauthenticator)
 - Spawning single-user servers with Docker, using the [DockerSpawner](https://github.com/jupyterhub/dockerspawner)

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

@@ -78,7 +78,7 @@ gives administrators more control over their setup and hardware.
 
 Because JupyterHub is an open-source, community-driven tool, it can be extended and
 modified to fit an institution's needs. It plays nicely with the open source data science
-stack, and can serve a variety of computing enviroments, user interfaces, and
+stack, and can serve a variety of computing environments, user interfaces, and
 computational hardware. It can also be deployed anywhere - on enterprise cloud infrastructure, on
 High-Performance-Computing machines, on local hardware, or even on a single laptop, which
 is not possible with most other tools for shared interactive computing.

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

@@ -5,8 +5,8 @@ Security settings
 
    You should not run JupyterHub without SSL encryption on a public network.
 
-Security is the most important aspect of configuring Jupyter. Three
-configuration settings are the main aspects of security configuration:
+Security is the most important aspect of configuring Jupyter.
+Three (3) configuration settings are the main aspects of security configuration:
 
 1. :ref:`SSL encryption <ssl-encryption>` (to enable HTTPS)
 2. :ref:`Cookie secret <cookie-secret>` (a key for encrypting browser cookies)
@@ -15,7 +15,7 @@ configuration settings are the main aspects of security configuration:
 
 The Hub hashes all secrets (e.g., auth tokens) before storing them in its
 database. A loss of control over read-access to the database should have
-minimal impact on your deployment; if your database has been compromised, it
+minimal impact on your deployment. If your database has been compromised, it
 is still a good idea to revoke existing tokens.
 
 .. _ssl-encryption:
@@ -31,7 +31,7 @@ Using an SSL certificate
 
 This will require you to obtain an official, trusted SSL certificate or create a
 self-signed certificate. Once you have obtained and installed a key and
-certificate you need to specify their locations in the ``jupyterhub_config.py``
+certificate, you need to specify their locations in the ``jupyterhub_config.py``
 configuration file as follows:
 
 .. code-block:: python
@@ -72,13 +72,13 @@ would be the needed configuration:
 If SSL termination happens outside of the Hub
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-In certain cases, for example if the hub is running behind a reverse proxy, and
+In certain cases, for example, if the hub is running behind a reverse proxy, and
 `SSL termination is being provided by NGINX <https://www.nginx.com/resources/admin-guide/nginx-ssl-termination/>`_,
 it is reasonable to run the hub without SSL.
 
 To achieve this, simply omit the configuration settings
 ``c.JupyterHub.ssl_key`` and ``c.JupyterHub.ssl_cert``
-(setting them to ``None`` does not have the same effect, and is an error).
+(setting them to ``None`` does not have the same effect, but results in an error).
 
 .. _authentication-token:
 
@@ -92,7 +92,7 @@ use an auth token.
 
 The value of this token should be a random string (for example, generated by
 ``openssl rand -hex 32``). You can store it in the configuration file or an
-environment variable
+environment variable.
 
 Generating and storing token in the configuration file
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -119,7 +119,7 @@ Default if token is not set
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 If you don't set the Proxy authentication token, the Hub will generate a random
-key itself, which means that any time you restart the Hub you **must also
+key itself. This means that any time you restart the Hub, you **must also
 restart the Proxy**. If the proxy is a subprocess of the Hub, this should happen
 automatically (this is the default configuration).
 
@@ -128,7 +128,7 @@ automatically (this is the default configuration).
 Cookie secret
 -------------
 
-The cookie secret is an encryption key, used to encrypt the browser cookies
+The cookie secret is an encryption key, used to encrypt the browser cookies,
 which are used for authentication. Three common methods are described for
 generating and configuring the cookie secret.
 
@@ -136,8 +136,8 @@ Generating and storing as a cookie secret file
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The cookie secret should be 32 random bytes, encoded as hex, and is typically
-stored in a ``jupyterhub_cookie_secret`` file. An example command to generate the
-``jupyterhub_cookie_secret`` file is:
+stored in a ``jupyterhub_cookie_secret`` file. Below, is an example command to generate the
+``jupyterhub_cookie_secret`` file:
 
 .. code-block:: bash
 
@@ -155,7 +155,7 @@ The location of the ``jupyterhub_cookie_secret`` file can be specified in the
 
 If the cookie secret file doesn't exist when the Hub starts, a new cookie
 secret is generated and stored in the file. The file must not be readable by
-``group`` or ``other`` or the server won't start. The recommended permissions
+``group`` or ``other``, otherwise the server won't start. The recommended permissions
 for the cookie secret file are ``600`` (owner-only rw).
 
 Generating and storing as an environment variable
@@ -176,8 +176,8 @@ the Hub starts.
 Generating and storing as a binary string
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-You can also set the cookie secret in the configuration file
-itself, ``jupyterhub_config.py``, as a binary string:
+You can also set the cookie secret, as a binary string,
+in the configuration file (``jupyterhub_config.py``) itself:
 
 .. code-block:: python
 
@@ -198,7 +198,7 @@ jupyterhub-hub-login
 ~~~~~~~~~~~~~~~~~~~~
 
 This is the login token used when visiting Hub-served pages that are
-protected by authentication such as the main home, the spawn form, etc.
+protected by authentication, such as the main home, the spawn form, etc.
 If this cookie is set, then the user is logged in.
 
 Resetting the Hub cookie secret effectively revokes this cookie.
@@ -209,7 +209,7 @@ jupyterhub-user-<username>
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 This is the cookie used for authenticating with a single-user server.
-It is set by the single-user server after OAuth with the Hub.
+It is set by the single-user server, after OAuth with the Hub.
 
 Effectively the same as ``jupyterhub-hub-login``, but for the
 single-user server instead of the Hub. It contains an OAuth access token,
@@ -218,14 +218,13 @@ which is checked with the Hub to authenticate the browser.
 Each OAuth access token is associated with a session id (see ``jupyterhub-session-id`` section
 below).
 
-To avoid hitting the Hub on every request, the authentication response
-is cached. And to avoid a stale cache the cache key is comprised of both
-the token and session id.
+To avoid hitting the Hub on every request, the authentication response is cached.
+The cache key is comprised of both the token and session id, to avoid a stale cache.
 
 Resetting the Hub cookie secret effectively revokes this cookie.
 
-This cookie is restricted to the path ``/user/<username>``, so that
-only the user’s server receives it.
+This cookie is restricted to the path ``/user/<username>``,
+to ensure that only the user’s server receives it.
 
 jupyterhub-session-id
 ~~~~~~~~~~~~~~~~~~~~~
@@ -235,7 +234,7 @@ shared by the Hub and single-user servers.
 
 Its sole purpose is to coordinate logout of the multiple OAuth cookies.
 
-This cookie is set to ``/`` so all endpoints can receive it, or clear it, etc.
+This cookie is set to ``/`` so all endpoints can receive it, clear it, etc.
 
 jupyterhub-user-<username>-oauth-state
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -245,7 +244,7 @@ It is only set while OAuth between the single-user server and the Hub
 is processing.
 
 If you use your browser development tools, you should see this cookie
-for a very brief moment before your are logged in,
+for a very brief moment before you are logged in,
 with an expiration date shorter than ``jupyterhub-hub-login`` or
 ``jupyterhub-user-<username>``.
 

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

@@ -24,7 +24,7 @@ Hub via the REST API.
 
 ## API Token basics
 
-### Create an API token
+### Step 1: Generate an API token
 
 To run such an external service, an API token must be created and
 provided to the service.
@@ -43,12 +43,12 @@ generating an API token is available from the JupyterHub user interface:
 
 ![API TOKEN success page](../images/token-request-success.png)
 
-### Pass environment variable with token to the Hub
+### Step 2: Pass environment variable with token to the Hub
 
 In the case of `cull_idle_servers`, it is passed as the environment
 variable called `JUPYTERHUB_API_TOKEN`.
 
-### Use API tokens for services and tasks that require external access
+### Step 3: Use API tokens for services and tasks that require external access
 
 While API tokens are often associated with a specific user, API tokens
 can be used by services that require external access for activities
@@ -62,7 +62,7 @@ c.JupyterHub.services = [
 ]
 ```
 
-### Restart JupyterHub
+### Step 4: Restart JupyterHub
 
 Upon restarting JupyterHub, you should see a message like below in the
 logs:
@@ -78,16 +78,15 @@ single-user servers, and only cookies can be used for authentication.
 0.8 supports using JupyterHub API tokens to authenticate to single-user
 servers.
 
-## Configure the idle culler to run as a Hub-Managed Service
+## How to configure the idle culler to run as a Hub-Managed Service
 
-Install the idle culler:
+### Step 1: Install the idle culler:
 
 ```
 pip install jupyterhub-idle-culler
 ```
 
-In `jupyterhub_config.py`, add the following dictionary for the
-`idle-culler` Service to the `c.JupyterHub.services` list:
+### Step 2: In `jupyterhub_config.py`, add the following dictionary for the `idle-culler` Service to the `c.JupyterHub.services` list:
 
 ```python
 c.JupyterHub.services = [
@@ -127,7 +126,7 @@ It now needs the scopes:
 - `admin:servers` to start/stop servers
 ```
 
-## Run `cull-idle` manually as a standalone script
+## How to run `cull-idle` manually as a standalone script
 
 Now you can run your script by providing it
 the API token and it will authenticate through the REST API to

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

@@ -1,12 +1,12 @@
 # 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 aspects of that server that can be configured, and a lot
+A Spawner starts each single-user notebook server. Since the single-user server is an instance of `jupyter notebook`, an entire separate
+multi-process application, many aspects of that server can be configured and there are 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
-notebook directory is the highest level directory users will be able to access in the notebook
+notebook directory is the highest-level directory users will be able to access in the notebook
 dashboard. In this example, the root notebook directory is set to `~/notebooks`, where `~` is
 expanded to the user's home directory.
 
@@ -20,7 +20,7 @@ You can also specify extra command line arguments to the notebook server with:
 c.Spawner.args = ['--debug', '--profile=PHYS131']
 ```
 
-This could be used to set the users default page for the single user server:
+This could be used to set the user's default page for the single-user server:
 
 ```python
 c.Spawner.args = ['--NotebookApp.default_url=/notebooks/Welcome.ipynb']

docs/source/index.rst

@@ -3,30 +3,28 @@ JupyterHub
 ==========
 
 `JupyterHub`_ is the best way to serve `Jupyter notebook`_ for multiple users. 
-It can be used in a class of students, a corporate data science group or scientific
+Because JupyterHub manages a separate Jupyter environment for each user,
+it can be used in a class of students, a corporate data science group, or a scientific
 research group. It is a multi-user **Hub** that spawns, manages, and proxies multiple
 instances of the single-user `Jupyter notebook`_ server.
 
-To make life easier, JupyterHub has distributions. Be sure to
+JupyterHub offers distributions for different use cases. Be sure to
 take a look at them before continuing with the configuration of the broad
-original system of `JupyterHub`_. Today, you can find two main cases:
+original system of `JupyterHub`_. As of now, you can find two main cases:
 
-1. If you need a simple case for a small amount of users (0-100) and single server
-   take a look at
-   `The Littlest JupyterHub <https://github.com/jupyterhub/the-littlest-jupyterhub>`__ distribution.
-2. If you need to allow for even more users, a dynamic amount of servers can be used on a cloud,
-   take a look at the `Zero to JupyterHub with Kubernetes <https://github.com/jupyterhub/zero-to-jupyterhub-k8s>`__ .
+1. `The Littlest JupyterHub <https://github.com/jupyterhub/the-littlest-jupyterhub>`__ distribution is suitable if you need a small number of users (1-100) and a single server with a simple environment.
+2. `Zero to JupyterHub with Kubernetes <https://github.com/jupyterhub/zero-to-jupyterhub-k8s>`__ allows you to deploy dynamic servers on the cloud if you need even more users.
 
 
 Four subsystems make up JupyterHub:
 
 * a **Hub** (tornado process) that is the heart of JupyterHub
-* a **configurable http proxy** (node-http-proxy) that receives the requests from the client's browser
-* multiple **single-user Jupyter notebook servers** (Python/IPython/tornado) that are monitored by Spawners
-* an **authentication class** that manages how users can access the system
+* a **Configurable HTTP Proxy** (node-http-proxy) that receives the requests from the client's browser
+* multiple **Single-User Jupyter Notebook Servers** (Python/IPython/tornado) that are monitored by Spawners
+* an **Authentication Class** that manages how users can access the system
 
 
-Besides these central pieces, you can add optional configurations through a `config.py` file and manage users kernels on an admin panel. A simplification of the whole system can be seen in the figure below:
+Besides these central pieces, you can add optional configurations through a `config.py` file and manage users' environments through an admin panel. A simplification of the whole system can be seen in the figure below:
 
 .. image:: images/jhub-fluxogram.jpeg
    :alt: JupyterHub subsystems
@@ -56,17 +54,17 @@ Contents
 Distributions
 -------------
 
-A JupyterHub **distribution** is tailored towards a particular set of
+Each JupyterHub **distribution** is tailored toward a particular set of
 use cases. These are generally easier to set up than setting up
 JupyterHub from scratch, assuming they fit your use case.
 
 The two popular ones are:
 
-* `Zero to JupyterHub on Kubernetes <http://z2jh.jupyter.org>`_, for
-  running JupyterHub on top of `Kubernetes <https://k8s.io>`_. This
-  can scale to large number of machines & users.
 * `The Littlest JupyterHub <http://tljh.jupyter.org>`_, for an easy
   to set up & run JupyterHub supporting 1-100 users on a single machine.
+* `Zero to JupyterHub on Kubernetes <http://z2jh.jupyter.org>`_, for
+  running JupyterHub on top of `Kubernetes <https://k8s.io>`_. This
+  can scale to a large number of machines & users.
 
 Installation Guide
 ------------------
@@ -119,8 +117,8 @@ RBAC Reference
 Contributing
 ------------
 
-We want you to contribute to JupyterHub in ways that are most exciting
-& useful to you. We value documentation, testing, bug reporting & code equally,
+We welcome 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/HEAD/conduct/code_of_conduct.md>`_

docs/source/quickstart-docker.rst

@@ -1,49 +1,69 @@
-Using Docker
-============
+Install JupyterHub with Docker
+==============================
 
-.. important::
 
-   We highly recommend following the `Zero to JupyterHub`_ tutorial for
-   installing JupyterHub.
-
-Alternate installation using Docker
------------------------------------
-
-A ready to go `docker image <https://hub.docker.com/r/jupyterhub/jupyterhub/>`_
-gives a straightforward deployment of JupyterHub.
+The JupyterHub `docker image <https://hub.docker.com/r/jupyterhub/jupyterhub/>`_ is the fastest way to set up Jupyterhub in your local development environment.
 
 .. note::
-
     This ``jupyterhub/jupyterhub`` docker image is only an image for running
     the Hub service itself. It does not provide the other Jupyter components,
     such as Notebook installation, which are needed by the single-user servers.
     To run the single-user servers, which may be on the same system as the Hub or
-    not, Jupyter Notebook version 4 or greater must be installed.
+    not, `JupyterLab <https://jupyterlab.readthedocs.io/>`_ or Jupyter Notebook must be installed.
 
-Starting JupyterHub with docker
--------------------------------
 
-The JupyterHub docker image can be started with the following command::
+.. important::
+    We strongly recommend that you follow the `Zero to JupyterHub`_ tutorial to
+    install JupyterHub.
+   
+   
+Prerequisites
+-------------
+You should have `Docker`_ installed on a Linux/Unix based system.
+
+
+Run the Docker Image
+--------------------
+
+To pull the latest JupyterHub image and start the `jupyterhub` container, run this command in your terminal.
+::
    
     docker run -d -p 8000:8000 --name jupyterhub jupyterhub/jupyterhub jupyterhub
 
-This command will create a container named ``jupyterhub`` that you can
-**stop and resume** with ``docker stop/start``.
 
-The Hub service will be listening on all interfaces at port 8000, which makes
-this a good choice for **testing JupyterHub on your desktop or laptop**.
+This command exposes the Jupyter container on port:8000. Navigate to `http://localhost:8000` in a web browser to access the JupyterHub console.
 
-If you want to run docker on a computer that has a public IP then you should
-(as in MUST) **secure it with ssl** by adding ssl options to your docker
+You can stop and resume the container by running `docker stop` and `docker start` respectively.
+::
+
+    # find the container id
+    docker ps
+
+    # stop the running container
+    docker stop  <container-id>
+
+    # resume the paused container
+    docker start <container-id>
+
+
+If you are running Docker on a computer that has a public IP address, you must **secure it with ssl** by adding ssl options to your docker
 configuration or using a ssl enabled proxy.
 
-`Mounting volumes <https://docs.docker.com/engine/admin/volumes/volumes/>`_
-will allow you to store data outside the docker image (host system) so it will
-be persistent, even when you start a new image.
 
-The command ``docker exec -it jupyterhub bash`` will spawn a root shell in your
-docker container. You can use the root shell to **create system users in the container**.
-These accounts will be used for authentication in JupyterHub's default
+`Mounting volumes <https://docs.docker.com/engine/admin/volumes/volumes/>`_ 
+enables you to persist and store the data generated by the docker container, even when you stop the container. 
+The persistent data can be stored on the host system, outside the container.
+
+
+Create System Users
+-------------------
+
+Spawn a root shell in your docker container by running this command in the terminal.::
+
+    docker exec -it jupyterhub bash
+
+The created accounts will be used for authentication in JupyterHub's default
 configuration.
 
 .. _Zero to JupyterHub: https://zero-to-jupyterhub.readthedocs.io/en/latest/
+.. _Docker: https://www.docker.com/

docs/source/rbac/roles.md

@@ -1,8 +1,6 @@
-(roles)=
-
 # Roles
 
-JupyterHub provides four roles that are available by default:
+JupyterHub provides four (4) 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.
@@ -13,11 +11,11 @@ JupyterHub provides four roles that are available by default:
 **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,
+We call these 'default' roles because they are available by default and have a default collection of scopes.
+However, you can define the scopes associated with each role (excluding the admin role) 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.
+The `user`, `admin`, and `token` roles, by default, all preserve the permissions prior to Role-based Access Control (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.
 
@@ -31,10 +29,10 @@ Roles can be assigned to the following entities:
 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).
+When a new user gets created, they are assigned their default role, `user`. Additionally, 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.
+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.
@@ -113,7 +111,7 @@ In case the role with a certain name already exists in the database, its definit
 
 (overriding-default-roles)=
 
-### 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.
@@ -154,7 +152,7 @@ c.JupyterHub.load_roles = [
 
 (removing-roles-target)=
 
-## Removing roles
+## 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.
 

docs/source/rbac/tech-implementation.md

@@ -1,8 +1,8 @@
 # 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](roles) are stored in the database, where they are associated with users, services, and groups. Roles can be added or modified as explained in the {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 the future. The latter will allow for changing a user's role, and thereby its permissions, without the need to restart JupyterHub.
 
-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:
+Roles and scopes utilities can be found in `roles.py` and `scopes.py` modules. Scope variables take on five different formats that are reflected throughout the utilities via specific nomenclature:
 
 ```{admonition} **Scope variable nomenclature**
 :class: tip
@@ -11,22 +11,22 @@ Roles and scopes utilities can be found in `roles.py` and `scopes.py` modules. S
 - _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"]}}`.
+  Dictionary representation 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.
+  Set of expanded scopes needed for identity (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 roles** involves 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.
+**Resolving scopes** involves expanding scopes into all their possible subscopes (_expanded scopes_), parsing them into the 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.
+Roles and scopes are resolved on several occasions, for example when requesting an API token with specific scopes or when making an API request. The following sections provide more details.
 
