Merge branch 'rbac' into read_roles

2025-10-18 07:23:00 +00:00 · 2021-06-08 15:31:30 +02:00
parent 0233faf19d be7ad39b10
commit 32d1e3cbea
59 changed files with 968 additions and 681 deletions
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -80,7 +80,7 @@ jobs:
    steps:
      - name: Should we push this image to a public registry?
        run: |
-          if [ "${{ startsWith(github.ref, 'refs/tags/') || (github.ref == 'refs/heads/master') }}" = "true" ]; then
+          if [ "${{ startsWith(github.ref, 'refs/tags/') || (github.ref == 'refs/heads/main') }}" = "true" ]; then
              # Empty => Docker Hub
              echo "REGISTRY=" >> $GITHUB_ENV
          else
@@ -114,7 +114,7 @@ jobs:
        #    https://github.com/jupyterhub/jupyterhub/settings/secrets/actions
        if: env.REGISTRY != 'localhost:5000/'
        run: |
-          docker login -u "${{ secrets.DOCKER_USERNAME }}" -p "${{ secrets.DOCKERHUB_TOKEN }}"
+          docker login -u "${{ secrets.DOCKERHUB_USERNAME }}" -p "${{ secrets.DOCKERHUB_TOKEN }}"

      # https://github.com/jupyterhub/action-major-minor-tag-calculator
      # If this is a tagged build this will return additional parent tags.
--- a/.gitignore
+++ b/.gitignore
@@ -29,3 +29,4 @@ htmlcov
 pip-wheel-metadata
 docs/source/reference/metrics.rst
 oldest-requirements.txt
+jupyterhub-proxy.pid
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -1 +1 @@
-Please refer to [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md).
+Please refer to [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md).
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -3,7 +3,7 @@
 Welcome! As a [Jupyter](https://jupyter.org) project,
 you can follow the [Jupyter contributor guide](https://jupyter.readthedocs.io/en/latest/contributing/content-contributor.html).

-Make sure to also follow [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md)
+Make sure to also follow [Project Jupyter's Code of Conduct](https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md)
 for a friendly and welcoming collaborative environment.

 ## Setting up a development environment
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@
 [![GitHub Workflow Status - Test](https://img.shields.io/github/workflow/status/jupyterhub/jupyterhub/Test?logo=github&label=tests)](https://github.com/jupyterhub/jupyterhub/actions)
 [![DockerHub build status](https://img.shields.io/docker/build/jupyterhub/jupyterhub?logo=docker&label=build)](https://hub.docker.com/r/jupyterhub/jupyterhub/tags)
 [![CircleCI build status](https://img.shields.io/circleci/build/github/jupyterhub/jupyterhub?logo=circleci)](https://circleci.com/gh/jupyterhub/jupyterhub)<!-- CircleCI Token: b5b65862eb2617b9a8d39e79340b0a6b816da8cc -->
-[![Test coverage of code](https://codecov.io/gh/jupyterhub/jupyterhub/branch/master/graph/badge.svg)](https://codecov.io/gh/jupyterhub/jupyterhub)
+[![Test coverage of code](https://codecov.io/gh/jupyterhub/jupyterhub/branch/main/graph/badge.svg)](https://codecov.io/gh/jupyterhub/jupyterhub)
 [![GitHub](https://img.shields.io/badge/issue_tracking-github-blue?logo=github)](https://github.com/jupyterhub/jupyterhub/issues)
 [![Discourse](https://img.shields.io/badge/help_forum-discourse-blue?logo=discourse)](https://discourse.jupyter.org/c/jupyterhub)
 [![Gitter](https://img.shields.io/badge/social_chat-gitter-blue?logo=gitter)](https://gitter.im/jupyterhub/jupyterhub)
@@ -46,7 +46,7 @@ Basic principles for operation are:
  servers.

 JupyterHub also provides a
-[REST API](http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/jupyterhub/master/docs/rest-api.yml#/default)
+[REST API](https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyter/jupyterhub/HEAD/docs/rest-api.yml#/default)
 for administration of the Hub and its users.