 (requesting-api-token-target)=
 
@@ -43,25 +43,24 @@ 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.
+API tokens grant access to JupyterHub's APIs. The [RBAC framework](./index.md) 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).
+(provided 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.
+If a token has any scopes that its owner does not possess
+at the time of making the API request, 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.
+Resolving a token's scope (yellow box in {ref}`Figure 1 <token-request-chart>`) corresponds to resolving all the roles of the token's owner (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.
@@ -75,10 +74,10 @@ 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.
+With the RBAC framework, each authenticated JupyterHub API request is guarded by a scope decorator that specifies which scopes are required in order 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.
+When an API request is made, the requesting API token's scopes are again intersected with its owner's (yellow box in {ref}`Figure 2 <api-request-chart>`) to ensure that 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, 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:
 
@@ -86,7 +85,7 @@ The passed scopes are compared to the scopes required to access the API as follo
 
 - 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 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
 

docs/source/rbac/use-cases.md

@@ -9,12 +9,12 @@ To determine which scopes a role should have, one can follow these steps:
 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.
+Below, different use cases are presented on how to use the [RBAC framework](./index.md)
 
 ## 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.
+**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`.

docs/source/reference/authenticators.md

@@ -247,6 +247,23 @@ class MyAuthenticator(Authenticator):
         spawner.environment['UPSTREAM_TOKEN'] = auth_state['upstream_token']
 ```
 
+Note that environment variable names and values are always strings, so passing multiple values means setting multiple environment variables or serializing more complex data into a single variable, e.g. as a JSON string.
+
+auth state can also be used to configure the spawner via _config_ without subclassing
+by setting `c.Spawner.auth_state_hook`. This function will be called with `(spawner, auth_state)`,
+only when auth_state is defined.
+
+For example:
+(for KubeSpawner)
+
+```python
+def auth_state_hook(spawner, auth_state):
+    spawner.volumes = auth_state['user_volumes']
+    spawner.mounts = auth_state['user_mounts']
+
+c.Spawner.auth_state_hook = auth_state_hook
+```
+
 (authenticator-groups)=
 
 ## Authenticator-managed group membership

docs/source/reference/config-ghoauth.md

@@ -5,15 +5,15 @@ deployment with the following assumptions:
 
 - Running JupyterHub on a single cloud server
 - Using SSL on the standard HTTPS port 443
-- Using GitHub OAuth (using oauthenticator) for login
+- Using GitHub OAuth (using [OAuthenticator](https://oauthenticator.readthedocs.io/en/latest)) for login
 - Using the default spawner (to configure other spawners, uncomment and edit
   `spawner_class` as well as follow the instructions for your desired spawner)
 - Users exist locally on the server
 - Users' notebooks to be served from `~/assignments` to allow users to browse
   for notebooks within other users' home directories
 - You want the landing page for each user to be a `Welcome.ipynb` notebook in
-  their assignments directory.
-- All runtime files are put into `/srv/jupyterhub` and log files in `/var/log`.
+  their assignments directory
+- All runtime files are put into `/srv/jupyterhub` and log files in `/var/log`
 
 The `jupyterhub_config.py` file would have these settings:
 
@@ -69,7 +69,7 @@ c.Spawner.args = ['--NotebookApp.default_url=/notebooks/Welcome.ipynb']
 ```
 
 Using the GitHub Authenticator requires a few additional
-environment variable to be set prior to launching JupyterHub:
+environment variables to be set prior to launching JupyterHub:
 
 ```bash
 export GITHUB_CLIENT_ID=github_id
@@ -79,3 +79,5 @@ export CONFIGPROXY_AUTH_TOKEN=super-secret
 # append log output to log file /var/log/jupyterhub.log
 jupyterhub -f /etc/jupyterhub/jupyterhub_config.py &>> /var/log/jupyterhub.log
 ```
+
+Visit the [Github OAuthenticator reference](https://oauthenticator.readthedocs.io/en/latest/api/gen/oauthenticator.github.html) to see the full list of options for configuring Github OAuth with JupyterHub.

docs/source/reference/config-proxy.md

@@ -14,7 +14,7 @@ satisfy the following:
 - After testing, the server in question should be able to score at least an A on the
   Qualys SSL Labs [SSL Server Test](https://www.ssllabs.com/ssltest/)
 
-Let's start out with needed JupyterHub configuration in `jupyterhub_config.py`:
+Let's start out with the needed JupyterHub configuration in `jupyterhub_config.py`:
 
 ```python
 # Force the proxy to only listen to connections to 127.0.0.1 (on port 8000)
@@ -30,15 +30,15 @@ This can take a few minutes:
 openssl dhparam -out /etc/ssl/certs/dhparam.pem 4096
 ```
 
-## nginx
+## Nginx
 
 This **`nginx` config file** is fairly standard fare except for the two
 `location` blocks within the main section for HUB.DOMAIN.tld.
-To create a new site for jupyterhub in your nginx config, make a new file
+To create a new site for jupyterhub in your Nginx config, make a new file
 in `sites.enabled`, e.g. `/etc/nginx/sites.enabled/jupyterhub.conf`:
 
 ```bash
-# top-level http config for websocket headers
+# Top-level HTTP config for WebSocket headers
 # If Upgrade is defined, Connection = upgrade
 # If Upgrade is empty, Connection = close
 map $http_upgrade $connection_upgrade {
@@ -51,7 +51,7 @@ server {
     listen 80;
     server_name HUB.DOMAIN.TLD;
 
-    # Tell all requests to port 80 to be 302 redirected to HTTPS
+    # Redirect the request to HTTPS
     return 302 https://$host$request_uri;
 }
 
@@ -75,7 +75,7 @@ server {
     ssl_stapling_verify on;
     add_header Strict-Transport-Security max-age=15768000;
 
-    # Managing literal requests to the JupyterHub front end
+    # Managing literal requests to the JupyterHub frontend
     location / {
         proxy_pass http://127.0.0.1:8000;
         proxy_set_header X-Real-IP $remote_addr;
@@ -101,10 +101,10 @@ server {
 If `nginx` is not running on port 443, substitute `$http_host` for `$host` on
 the lines setting the `Host` header.
 
-`nginx` will now be the front facing element of JupyterHub on `443` which means
+`nginx` will now be the front-facing element of JupyterHub on `443` which means
 it is also free to bind other servers, like `NO_HUB.DOMAIN.TLD` to the same port
 on the same machine and network interface. In fact, one can simply use the same
-server blocks as above for `NO_HUB` and simply add line for the root directory
+server blocks as above for `NO_HUB` and simply add a line for the root directory
 of the site as well as the applicable location call:
 
 ```bash
@@ -112,7 +112,7 @@ server {
     listen 80;
     server_name NO_HUB.DOMAIN.TLD;
 
-    # Tell all requests to port 80 to be 302 redirected to HTTPS
+    # Redirect the request to HTTPS
     return 302 https://$host$request_uri;
 }
 
@@ -143,12 +143,12 @@ Now restart `nginx`, restart the JupyterHub, and enjoy accessing
 `https://HUB.DOMAIN.TLD` while serving other content securely on
 `https://NO_HUB.DOMAIN.TLD`.
 
-### SELinux permissions for nginx
+### SELinux permissions for Nginx
 
 On distributions with SELinux enabled (e.g. Fedora), one may encounter permission errors
-when the nginx service is started.
+when the Nginx service is started.
 
-We need to allow nginx to perform network relay and connect to the jupyterhub port. The
+We need to allow Nginx to perform network relay and connect to the JupyterHub port. The
 following commands do that:
 
 ```bash
@@ -157,26 +157,26 @@ setsebool -P httpd_can_network_relay 1
 setsebool -P httpd_can_network_connect 1
 ```
 
-Replace 8000 with the port the jupyterhub server is running from.
+Replace 8000 with the port the JupyterHub server is running from.
 
 ## Apache
 
-As with nginx above, you can use [Apache](https://httpd.apache.org) as the reverse proxy.
-First, we will need to enable the apache modules that we are going to need:
+As with Nginx above, you can use [Apache](https://httpd.apache.org) as the reverse proxy.
+First, we will need to enable the Apache modules that we are going to need:
 
 ```bash
 a2enmod ssl rewrite proxy headers proxy_http proxy_wstunnel
 ```
 
-Our Apache configuration is equivalent to the nginx configuration above:
+Our Apache configuration is equivalent to the Nginx configuration above:
 
 - Redirect HTTP to HTTPS
 - Good SSL Configuration
-- Support for websockets on any proxied URL
+- Support for WebSocket on any proxied URL
 - JupyterHub is running locally at http://127.0.0.1:8000
 
 ```bash
-# redirect HTTP to HTTPS
+# Redirect HTTP to HTTPS
 Listen 80
 <VirtualHost HUB.DOMAIN.TLD:80>
   ServerName HUB.DOMAIN.TLD
@@ -188,26 +188,26 @@ Listen 443
 
   ServerName HUB.DOMAIN.TLD
 
-  # enable HTTP/2, if available
+  # 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
+  # Configure SSL
   SSLEngine on
   SSLCertificateFile /etc/letsencrypt/live/HUB.DOMAIN.TLD/fullchain.pem
   SSLCertificateKeyFile /etc/letsencrypt/live/HUB.DOMAIN.TLD/privkey.pem
   SSLOpenSSLConfCmd DHParameters /etc/ssl/certs/dhparam.pem
 
-  # 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/
+  # Intermediate configuration from SSL-config.mozilla.org (2022-03-03)
+  # Please note, that this configuration might be outdated - 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
+  # Use RewriteEngine to handle WebSocket connection upgrades
   RewriteEngine On
   RewriteCond %{HTTP:Connection} Upgrade [NC]
   RewriteCond %{HTTP:Upgrade} websocket [NC]
@@ -224,7 +224,7 @@ Listen 443
 </VirtualHost>
 ```
 
-In case of the need to run the jupyterhub under /jhub/ or other location please use the below configurations:
+In case of the need to run JupyterHub under /jhub/ or another location please use the below configurations:
 
 - JupyterHub running locally at http://127.0.0.1:8000/jhub/ or other location
 
@@ -241,7 +241,7 @@ httpd.conf amendments:
 jupyterhub_config.py amendments:
 
 ```bash
- --The public facing URL of the whole JupyterHub application.
- --This is the address on which the proxy will bind. Sets protocol, ip, base_url
+ --The public-facing URL of the whole JupyterHub application.
+ --This is the address on which the proxy will bind. Sets protocol, IP, base_url
  c.JupyterHub.bind_url = 'http://127.0.0.1:8000/jhub/'
 ```

docs/source/reference/config-sudo.md

@@ -6,10 +6,10 @@ Only do this if you are very sure you must.
 
 ## Overview
 
-There are many Authenticators and Spawners available for JupyterHub. Some, such
-as DockerSpawner or OAuthenticator, do not need any elevated permissions. This
+There are many [Authenticators](./authenticators-users-basics) and [Spawners](./spawners-basics) available for JupyterHub. Some, such
+as [DockerSpawner](https://github.com/jupyterhub/dockerspawner) or [OAuthenticator](https://github.com/jupyterhub/oauthenticator), do not need any elevated permissions. This
 document describes how to get the full default behavior of JupyterHub while
-running notebook servers as real system users on a shared system without
+running notebook servers as real system users on a shared system, without
 running the Hub itself as root.
 
 Since JupyterHub needs to spawn processes as other users, the simplest way
@@ -90,7 +90,7 @@ $ adduser -G jupyterhub newuser
 Test that the new user doesn't need to enter a password to run the sudospawner
 command.
 
-This should prompt for your password to switch to rhea, but _not_ prompt for
+This should prompt for your password to switch to `rhea`, but _not_ prompt for
 any password for the second switch. It should show some help output about
 logging options:
 
@@ -119,7 +119,7 @@ the shadow password database.
 
 ### Shadow group (Linux)
 
-**Note:** On Fedora based distributions there is no clear way to configure
+**Note:** On [Fedora based distributions](https://fedoraproject.org/wiki/List_of_Fedora_remixes) there is no clear way to configure
 the PAM database to allow sufficient access for authenticating with the target user's password
 from JupyterHub. As a workaround we recommend use an
 [alternative authentication method](https://github.com/jupyterhub/jupyterhub/wiki/Authenticators).
@@ -150,7 +150,7 @@ We want our new user to be able to read the shadow passwords, so add it to the s
     $ sudo usermod -a -G shadow rhea
 ```
 
-If you want jupyterhub to serve pages on a restricted port (such as port 80 for http),
+If you want jupyterhub to serve pages on a restricted port (such as port 80 for HTTP),
 then you will need to give `node` permission to do so:
 
 ```bash
@@ -226,7 +226,7 @@ And try logging in.
 ## Troubleshooting: SELinux
 
 If you still get a generic `Permission denied` `PermissionError`, it's possible SELinux is blocking you.  
-Here's how you can make a module to allow this.
+Here's how you can make a module to resolve this.
 First, put this in a file named `sudo_exec_selinux.te`:
 
 ```bash
@@ -253,6 +253,6 @@ $ semodule -i sudo_exec_selinux.pp
 ## Troubleshooting: PAM session errors
 
 If the PAM authentication doesn't work and you see errors for
-`login:session-auth`, or similar, considering updating to a more recent version
+`login:session-auth`, or similar, consider updating to a more recent version
 of jupyterhub and disabling the opening of PAM sessions with
 `c.PAMAuthenticator.open_sessions=False`.

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

@@ -1,49 +1,43 @@
 # Configuring user environments
 
-Deploying JupyterHub means you are providing Jupyter notebook environments for
+To deploy JupyterHub means you are providing Jupyter notebook environments for
 multiple users. Often, this includes a desire to configure the user
-environment in some way.
+environment in a custom way.
 
 Since the `jupyterhub-singleuser` server extends the standard Jupyter notebook
 server, most configuration and documentation that applies to Jupyter Notebook
 applies to the single-user environments. Configuration of user environments
-typically does not occur through JupyterHub itself, but rather through system-
-wide configuration of Jupyter, which is inherited by `jupyterhub-singleuser`.
+typically does not occur through JupyterHub itself, but rather through the system-wide
+configuration of Jupyter, which is inherited by `jupyterhub-singleuser`.
 
-**Tip:** When searching for configuration tips for JupyterHub user
-environments, try removing JupyterHub from your search because there are a lot
-more people out there configuring Jupyter than JupyterHub and the
-configuration is the same.
+**Tip:** When searching for configuration tips for JupyterHub user environments, you might want to remove JupyterHub from your search because there are a lot more people out there configuring Jupyter than JupyterHub and the configuration is the same.
 
-This section will focus on user environments, including:
+This section will focus on user environments, which includes the following:
 
-- Installing packages
-- Configuring Jupyter and IPython
-- Installing kernelspecs
-- Using containers vs. multi-user hosts
+- [Installing packages](#installing-packages)
+- [Configuring Jupyter and IPython](#configuring-jupyter-and-ipython)
+- [Installing kernelspecs](#installing-kernelspecs)
+- [Using containers vs. multi-user hosts](#multi-user-hosts-vs-containers)
 
 ## Installing packages
 
-To make packages available to users, you generally will install packages
-system-wide or in a shared environment.
+To make packages available to users, you will typically install packages system-wide or in a shared environment.
 
-This installation location should always be in the same environment that
+This installation location should always be in the same environment where
 `jupyterhub-singleuser` itself is installed in, and must be _readable and
-executable_ by your users. If you want users to be able to install additional
-packages, it must also be _writable_ by your users.
+executable_ by your users. If you want your users to be able to install additional
+packages, the installation location must also be _writable_ by your users.
 
-If you are using a standard system Python install, you would use:
+If you are using a standard Python installation on your system, use the following command:
 
 ```bash
 sudo python3 -m pip install numpy
 ```
 
-to install the numpy package in the default system Python 3 environment
+to install the numpy package in the default Python 3 environment on your system
 (typically `/usr/local`).
 
-You may also use conda to install packages. If you do, you should make sure
-that the conda environment has appropriate permissions for users to be able to
-run Python code in the env.
+Alternatively, You may also use conda to install packages. To do this, ensure that the conda environment has appropriate users permissions needed to run Python code in the environment.
 
 ## Configuring Jupyter and IPython
 
@@ -51,15 +45,9 @@ run Python code in the env.
 and [IPython](https://ipython.readthedocs.io/en/stable/development/config.html)
 have their own configuration systems.
 
-As a JupyterHub administrator, you will typically want to install and configure
-environments for all JupyterHub users. For example, you wish for each student in
-a class to have the same user environment configuration.
-
-Jupyter and IPython support **"system-wide"** locations for configuration, which
-is the logical place to put global configuration that you want to affect all
-users. It's generally more efficient to configure user environments "system-wide",
-and it's a good idea to avoid creating files in users' home directories.
+As a JupyterHub administrator, you will typically want to install and configure environments for all JupyterHub users. For example, let's say you wish for each student in a class to have the same user environment configuration.
 
+Jupyter and IPython support **"system-wide"** locations for configuration, which is the logical place to put global configuration that you want to affect all users. It's generally more efficient to configure user environments "system-wide", and it's a good practice to avoid creating files in the users' home directories.
 The typical locations for these config files are:
 
 - **system-wide** in `/etc/{jupyter|ipython}`
@@ -67,8 +55,7 @@ The typical locations for these config files are:
 
 ### Example: Enable an extension system-wide
 
-For example, to enable the `cython` IPython extension for all of your users,
-create the file `/etc/ipython/ipython_config.py`:
+For example, to enable the `cython` IPython extension for all of your users, create the file `/etc/ipython/ipython_config.py`:
 
 ```python
 c.InteractiveShellApp.extensions.append("cython")
@@ -77,21 +64,18 @@ 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.
+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`
+- Search for `jupyter_server_config`, and replace with `jupyter_notebook_config`
+- Search for `NotebookApp`, and replace with `ServerApp`
 
 :::
 
-To enable Jupyter notebook's internal idle-shutdown behavior (requires
-notebook ≥ 5.4), set the following in the `/etc/jupyter/jupyter_server_config.py`
-file:
+To enable Jupyter notebook's internal idle-shutdown behavior (requires 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
@@ -104,16 +88,14 @@ c.MappingKernelManager.cull_interval = 2 * 60
 
 ## Installing kernelspecs
 
-You may have multiple Jupyter kernels installed and want to make sure that
-they are available to all of your users. This means installing kernelspecs
-either system-wide (e.g. in /usr/local/) or in the `sys.prefix` of JupyterHub
+You may have multiple Jupyter kernels installed and want to make sure that they are available to all of your users. This means installing kernelspecs either system-wide (e.g. in /usr/local/) or in the `sys.prefix` of JupyterHub
 itself.
 
-Jupyter kernelspec installation is system wide by default, but some kernels
+Jupyter kernelspec installation is system-wide by default, but some kernels
 may default to installing kernelspecs in your home directory. These will need
 to be moved system-wide to ensure that they are accessible.
 
-You can see where your kernelspecs are with:
+To see where your kernelspecs are, you can use the following command:
 
 ```bash
 jupyter kernelspec list
@@ -121,8 +103,7 @@ jupyter kernelspec list
 
 ### Example: Installing kernels system-wide
 
-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:
+Let's assume that 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) using the following command:
 
 ```bash
 /path/to/python3 -m ipykernel install --prefix=/usr/local
@@ -141,31 +122,25 @@ How you configure user environments for each category can differ a bit
 depending on what Spawner you are using.
 
 The first category is a **shared system (multi-user host)** where
-each user has a JupyterHub account and a home directory as well as being
+each user has a JupyterHub account, a home directory as well as being
 a real system user. In this example, shared configuration and installation
-must be in a 'system-wide' location, such as `/etc/` or `/usr/local`
+must be in a 'system-wide' location, such as `/etc/`, or `/usr/local`
 or a custom prefix such as `/opt/conda`.
 
 When JupyterHub uses **container-based** Spawners (e.g. KubeSpawner or
-DockerSpawner), the 'system-wide' environment is really the container image
-which you are using for users.
+DockerSpawner), the 'system-wide' environment is really the container image used for users.
 
 In both cases, you want to _avoid putting configuration in user home
-directories_ because users can change those configuration settings. Also,
-home directories typically persist once they are created, so they are
-difficult for admins to update later.
+directories_ because users can change those configuration settings. Also, home directories typically persist once they are created, thereby making it difficult for admins to update later.
 
 ## Named servers
 
-By default, in a JupyterHub deployment each user has exactly one server.
+By default, in a JupyterHub deployment, each user has one server only.
 
 JupyterHub can, however, have multiple servers per user.
-This is most useful in deployments where users can configure the environment
-in which their server will start (e.g. resource requests on an HPC cluster),
-so that a given user can have multiple configurations running at the same time,
-without having to stop and restart their one server.
+This is mostly useful in deployments where users can configure the environment in which their server will start (e.g. resource requests on an HPC cluster), so that a given user can have multiple configurations running at the same time, without having to stop and restart their own server.
 
-To allow named servers:
+To allow named servers, include this code snippet in your config file:
 
 ```python
 c.JupyterHub.allow_named_servers = True
@@ -181,22 +156,39 @@ as well as the admin page:
 ![named servers on the admin page](../images/named-servers-admin.png)
 
 Named servers can be accessed, created, started, stopped, and deleted
-from these pages. Activity tracking is now per-server as well.
+from these pages. Activity tracking is now per server as well.
 
-The number of named servers per user can be limited by setting
+To limit the number of **named server** per user by setting a constant value, include this code snippet in your config file:
 
 ```python
 c.JupyterHub.named_server_limit_per_user = 5
 ```
 
+Alternatively, to use a callable/awaitable based on the handler object, include this code snippet in your config file:
+
+```python
+def named_server_limit_per_user_fn(handler):
+    user = handler.current_user
+    if user and user.admin:
+        return 0
+    return 5
+
+c.JupyterHub.named_server_limit_per_user = named_server_limit_per_user_fn
+```
+
+This can be useful for quota service implementations. The example above limits the number of named servers for non-admin users only.
+
+If `named_server_limit_per_user` is set to `0`, no limit is enforced.
+
 (classic-notebook-ui)=
 
-## Switching back to classic notebook
+## Switching back to the classic notebook
 
-By default the single-user server launches JupyterLab,
+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
+To switch to using the legacy Jupyter Notebook server, you can set the `JUPYTERHUB_SINGLEUSER_APP` environment variable
 (in the single-user environment) to:
 
 ```bash
@@ -207,19 +199,20 @@ export JUPYTERHUB_SINGLEUSER_APP='notebook.notebookapp.NotebookApp'
 [jupyter notebook]: https://jupyter-notebook.readthedocs.io
 
 :::{versionchanged} 2.0
-JupyterLab is now the default singleuser UI, if available,
+
+JupyterLab is now the default single-user 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
+and the Jupyter server could be selected by specifying the following:
 
 ```python
 # jupyterhub_config.py
 c.Spawner.cmd = ["jupyter-labhub"]
 ```
 
-or for an otherwise customized Jupyter Server app,
-set the environment variable:
+Alternatively, for an otherwise customized Jupyter Server app,
+set the environment variable using the following command:
 
 ```bash
 export JUPYTERHUB_SINGLEUSER_APP='jupyter_server.serverapp.ServerApp'

docs/source/reference/oauth.md

@@ -1,26 +1,26 @@
 # JupyterHub and OAuth
 
-JupyterHub uses OAuth 2 internally as a mechanism for authenticating users.
+JupyterHub uses [OAuth 2](https://oauth.net/2/) as an internal mechanism for authenticating users.
 As such, JupyterHub itself always functions as an OAuth **provider**.
-More on what that means [below](oauth-terms).
+You can find out more about what that means [below](oauth-terms).
 
-Additionally, JupyterHub is _often_ deployed with [oauthenticator](https://oauthenticator.readthedocs.io),
+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**.
+When this is the case, there are _two_ nested OAuth flows:
+an _internal_ OAuth flow where JupyterHub is the **provider**,
+and an _external_ OAuth flow, where JupyterHub is the **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:
+The following points are noteworthy:
 
 - 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,
+  As far as the servers 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,
+- When interacting with 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.
+  first, a token issued to the server itself to communicate with the Hub API,
+  and second, a per-user token in the browser to represent the completed login process and authorized permissions.
   More on this [later](two-tokens).
 
 (oauth-terms)=
@@ -28,66 +28,66 @@ Some relevant points:
 ## 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/).
+You can also read more in detail [here](https://www.oauth.com/oauth2-servers/definitions/).
 
-- **provider** the entity responsible for managing identity and authorization,
+- **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,
+  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."
+  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.
+OAuth **flow** is what we call the sequence of HTTP requests involved in authenticating a user and issuing a token, ultimately used for authorizing access to a service or single-user server.
 
-A single oauth flow generally goes like this:
+A single OAuth flow typically 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
+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!
+   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.
+   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**.
+That marks 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.
+- The browser is authenticated with the _provider_.
+- The user's authorized permissions are recorded in an _OAuth code_.
+- The _provider_ knows that the permissions requested by the OAuth client have been granted, but the client doesn't know this yet.
+- All the requests so far have been made directly by the browser.
+  No requests have originated from 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
+At this stage, we get to finish the OAuth process.
+Let's dig into what the OAuth client does when it handles
+the OAuth callback request.
 
 - 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_.
@@ -95,12 +95,12 @@ the oauth callback request with the
   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),
+  Up to this point, all OAuth providers are the same, following the OAuth specification.
+  However, OAuth does not define a standard for issuing tokens in exchange 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.
+- 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,
+- 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
@@ -113,24 +113,24 @@ 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.
+Let's go through the above OAuth process in JupyterHub,
+with specific examples of each HTTP request and what information it contains.
+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."
+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
+- 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**)
+- 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`
@@ -138,9 +138,9 @@ First request:
 
 Second request, following redirect:
 
-- browser->jupyterhub
+- browser->JupyterHub
 - `GET /hub/api/oauth2/authorize`
-- no credentials, so jupyterhub starts external oauth process _with GitHub_
+- 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`
@@ -154,8 +154,8 @@ 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.
+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.
@@ -171,7 +171,7 @@ Here, GitHub prompts for login and asks for confirmation of authorization
 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`
+GitHub issues an **OAuth code** and redirects to `/hub/oauth_callback?code=github-code`
 
 Next request:
 
@@ -184,7 +184,7 @@ The first:
 
 - JupyterHub->GitHub
 - `POST https://github.com/login/oauth/access_token`
-- request made with oauth **code** from url parameter
+- request made with OAuth **code** from URL parameter
 - response includes an access **token**
 
 The second:
@@ -194,9 +194,9 @@ The second:
 - 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:
+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
+- 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! 🎉
@@ -211,14 +211,14 @@ Now, we get our first repeated request:
   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
+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,
+Inside the internal OAuth callback handler,
 Danez's server makes two API requests to JupyterHub:
 
 The first:
@@ -271,15 +271,15 @@ 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:
+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,
+- 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),
+- 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,
+- The internal OAuth token itself can also 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,
@@ -317,9 +317,9 @@ triggering the external login process anew before letting a user proceed.
 - 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.
+  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.
+  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
@@ -352,7 +352,7 @@ Logging out of JupyterHub means clearing and revoking many of these credentials:
 ### 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 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,

docs/source/reference/proxy.md

@@ -7,9 +7,12 @@ Hub manages by default as a subprocess (it can be run externally, as well, and
 typically is in production deployments).
 
 The upside to CHP, and why we use it by default, is that it's easy to install
-and run (if you have nodejs, you are set!). The downsides are that it's a
-single process and does not support any persistence of the routing table. So
-if the proxy process dies, your whole JupyterHub instance is inaccessible
+and run (if you have nodejs, you are set!). The downsides are that
+
+- it's a single process and
+- does not support any persistence of the routing table.
+
+So if the proxy process dies, your whole JupyterHub instance is inaccessible
 until the Hub notices, restarts the proxy, and restores the routing table. For
 deployments that want to avoid such a single point of failure, or leverage
 existing proxy infrastructure in their chosen deployment (such as Kubernetes

docs/source/reference/rest.md

@@ -4,33 +4,36 @@
 
 This section will give you information on:
 
-- what you can do with the API
-- create an API token
-- add API tokens to the config files
-- make an API request programmatically using the requests library
-- learn more about JupyterHub's API
+- What you can do with the API
+- How to create an API token
+- Assigning permissions to a token
+- Updating to admin services
+- Making an API request programmatically using the requests library
+- Paginating API requests
+- Enabling users to spawn multiple named-servers via the API
+- Learn more about JupyterHub's API
+
+Before we discuss about JupyterHub's REST API, you can learn about [REST APIs here](https://en.wikipedia.org/wiki/Representational_state_transfer). A REST
+API provides a standard way for users to get and send information to the
+Hub.
 
 ## What you can do with the API
 
 Using the [JupyterHub REST API][], you can perform actions on the Hub,
 such as:
 
-- checking which users are active
-- 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
-Hub.
+- Checking which users are active
+- Adding or removing users
+- Stopping or starting single user notebook servers
+- Authenticating services
+- Communicating with an individual Jupyter server's REST API
 
 ## Create an API token
 
-To send requests using JupyterHub API, you must pass an API token with
+To send requests using the JupyterHub API, you must pass an API token with
 the request.
 
-The preferred way of generating an API token is:
+The preferred way of generating an API token is by running:
 
 ```bash
 openssl rand -hex 32
@@ -40,8 +43,12 @@ This `openssl` command generates a potential token that can then be
 added to JupyterHub using `.api_tokens` configuration setting in
 `jupyterhub_config.py`.
 
-Alternatively, use the `jupyterhub token` command to generate a token
-for a specific hub user by passing the 'username':
+```{note}
+The api_tokens configuration has been softly deprecated since the introduction of services.
+```
+
+Alternatively, you can use the `jupyterhub token` command to generate a token
+for a specific hub user by passing the **username**:
 
 ```bash
 jupyterhub token <username>
@@ -53,9 +60,19 @@ it for the given user with the Hub's database.
 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)
+:::{figure-md}
 
-![API token success page](../images/token-request-success.png)
+![token request page](../images/token-request.png)
+
+JupyterHub's API token page
+:::
+
+:::{figure-md}
+![token-request-success](../images/token-request-success.png)
+
+JupyterHub's token page after successfully requesting a token.
+
+:::
 
 ## Assigning permissions to a token
 
@@ -67,25 +84,26 @@ Prior to JupyterHub 2.0, there were two levels of permissions:
 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',
+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
+## Updating to admin services
 
+```{note}
 The `api_tokens` configuration has been softly deprecated since the introduction of services.
 We have no plans to remove it,
 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,
-the services mechanism may be a better fit.
-If you have the following configuration:
+and the token for that user to perform some automations, then
+the services' mechanism may be a better fit if you have the following configuration:
 
 ```python
-c.JupyterHub.admin_users = {"service-admin",}
+c.JupyterHub.admin_users = {"service-admin"}
 c.JupyterHub.api_tokens = {
     "secret-token": "service-admin",
 }
@@ -103,9 +121,8 @@ c.JupyterHub.services = [
     },
 ]
 
-# roles are new in JupyterHub 2.0
-# prior to 2.0, only 'admin': True or False
-# was available
+# roles were introduced in JupyterHub 2.0
+# prior to 2.0, only "admin": True or False was available
 
 c.JupyterHub.load_roles = [
     {
@@ -125,7 +142,7 @@ c.JupyterHub.load_roles = [
 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
+The main noticeable difference between a user and a service 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.
 
 ## Make an API request
@@ -136,9 +153,8 @@ Authorization header.
 ### Use requests
 
 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:
+library, an API GET request is made, and the request sends an API token for
+authorization. The response contains information about the users, here's example code to make an API request for the users of a JupyterHub deployment
 
 ```python
 import requests
@@ -176,7 +192,8 @@ r.json()
 ```
 
 The same API token can also authorize access to the [Jupyter Notebook REST API][]
-provided by notebook servers managed by JupyterHub if it has the necessary `access:users:servers` scope:
+
+provided by notebook servers managed by JupyterHub if it has the necessary `access:users:servers` scope.
 
 (api-pagination)=
 
@@ -245,7 +262,7 @@ with your request, in which case a response will look like:
 
 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.
+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:
@@ -259,7 +276,7 @@ Pagination is enabled on the `GET /users`, `GET /groups`, and `GET /proxy` REST
 
 ## Enabling users to spawn multiple named-servers via the API
 
-With JupyterHub version 0.8, support for multiple servers per user has landed.
+Support for multiple servers per user was introduced in JupyterHub [version 0.8.](../changelog.md)
 Prior to that, each user could only launch a single default server via the API
 like this:
 
@@ -275,7 +292,7 @@ First you must enable named-servers by including the following setting in the `j
 
 `c.JupyterHub.allow_named_servers = True`
 
-If using the [zero-to-jupyterhub-k8s](https://github.com/jupyterhub/zero-to-jupyterhub-k8s) set-up to run JupyterHub,
+If you are using the [zero-to-jupyterhub-k8s](https://github.com/jupyterhub/zero-to-jupyterhub-k8s) set-up to run JupyterHub,
 then instead of editing the `jupyterhub_config.py` file directly, you could pass
 the following as part of the `config.yaml` file, as per the [tutorial](https://zero-to-jupyterhub.readthedocs.io/en/latest/):
 
@@ -303,8 +320,9 @@ or kubernetes pods.
 
 ## Learn more about the API
 
-You can see the full [JupyterHub REST API][] for details.
+You can see the full [JupyterHub REST API][] for more details.
 
 [openapi initiative]: https://www.openapis.org/
 [jupyterhub rest api]: ./rest-api
+[scopes]: ../rbac/scopes.md
 [jupyter notebook rest api]: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyter/notebook/HEAD/notebook/services/api/api.yaml

docs/source/reference/separate-proxy.md

@@ -2,7 +2,7 @@
 
 ## Background
 
-The thing which users directly connect to is the proxy, by default
+The thing which users directly connect to is the proxy, which by default is
 `configurable-http-proxy`. The proxy either redirects users to the
 hub (for login and managing servers), or to their own single-user
 servers. Thus, as long as the proxy stays running, access to existing
@@ -10,16 +10,15 @@ servers continues, even if the hub itself restarts or goes down.
 
 When you first configure the hub, you may not even realize this
 because the proxy is automatically managed by the hub. This is great
-for getting started and even most use, but everytime you restart the
-hub, all user connections also get restarted. But it's also simple to
+for getting started and even most use-cases, although, everytime you restart the
+hub, all user connections are also restarted. However, it is also simple to
 run the proxy as a service separate from the hub, so that you are free
 to reconfigure the hub while only interrupting users who are currently
 actively starting the hub.
 
 The default JupyterHub proxy is
-[configurable-http-proxy](https://github.com/jupyterhub/configurable-http-proxy),
-and that page has some docs. If you are using a different proxy, such
-as Traefik, these instructions are probably not relevant to you.
+[configurable-http-proxy](https://github.com/jupyterhub/configurable-http-proxy). If you are using a different proxy, such
+as [Traefik](https://github.com/traefik/traefik), these instructions are probably not relevant to you.
 
 ## Configuration options
 
@@ -40,9 +39,14 @@ set to the URL which the hub uses to connect _to the proxy's API_.
 ## Proxy configuration
 
 You need to configure a service to start the proxy. An example
-command line for this is `configurable-http-proxy --ip=127.0.0.1 --port=8000 --api-ip=127.0.0.1 --api-port=8001 --default-target=http://localhost:8081 --error-target=http://localhost:8081/hub/error`. (Details for how to
-do this is out of scope for this tutorial - for example it might be a
-systemd service on within another docker cotainer). The proxy has no
+command line argument for this is:
+
+```bash
+$ configurable-http-proxy --ip=127.0.0.1 --port=8000 --api-ip=127.0.0.1 --api-port=8001 --default-target=http://localhost:8081 --error-target=http://localhost:8081/hub/error
+```
+
+(Details on how to do this is out of the scope of this tutorial. For example, it might be a
+systemd service configured within another docker container). The proxy has no
 configuration files, all configuration is via the command line and
 environment variables.
 
@@ -57,9 +61,9 @@ match the token given to `c.ConfigurableHTTPProxy.auth_token`.
 
 You should check the [configurable-http-proxy
 options](https://github.com/jupyterhub/configurable-http-proxy) to see
-what other options are needed, for example SSL options. Note that
-these are configured in the hub if the hub is starting the proxy - you
-need to move the options to here.
+what other options are needed, for example, SSL options. Note that
+these options are configured in the hub if the hub is starting the proxy, so you
+need to configure the options there.
 
 ## Docker image
 

docs/source/reference/server-api.md

@@ -1,37 +1,32 @@
 # 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.
+Sometimes, when working with applications such as [BinderHub](https://binderhub.readthedocs.io), it may be necessary to launch Jupyter-based services on behalf of your users.
+Doing so can be achieved through JupyterHub's [REST API](../reference/rest.md), which allows one to launch and manage servers on behalf of users through API calls instead of the JupyterHub UI.
+This way, you can take advantage of other user/launch/lifecycle patterns that are not natively supported by the JupyterHub UI, all without the need to develop the server management features of JupyterHub Spawners and/or Authenticators.
 
-[binderhub]: https://binderhub.readthedocs.io
-[rest api]: ../reference/rest.md
+This tutorial goes through working with the JupyterHub API to manage servers for users.
+In particular, it covers how to:
 
-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 the 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)
 
-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)
+At the end, we also provide sample Python code that can be used to implement these steps.
 
 (checking)=
 
 ## Checking server status
 
-Requesting information about a user includes a `servers` field,
-which is a dictionary.
+First, request information about a particular user using a GET request:
 
 ```
 GET /hub/api/users/:username
 ```
 
+The response you get will include a `servers` field, which is a dictionary, as shown in this JSON-formatted response:
+
 **Required scope: `read:servers`**
 
 ```json
@@ -49,13 +44,9 @@ GET /hub/api/users/:username
 }
 ```
 
-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.
+Many JupyterHub deployments only use a 'default' server, represented as an empty string `''` for a name. An investigation of the `servers` field can yield one of two results. First, it can be empty as in the sample JSON response above. In such a case, the user has no running servers.
 
-This is the servers dict when the user's default server is fully running and ready:
+However, should the user have running servers, then the returned dict should contain various information, as shown in this response:
 
 ```json
   "servers": {
@@ -75,34 +66,28 @@ This is the servers dict when the user's default server is fully running and rea
 Key properties of a server:
 
 name
-: the server's name. Always the same as the key in `servers`
+: 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.
+Will always be `null` if `ready` is true or a string if false.
 
 url
-: The server's url (just the path, e.g. `/users/:name/:servername/`)
-where the server can be accessed if `ready` is true.
+: The server's url 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.
+: The API URL path (starting with `/hub/api`) where the progress API can be used to wait for the server to be ready.
 
 last_activity
-: ISO8601 timestamp indicating when activity was last observed on the server
+: ISO8601 timestamp indicating when activity was last observed on the server.
 
 started
-: ISO801 timestamp indicating when the server was last 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:
+The two responses above are from a user with no servers and another with one `ready` server. The sample below is a response likely to be received when one requests a server launch while the server is not yet ready:
 
 ```json
   "servers": {
@@ -119,11 +104,7 @@ while the server is not ready yet:
   }
 ```
 
-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][].
+Note that `ready` is `false` and `pending` has the value `spawn`, meaning that the server is not ready and attempting to access it may not work as it is still in the process of spawning. We'll get more into this below in [waiting for a server][].
 
 [waiting for a server]: waiting
 
@@ -131,7 +112,7 @@ We'll get more into that below in [waiting for a server][].
 
 ## Starting servers
 
-To start a server, make the request
+To start a server, make this API request:
 
 ```
 POST /hub/api/users/:username/servers/[:servername]
@@ -139,47 +120,35 @@ 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:
+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.
+: This status code means the launch completed and the server is ready and is 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._
+: This is the more likely response, and means that the server has begun launching,
+but is not immediately ready. As a result, the server shows `pending: 'spawn'` at this point and you should wait for it to start.
 