 ## Installation
@@ -239,7 +239,7 @@ our JupyterHub [Gitter](https://gitter.im/jupyterhub/jupyterhub) channel.
 - [Reporting Issues](https://github.com/jupyterhub/jupyterhub/issues)
 - [JupyterHub tutorial](https://github.com/jupyterhub/jupyterhub-tutorial)
 - [Documentation for JupyterHub](https://jupyterhub.readthedocs.io/en/latest/) | [PDF (latest)](https://media.readthedocs.org/pdf/jupyterhub/latest/jupyterhub.pdf) | [PDF (stable)](https://media.readthedocs.org/pdf/jupyterhub/stable/jupyterhub.pdf)
- [Documentation for JupyterHub's REST API](http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/jupyterhub/master/docs/rest-api.yml#/default)
+- [Documentation for JupyterHub's REST API](https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyter/jupyterhub/HEAD/docs/rest-api.yml#/default)
 - [Documentation for Project Jupyter](http://jupyter.readthedocs.io/en/latest/index.html) | [PDF](https://media.readthedocs.org/pdf/jupyter/latest/jupyter.pdf)
 - [Project Jupyter website](https://jupyter.org)
 - [Project Jupyter community](https://jupyter.org/community)
--- a/docs/rest-api.yml
+++ b/docs/rest-api.yml
@@ -1,4 +1,4 @@
-# see me at: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#/default
+# see me at: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/HEAD/docs/rest-api.yml#/default
 swagger: "2.0"
 info:
  title: JupyterHub
@@ -143,6 +143,22 @@ paths:
            inactive: all users who have *no* active servers (complement of active)

            Added in JupyterHub 1.3
+        - name: offset
+          in: query
+          required: false
+          type: number
+          description: |
+            Return a number users starting at the given offset.
+            Can be used with limit to paginate.
+            If unspecified, return all users.
+        - name: limit
+          in: query
+          requred: false
+          type: number
+          description: |
+            Return a finite number of users.
+            Can be used with offset to paginate.
+            If unspecified, use api_page_default_limit.
      responses:
        "200":
          description: The Hub's user list
@@ -379,7 +395,7 @@ paths:
          type: string
        - name: server_name
          description: |
-            name given to a named-server. 
+            name given to a named-server.

            Note that depending on your JupyterHub infrastructure there are chracterter size limitation to `server_name`. Default spawner with K8s pod will not allow Jupyter Notebooks to be spawned with a name that contains more than 253 characters (keep in mind that the pod will be spawned with extra characters to identify the user and hub).
          in: path
@@ -540,6 +556,23 @@ paths:
      security:
        - oauth2:
            - read:groups
+      parameters:
+        - name: offset
+          in: query
+          required: false
+          type: number
+          description: |
+            Return a number of groups starting at the specified offset.
+            Can be used with limit to paginate.
+            If unspecified, return all groups.
+        - name: limit
+          in: query
+          required: false
+          type: number
+          description: |
+            Return a finite number of groups.
+            Can be used with offset to paginate.
+            If unspecified, use api_page_default_limit.
      responses:
        "200":
          description: The list of groups
@@ -686,6 +719,23 @@ paths:
      security:
        - oauth2:
            - proxy
+      parameters:
+        - name: offset
+          in: query
+          required: false
+          type: number
+          description: |
+            Return a number of routes starting at the given offset.
+            Can be used with limit to paginate.
+            If unspecified, return all routes.
+        - name: limit
+          in: query
+          requred: false
+          type: number
+          description: |
+            Return a finite number of routes.
+            Can be used with offset to paginate.
+            If unspecified, use api_page_default_limit
      responses:
        "200":
          description: Routing table
--- a/docs/source/api/index.rst
+++ b/docs/source/api/index.rst
@@ -18,7 +18,7 @@ information on:
 - learning more about JupyterHub's API

 The same JupyterHub API spec, as found here, is available in an interactive form
-`here (on swagger's petstore) <http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default>`__.
+`here (on swagger's petstore) <https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/HEAD/docs/rest-api.yml#!/default>`__.
 The `OpenAPI Initiative`_ (fka Swagger™) is a project used to describe
 and document RESTful APIs.