 (waiting)=
 
-## Waiting for a server
+## Waiting for a server to start
 
-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:
+After receiving a `202 Accepted` response, you have to wait for the server to start.
+Two approaches can be applied to establish when the server is ready:
 
 1. {ref}`Polling the server model <polling>`
-2. the {ref}`progress API <progress>`
+2. {ref}`Using the progress API <progress>`
 
 (polling)=
 
 ### Polling the server model
 
-The simplest way to check if a server is ready
-is to request the user model.
+The simplest way to check if a server is ready is to programmatically query the server model until two conditions are true:
 
-If:
+1. The server name is contained in the `servers` response, and
+2. `servers['servername']['ready']` is true.
 
-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:
+The Python code snippet below can be used to check if a server is ready:
 
 ```python
 def server_ready(hub_url, user, server_name="", token):
@@ -206,14 +175,12 @@ You can keep making this check until `ready` is true.
 
 (progress)=
 
-### Progress API
+### Using the progress API
 
-The most _efficient_ way to wait for a server to start is the progress API.
+The most _efficient_ way to wait for a server to start is by using 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 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`_
+The default server progress can be accessed at `:user/servers//progress` or `:user/server/progress` as demonstrated in the following GET request:
 
 ```
 GET /hub/api/users/:user/servers/:servername/progress
@@ -221,8 +188,8 @@ 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:
+The progress API is an example of an [EventStream][] API.
+Messages are _streamed_ and delivered in the form:
 
 ```
 data: {"progress": 10, "message": "...", ...}
@@ -233,7 +200,7 @@ 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:
+Progress events have the form:
 
 ```python
 {
@@ -254,11 +221,10 @@ 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
+: 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:
+The progress API can be used even with fully ready servers.
+If the server is ready, there will only be one event, which will look like:
 
 ```json
 {
@@ -270,9 +236,10 @@ there will only be one event that looks like:
 }
 ```
 
-where `ready` and `url` are the same as in the server model (`ready` will always be true).
+where `ready` and `url` are the same as in the server model, and `ready` will always be true.
 
-A typical complete stream from the event-stream API:
+A significant advantage of the progress API is that it shows the status of the server through a stream of messages.
+Below is an example of a typical complete stream from the API:
 
 ```
 
@@ -302,21 +269,21 @@ 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:
+Similar to when starting a server, issuing the DELETE request above might not stop the server immediately.
+Instead, 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.
+: This code means your request was accepted but is not yet completely processed.
 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.
+There is no progress API for checking when a server actually stops.
+The only way to wait for a server to stop is to poll it and wait for the server to disappear from the user `servers` model.
+
+This Python code snippet can be used to stop a server and the wait for the process to complete:
 
 ```{literalinclude} ../../../examples/server-api/start-stop-server.py
 :language: python
@@ -327,9 +294,8 @@ and wait for the server to disappear from the user `servers` model.
 
 ## 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.
+JupyterHub tokens with the `access:servers` scope can be used to communicate with servers themselves.
+The tokens can be the same as those you used to launch your service.
 
 ```{note}
 Access scopes are new in JupyterHub 2.0.
@@ -338,29 +304,26 @@ 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,
+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`.
+The returned URL is of the form `{hub_url}{server_url}`,
+where `hub_url` would be `http://127.0.0.1:8000` by default and `server_url` is `/user/myname`.
+When combined, the two give 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.
+that ties all theses steps together.
 
-To summarize the steps:
+In summary, the processes involved in managing servers on behalf of users are:
 
-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
+1. Get user information 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.
+The example below demonstrates starting and stopping servers via the JupyterHub API,
+including waiting for them to start via the progress API and waiting for them to stop by polling the user model.
 
 ```{literalinclude} ../../../examples/server-api/start-stop-server.py
 :language: python

docs/source/reference/services.md

@@ -186,7 +186,7 @@ information to the Service via the environment variables described above. A
 flexible Service, whether managed by the Hub or not, can make use of these
 same environment variables.
 
-When you run a service that has a url, it will be accessible under a
+When you run a service that has a URL, it will be accessible under a
 `/services/` prefix, such as `https://myhub.horse/services/my-service/`. For
 your service to route proxied requests properly, it must take
 `JUPYTERHUB_SERVICE_PREFIX` into account when routing requests. For example, a
@@ -268,7 +268,7 @@ you can access the token authenticating the current request with {meth}`.HubAuth
 :::{versionchanged} 2.2
 
 {meth}`.HubAuth.get_token` adds support for retrieving
-tokens stored in tornado cookies after completion of OAuth.
+tokens stored in tornado cookies after the 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.
 :::

docs/source/reference/spawners.md

@@ -4,9 +4,9 @@ A [Spawner][] starts each single-user notebook server.
 The Spawner represents an abstract interface to a process,
 and a custom Spawner needs to be able to take three actions:
 
-- start the process
-- poll whether the process is still running
-- stop the process
+- start a process
+- poll whether a process is still running
+- stop a process
 
 ## Examples
 
@@ -15,9 +15,9 @@ Some examples include:
 
 - [DockerSpawner](https://github.com/jupyterhub/dockerspawner) for spawning user servers in Docker containers
   - `dockerspawner.DockerSpawner` for spawning identical Docker containers for
-    each users
+    each user
   - `dockerspawner.SystemUserSpawner` for spawning Docker containers with an
-    environment and home directory for each users
+    environment and home directory for each user
   - both `DockerSpawner` and `SystemUserSpawner` also work with Docker Swarm for
     launching containers on remote machines
 - [SudoSpawner](https://github.com/jupyterhub/sudospawner) enables JupyterHub to
@@ -28,12 +28,13 @@ Some examples include:
   servers in YARN containers on a Hadoop cluster
 - [SSHSpawner](https://github.com/NERSC/sshspawner) to spawn notebooks
   on a remote server using SSH
+- [KubeSpawner](https://github.com/jupyterhub/kubespawner) to spawn notebook servers on kubernetes cluster.
 
 ## Spawner control methods
 
 ### Spawner.start
 
-`Spawner.start` should start the single-user server for a single user.
+`Spawner.start` should start a single-user server for a single user.
 Information about the user can be retrieved from `self.user`,
 an object encapsulating the user's name, authentication, and server info.
 
@@ -68,13 +69,13 @@ via relaxing the `Spawner.start_timeout` config value.
 
 #### Note on IPs and ports
 
-`Spawner.ip` and `Spawner.port` attributes set the _bind_ url,
+`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_.
+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}`,
+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,
@@ -110,7 +111,7 @@ class MySpawner(Spawner):
 
 #### 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 `Spawner.start` raises an Exception, a message can be passed on to the user via the exception using 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.
 
@@ -120,11 +121,11 @@ If both attributes are not present, the Exception will be shown to the user as u
 
 ### Spawner.poll
 
-`Spawner.poll` should check if the spawner is still running.
+`Spawner.poll` checks if the spawner is still running.
 It should return `None` if it is still running,
 and an integer exit status, otherwise.
 
-For the local process case, `Spawner.poll` uses `os.kill(PID, 0)`
+In the case of local processes, `Spawner.poll` uses `os.kill(PID, 0)`
 to check if the local process is still running. On Windows, it uses `psutil.pid_exists`.
 
 ### Spawner.stop
@@ -140,7 +141,7 @@ A JSON-able dictionary of state can be used to store persisted information.
 
 Unlike start, stop, and poll methods, the state methods must not be coroutines.
 
-For the single-process case, the Spawner state is only the process ID of the server:
+In the case of single processes, the Spawner state is only the process ID of the server:
 
 ```python
 def get_state(self):
@@ -266,8 +267,8 @@ 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)
+- Spawner.cmd (default: `['jupyterhub-singleuser']`)
+- Spawner.args (CLI args to pass to the cmd, default: empty)
 
 where the configuration:
 
@@ -282,7 +283,7 @@ would result in spawning the command:
 my-singleuser-wrapper --debug --flag
 ```
 
-The `Spawner.get_args()` method is how Spawner.args is accessed,
+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,
@@ -296,36 +297,36 @@ Additional variables can be specified via the `Spawner.environment` configuratio
 
 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_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_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_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*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)
+  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.
+- 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.
@@ -337,7 +338,7 @@ guarantees on resources, such as CPU and memory. To provide a consistent
 experience for sysadmins and users, we provide a standard way to set and
 discover these resource limits and guarantees, such as for memory and CPU.
 For the limits and guarantees to be useful, **the spawner must implement
-support for them**. For example, LocalProcessSpawner, the default
+support for them**. For example, `LocalProcessSpawner`, the default
 spawner, does not support limits and guarantees. One of the spawners
 that supports limits and guarantees is the `systemdspawner`.
 
@@ -366,7 +367,7 @@ limits or guarantees are provided, and no environment values are set.
 `c.Spawner.cpu_limit`: In supported spawners, you can set
 `c.Spawner.cpu_limit` to limit the total number of cpu-cores that a
 single-user notebook server can use. These can be fractional - `0.5` means 50%
-of one CPU core, `4.0` is 4 cpu-cores, etc. This value is also set in the
+of one CPU core, `4.0` is 4 CPU-cores, etc. This value is also set in the
 single-user notebook server's environment variable `CPU_LIMIT`. The limit does
 not claim that you will be able to use all the CPU up to your limit as other
 higher priority applications might be taking up CPU.

docs/source/reference/technical-overview.md

@@ -2,7 +2,7 @@
 
 The **Technical Overview** section gives you a high-level view of:
 
-- JupyterHub's Subsystems: Hub, Proxy, Single-User Notebook Server
+- JupyterHub's major Subsystems: Hub, Proxy, Single-User Notebook Server
 - how the subsystems interact
 - the process from JupyterHub access to user login
 - JupyterHub's default behavior
@@ -11,16 +11,16 @@ The **Technical Overview** section gives you a high-level view of:
 The goal of this section is to share a deeper technical understanding of
 JupyterHub and how it works.
 
-## The Subsystems: Hub, Proxy, Single-User Notebook Server
+## The Major Subsystems: Hub, Proxy, Single-User Notebook Server
 
-JupyterHub is a set of processes that together provide a single user Jupyter
-Notebook server for each person in a group. Three major subsystems are started
+JupyterHub is a set of processes that together, provide a single-user Jupyter
+Notebook server for each person in a group. Three subsystems are started
 by the `jupyterhub` command line program:
 
 - **Hub** (Python/Tornado): manages user accounts, authentication, and
-  coordinates Single User Notebook Servers using a Spawner.
+  coordinates Single User Notebook Servers using a [Spawner](./spawners.md).
 
-- **Proxy**: the public facing part of JupyterHub that uses a dynamic proxy
+- **Proxy**: the public-facing part of JupyterHub that uses a dynamic proxy
   to route HTTP requests to the Hub and Single User Notebook Servers.
   [configurable http proxy](https://github.com/jupyterhub/configurable-http-proxy)
   (node-http-proxy) is the default proxy.
@@ -28,7 +28,7 @@ by the `jupyterhub` command line program:
 - **Single-User Notebook Server** (Python/Tornado): a dedicated,
   single-user, Jupyter Notebook server is started for each user on the system
   when the user logs in. The object that starts the single-user notebook
-  servers is called a **Spawner**.
+  servers is called a **[Spawner](./spawners.md)**.
 
 ![JupyterHub subsystems](../images/jhub-parts.png)
 
@@ -41,8 +41,8 @@ The basic principles of operation are:
 
 - The Hub spawns the proxy (in the default JupyterHub configuration)
 - The proxy forwards all requests to the Hub by default
-- The Hub handles login, and spawns single-user notebook servers on demand
-- The Hub configures the proxy to forward url prefixes to single-user notebook
+- The Hub handles login and spawns single-user notebook servers on demand
+- The Hub configures the proxy to forward URL prefixes to single-user notebook
   servers
 
 The proxy is the only process that listens on a public interface. The Hub sits
@@ -50,17 +50,16 @@ behind the proxy at `/hub`. Single-user servers sit behind the proxy at
 `/user/[username]`.
 
 Different **[authenticators](./authenticators.md)** control access
-to JupyterHub. The default one (PAM) uses the user accounts on the server where
+to JupyterHub. The default one [(PAM)](https://en.wikipedia.org/wiki/Pluggable_authentication_module) uses the user accounts on the server where
 JupyterHub is running. If you use this, you will need to create a user account
-on the system for each user on your team. Using other authenticators, you can
+on the system for each user on your team. However, using other authenticators you can
 allow users to sign in with e.g. a GitHub account, or with any single-sign-on
 system your organization has.
 
 Next, **[spawners](./spawners.md)** control how JupyterHub starts
 the individual notebook server for each user. The default spawner will
 start a notebook server on the same machine running under their system username.
-The other main option is to start each server in a separate container, often
-using Docker.
+The other main option is to start each server in a separate container, often using [Docker](https://jupyterhub-dockerspawner.readthedocs.io/en/latest/).
 
 ## The Process from JupyterHub Access to User Login
 
@@ -72,20 +71,20 @@ When a user accesses JupyterHub, the following events take place:
 - A single-user notebook server instance is [spawned](./spawners.md) for the
   logged-in user
 - When the single-user notebook server starts, the proxy is notified to forward
-  requests to `/user/[username]/*` to the single-user notebook server.
-- A cookie is set on `/hub/`, containing an encrypted token. (Prior to version
+  requests made to `/user/[username]/*`, to the single-user notebook server.
+- A [cookie](https://en.wikipedia.org/wiki/HTTP_cookie) is set on `/hub/`, containing an encrypted token. (Prior to version
   0.8, a cookie for `/user/[username]` was used too.)
 - The browser is redirected to `/user/[username]`, and the request is handled by
   the single-user notebook server.
 
-The single-user server identifies the user with the Hub via OAuth:
+How does the single-user server identify the user with the Hub via OAuth?
 
-- on request, the single-user server checks a cookie
-- if no cookie is set, redirect to the Hub for verification via OAuth
-- after verification at the Hub, the browser is redirected back to the
+- On request, the single-user server checks a cookie
+- If no cookie is set, the single-user server redirects to the Hub for verification via OAuth
+- After verification at the Hub, the browser is redirected back to the
   single-user server
-- the token is verified and stored in a cookie
-- if no user is identified, the browser is redirected back to `/hub/login`
+- The token is verified and stored in a cookie
+- If no user is identified, the browser is redirected back to `/hub/login`
 
 ## Default Behavior
 
@@ -111,7 +110,7 @@ working directory:
   This file needs to persist so that a **Hub** server restart will avoid
   invalidating cookies. Conversely, deleting this file and restarting the server
   effectively invalidates all login cookies. The cookie secret file is discussed
-  in the [Cookie Secret section of the Security Settings document](../getting-started/security-basics.md).
+  in the [Cookie Secret section of the Security Settings document](../getting-started/security-basics.rst).
 
 The location of these files can be specified via configuration settings. It is
 recommended that these files be stored in standard UNIX filesystem locations,

docs/source/reference/templates.md

@@ -84,5 +84,5 @@ template (for example, `login.html`) with:
 ```
 
 Extending `page.html` puts the message on all pages, but note that
-extending `page.html` take precedence over an extension of a specific
+extending `page.html` takes precedence over an extension of a specific
 page (unlike the variable-based approach above).

docs/source/reference/urls.md

@@ -2,13 +2,13 @@
 
 This document describes how JupyterHub routes requests.
 
-This does not include the [REST API](./rest.md) urls.
+This does not include the [REST API](./rest.md) URLs.
 
 In general, all URLs can be prefixed with `c.JupyterHub.base_url` to
 run the whole JupyterHub application on a prefix.
 
-All authenticated handlers redirect to `/hub/login` to login users
-prior to being redirected back to the originating page.
+All authenticated handlers redirect to `/hub/login` to log-in users
+before being redirected back to the originating page.
 The returned request should preserve all query parameters.
 
 ## `/`
@@ -25,12 +25,12 @@ This is an authenticated URL.
 
 This handler redirects users to the default URL of the application,
 which defaults to the user's default server.
-That is, it redirects to `/hub/spawn` if the user's server is not running,
-or the server itself (`/user/:name`) if the server is running.
+That is, the handler redirects to `/hub/spawn` if the user's server is not running,
+or to the server itself (`/user/:name`) if the server is running.
 
-This default url behavior can be customized in two ways:
+This default URL behavior can be customized in two ways:
 
-To redirect users to the JupyterHub home page (`/hub/home`)
+First, to redirect users to the JupyterHub home page (`/hub/home`)
 instead of spawning their server,
 set `redirect_to_server` to False:
 
@@ -40,7 +40,7 @@ c.JupyterHub.redirect_to_server = False
 
 This might be useful if you have a Hub where you expect
 users to be managing multiple server configurations
-and automatic spawning is not desirable.
+but automatic spawning is not desirable.
 
 Second, you can customise the landing page to any page you like,
 such as a custom service you have deployed e.g. with course information:
@@ -57,7 +57,7 @@ By default, the Hub home page has just one or two buttons
 for starting and stopping the user's server.
 
 If named servers are enabled, there will be some additional
-tools for management of named servers.
+tools for management of the named servers.
 
 _Version added: 1.0_ named server UI is new in 1.0.
 
@@ -65,34 +65,34 @@ _Version added: 1.0_ named server UI is new in 1.0.
 
 This is the JupyterHub login page.
 If you have a form-based username+password login,
-such as the default PAMAuthenticator,
+such as the default [PAMAuthenticator](https://en.wikipedia.org/wiki/Pluggable_authentication_module),
 this page will render the login form.
 
 ![A login form](../images/login-form.png)
 
 If login is handled by an external service,
 e.g. with OAuth, this page will have a button,
-declaring "Login with ..." which users can click
-to login with the chosen service.
+declaring "Log in with ..." which users can click
+to log in with the chosen service.
 
 ![A login redirect button](../images/login-button.png)
 
-If you want to skip the user-interaction to initiate logging in
-via the button, you can set
+If you want to skip the user interaction and initiate login
+via the button, you can set:
 
 ```python
 c.Authenticator.auto_login = True
 ```
 
-This can be useful when the user is "already logged in" via some mechanism,
-but a handshake via redirects is necessary to complete the authentication with JupyterHub.
+This can be useful when the user is "already logged in" via some mechanism.
+However, a handshake via `redirects` is necessary to complete the authentication with JupyterHub.
 
 ## `/hub/logout`
 
-Visiting `/hub/logout` clears cookies from the current browser.
+Visiting `/hub/logout` clears [cookies](https://en.wikipedia.org/wiki/HTTP_cookie) from the current browser.
 Note that **logging out does not stop a user's server(s)** by default.
 
-If you would like to shutdown user servers on logout,
+If you would like to shut down user servers on logout,
 you can enable this behavior with:
 
 ```python
@@ -105,8 +105,8 @@ does not mean the user is no longer actively using their server from another mac
 ## `/user/:username[/:servername]`
 
 If a user's server is running, this URL is handled by the user's given server,
-not the Hub.
-The username is the first part and, if using named servers,
+not by the Hub.
+The username is the first part, and if using named servers,
 the server name is the second part.
 
 If the user's server is _not_ running, this will be redirected to `/hub/user/:username/...`
@@ -120,11 +120,11 @@ if the specified server were running).
 Handling this URL is the most complicated condition in JupyterHub,
 because there can be many states:
 
-1. server is not active
+1. the server is not active
    a. user matches
    b. user doesn't match
-2. server is ready
-3. server is pending, but not ready
+2. the server is ready
+3. the server is pending, but not ready
 
 If the server is pending spawn,
 the browser will be redirected to `/hub/spawn-pending/:username/:servername`
@@ -140,39 +140,37 @@ Some checks are performed and a delay is added before redirecting back to `/user
 If something is really wrong, this can result in a redirect loop.
 
 Visiting this page will never result in triggering the spawn of servers
-without additional user action (i.e. clicking the link on the page)
+without additional user action (i.e. clicking the link on the page).
 
 ![Visiting a URL for a server that's not running](../images/not-running.png)
 
 _Version changed: 1.0_
 
-Prior to 1.0, this URL itself was responsible for spawning servers,
-and served the progress page if it was pending,
-redirected to running servers, and
-This was useful because it made sure that requested servers were restarted after they stopped,
-but could also be harmful because unused servers would continuously be restarted if e.g.
-an idle JupyterLab frontend were open pointed at it,
-which constantly makes polling requests.
+Prior to 1.0, this URL itself was responsible for spawning servers.
+If the progress page was pending, the URL redirected it to running servers.
+This was useful because it made sure that the requested servers were restarted after they stopped.
+However, it could also be harmful because unused servers would continuously be restarted if e.g.
+an idle JupyterLab frontend that constantly makes polling requests was openly pointed at it.
 
 ### Special handling of API requests
 
 Requests to `/user/:username[/:servername]/api/...` are assumed to be
 from applications connected to stopped servers.
-These are failed with 503 and an informative JSON error message
-indicating how to spawn the server.
-This is meant to help applications such as JupyterLab
+These requests fail with a `503` status code and an informative JSON error message
+that indicates how to spawn the server.
+This is meant to help applications such as JupyterLab,
 that are connected to a server that has stopped.
 
 _Version changed: 1.0_
 
-JupyterHub 0.9 failed these API requests with status 404,
-but 1.0 uses 503.
+JupyterHub version 0.9 failed these API requests with status `404`,
+but version 1.0 uses 503.
 
 ## `/user-redirect/...`
 
-This URL is for sharing a URL that will redirect a user
+The `/user-redirect/...` URL is for sharing a URL that will redirect a user
 to a path on their own default server.
-This is useful when users have the same file at the same URL on their servers,
+This is useful when different users have the same file at the same URL on their servers,
 and you want a single link to give to any user that will open that file on their server.
 
 e.g. a link to `/user-redirect/notebooks/Index.ipynb`
@@ -194,7 +192,7 @@ that is intended to make it possible.
 ### `/hub/spawn[/:username[/:servername]]`
 
 Requesting `/hub/spawn` will spawn the default server for the current user.
-If `username` and optionally `servername` are specified,
+If the `username` and optionally `servername` are specified,
 then the specified server for the specified user will be spawned.
 Once spawn has been requested,
 the browser is redirected to `/hub/spawn-pending/...`.
@@ -207,7 +205,7 @@ and a POST request will trigger the actual spawn and redirect.
 
 _Version added: 1.0_
 
-1.0 adds the ability to specify username and servername.
+1.0 adds the ability to specify `username` and `servername`.
 Prior to 1.0, only `/hub/spawn` was recognized for the default server.
 
 _Version changed: 1.0_
@@ -247,7 +245,7 @@ against the [JupyterHub REST API](./rest.md).
 
 Administrators can take various administrative actions from this page:
 
-1. add/remove users
-2. grant admin privileges
-3. start/stop user servers
-4. shutdown JupyterHub itself
+- add/remove users
+- grant admin privileges
+- start/stop user servers
+- shutdown JupyterHub itself

docs/source/reference/websecurity.md

@@ -5,7 +5,7 @@ The **Security Overview** section helps you learn about:
 - the design of JupyterHub with respect to web security
 - the semi-trusted user
 - the available mitigations to protect untrusted users from each other
-- the value of periodic security audits.
+- the value of periodic security audits
 
 This overview also helps you obtain a deeper understanding of how JupyterHub
 works.
@@ -16,9 +16,9 @@ JupyterHub is designed to be a _simple multi-user server for modestly sized
 groups_ of **semi-trusted** users. While the design reflects serving semi-trusted
 users, JupyterHub is not necessarily unsuitable for serving **untrusted** users.
 
-Using JupyterHub with **untrusted** users does mean more work by the
+Using JupyterHub with **untrusted** users does mean more work for the
 administrator. Much care is required to secure a Hub, with extra caution on
-protecting users from each other as the Hub is serving untrusted users.
+protecting users from each other, since the Hub serves untrusted users.
 
 One aspect of JupyterHub's _design simplicity_ for **semi-trusted** users is that
 the Hub and single-user servers are placed in a _single domain_, behind a
@@ -32,7 +32,7 @@ servers) as a single website (i.e. single domain).
 
 To protect users from each other, a user must **never** be able to write arbitrary
 HTML and serve it to another user on the Hub's domain. JupyterHub's
-authentication setup prevents a user writing arbitrary HTML and serving it to
+authentication setup prevents a user from writing arbitrary HTML and serving it to
 another user because only the owner of a given single-user notebook server is
 allowed to view user-authored pages served by the given single-user notebook
 server.
@@ -47,7 +47,7 @@ ensure that:
   - If the `PATH` is used to resolve the single-user executable (instead of
     using an absolute path), a user **may not** create new files in any `PATH`
     directory that precedes the directory containing `jupyterhub-singleuser`.
-  - A user may not modify environment variables (e.g. PATH, PYTHONPATH) for
+  - A user may not modify environment variables (e.g. `PATH`, `PYTHONPATH`) for
     their single-user server.
 - A user **may not** modify the configuration of the notebook server
   (the `~/.jupyter` or `JUPYTER_CONFIG_DIR` directory).
@@ -58,7 +58,7 @@ If any additional services are run on the same domain as the Hub, the services
 
 ## Mitigate security issues
 
-Several approaches to mitigating these issues with configuration
+The several approaches to mitigating security issues with configuration
 options provided by JupyterHub include:
 
 ### Enable subdomains
@@ -76,10 +76,10 @@ resolves the cross-site issues.
 
 ### Disable user config
 
-If subdomains are not available or not desirable, JupyterHub provides a
+If subdomains are unavailable or undesirable, JupyterHub provides a
 configuration option `Spawner.disable_user_config`, which can be set to prevent
 the user-owned configuration files from being loaded. After implementing this
-option, PATHs and package installation and PATHs are the other things that the
+option, `PATH`s and package installation are the other things that the
 admin must enforce.
 
 ### Prevent spawners from evaluating shell configuration files
@@ -101,8 +101,8 @@ pose additional risk to the web application's security.
 
 ### Encrypt internal connections with SSL/TLS
 
-By default, all communication on the server, between the proxy, hub, and single
--user notebooks is performed unencrypted. Setting the `internal_ssl` flag in
+By default, all communications on the server, between the proxy, hub, and single
+-user notebooks are performed unencrypted. Setting the `internal_ssl` flag in
 `jupyterhub_config.py` secures the aforementioned routes. Turning this
 feature on does require that the enabled `Spawner` can use the certificates
 generated by the `Hub` (the default `LocalProcessSpawner` can, for instance).
@@ -119,8 +119,8 @@ extend to securing the `tcp` sockets as well.
 ## Security audits
 
 We recommend that you do periodic reviews of your deployment's security. It's
-good practice to keep JupyterHub, configurable-http-proxy, and nodejs
-versions up to date.
+good practice to keep [JupyterHub](https://readthedocs.org/projects/jupyterhub/), [configurable-http-proxy][], and [nodejs
+versions](https://github.com/nodejs/Release) up to date.
 
 A handy website for testing your deployment is
 [Qualsys' SSL analyzer tool](https://www.ssllabs.com/ssltest/analyze.html).
@@ -129,7 +129,7 @@ A handy website for testing your deployment is
 
 ## Vulnerability reporting
 
-If you believe you’ve found a security vulnerability in JupyterHub, or any
+If you believe you have found a security vulnerability in JupyterHub, or any
 Jupyter project, please report it to
 [security@ipython.org](mailto:security@ipython.org). If you prefer to encrypt
 your security reports, you can use [this PGP public

docs/source/troubleshooting.md

@@ -1,35 +1,9 @@
 # Troubleshooting
 
 When troubleshooting, you may see unexpected behaviors or receive an error
-message. This section provide links for identifying the cause of the
+message. This section provides links for identifying the cause of the
 problem and how to resolve it.
 
-[_Behavior_](#behavior)
-
-- JupyterHub proxy fails to start
-- sudospawner fails to run
-- What is the default behavior when none of the lists (admin, allowed,
-  allowed groups) are set?
-- JupyterHub Docker container not accessible at localhost
-
-[_Errors_](#errors)
-
-- 500 error after spawning my single-user server
-
-[_How do I...?_](#how-do-i)
-
-- Use a chained SSL certificate
-- Install JupyterHub without a network connection
-- I want access to the whole filesystem, but still default users to their home directory
-- How do I increase the number of pySpark executors on YARN?
-- How do I use JupyterLab's prerelease version with JupyterHub?
-- How do I set up JupyterHub for a workshop (when users are not known ahead of time)?
-- How do I set up rotating daily logs?
-- Toree integration with HDFS rack awareness script
-- Where do I find Docker images and Dockerfiles related to JupyterHub?
-
-[_Troubleshooting commands_](#troubleshooting-commands)
-
 ## Behavior
 
 ### JupyterHub proxy fails to start
@@ -40,9 +14,9 @@ If you have tried to start the JupyterHub proxy and it fails to start:
   `c.JupyterHub.ip = '*'`; if it is, try `c.JupyterHub.ip = ''`
 - Try starting with `jupyterhub --ip=0.0.0.0`
 
-**Note**: If this occurs on Ubuntu/Debian, check that the you are using a
-recent version of node. Some versions of Ubuntu/Debian come with a version
-of node that is very old, and it is necessary to update node.
+**Note**: If this occurs on Ubuntu/Debian, check that you are using a
+recent version of [Node](https://nodejs.org). Some versions of Ubuntu/Debian come with a very old version
+of Node and it is necessary to update Node.
 
 ### sudospawner fails to run
 
@@ -61,24 +35,24 @@ to the config file, `jupyterhub_config.py`.
 ### What is the default behavior when none of the lists (admin, allowed, allowed groups) are set?
 
 When nothing is given for these lists, there will be no admins, and all users
-who can authenticate on the system (i.e. all the unix users on the server with
+who can authenticate on the system (i.e. all the Unix users on the server with
 a password) will be allowed to start a server. The allowed username set lets you limit
 this to a particular set of users, and admin_users lets you specify who
 among them may use the admin interface (not necessary, unless you need to do
-things like inspect other users' servers, or modify the user list at runtime).
+things like inspect other users' servers or modify the user list at runtime).
 
-### JupyterHub Docker container not accessible at localhost
+### JupyterHub Docker container is not accessible at localhost
 
 Even though the command to start your Docker container exposes port 8000
 (`docker run -p 8000:8000 -d --name jupyterhub jupyterhub/jupyterhub jupyterhub`),
-it is possible that the IP address itself is not accessible/visible. As a result
+it is possible that the IP address itself is not accessible/visible. As a result,
 when you try http://localhost:8000 in your browser, you are unable to connect
 even though the container is running properly. One workaround is to explicitly
 tell Jupyterhub to start at `0.0.0.0` which is visible to everyone. Try this
 command:
 `docker run -p 8000:8000 -d --name jupyterhub jupyterhub/jupyterhub jupyterhub --ip 0.0.0.0 --port 8000`
 
-### How can I kill ports from JupyterHub managed services that have been orphaned?
+### How can I kill ports from JupyterHub-managed services that have been orphaned?
 
 I started JupyterHub + nbgrader on the same host without containers. When I try to restart JupyterHub + nbgrader with this configuration, errors appear that the service accounts cannot start because the ports are being used.
 
@@ -92,12 +66,12 @@ Where `<service_port>` is the port used by the nbgrader course service. This con
 
 ### Why am I getting a Spawn failed error message?
 
-After successfully logging in to JupyterHub with a compatible authenticators, I get a 'Spawn failed' error message in the browser. The JupyterHub logs have `jupyterhub KeyError: "getpwnam(): name not found: <my_user_name>`.
+After successfully logging in to JupyterHub with a compatible authenticator, I get a 'Spawn failed' error message in the browser. The JupyterHub logs have `jupyterhub KeyError: "getpwnam(): name not found: <my_user_name>`.
 
 This issue occurs when the authenticator requires a local system user to exist. In these cases, you need to use a spawner
 that does not require an existing system user account, such as `DockerSpawner` or `KubeSpawner`.
 
-### How can I run JupyterHub with sudo but use my current env vars and virtualenv location?
+### How can I run JupyterHub with sudo but use my current environment variables and virtualenv location?
 
 When launching JupyterHub with `sudo jupyterhub` I get import errors and my environment variables don't work.
 
@@ -109,25 +83,11 @@ sudo MY_ENV=abc123 \
   /srv/jupyterhub/jupyterhub
 ```
 
-### How can I view the logs for JupyterHub or the user's Notebook servers when using the DockerSpawner?
-
-Use `docker logs <container>` where `<container>` is the container name defined within `docker-compose.yml`. For example, to view the logs of the JupyterHub container use:
-
-    docker logs hub
-
-By default, the user's notebook server is named `jupyter-<username>` where `username` is the user's username within JupyterHub's db. So if you wanted to see the logs for user `foo` you would use:
-
-    docker logs jupyter-foo
-
-You can also tail logs to view them in real time using the `-f` option:
-
-    docker logs -f hub
-
 ## Errors
 
-### 500 error after spawning my single-user server
+### Error 500 after spawning my single-user server
 
-You receive a 500 error when accessing the URL `/user/<your_name>/...`.
+You receive a 500 error while accessing the URL `/user/<your_name>/...`.
 This is often seen when your single-user server cannot verify your user cookie
 with the Hub.
 
@@ -185,10 +145,10 @@ If you receive a 403 error, the API token for the single-user server is likely
 invalid. Commonly, the 403 error is caused by resetting the JupyterHub
 database (either removing jupyterhub.sqlite or some other action) while
 leaving single-user servers running. This happens most frequently when using
-DockerSpawner, because Docker's default behavior is to stop/start containers
-which resets the JupyterHub database, rather than destroying and recreating
+DockerSpawner because Docker's default behavior is to stop/start containers
+that reset the JupyterHub database, rather than destroying and recreating
 the container every time. This means that the same API token is used by the
-server for its whole life, until the container is rebuilt.
+server for its whole life until the container is rebuilt.
 
 The fix for this Docker case is to remove any Docker containers seeing this
 issue (typically all containers created before a certain point in time):
@@ -201,14 +161,14 @@ your server again.
 
 ##### Proxy settings (403 GET)
 
-When your whole JupyterHub sits behind a organization proxy (_not_ a reverse proxy like NGINX as part of your setup and _not_ the configurable-http-proxy) the environment variables `HTTP_PROXY`, `HTTPS_PROXY`, `http_proxy` and `https_proxy` might be set. This confuses the jupyterhub-singleuser servers: When connecting to the Hub for authorization they connect via the proxy instead of directly connecting to the Hub on localhost. The proxy might deny the request (403 GET). This results in the singleuser server thinking it has a wrong auth token. To circumvent this you should add `<hub_url>,<hub_ip>,localhost,127.0.0.1` to the environment variables `NO_PROXY` and `no_proxy`.
+When your whole JupyterHub sits behind an organization proxy (_not_ a reverse proxy like NGINX as part of your setup and _not_ the configurable-http-proxy) the environment variables `HTTP_PROXY`, `HTTPS_PROXY`, `http_proxy`, and `https_proxy` might be set. This confuses the JupyterHub single-user servers: When connecting to the Hub for authorization they connect via the proxy instead of directly connecting to the Hub on localhost. The proxy might deny the request (403 GET). This results in the single-user server thinking it has the wrong auth token. To circumvent this you should add `<hub_url>,<hub_ip>,localhost,127.0.0.1` to the environment variables `NO_PROXY` and `no_proxy`.
 
 ### Launching Jupyter Notebooks to run as an externally managed JupyterHub service with the `jupyterhub-singleuser` command returns a `JUPYTERHUB_API_TOKEN` error
 
 [JupyterHub services](https://jupyterhub.readthedocs.io/en/stable/reference/services.html) allow processes to interact with JupyterHub's REST API. Example use-cases include:
 
 - **Secure Testing**: provide a canonical Jupyter Notebook for testing production data to reduce the number of entry points into production systems.
-- **Grading Assignments**: provide access to shared Jupyter Notebooks that may be used for management tasks such grading assignments.
+- **Grading Assignments**: provide access to shared Jupyter Notebooks that may be used for management tasks such as grading assignments.
 - **Private Dashboards**: share dashboards with certain group members.
 
 If possible, try to run the Jupyter Notebook as an externally managed service with one of the provided [jupyter/docker-stacks](https://github.com/jupyter/docker-stacks).
@@ -222,7 +182,7 @@ If you launch a Jupyter Notebook with the `jupyterhub-singleuser` command direct
     Did you launch it manually?
 ```
 
-If you plan on testing `jupyterhub-singleuser` independently from JupyterHub, then you can set the api token environment variable. For example, if were to run the single-user Jupyter Notebook on the host, then:
+If you plan on testing `jupyterhub-singleuser` independently from JupyterHub, then you can set the API token environment variable. For example, if you were to run the single-user Jupyter Notebook on the host, then:
 
     export JUPYTERHUB_API_TOKEN=my_secret_token
     jupyterhub-singleuser
@@ -256,7 +216,7 @@ You would then set in your `jupyterhub_config.py` file the `ssl_key` and
 #### Example
 
 Your certificate provider gives you the following files: `example_host.crt`,
-`Entrust_L1Kroot.txt` and `Entrust_Root.txt`.
+`Entrust_L1Kroot.txt`, and `Entrust_Root.txt`.
 
 Concatenate the files appending the chain cert and root cert to your host cert:
 
@@ -289,7 +249,7 @@ with npmbox:
     python3 -m pip wheel jupyterhub
     npmbox configurable-http-proxy
 
-### I want access to the whole filesystem, but still default users to their home directory
+### I want access to the whole filesystem and still default users to their home directory
 
 Setting the following in `jupyterhub_config.py` will configure access to
 the entire filesystem and set the default to the user's home directory.
@@ -308,7 +268,7 @@ similar to this one:
 provides additional information. The [pySpark configuration documentation](https://spark.apache.org/docs/0.9.0/configuration.html)
 is also helpful for programmatic configuration examples.
 
-### How do I use JupyterLab's prerelease version with JupyterHub?
+### How do I use JupyterLab's pre-release version with JupyterHub?
 
 While JupyterLab is still under active development, we have had users
 ask about how to try out JupyterLab with JupyterHub.
@@ -321,7 +281,7 @@ For instance:
     python3 -m pip install jupyterlab
     jupyter serverextension enable --py jupyterlab --sys-prefix
 
-The important thing is that jupyterlab is installed and enabled in the
+The important thing is that JupyterLab is installed and enabled in the
 single-user notebook server environment. For system users, this means
 system-wide, as indicated above. For Docker containers, it means inside
 the single-user docker image, etc.
@@ -334,14 +294,14 @@ notebook servers to default to JupyterLab:
 ### How do I set up JupyterHub for a workshop (when users are not known ahead of time)?
 
 1. Set up JupyterHub using OAuthenticator for GitHub authentication
-2. Configure admin list to have workshop leaders be listed with administrator privileges.
+2. Configure the admin list to have workshop leaders listed with administrator privileges.
 
-Users will need a GitHub account to login and be authenticated by the Hub.
+Users will need a GitHub account to log in and be authenticated by the Hub.
 
 ### How do I set up rotating daily logs?
 
 You can do this with [logrotate](https://linux.die.net/man/8/logrotate),
-or pipe to `logger` to use syslog instead of directly to a file.
+or pipe to `logger` to use Syslog instead of directly to a file.
 