--- a/docs/source/changelog.md
+++ b/docs/source/changelog.md
@@ -985,7 +985,7 @@ Bugfixes on 0.6:

 ### [0.6.0] - 2016-04-25

- JupyterHub has moved to a new `jupyterhub` namespace on GitHub and Docker. What was `juptyer/jupyterhub` is now `jupyterhub/jupyterhub`, etc.
+- JupyterHub has moved to a new `jupyterhub` namespace on GitHub and Docker. What was `jupyter/jupyterhub` is now `jupyterhub/jupyterhub`, etc.
 - `jupyterhub/jupyterhub` image on DockerHub no longer loads the jupyterhub_config.py in an ONBUILD step. A new `jupyterhub/jupyterhub-onbuild` image does this
 - Add statsd support, via `c.JupyterHub.statsd_{host,port,prefix}`
 - Update to traitlets 4.1 `@default`, `@observe` APIs for traits
--- a/docs/source/contributing/docs.rst
+++ b/docs/source/contributing/docs.rst
@@ -13,7 +13,7 @@ Building documentation locally
 We use `sphinx <http://sphinx-doc.org>`_ to build our documentation. It takes
 our documentation source files (written in `markdown
 <https://daringfireball.net/projects/markdown/>`_ or `reStructuredText
-<http://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ &
+<https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html>`_ &
 stored under the ``docs/source`` directory) and converts it into various
 formats for people to read. To make sure the documentation you write or
 change renders correctly, it is good practice to test it locally.
@@ -39,8 +39,8 @@ change renders correctly, it is good practice to test it locally.
   along with the filename / line number in which they occurred. Fix them,
   and re-run the ``make html`` command to re-render the documentation.

-#. View the rendered documentation by opening ``build/html/index.html`` in 
-   a web browser. 
+#. View the rendered documentation by opening ``build/html/index.html`` in
+   a web browser.

   .. tip::

--- a/docs/source/contributing/index.rst
+++ b/docs/source/contributing/index.rst
@@ -6,8 +6,8 @@ We want you to contribute to JupyterHub in ways that are most exciting
 & useful to you. We value documentation, testing, bug reporting & code equally,
 and are glad to have your contributions in whatever form you wish :)

-Our `Code of Conduct <https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md>`_
-(`reporting guidelines <https://github.com/jupyter/governance/blob/master/conduct/reporting_online.md>`_)
+Our `Code of Conduct <https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md>`_
+(`reporting guidelines <https://github.com/jupyter/governance/blob/HEAD/conduct/reporting_online.md>`_)
 helps keep our community welcoming to as many people as possible.

 .. toctree::
--- a/docs/source/gallery-jhub-deployments.md
+++ b/docs/source/gallery-jhub-deployments.md
@@ -30,7 +30,7 @@ Please submit pull requests to update information or to add new institutions or

 ### University of California Davis

- [Spinning up multiple Jupyter Notebooks on AWS for a tutorial](https://github.com/mblmicdiv/course2017/blob/master/exercises/sourmash-setup.md)
+- [Spinning up multiple Jupyter Notebooks on AWS for a tutorial](https://github.com/mblmicdiv/course2017/blob/HEAD/exercises/sourmash-setup.md)

 Although not technically a JupyterHub deployment, this tutorial setup
 may be helpful to others in the Jupyter community.
--- a/docs/source/getting-started/authenticators-users-basics.md
+++ b/docs/source/getting-started/authenticators-users-basics.md
@@ -22,7 +22,7 @@ Admin users of JupyterHub, `admin_users`, can add and remove users from
 the user `allowed_users` set. `admin_users` can take actions on other users'
 behalf, such as stopping and restarting their servers.