 For example, with this logrotate config file:
 
@@ -362,6 +322,51 @@ Or use syslog:
 
     jupyterhub | logger -t jupyterhub
 
+### Toree integration with HDFS rack awareness script
+
+The Apache Toree kernel will have an issue when running with JupyterHub if the standard HDFS rack awareness script is used. This will materialize in the logs as a repeated WARN:
+
+```bash
+16/11/29 16:24:20 WARN ScriptBasedMapping: Exception running /etc/hadoop/conf/topology_script.py some.ip.address
+ExitCodeException exitCode=1:   File "/etc/hadoop/conf/topology_script.py", line 63
+    print rack
+             ^
+SyntaxError: Missing parentheses in call to 'print'
+
+    at `org.apache.hadoop.util.Shell.runCommand(Shell.java:576)`
+```
+
+In order to resolve this issue, there are two potential options.
+
+1. Update HDFS core-site.xml, so the parameter "net.topology.script.file.name" points to a custom
+   script (e.g. /etc/hadoop/conf/custom_topology_script.py). Copy the original script and change the first line point
+   to a python two installation (e.g. /usr/bin/python).
+2. In spark-env.sh add a Python 2 installation to your path (e.g. export PATH=/opt/anaconda2/bin:$PATH).
+
+### Where do I find Docker images and Dockerfiles related to JupyterHub?
+
+Docker images can be found at the [JupyterHub organization on DockerHub](https://hub.docker.com/u/jupyterhub/).
+The Docker image [jupyterhub/singleuser](https://hub.docker.com/r/jupyterhub/singleuser/)
+provides an example single-user notebook server for use with DockerSpawner.
+
+Additional single-user notebook server images can be found at the [Jupyter
+organization on DockerHub](https://hub.docker.com/r/jupyter/) and information
+about each image at the [jupyter/docker-stacks repo](https://github.com/jupyter/docker-stacks).
+
+### How can I view the logs for JupyterHub or the user's Notebook servers when using the DockerSpawner?
+
+Use `docker logs <container>` where `<container>` is the container name defined within `docker-compose.yml`. For example, to view the logs of the JupyterHub container use:
+
+    docker logs hub
+
+By default, the user's notebook server is named `jupyter-<username>` where `username` is the user's username within JupyterHub's db. So if you wanted to see the logs for user `foo` you would use:
+
+    docker logs jupyter-foo
+
+You can also tail logs to view them in real-time using the `-f` option:
+
+    docker logs -f hub
+
 ## Troubleshooting commands
 
 The following commands provide additional detail about installed packages,
@@ -385,35 +390,3 @@ jupyter kernelspec list
 ```bash
 jupyterhub --debug
 ```
-
-### Toree integration with HDFS rack awareness script
-
-The Apache Toree kernel will an issue, when running with JupyterHub, if the standard HDFS
-rack awareness script is used. This will materialize in the logs as a repeated WARN:
-
-```bash
-16/11/29 16:24:20 WARN ScriptBasedMapping: Exception running /etc/hadoop/conf/topology_script.py some.ip.address
-ExitCodeException exitCode=1:   File "/etc/hadoop/conf/topology_script.py", line 63
-    print rack
-             ^
-SyntaxError: Missing parentheses in call to 'print'
-
-    at `org.apache.hadoop.util.Shell.runCommand(Shell.java:576)`
-```
-
-In order to resolve this issue, there are two potential options.
-
-1. Update HDFS core-site.xml, so the parameter "net.topology.script.file.name" points to a custom
-   script (e.g. /etc/hadoop/conf/custom_topology_script.py). Copy the original script and change the first line point
-   to a python two installation (e.g. /usr/bin/python).
-2. In spark-env.sh add a Python 2 installation to your path (e.g. export PATH=/opt/anaconda2/bin:$PATH).
-
-### Where do I find Docker images and Dockerfiles related to JupyterHub?
-
-Docker images can be found at the [JupyterHub organization on DockerHub](https://hub.docker.com/u/jupyterhub/).
-The Docker image [jupyterhub/singleuser](https://hub.docker.com/r/jupyterhub/singleuser/)
-provides an example single user notebook server for use with DockerSpawner.
-
-Additional single user notebook server images can be found at the [Jupyter
-organization on DockerHub](https://hub.docker.com/r/jupyter/) and information
-about each image at the [jupyter/docker-stacks repo](https://github.com/jupyter/docker-stacks).

examples/bootstrap-script/README.md

@@ -9,7 +9,7 @@ _Providing writeable storage for LDAP users_
 
 Your Jupyterhub is configured to use the LDAPAuthenticator and DockerSpawer.
 
-- The user has no file directory on the host since your are using LDAP.
+- The user has no file directory on the host since you are using LDAP.
 - When a user has no directory and DockerSpawner wants to mount a volume,
   the spawner will use docker to create a directory.
   Since the docker daemon is running as root, the generated directory for the volume
@@ -23,7 +23,7 @@ Another use would be to copy initial content, such as tutorial files or referenc
 material, into the user's space when a notebook server is newly spawned.
 
 You can define your own bootstrap process by implementing a `pre_spawn_hook` on any spawner.
-The Spawner itself is passed as parameter to your hook and you can easily get the contextual information out of the spawning process.
+The Spawner itself is passed as a parameter to your hook and you can easily get the contextual information out of the spawning process.
 
 Similarly, there may be cases where you would like to clean up after a spawner stops.
 You may implement a `post_stop_hook` that is always executed after the spawner stops.

examples/service-announcement/README.md

@@ -6,12 +6,28 @@ that appear when JupyterHub renders pages.
 To run the service as a hub-managed service simply include in your JupyterHub
 configuration file something like:
 
+:notebook:**Info**: You can run the announcement service example from the `examples`
+directory, using one of the several services provided by JupyterHub.
+
 ```python
+
+import sys
+
+from pathlib import Path
+# absolute path to announcement.py
+announcement_py = str(Path(__file__).parent.joinpath("announcement.py").resolve())
+
+#ensure get_config() is added in
+ c = get_config()
+
+...
+..
+
 c.JupyterHub.services = [
         {
             'name': 'announcement',
             'url': 'http://127.0.0.1:8888',
-            'command': [sys.executable, "-m", "announcement", "--port", "8888"],
+            'command': [sys.executable, announcement_py, "--port", "8888"],
         }
 ]
 ```

examples/service-announcement/jupyterhub_config.py

@@ -1,5 +1,7 @@
 import sys
 
+c = get_config()
+
 # To run the announcement service managed by the hub, add this.
 
 port = 9999

jsx/README.md

@@ -23,7 +23,7 @@ This app is written in JSX, and then transpiled into an ES5 bundle with Babel an
 
 #### Centralized state and data management with Redux:
 
-The app use Redux throughout the components via the `useSelector` and `useDispatch` hooks to store and update user and group data from the API. With Redux, this data is available to any connected component. This means that if one component recieves new data, they all do.
+The app uses Redux throughout the components via the `useSelector` and `useDispatch` hooks to store and update user and group data from the API. With Redux, this data is available to any connected component. This means that if one component receives new data, they all do.
 
 #### API functions
 
@@ -31,7 +31,7 @@ All API functions used by the front end are packaged as a library of props withi
 
 #### Pagination
 
-Indicies of paginated user and group data is stored in a `page` variable in the query string, as well as the `user_page` / `group_page` state variables in Redux. This allows the app to maintain two sources of truth, as well as protect the admin user's place in the collection on page reload. Limit is constant at this point and is held in the Redux state.
+Indicies of paginated user and group data are stored in a `page` variable in the query string, as well as the `user_page` / `group_page` state variables in Redux. This allows the app to maintain two sources of truth, as well as protect the admin user's place in the collection on page reload. The limit is constant at this point and is held in the Redux state.
 
 On updates to the paginated data, the app can respond in one of two ways. If a user/group record is either added or deleted, the pagination will reset and data will be pulled back with no offset. Alternatively, if a record is modified, the offset will remain and the change will be shown.
 
@@ -55,7 +55,7 @@ startServer().then(() => {
     .then((data) => dispatchPageChange(data, page));
 });
 
-// Alternatively, a new user was added, user data is being refreshed from offset 0.
+// Alternatively, a new user was added, and user data is being refreshed from offset 0.
 addUser().then(() => {
   updateUsers(0, limit)
     // After data is fetched, the Redux store is updated with the data and asserts page 0.

jsx/src/components/AddUser/AddUser.jsx

@@ -98,13 +98,13 @@ const AddUser = (props) => {
                               .then((data) => dispatchPageChange(data, 0))
                               .then(() => history.push("/"))
                               .catch(() =>
-                                setErrorAlert(`Failed to update users.`)
+                                setErrorAlert(`Failed to update users.`),
                               )
                           : setErrorAlert(
                               `Failed to create user. ${
                                 data.status == 409 ? "User already exists." : ""
-                              }`
-                            )
+                              }`,
+                            ),
                       )
                       .catch(() => setErrorAlert(`Failed to create user.`));
                   }}

jsx/src/components/AddUser/AddUser.test.js

@@ -131,7 +131,7 @@ test("Shows a more specific UI error dialogue when user creation returns an impr
   });
 
   let errorDialog = screen.getByText(
-    "Failed to create user. User already exists."
+    "Failed to create user. User already exists.",
   );
 
   expect(errorDialog).toBeVisible();

jsx/src/components/CreateGroup/CreateGroup.jsx

@@ -81,14 +81,14 @@ const CreateGroup = (props) => {
                               .then((data) => dispatchPageUpdate(data, 0))
                               .then(() => history.push("/groups"))
                               .catch(() =>
-                                setErrorAlert(`Could not update groups list.`)
+                                setErrorAlert(`Could not update groups list.`),
                               )
                           : setErrorAlert(
                               `Failed to create group. ${
                                 data.status == 409
                                   ? "Group already exists."
                                   : ""
-                              }`
+                              }`,
                             );
                       })
                       .catch(() => setErrorAlert(`Failed to create group.`));

jsx/src/components/CreateGroup/CreateGroup.test.js

@@ -107,7 +107,7 @@ test("Shows a more specific UI error dialogue when user creation returns an impr
   });
 
   let errorDialog = screen.getByText(
-    "Failed to create group. Group already exists."
+    "Failed to create group. Group already exists.",
   );
 
   expect(errorDialog).toBeVisible();

jsx/src/components/EditUser/EditUser.jsx

@@ -96,8 +96,8 @@ const EditUser = (props) => {
                                   .then(() => history.push("/"))
                                   .catch(() =>
                                     setErrorAlert(
-                                      `Could not update users list.`
-                                    )
+                                      `Could not update users list.`,
+                                    ),
                                   )
                               : setErrorAlert(`Failed to edit user.`);
                           })
@@ -129,7 +129,7 @@ const EditUser = (props) => {
                       editUser(
                         username,
                         updatedUsername != "" ? updatedUsername : username,
-                        admin
+                        admin,
                       )
                         .then((data) => {
                           data.status < 300
@@ -137,7 +137,7 @@ const EditUser = (props) => {
                                 .then((data) => dispatchPageChange(data, 0))
                                 .then(() => history.push("/"))
                                 .catch(() =>
-                                  setErrorAlert(`Could not update users list.`)
+                                  setErrorAlert(`Could not update users list.`),
                                 )
                             : setErrorAlert(`Failed to edit user.`);
                         })

jsx/src/components/GroupEdit/GroupEdit.jsx

@@ -111,21 +111,18 @@ const GroupEdit = (props) => {
             className="btn btn-primary"
             onClick={() => {
               let new_users = selected.filter(
-                (e) => !group_data.users.includes(e)
+                (e) => !group_data.users.includes(e),
               );
               let removed_users = group_data.users.filter(
-                (e) => !selected.includes(e)
+                (e) => !selected.includes(e),
               );
               let promiseQueue = [];
-              // check for changes
-              if (changed) {
               if (new_users.length > 0)
                 promiseQueue.push(addToGroup(new_users, group_data.name));
               if (removed_users.length > 0)
                 promiseQueue.push(
-                    removeFromGroup(removed_users, group_data.name)
+                  removeFromGroup(removed_users, group_data.name),
                 );
-              }
 
               if (hasDuplicates(propkeys) == true) {
                 setErrorAlert(`Duplicate keys found!`);

jsx/src/components/GroupSelect/GroupSelect.jsx

@@ -90,7 +90,7 @@ const GroupSelect = (props) => {
                 >
                   {e}
                 </div>
-              )
+              ),
             )}
           </div>
         </div>

jsx/src/components/Groups/Groups.jsx

@@ -1,4 +1,4 @@
-import React, { useEffect, useState } from "react";
+import React, { useEffect } from "react";
 import { useSelector, useDispatch } from "react-redux";
 import PropTypes from "prop-types";
 
@@ -37,7 +37,7 @@ const Groups = (props) => {
 
   useEffect(() => {
     updateGroups(offset, limit).then((data) =>
-      dispatchPageUpdate(data.items, data._pagination)
+      dispatchPageUpdate(data.items, data._pagination),
     );
   }, [offset, limit]);
 

jsx/src/components/ServerDashboard/ServerDashboard.jsx

@@ -38,11 +38,11 @@ const ServerDashboard = (props) => {
     adminAsc = (e) => e.sort((a) => (a.admin ? 1 : -1)),
     dateDesc = (e) =>
       e.sort((a, b) =>
-        new Date(a.last_activity) - new Date(b.last_activity) > 0 ? -1 : 1
+        new Date(a.last_activity) - new Date(b.last_activity) > 0 ? -1 : 1,
       ),
     dateAsc = (e) =>
       e.sort((a, b) =>
-        new Date(a.last_activity) - new Date(b.last_activity) > 0 ? 1 : -1
+        new Date(a.last_activity) - new Date(b.last_activity) > 0 ? 1 : -1,
       ),
     runningAsc = (e) => e.sort((a) => (a.server == null ? -1 : 1)),
     runningDesc = (e) => e.sort((a) => (a.server == null ? 1 : -1));
@@ -136,7 +136,7 @@ const ServerDashboard = (props) => {
                     dispatchPageUpdate(
                       data.items,
                       data._pagination,
-                      name_filter
+                      name_filter,
                     );
                   })
                   .catch(() => {
@@ -176,7 +176,7 @@ const ServerDashboard = (props) => {
                     dispatchPageUpdate(
                       data.items,
                       data._pagination,
-                      name_filter
+                      name_filter,
                     );
                   })
                   .catch(() => {
@@ -471,7 +471,7 @@ const ServerDashboard = (props) => {
                               failedServers.length > 1 ? "servers" : "server"
                             }. ${
                               failedServers.length > 1 ? "Are they " : "Is it "
-                            } already running?`
+                            } already running?`,
                           );
                         }
                         return res;
@@ -482,11 +482,11 @@ const ServerDashboard = (props) => {
                             dispatchPageUpdate(
                               data.items,
                               data._pagination,
-                              name_filter
+                              name_filter,
                             );
                           })
                           .catch(() =>
-                            setErrorAlert(`Failed to update users list.`)
+                            setErrorAlert(`Failed to update users list.`),
                           );
                         return res;
                       })
@@ -511,7 +511,7 @@ const ServerDashboard = (props) => {
                               failedServers.length > 1 ? "servers" : "server"
                             }. ${
                               failedServers.length > 1 ? "Are they " : "Is it "
-                            } already stopped?`
+                            } already stopped?`,
                           );
                         }
                         return res;
@@ -522,11 +522,11 @@ const ServerDashboard = (props) => {
                             dispatchPageUpdate(
                               data.items,
                               data._pagination,
-                              name_filter
+                              name_filter,
                             );
                           })
                           .catch(() =>
-                            setErrorAlert(`Failed to update users list.`)
+                            setErrorAlert(`Failed to update users list.`),
                           );
                         return res;
                       })

jsx/src/components/ServerDashboard/ServerDashboard.test.js

@@ -369,7 +369,7 @@ test("Shows a UI error dialogue when start all servers fails", async () => {
             />
           </Switch>
         </HashRouter>
-      </Provider>
+      </Provider>,
     );
   });
 
@@ -403,7 +403,7 @@ test("Shows a UI error dialogue when stop all servers fails", async () => {
             />
           </Switch>
         </HashRouter>
-      </Provider>
+      </Provider>,
     );
   });
 
@@ -437,7 +437,7 @@ test("Shows a UI error dialogue when start user server fails", async () => {
             />
           </Switch>
         </HashRouter>
-      </Provider>
+      </Provider>,
     );
   });
 
@@ -471,7 +471,7 @@ test("Shows a UI error dialogue when start user server returns an improper statu
             />
           </Switch>
         </HashRouter>
-      </Provider>
+      </Provider>,
     );
   });
 
@@ -505,7 +505,7 @@ test("Shows a UI error dialogue when stop user servers fails", async () => {
             />
           </Switch>
         </HashRouter>
-      </Provider>
+      </Provider>,
     );
   });
 
@@ -539,7 +539,7 @@ test("Shows a UI error dialogue when stop user server returns an improper status
             />
           </Switch>
         </HashRouter>
-      </Provider>
+      </Provider>,
     );
   });
 
@@ -585,7 +585,7 @@ test("Search for user calls updateUsers with name filter", async () => {
             />
           </Switch>
         </HashRouter>
-      </Provider>
+      </Provider>,
     );
   });
 

jsx/src/util/withAPI.js

@@ -7,11 +7,11 @@ const withAPI = withProps(() => ({
       `/users?include_stopped_servers&offset=${offset}&limit=${limit}&name_filter=${
         name_filter || ""
       }`,
-      "GET"
+      "GET",
     ).then((data) => data.json()),
   updateGroups: (offset, limit) =>
     jhapiRequest(`/groups?offset=${offset}&limit=${limit}`, "GET").then(
-      (data) => data.json()
+      (data) => data.json(),
     ),
   shutdownHub: () => jhapiRequest("/shutdown", "POST"),
   startServer: (name, serverName = "") =>

jsx/webpack.config.js

@@ -41,10 +41,10 @@ module.exports = {
       const app = devServer.app;
 
       var user_data = JSON.parse(
-        '[{"kind":"user","name":"foo","admin":true,"groups":[],"server":"/user/foo/","pending":null,"created":"2020-12-07T18:46:27.112695Z","last_activity":"2020-12-07T21:00:33.336354Z","servers":{"":{"name":"","last_activity":"2020-12-07T20:58:02.437408Z","started":"2020-12-07T20:58:01.508266Z","pending":null,"ready":true,"state":{"pid":28085},"url":"/user/foo/","user_options":{},"progress_url":"/hub/api/users/foo/server/progress"}}},{"kind":"user","name":"bar","admin":false,"groups":[],"server":null,"pending":null,"created":"2020-12-07T18:46:27.115528Z","last_activity":"2020-12-07T20:43:51.013613Z","servers":{}}]'
+        '[{"kind":"user","name":"foo","admin":true,"groups":[],"server":"/user/foo/","pending":null,"created":"2020-12-07T18:46:27.112695Z","last_activity":"2020-12-07T21:00:33.336354Z","servers":{"":{"name":"","last_activity":"2020-12-07T20:58:02.437408Z","started":"2020-12-07T20:58:01.508266Z","pending":null,"ready":true,"state":{"pid":28085},"url":"/user/foo/","user_options":{},"progress_url":"/hub/api/users/foo/server/progress"}}},{"kind":"user","name":"bar","admin":false,"groups":[],"server":null,"pending":null,"created":"2020-12-07T18:46:27.115528Z","last_activity":"2020-12-07T20:43:51.013613Z","servers":{}}]',
       );
       var group_data = JSON.parse(
-        '[{"kind":"group","name":"testgroup","users":[]}, {"kind":"group","name":"testgroup2","users":["foo", "bar"]}]'
+        '[{"kind":"group","name":"testgroup","users":[]}, {"kind":"group","name":"testgroup2","users":["foo", "bar"]}]',
       );
 
       // get user_data

jupyterhub/apihandlers/auth.py

@@ -3,6 +3,7 @@
 # Distributed under the terms of the Modified BSD License.
 import json
 from datetime import datetime
+from unittest import mock
 from urllib.parse import parse_qsl, quote, urlencode, urlparse, urlunparse
 
 from oauthlib import oauth2
@@ -241,6 +242,12 @@ class OAuthAuthorizeHandler(OAuthHandler, BaseHandler):
 
         uri, http_method, body, headers = self.extract_oauth_params()
         try:
+            with mock.patch.object(
+                self.oauth_provider.request_validator,
+                "_current_user",
+                self.current_user,
+                create=True,
+            ):
                 (
                     requested_scopes,
                     credentials,
@@ -289,12 +296,15 @@ class OAuthAuthorizeHandler(OAuthHandler, BaseHandler):
             required_scopes = {*scopes.identify_scopes(), *scopes.access_scopes(client)}
             user_scopes |= {"inherit", *required_scopes}
 
-            allowed_scopes = requested_scopes.intersection(user_scopes)
-            excluded_scopes = requested_scopes.difference(user_scopes)
-            # TODO: compute lower-level intersection of remaining _expanded_ scopes
-            # (e.g. user has admin:users, requesting read:users!group=x)
+            allowed_scopes, disallowed_scopes = scopes._resolve_requested_scopes(
+                requested_scopes,
+                user_scopes,
+                user=user.orm_user,
+                client=client,
+                db=self.db,
+            )
 
-            if excluded_scopes:
+            if disallowed_scopes:
                 self.log.warning(
                     f"Service {client.description} requested scopes {','.join(requested_scopes)}"
                     f" for user {self.current_user.name},"

jupyterhub/apihandlers/users.py

@@ -502,17 +502,19 @@ class UserServerAPIHandler(APIHandler):
         if server_name:
             if not self.allow_named_servers:
                 raise web.HTTPError(400, "Named servers are not enabled.")
-            if (
-                self.named_server_limit_per_user > 0
-                and server_name not in user.orm_spawners
-            ):
+
+            named_server_limit_per_user = (
+                await self.get_current_user_named_server_limit()
+            )
+
+            if named_server_limit_per_user > 0 and server_name not in user.orm_spawners:
                 named_spawners = list(user.all_spawners(include_default=False))
-                if self.named_server_limit_per_user <= len(named_spawners):
+                if named_server_limit_per_user <= len(named_spawners):
                     raise web.HTTPError(
                         400,
                         "User {} already has the maximum of {} named servers."
                         "  One must be deleted before a new server can be created".format(
-                            user_name, self.named_server_limit_per_user
+                            user_name, named_server_limit_per_user
                         ),
                     )
         spawner = user.get_spawner(server_name, replace_failed=True)

jupyterhub/app.py

@@ -1154,14 +1154,27 @@ class JupyterHub(Application):
         False, help="Allow named single-user servers per user"
     ).tag(config=True)
 
-    named_server_limit_per_user = Integer(
-        0,
+    named_server_limit_per_user = Union(
+        [Integer(), Callable()],
+        default_value=0,
         help="""
         Maximum number of concurrent named servers that can be created by a user at a time.
 
         Setting this can limit the total resources a user can consume.
 
         If set to 0, no limit is enforced.
+        
+        Can be an integer or a callable/awaitable based on the handler object:
+
+        ::
+
+            def named_server_limit_per_user_fn(handler):
+                user = handler.current_user
+                if user and user.admin:
+                    return 0
+                return 5
+
+            c.JupyterHub.named_server_limit_per_user = named_server_limit_per_user_fn
         """,
     ).tag(config=True)
 
@@ -2072,7 +2085,7 @@ class JupyterHub(Application):
             # Check if some roles have obtained new permissions (to avoid 'scope creep')
             old_role = orm.Role.find(self.db, name=role_name)
             if old_role:
-                if not set(role_spec['scopes']).issubset(old_role.scopes):
+                if not set(role_spec.get('scopes', [])).issubset(old_role.scopes):
                     self.log.warning(
                         "Role %s has obtained extra permissions" % role_name
                     )

jupyterhub/handlers/base.py

@@ -248,6 +248,17 @@ class BaseHandler(RequestHandler):
     def authenticate_prometheus(self):
         return self.settings.get('authenticate_prometheus', True)
 
+    async def get_current_user_named_server_limit(self):
+        """
+        Return named server limit for current user.
+        """
+        named_server_limit_per_user = self.named_server_limit_per_user
+
+        if callable(named_server_limit_per_user):
+            return await maybe_future(named_server_limit_per_user(self))
+
+        return named_server_limit_per_user
+
     def get_auth_token(self):
         """Get the authorization token from Authorization header"""
         auth_header = self.request.headers.get('Authorization', '')

jupyterhub/handlers/pages.py

@@ -72,7 +72,7 @@ class HomeHandler(BaseHandler):
             user=user,
             url=url,
             allow_named_servers=self.allow_named_servers,
-            named_server_limit_per_user=self.named_server_limit_per_user,
+            named_server_limit_per_user=await self.get_current_user_named_server_limit(),
             url_path_join=url_path_join,
             # can't use user.spawners because the stop method of User pops named servers from user.spawners when they're stopped
             spawners=user.orm_user._orm_spawners,
@@ -129,17 +129,19 @@ class SpawnHandler(BaseHandler):
         if server_name:
             if not self.allow_named_servers:
                 raise web.HTTPError(400, "Named servers are not enabled.")
-            if (
-                self.named_server_limit_per_user > 0
-                and server_name not in user.orm_spawners
-            ):
+
+            named_server_limit_per_user = (
+                await self.get_current_user_named_server_limit()
+            )
+
+            if named_server_limit_per_user > 0 and server_name not in user.orm_spawners:
                 named_spawners = list(user.all_spawners(include_default=False))
-                if self.named_server_limit_per_user <= len(named_spawners):
+                if named_server_limit_per_user <= len(named_spawners):
                     raise web.HTTPError(
                         400,
                         "User {} already has the maximum of {} named servers."
                         "  One must be deleted before a new server can be created".format(
-                            user.name, self.named_server_limit_per_user
+                            user.name, named_server_limit_per_user
                         ),
                     )
 
@@ -458,7 +460,7 @@ class AdminHandler(BaseHandler):
             auth_state=auth_state,
             admin_access=True,
             allow_named_servers=self.allow_named_servers,
-            named_server_limit_per_user=self.named_server_limit_per_user,
+            named_server_limit_per_user=await self.get_current_user_named_server_limit(),
             server_version=f'{__version__} {self.version_hash}',
             api_page_limit=self.settings["api_page_default_limit"],
             base_url=self.settings["base_url"],

jupyterhub/oauth/provider.py

@@ -9,7 +9,13 @@ from tornado.log import app_log
 
 from .. import orm
 from ..roles import roles_to_scopes
-from ..scopes import _check_scopes_exist, access_scopes, identify_scopes
+from ..scopes import (
+    _check_scopes_exist,
+    _resolve_requested_scopes,
+    access_scopes,
+    expand_scopes,
+    identify_scopes,
+)
 from ..utils import compare_token, hash_token
 
 # patch absolute-uri check
@@ -551,7 +557,6 @@ class JupyterHubRequestValidator(RequestValidator):
             - Resource Owner Password Credentials Grant
             - Client Credentials Grant
         """
-
         orm_client = (
             self.db.query(orm.OAuthClient).filter_by(identifier=client_id).one_or_none()
         )
@@ -591,19 +596,23 @@ class JupyterHubRequestValidator(RequestValidator):
 
         client_allowed_scopes = set(orm_client.allowed_scopes)
 
+        # scope resolution only works if we have a user defined
+        user = request.user or getattr(self, "_current_user")
+
         # always grant reading the token-owner's name
         # and accessing the service itself
         required_scopes = {*identify_scopes(), *access_scopes(orm_client)}
         requested_scopes.update(required_scopes)
         client_allowed_scopes.update(required_scopes)
 
-        # TODO: handle expanded_scopes intersection here?
-        # e.g. client allowed to request admin:users,
-        # but requests admin:users!name=x will not be allowed
-        # This can probably be dealt with in config by listing expected requests
-        # as explcitly allowed
+        allowed_scopes, disallowed_scopes = _resolve_requested_scopes(
+            requested_scopes,
+            client_allowed_scopes,
+            user=user.orm_user,
+            client=orm_client,
+            db=self.db,
+        )
 
-        disallowed_scopes = requested_scopes.difference(client_allowed_scopes)
         if disallowed_scopes:
             app_log.error(
                 f"Scope(s) not allowed for {client_id}: {', '.join(disallowed_scopes)}"

jupyterhub/roles.py

@@ -162,21 +162,21 @@ def create_role(db, role_dict):
         from .scopes import _check_scopes_exist
 
         _check_scopes_exist(scopes, who_for=f"role {role_dict['name']}")
+    else:
+        app_log.warning('Role %s will have no scopes', name)
 
     if role is None:
-        if not scopes:
-            app_log.warning('Warning: New defined role %s has no scopes', name)
-
         role = orm.Role(name=name, description=description, scopes=scopes)
         db.add(role)
         if role_dict not in default_roles:
             app_log.info('Role %s added to database', name)
     else:
         for attr in ["description", "scopes"]:
-            try:
-                new_value = role_dict[attr]
-            except KeyError:
-                continue
+            default_value = getattr(orm.Role, attr).default
+            if default_value:
+                default_value = default_value.arg
+
+            new_value = role_dict.get(attr, default_value)
             old_value = getattr(role, attr)
             if new_value != old_value:
                 setattr(role, attr, new_value)

jupyterhub/scopes.py

@@ -461,16 +461,13 @@ def _expand_scope(scope):
     # reapply !filter
     if filter_:
         expanded_scopes = {
-            f"{scope_name}!{filter_}" for scope_name in expanded_scope_names
+            f"{scope_name}!{filter_}"
+            for scope_name in expanded_scope_names
+            # server scopes have some cross-resource subscopes
+            # where the !server filter doesn't make sense,
+            # e.g. read:servers -> read:users:name
+            if not (filter_.startswith("server") and scope_name.startswith("read:user"))
         }
-        # special handling of server filter
-        # any read access via server filter includes permission to read the user's name
-        resource, _, value = filter_.partition('=')
-        if resource == 'server' and any(
-            scope_name.startswith("read:") for scope_name in expanded_scope_names
-        ):
-            username, _, server = value.partition('/')
-            expanded_scopes.add(f'read:users:name!user={username}')
     else:
         expanded_scopes = expanded_scope_names
 
@@ -569,6 +566,76 @@ def expand_scopes(scopes, owner=None, oauth_client=None):
     return frozenset(reduce_scopes(expanded_scopes))
 
 
+def _resolve_requested_scopes(requested_scopes, have_scopes, user, client, db):
+    """Resolve requested scopes for an OAuth token
+
+    Intersects requested scopes with user scopes.
+
+    First, at the raw scope level,
+    then if some scopes remain, intersect expanded scopes.
+
+    Args:
+        requested_scopes (set):
+            raw scopes being requested.
+        have_scopes (set):
+            raw scopes currently held, against which requested_scopes will be checked.
+        user (orm.User):
+            user for whom the scopes will be issued
+        client (orm.OAuthClient):
+            oauth client which will own the token
+        db:
+            database session, required to resolve user|group intersections
+
+    Returns:
+        (allowed_scopes, disallowed_scopes):
+            sets of allowed and disallowed scopes from the request
+    """
+
+    allowed_scopes = requested_scopes.intersection(have_scopes)
+    disallowed_scopes = requested_scopes.difference(have_scopes)
+
+    if not disallowed_scopes:
+        # simple intersection worked, all scopes granted
+        return (allowed_scopes, disallowed_scopes)
+
+    # if we got here, some scopes were disallowed.
+    # resolve fully expanded scopes to make sure scope intersections are properly allowed.
+    expanded_allowed = expand_scopes(allowed_scopes, user, client)
+    expanded_have = expand_scopes(have_scopes, user, client)
+    # compute one at a time so we can keep the abbreviated scopes
+    # if they are a subset of user scopes (e.g. requested !server, have !user)
+    for scope in list(disallowed_scopes):
+        expanded_disallowed = expand_scopes({scope}, user, client)
+        # don't check already-allowed scopes
+        expanded_disallowed -= expanded_allowed
+        if expanded_disallowed:
+            allowed_intersection = _intersect_expanded_scopes(
+                expanded_disallowed, expanded_have, db=db
+            )
+        else:
+            allowed_intersection = set()
+
+        if allowed_intersection == expanded_disallowed:
+            # full scope allowed (requested scope is subset of user scopes)
+            allowed_scopes.add(scope)
+            disallowed_scopes.remove(scope)
+            expanded_allowed = expand_scopes(allowed_scopes, user, client)
+
+        elif allowed_intersection:
+            # some scopes get through, but not all,
+            # allow the subset
+            allowed_scopes |= allowed_intersection
+            expanded_allowed = expand_scopes(allowed_scopes, user, client)
+            # choice: report that the requested scope wasn't _fully_ granted (current behavior)
+            # or report the exact (likely too detailed) set of not granted scopes (below)
+            # disallowed_scopes.remove(scope)
+            # disallowed_scopes |= expanded_disallowed.difference(allowed_intersection)
+        else:
+            # no new scopes granted, original check was right
+            pass
+    return (allowed_scopes, disallowed_scopes)
+
+
 def _needs_scope_expansion(filter_, filter_value, sub_scope):
     """
     Check if there is a requirements to expand the `group` scope to individual `user` scopes.

jupyterhub/services/auth.py

@@ -349,7 +349,9 @@ class HubAuth(SingletonConfigurable):
     @property
     def oauth_scopes(self):
         warnings.warn(
-            "HubAuth.oauth_scopes is deprecated in JupyterHub 3.0. Use .access_scopes"
+            "HubAuth.oauth_scopes is deprecated in JupyterHub 3.0. Use .access_scopes",
+            DeprecationWarning,
+            stacklevel=2,
         )
         return self.access_scopes
 

jupyterhub/spawner.py

@@ -378,8 +378,8 @@ class Spawner(LoggingConfigurable):
                     raise ValueError(f"No such role(s): {', '.join(missing_roles)}")
                 scopes.extend(roles_to_scopes(roles))
 
-        # always add access scopes
-        scopes.extend(self.oauth_access_scopes)
+        # always add access scope
+        scopes.append(f"access:servers!server={self.user.name}/{self.name}")
         return sorted(set(scopes))
 
     will_resume = Bool(

jupyterhub/tests/selenium/conftest.py

@@ -0,0 +1,13 @@
+import pytest
+from selenium import webdriver
+from selenium.webdriver.firefox.options import Options as FirefoxOptions
+
+
+@pytest.fixture()
+def browser():
+    options = webdriver.FirefoxOptions()
+    options.headless = True
+    driver = webdriver.Firefox(options=options)
+    yield driver
+    driver.close()
+    driver.quit()

jupyterhub/tests/selenium/locators.py

@@ -0,0 +1,47 @@
+from selenium.webdriver.common.by import By
+
+
+class LoginPageLocators:
+    """class for handling the login page locators"""
+
+    FORM_LOGIN = (By.XPATH, '//*[@id="login-main"]/form')
+    SIGN_IN = (By.CLASS_NAME, 'auth-form-header')
+    ACCOUNT = (By.ID, "username_input")
+    PASSWORD = (By.ID, "password_input")
+    LOGIN_BUTTON = (By.ID, "login_submit")
+    LOGO = (By.ID, "jupyterhub-logo")
+    LOGO_LINK = (By.XPATH, '//*[@id="jupyterhub-logo"]/a')
+    LOGO_TITLE = (By.XPATH, '//*[@id="jupyterhub-logo"]/a/img')
+    ERROR_INVALID_CREDANTIALS = (By.CSS_SELECTOR, "p.login_error")
+    PAGE_TITLE = 'JupyterHub'
+    ERROR_MESSAGES_LOGIN = "Invalid username or password"
+    ERROR_403 = (By.CLASS_NAME, "error")
+    ERROR_MESSAGES_403 = (
+        "Action is not authorized with current scopes; requires any of [admin-ui]"
+    )
+
+
+class HomePageLocators:
+    """class for handling the home page locators"""
+
+    LINK_HOME_BAR = (By.CSS_SELECTOR, "div.container-fluid a")
+    LINK_HOME = (By.CSS_SELECTOR, "a[href*='/hub/home']")
+    LINK_TOKEN = (By.CSS_SELECTOR, "a[href*='/hub/token']")
+    BUTTON_LOGOUT = (By.ID, "logout")
+    BUTTON_START_SERVER = (By.ID, "start")
+    BUTTON_STOP_SERVER = (By.ID, "stop")
+
+
+class TokenPageLocators:
+    """class for handling the Token page locators"""
+
+    BUTTON_API_REQ = (By.XPATH, '//*[@id="request-token-form"]/div[1]/button')
+    INPUT_TOKEN = (By.ID, "token-note")
+    LIST_EXP_TOKEN_FIELD = (By.ID, "token-expiration-seconds")
+    LIST_EXP_TOKEN_OPT = (By.XPATH, '//option')
+    NEVER_EXP = (By.ID, "Never")
+    DAY1 = (By.ID, "3600")
+    PANEL_AREA = (By.ID, 'token-area')
+    PANEL_TOKEN = (By.CLASS_NAME, 'panel-heading')
+    RESULT_TOKEN = (By.ID, 'token-result')
+    TEXT = "Copy this token. You won't be able to see it again, but you can always come back here to get a new one."