-A set of initial admin users, `admin_users` can configured be as follows:
+A set of initial admin users, `admin_users` can be configured as follows:

 ```python
 c.Authenticator.admin_users = {'mal', 'zoe'}
@@ -32,9 +32,9 @@ Users in the admin set are automatically added to the user `allowed_users` set,
 if they are not already present.

 Each authenticator may have different ways of determining whether a user is an
-administrator. By default JupyterHub use the PAMAuthenticator which provide the
-`admin_groups` option and can determine administrator status base on a user
-groups. For example we can let any users in the `wheel` group be admin:
+administrator. By default JupyterHub uses the PAMAuthenticator which provides the
+`admin_groups` option and can set administrator status based on a user
+group. For example we can let any user in the `wheel` group be admin:

 ```python
 c.PAMAuthenticator.admin_groups = {'wheel'}
@@ -42,9 +42,9 @@ c.PAMAuthenticator.admin_groups = {'wheel'}

 ## Give admin access to other users' notebook servers (`admin_access`)

-Since the default `JupyterHub.admin_access` setting is False, the admins
+Since the default `JupyterHub.admin_access` setting is `False`, the admins
 do not have permission to log in to the single user notebook servers
-owned by _other users_. If `JupyterHub.admin_access` is set to True,
+owned by _other users_. If `JupyterHub.admin_access` is set to `True`,
 then admins have permission to log in _as other users_ on their
 respective machines, for debugging. **As a courtesy, you should make
 sure your users know if admin_access is enabled.**
@@ -53,8 +53,8 @@ sure your users know if admin_access is enabled.**

 Users can be added to and removed from the Hub via either the admin
 panel or the REST API. When a user is **added**, the user will be
-automatically added to the allowed users set and database. Restarting the Hub
-will not require manually updating the allowed users set in your config file,
+automatically added to the `allowed_users` set and database. Restarting the Hub
+will not require manually updating the `allowed_users` set in your config file,
 as the users will be loaded from the database.

 After starting the Hub once, it is not sufficient to **remove** a user
@@ -107,8 +107,8 @@ with any provider, is also available.

 ## Use DummyAuthenticator for testing

-The :class:`~jupyterhub.auth.DummyAuthenticator` is a simple authenticator that
-allows for any username/password unless if a global password has been set. If
+The `DummyAuthenticator` is a simple authenticator that
+allows for any username/password unless a global password has been set. If
 set, it will allow for any username as long as the correct password is provided.
 To set a global password, add this to the config file:

--- a/docs/source/getting-started/config-basics.md
+++ b/docs/source/getting-started/config-basics.md
@@ -44,7 +44,7 @@ jupyterhub -f /etc/jupyterhub/jupyterhub_config.py
 ```

 The IPython documentation provides additional information on the
-[config system](http://ipython.readthedocs.io/en/stable/development/config)
+[config system](http://ipython.readthedocs.io/en/stable/development/config.html)
 that Jupyter uses.

 ## Configure using command line options
@@ -63,11 +63,11 @@ would enter:
    jupyterhub --ip 10.0.1.2 --port 443 --ssl-key my_ssl.key --ssl-cert my_ssl.cert
 ```

-All configurable options may technically be set on the command-line,
+All configurable options may technically be set on the command line,
 though some are inconvenient to type. To set a particular configuration
 parameter, `c.Class.trait`, you would use the command line option,
 `--Class.trait`, when starting JupyterHub. For example, to configure the
-`c.Spawner.notebook_dir` trait from the command-line, use the
+`c.Spawner.notebook_dir` trait from the command line, use the
 `--Spawner.notebook_dir` option:

 ```bash
@@ -89,11 +89,11 @@ meant as illustration, are:
 ## Run the proxy separately

 This is _not_ strictly necessary, but useful in many cases. If you
-use a custom proxy (e.g. Traefik), this also not needed.
+use a custom proxy (e.g. Traefik), this is also not needed.

 Connections to user servers go through the proxy, and _not_ the hub
 itself. If the proxy stays running when the hub restarts (for
-maintenance, re-configuration, etc.), then use connections are not
+maintenance, re-configuration, etc.), then user connections are not
 interrupted. For simplicity, by default the hub starts the proxy
 automatically, so if the hub restarts, the proxy restarts, and user
 connections are interrupted. It is easy to run the proxy separately,
--- a/docs/source/getting-started/faq.md
+++ b/docs/source/getting-started/faq.md
@@ -26,7 +26,7 @@ so Breq would open `/user/breq/notebooks/foo.ipynb` and
 Seivarden would open `/user/seivarden/notebooks/foo.ipynb`, etc.

 JupyterHub has a special URL that does exactly this!
-It's called `/hub/user-redirect/...` and after the visitor logs in,
+It's called `/hub/user-redirect/...`.
 So if you replace `/user/yourname` in your URL bar
 with `/hub/user-redirect` any visitor should get the same
 URL on their own server, rather than visiting yours.
--- a/docs/source/getting-started/institutional-faq.md
+++ b/docs/source/getting-started/institutional-faq.md
@@ -11,7 +11,7 @@ Yes! JupyterHub has been used at-scale for large pools of users, as well
 as complex and high-performance computing. For example, UC Berkeley uses
 JupyterHub for its Data Science Education Program courses (serving over
 3,000 students). The Pangeo project uses JupyterHub to provide access
-to scalable cloud computing with Dask. JupyterHub is stable customizable
+to scalable cloud computing with Dask. JupyterHub is stable and customizable
 to the use-cases of large organizations.

 ### I keep hearing about Jupyter Notebook, JupyterLab, and now JupyterHub. What’s the difference?
@@ -27,14 +27,14 @@ Here is a quick breakdown of these three tools:
  for other parts of the data science stack.
 - **JupyterHub** is an application that manages interactive computing sessions for **multiple users**.
  It also connects them with infrastructure those users wish to access. It can provide
-  remote access to Jupyter Notebooks and Jupyter Lab for many people.
+  remote access to Jupyter Notebooks and JupyterLab for many people.

 ## For management

 ### Briefly, what problem does JupyterHub solve for us?

 JupyterHub provides a shared platform for data science and collaboration.
-It allows users to utilize familiar data science workflows (such as the scientific python stack,
+It allows users to utilize familiar data science workflows (such as the scientific Python stack,
 the R tidyverse, and Jupyter Notebooks) on institutional infrastructure. It also allows administrators
 some control over access to resources, security, environments, and authentication.

@@ -55,7 +55,7 @@ industry, and government research labs. It is most-commonly used by two kinds of
 - Large teams (e.g., a department, a large class, or a large group of remote users) to provide
  access to organizational hardware, data, and analytics environments at scale.

-Here are a sample of organizations that use JupyterHub:
+Here is a sample of organizations that use JupyterHub:

 - **Universities and colleges**: UC Berkeley, UC San Diego, Cal Poly SLO, Harvard University, University of Chicago,
  University of Oslo, University of Sheffield, Université Paris Sud, University of Versailles
@@ -99,7 +99,7 @@ that we currently suggest are:
  guide that runs on Kubernetes. Better for larger or dynamic user groups (50-10,000) or more complex
  compute/data needs.
 - [The Littlest JupyterHub](https://tljh.jupyter.org) is a lightweight JupyterHub that runs on a single
-  single machine (in the cloud or under your desk). Better for smaller usergroups (4-80) or more