jupyterhub/tests/selenium/test_browser.py

@@ -0,0 +1,244 @@
+import asyncio
+import time
+from functools import partial
+
+import pytest
+from selenium import webdriver
+from selenium.common.exceptions import NoSuchElementException, TimeoutException
+from selenium.webdriver.common.by import By
+from selenium.webdriver.support import expected_conditions as EC
+from selenium.webdriver.support.ui import WebDriverWait
+from tornado.escape import url_escape
+from tornado.httputil import url_concat
+
+from jupyterhub.tests.selenium.locators import (
+    HomePageLocators,
+    LoginPageLocators,
+    TokenPageLocators,
+)
+from jupyterhub.utils import exponential_backoff
+
+from ...utils import url_path_join
+from ..utils import public_host, public_url, ujoin
+
+pytestmark = pytest.mark.selenium
+
+
+async def webdriver_wait(driver, condition, timeout=30):
+    """an async wrapper for selenium's wait function,
+    a condition is something from selenium's expected_conditions"""
+
+    return await exponential_backoff(
+        partial(condition, driver),
+        timeout=timeout,
+        fail_message=f"WebDriver condition not met: {condition}",
+    )
+
+
+def in_thread(f, *args, **kwargs):
+    """Run a function in a background thread
+
+    via current event loop's run_in_executor
+
+    Returns asyncio.Future
+    """
+
+    return asyncio.get_event_loop().run_in_executor(None, partial(f, *args, **kwargs))
+
+
+async def open_url(app, browser, url="login"):
+    """initiating open the login page in the browser"""
+
+    url = url_path_join(public_host(app), app.hub.base_url, url)
+    await in_thread(browser.get, url)
+    return url
+
+
+def click(browser, by_locator):
+    """wait for element to be visible, then click on it"""
+
+    WebDriverWait(browser, 10).until(
+        EC.visibility_of_element_located(by_locator)
+    ).click()
+
+
+def is_displayed(browser, by_locator):
+    """Whether the element is visible or not"""
+
+    return (
+        WebDriverWait(browser, 10)
+        .until(EC.visibility_of_element_located(by_locator))
+        .is_displayed()
+    )
+
+
+def send_text(browser, by_locator, text):
+    """wait for element to be presented, then put the text in it"""
+
+    return (
+        WebDriverWait(browser, 10)
+        .until(EC.presence_of_element_located(by_locator))
+        .send_keys(text)
+    )
+
+
+def clear(browser, by_locator):
+    """wait for element to be presented, then clear the text in it"""
+
+    return (
+        WebDriverWait(browser, 10)
+        .until(EC.presence_of_element_located(by_locator))
+        .clear()
+    )
+
+
+# LOGIN PAGE
+async def test_elements_of_login_page(app, browser):
+    await open_url(app, browser)
+    logo = is_displayed(browser, LoginPageLocators.LOGO)
+    logo_text = browser.find_element(*LoginPageLocators.LOGO).get_attribute("innerHTML")
+    assert logo == True
+
+
+async def login(browser, user, pass_w):
+    # fill in username field
+    send_text(browser, LoginPageLocators.ACCOUNT, user)
+    # fill in password field
+    send_text(browser, LoginPageLocators.PASSWORD, pass_w)
+    # click submit button
+    click(browser, LoginPageLocators.LOGIN_BUTTON)
+    await webdriver_wait(browser, EC.url_changes(browser.current_url))
+
+
+async def test_submit_login_form(app, browser):
+    user = "test_user"
+    pass_w = "test_user"
+
+    await open_url(app, browser, url="login")
+    redirected_url = ujoin(public_url(app), f"/user/{user}/")
+    await login(browser, user, pass_w)
+    # verify url contains username
+    if f"/user/{user}/" not in browser.current_url:
+        await webdriver_wait(browser, EC.url_to_be(redirected_url))
+    else:
+        pass
+    assert browser.current_url == redirected_url
+
+
+@pytest.mark.parametrize(
+    'url, params, redirected_url, form_action',
+    [
+        (
+            # spawn?param=value
+            # will encode given parameters for an unauthenticated URL in the next url
+            # the next parameter will contain the app base URL (replaces BASE_URL in tests)
+            'spawn',
+            [('param', 'value')],
+            '/hub/login?next={{BASE_URL}}hub%2Fspawn%3Fparam%3Dvalue',
+            '/hub/login?next={{BASE_URL}}hub%2Fspawn%3Fparam%3Dvalue',
+        ),
+        (
+            # login?param=fromlogin&next=encoded(/hub/spawn?param=value)
+            # will drop parameters given to the login page, passing only the next url
+            'login',
+            [('param', 'fromlogin'), ('next', '/hub/spawn?param=value')],
+            '/hub/login?param=fromlogin&next=%2Fhub%2Fspawn%3Fparam%3Dvalue',
+            '/hub/login?next=%2Fhub%2Fspawn%3Fparam%3Dvalue',
+        ),
+        (
+            # login?param=value&anotherparam=anothervalue
+            # will drop parameters given to the login page, and use an empty next url
+            'login',
+            [('param', 'value'), ('anotherparam', 'anothervalue')],
+            '/hub/login?param=value&anotherparam=anothervalue',
+            '/hub/login?next=',
+        ),
+        (
+            # login
+            # simplest case, accessing the login URL, gives an empty next url
+            'login',
+            [],
+            '/hub/login',
+            '/hub/login?next=',
+        ),
+    ],
+)
+async def test_open_url_login(
+    app,
+    browser,
+    url,
+    params,
+    redirected_url,
+    form_action,
+    user='test_user',
+    pass_w='test_user',
+):
+    url = url_path_join(public_host(app), app.hub.base_url, url)
+    url_new = url_concat(url, params)
+    await in_thread(browser.get, url_new)
+    redirected_url = redirected_url.replace('{{BASE_URL}}', url_escape(app.base_url))
+    form_action = form_action.replace('{{BASE_URL}}', url_escape(app.base_url))
+    form = browser.find_element(*LoginPageLocators.FORM_LOGIN).get_attribute('action')
+
+    # verify title / url
+    assert browser.title == LoginPageLocators.PAGE_TITLE
+    assert form.endswith(form_action)
+    # login in with params
+    await login(browser, user, pass_w)
+    # verify next url + params
+    next_url = browser.current_url
+    if url_escape(app.base_url) in form_action:
+        assert next_url.endswith("param=value")
+    elif "next=%2Fhub" in form_action:
+        assert next_url.endswith("spawn?param=value")
+        assert f"user/{user}/" not in next_url
+    else:
+        if next_url.endswith(f"/user/{user}/") == False:
+            await webdriver_wait(
+                browser, EC.url_to_be(ujoin(public_url(app), f"/user/{user}/"))
+            )
+        assert next_url.endswith(f"/user/{user}/")
+
+
+@pytest.mark.parametrize(
+    "user, pass_w",
+    [
+        (" ", ""),
+        ("user", ""),
+        (" ", "password"),
+        ("user", "password"),
+    ],
+)
+async def test_invalid_credantials(app, browser, user, pass_w):
+    await open_url(app, browser)
+    await login(browser, user, pass_w)
+    await asyncio.sleep(0.1)
+    """adding for a catching of the reflected error"""
+    try:
+        error = browser.find_element(*LoginPageLocators.ERROR_INVALID_CREDANTIALS)
+        await webdriver_wait(browser, EC.visibility_of(error))
+    except NoSuchElementException:
+        error = None
+
+    # verify error message and url still eguals to the login page
+    assert LoginPageLocators.ERROR_MESSAGES_LOGIN == error.text
+    assert 'hub/login' in browser.current_url
+
+
+# HOME PAGE
+async def open_home_page(app, browser, user="test_user", pass_w="test_user"):
+    url = url_path_join(public_host(app), app.hub.base_url, "/login?next=/hub/home")
+    await in_thread(browser.get, url)
+    redirected_url = url_path_join(public_host(app), app.base_url, '/hub/home')
+    await login(browser, user, pass_w)
+    await in_thread(browser.get, redirected_url)
+
+
+# TOKEN PAGE
+async def open_token_page(app, browser, user="test_user", pass_w="test_user"):
+
+    url = url_path_join(public_host(app), app.hub.base_url, "/login?next=/hub/token")
+    await in_thread(browser.get, url)
+    redirected_url = url_path_join(public_host(app), app.base_url, '/hub/token')
+    await login(browser, user, pass_w)
+    await in_thread(browser.get, redirected_url)

jupyterhub/tests/test_named_servers.py

@@ -25,6 +25,25 @@ def named_servers(app):
         yield
 
 
+@pytest.fixture
+def named_servers_with_callable_limit(app):
+    def named_server_limit_per_user_fn(handler):
+        """Limit number of named servers to `2` for non-admin users. No limit for admin users."""
+        user = handler.current_user
+        if user and user.admin:
+            return 0
+        return 2
+
+    with mock.patch.dict(
+        app.tornado_settings,
+        {
+            'allow_named_servers': True,
+            'named_server_limit_per_user': named_server_limit_per_user_fn,
+        },
+    ):
+        yield
+
+
 @pytest.fixture
 def default_server_name(app, named_servers):
     """configure app to use a default server name"""
@@ -292,6 +311,57 @@ async def test_named_server_limit(app, named_servers):
     assert r.text == ''
 
 
+@pytest.mark.parametrize(
+    'username,admin',
+    [
+        ('nonsuperfoo', False),
+        ('superfoo', True),
+    ],
+)
+async def test_named_server_limit_as_callable(
+    app, named_servers_with_callable_limit, username, admin
+):
+    """Test named server limit based on `named_server_limit_per_user_fn` callable"""
+    user = add_user(app.db, app, name=username, admin=admin)
+    cookies = await app.login_user(username)
+
+    # Create 1st named server
+    servername1 = 'bar-1'
+    r = await api_request(
+        app, 'users', username, 'servers', servername1, method='post', cookies=cookies
+    )
+    r.raise_for_status()
+    assert r.status_code == 201
+    assert r.text == ''
+
+    # Create 2nd named server
+    servername2 = 'bar-2'
+    r = await api_request(
+        app, 'users', username, 'servers', servername2, method='post', cookies=cookies
+    )
+    r.raise_for_status()
+    assert r.status_code == 201
+    assert r.text == ''
+
+    # Create 3rd named server
+    servername3 = 'bar-3'
+    r = await api_request(
+        app, 'users', username, 'servers', servername3, method='post', cookies=cookies
+    )
+
+    # No named server limit for admin users as in `named_server_limit_per_user_fn` callable
+    if admin:
+        r.raise_for_status()
+        assert r.status_code == 201
+        assert r.text == ''
+    else:
+        assert r.status_code == 400
+        assert r.json() == {
+            "status": 400,
+            "message": f"User {username} already has the maximum of 2 named servers.  One must be deleted before a new server can be created",
+        }
+
+
 async def test_named_server_spawn_form(app, username, named_servers):
     server_name = "myserver"
     base_url = public_url(app)

jupyterhub/tests/test_scopes.py

@@ -15,6 +15,7 @@ from ..scopes import (
     _check_scope_access,
     _expand_self_scope,
     _intersect_expanded_scopes,
+    _resolve_requested_scopes,
     expand_scopes,
     get_scopes_for,
     identify_scopes,
@@ -554,13 +555,17 @@ async def test_server_state_access(
             await api_request(
                 app, 'users', user.name, 'servers', server_name, method='post'
             )
-        service = create_service_with_scopes(*scopes)
+        service = create_service_with_scopes("read:users:name!user=", *scopes)
         api_token = service.new_api_token()
         headers = {'Authorization': 'token %s' % api_token}
+
+        # can I get the user model?
         r = await api_request(app, 'users', user.name, headers=headers)
+        can_read_user_model = num_servers > 1 or 'read:users' in scopes
+        if can_read_user_model:
             r.raise_for_status()
             user_model = r.json()
-        if num_servers:
+            if num_servers > 1:
                 assert 'servers' in user_model
                 server_models = user_model['servers']
                 assert len(server_models) == num_servers
@@ -569,6 +574,9 @@ async def test_server_state_access(
                     assert keys_out.isdisjoint(server_model)
             else:
                 assert 'servers' not in user_model
+        else:
+            assert r.status_code == 404
+
         r = await api_request(
             app,
             'users',
@@ -1201,3 +1209,88 @@ def test_expand_scopes(app, user, scopes, expected, mockservice_external):
     expanded = expand_scopes(scopes, owner=user.orm_user, oauth_client=oauth_client)
     assert isinstance(expanded, frozenset)
     assert sorted(expanded) == sorted(expected)
+
+
+@pytest.mark.parametrize(
+    "requested_scopes, have_scopes, expected_allowed, expected_disallowed",
+    [
+        (
+            ["read:users:name!user"],
+            ["read:users:name!user={user}"],
+            ["read:users:name!user"],
+            [],
+        ),
+        (
+            ["read:servers!server"],
+            ["read:servers!user"],
+            ["read:servers!server"],
+            [],
+        ),
+        (
+            ["read:servers!server={server}"],
+            ["read:servers"],
+            ["read:servers!server={server}"],
+            [],
+        ),
+        (
+            ["admin:servers!server"],
+            ["read:servers"],
+            ["read:servers!server={server}"],
+            ["admin:servers!server"],
+        ),
+        (
+            ["admin:servers", "read:users"],
+            ["read:users"],
+            ["read:users"],
+            ["admin:servers"],
+        ),
+    ],
+)
+def test_resolve_requested_scopes(
+    app,
+    user,
+    group,
+    requested_scopes,
+    have_scopes,
+    expected_allowed,
+    expected_disallowed,
+    mockservice_external,
+):
+    if isinstance(requested_scopes, str):
+        requested_scopes = [requested_scopes]
+
+    db = app.db
+    service = mockservice_external
+    spawner_name = "salmon"
+    server_name = f"{user.name}/{spawner_name}"
+    if '!server' in str(requested_scopes + have_scopes):
+        oauth_client = orm.OAuthClient()
+        db.add(oauth_client)
+        spawner = user.spawners[spawner_name]
+        spawner.orm_spawner.oauth_client = oauth_client
+        db.commit()
+        assert oauth_client.spawner is spawner.orm_spawner
+    else:
+        oauth_client = service.oauth_client
+        assert oauth_client is not None
+
+    def format_scopes(scopes):
+        return {
+            s.format(service=service.name, server=server_name, user=user.name)
+            for s in scopes
+        }
+
+    requested_scopes = format_scopes(requested_scopes)
+    have_scopes = format_scopes(have_scopes)
+    expected_allowed = format_scopes(expected_allowed)
+    expected_disallowed = format_scopes(expected_disallowed)
+
+    allowed, disallowed = _resolve_requested_scopes(
+        requested_scopes,
+        have_scopes,
+        user=user.orm_user,
+        client=oauth_client,
+        db=db,
+    )
+    assert allowed == expected_allowed
+    assert disallowed == expected_disallowed

jupyterhub/tests/test_services_auth.py

@@ -223,7 +223,7 @@ async def test_hubauth_service_token(request, app, mockservice_url, scopes, allo
         # explicit 'identify' maps to read:users:name!user
         (["token", "user"], ["identify"], ["read:users:name!user=$user"]),
         # any item outside the list isn't allowed
-        (["token", "user"], ["token", "server"], None),
+        (["token", "server"], ["token", "user"], None),
         (["read-only"], ["access:services"], None),
         # requesting subset
         (["admin", "user"], ["user"], ["user"]),
@@ -246,7 +246,11 @@ async def test_hubauth_service_token(request, app, mockservice_url, scopes, allo
             ["custom:jupyter_server:read:*"],
         ),
         # this one _should_ work, but doesn't until we implement expanded_scope filtering
-        # (["read-only"], ["custom:jupyter_server:read:*!user=$user"], ["custom:jupyter_server:read:*!user=$user"]),
+        (
+            ["read-only"],
+            ["custom:jupyter_server:read:*!user=$user"],
+            ["custom:jupyter_server:read:*!user=$user"],
+        ),
     ],
 )
 async def test_oauth_service_roles(
@@ -289,7 +293,7 @@ async def test_oauth_service_roles(
             "name": "other",
             "description": "A role not held by our test user",
             "scopes": [
-                "admin:users",
+                "admin-ui",
             ],
         },
     )
@@ -299,12 +303,13 @@ async def test_oauth_service_roles(
         )
     )
     app.db.commit()
+    user = create_user_with_scopes("access:services")
     url = url_path_join(public_url(app, mockservice_url) + 'owhoami/?arg=x')
     if request_scopes:
+        request_scopes = {s.replace("$user", user.name) for s in request_scopes}
         url = url_concat(url, {"request-scope": " ".join(request_scopes)})
     # first request is only going to login and get us to the oauth form page
     s = AsyncSession()
-    user = create_user_with_scopes("access:services")
     roles.grant_role(app.db, user, "user")
     roles.grant_role(app.db, user, "read-only")
     name = user.name

jupyterhub/tests/test_spawner.py

@@ -17,6 +17,7 @@ import pytest
 from .. import orm
 from .. import spawner as spawnermod
 from ..objects import Hub, Server
+from ..scopes import access_scopes
 from ..spawner import LocalProcessSpawner, Spawner
 from ..user import User
 from ..utils import AnyTimeoutError, new_token, url_path_join
@@ -444,7 +445,7 @@ async def test_spawner_oauth_scopes(app, user):
     await spawner.user.spawn()
     oauth_client = spawner.orm_spawner.oauth_client
     assert sorted(oauth_client.allowed_scopes) == sorted(
-        allowed_scopes + spawner.oauth_access_scopes
+        allowed_scopes + list(access_scopes(oauth_client))
     )
     await spawner.user.stop()
 

pytest.ini

@@ -7,7 +7,7 @@
 asyncio_mode = auto
 
 # jupyter_server plugin is incompatible with notebook imports
-addopts = -p no:jupyter_server
+addopts = -p no:jupyter_server -m 'not selenium'
 
 python_files = test_*.py
 markers =
@@ -17,3 +17,4 @@ markers =
     user: mark as a test for a user
     slow: mark a test as slow
     role: mark as a test for roles
+    selenium: web tests that run with selenium

setup.py

@@ -168,9 +168,6 @@ class NPM(BaseCommand):
     bower_dir = pjoin(static, 'components')
 
     def should_run(self):
-        if not shutil.which('npm'):
-            print("npm unavailable", file=sys.stderr)
-            return False
         if not os.path.exists(self.bower_dir):
             return True
         if not os.path.exists(self.node_modules):
@@ -195,6 +192,7 @@ class NPM(BaseCommand):
         os.utime(self.bower_dir)
         # update data-files in case this created new files
         self.distribution.data_files = get_data_files()
+        assert not self.should_run(), 'NPM.run failed'
 
 
 class CSS(BaseCommand):
@@ -255,6 +253,7 @@ class CSS(BaseCommand):
             raise
         # update data-files in case this created new files
         self.distribution.data_files = get_data_files()
+        assert not self.should_run(), 'CSS.run failed'
 
 
 class JSX(BaseCommand):
@@ -314,6 +313,7 @@ class JSX(BaseCommand):
 
         # update data-files in case this created new files
         self.distribution.data_files = get_data_files()
+        assert not self.should_run(), 'JSX.run failed'
 
 
 def js_css_first(cls, strict=True):

share/jupyterhub/static/js/admin.js

@@ -5,7 +5,7 @@ require(["jquery", "moment", "jhapi", "utils"], function (
   $,
   moment,
   JHAPI,
-  utils
+  utils,
 ) {
   "use strict";
 
@@ -113,7 +113,7 @@ require(["jquery", "moment", "jhapi", "utils"], function (
     var serverName = row.data("server-name");
     el.attr(
       "href",
-      utils.url_path_join(prefix, "user", user, serverName) + "/"
+      utils.url_path_join(prefix, "user", user, serverName) + "/",
     );
   });
 
@@ -127,7 +127,7 @@ require(["jquery", "moment", "jhapi", "utils"], function (
       var serverName = row.data("server-name");
       el.attr(
         "href",
-        utils.url_path_join(prefix, "hub/spawn", user, serverName)
+        utils.url_path_join(prefix, "hub/spawn", user, serverName),
       );
     });
     // cannot start all servers in this case
@@ -187,7 +187,7 @@ require(["jquery", "moment", "jhapi", "utils"], function (
           success: function () {
             window.location.reload();
           },
-        }
+        },
       );
     });
 
@@ -241,7 +241,7 @@ require(["jquery", "moment", "jhapi", "utils"], function (
           success: function () {
             window.location.reload();
           },
-        }
+        },
       );
     });
 

share/jupyterhub/static/js/jhapi.js

@@ -38,7 +38,7 @@ define(["jquery", "utils"], function ($, utils) {
     var url = utils.url_path_join(
       this.base_url,
       "api",
-      utils.encode_uri_components(path)
+      utils.encode_uri_components(path),
     );
     $.ajax(url, options);
   };
@@ -54,7 +54,7 @@ define(["jquery", "utils"], function ($, utils) {
     options = update(options, { type: "POST", dataType: null });
     this.api_request(
       utils.url_path_join("users", user, "servers", server_name),
-      options
+      options,
     );
   };
 
@@ -69,7 +69,7 @@ define(["jquery", "utils"], function ($, utils) {
     options = update(options, { type: "DELETE", dataType: null });
     this.api_request(
       utils.url_path_join("users", user, "servers", server_name),
-      options
+      options,
     );
   };
 
@@ -119,7 +119,7 @@ define(["jquery", "utils"], function ($, utils) {
 
     this.api_request(
       utils.url_path_join("users", user, "admin-access"),
-      options
+      options,
     );
   };
 
@@ -143,7 +143,7 @@ define(["jquery", "utils"], function ($, utils) {
     options = update(options, { type: "DELETE" });
     this.api_request(
       utils.url_path_join("users", user, "tokens", token_id),
-      options
+      options,
     );
   };
 

share/jupyterhub/static/js/token.js

@@ -33,7 +33,7 @@ require(["jquery", "jhapi", "moment"], function ($, JHAPI, moment) {
           $("#token-result").text(reply.token);
           $("#token-area").show();
         },
-      }
+      },
     );
     return false;
   });

share/jupyterhub/static/js/utils.js

@@ -73,7 +73,7 @@ define(["jquery"], function ($) {
       ua = navigator.userAgent,
       tem;
     var M = ua.match(
-      /(opera|chrome|safari|firefox|msie)\/?\s*(\.?\d+(\.\d+)*)/i
+      /(opera|chrome|safari|firefox|msie)\/?\s*(\.?\d+(\.\d+)*)/i,
     );
     if (M && (tem = ua.match(/version\/([\.\d]+)/i)) !== null) M[2] = tem[1];
     M = M ? [M[1], M[2]] : [N, navigator.appVersion, "-?"];