+  single machine (in the cloud or under your desk). Better for smaller user groups (4-80) or more
  lightweight computational resources.

 ### Does JupyterHub run well in the cloud?
@@ -123,7 +123,7 @@ level for several years, and makes a number of "default" security decisions that
 users.

 - For security considerations in the base JupyterHub application,
-  [see the JupyterHub security page](https://jupyterhub.readthedocs.io/en/stable/reference/websecurity.html)
+  [see the JupyterHub security page](https://jupyterhub.readthedocs.io/en/stable/reference/websecurity.html).
 - For security considerations when deploying JupyterHub on Kubernetes, see the
  [JupyterHub on Kubernetes security page](https://zero-to-jupyterhub.readthedocs.io/en/latest/security.html).

@@ -183,7 +183,7 @@ how those resources are controlled is taken care of by the non-JupyterHub applic

 Yes - JupyterHub can provide access to many kinds of computing infrastructure.
 Especially when combined with other open-source schedulers such as Dask, you can manage fairly
-complex computing infrastructure from the interactive sessions of a JupyterHub. For example
+complex computing infrastructures from the interactive sessions of a JupyterHub. For example
 [see the Dask HPC page](https://docs.dask.org/en/latest/setup/hpc.html).

 ### How much resources do user sessions take?
@@ -192,7 +192,7 @@ This is highly configurable by the administrator. If you wish for your users to
 data analytics environments for prototyping and light data exploring, you can restrict their
 memory and CPU based on the resources that you have available. If you'd like your JupyterHub
 to serve as a gateway to high-performance compute or data resources, you may increase the
-resources available on user machines, or connect them with computing infrastructure elsewhere.
+resources available on user machines, or connect them with computing infrastructures elsewhere.

 ### Can I customize the look and feel of a JupyterHub?

@@ -217,7 +217,7 @@ your JupyterHub with the various services and tools that you wish to provide to
 ### How well does JupyterHub scale? What are JupyterHub's limitations?

 JupyterHub works well at both a small scale (e.g., a single VM or machine) as well as a
-high scale (e.g., a scalable Kubernetes cluster). It can be used for teams as small a 2, and
+high scale (e.g., a scalable Kubernetes cluster). It can be used for teams as small as 2, and
 for user bases as large as 10,000. The scalability of JupyterHub largely depends on the
 infrastructure on which it is deployed. JupyterHub has been designed to be lightweight and
 flexible, so you can tailor your JupyterHub deployment to your needs.
@@ -249,7 +249,7 @@ share their results with one another.

 JupyterHub also provides a computational framework to share computational narratives between
 different levels of an organization. For example, data scientists can share Jupyter Notebooks
-rendered as [voila dashboards](https://voila.readthedocs.io/en/stable/) with those who are not
+rendered as [Voilà dashboards](https://voila.readthedocs.io/en/stable/) with those who are not
 familiar with programming, or create publicly-available interactive analyses to allow others to
 interact with your work.

--- a/docs/source/getting-started/networking-basics.md
+++ b/docs/source/getting-started/networking-basics.md
@@ -43,7 +43,7 @@ port.

 By default, this REST API listens on port 8001 of `localhost` only.
 The Hub service talks to the proxy via a REST API on a secondary port. The
-API URL can be configured separately and override the default settings.
+API URL can be configured separately to override the default settings.

 ### Set api_url

@@ -82,13 +82,13 @@ c.JupyterHub.hub_ip = '10.0.1.4'
 c.JupyterHub.hub_port = 54321
 ```

-**Added in 0.8:** The `c.JupyterHub.hub_connect_ip` setting is the ip address or
+**Added in 0.8:** The `c.JupyterHub.hub_connect_ip` setting is the IP address or
 hostname that other services should use to connect to the Hub. A common
 configuration for, e.g. docker, is:

 ```python
 c.JupyterHub.hub_ip = '0.0.0.0'  # listen on all interfaces
-c.JupyterHub.hub_connect_ip = '10.0.1.4'  # ip as seen on the docker network. Can also be a hostname.
+c.JupyterHub.hub_connect_ip = '10.0.1.4'  # IP as seen on the docker network. Can also be a hostname.
 ```

 ## Adjusting the hub's URL
--- a/docs/source/getting-started/services-basics.md
+++ b/docs/source/getting-started/services-basics.md
@@ -2,7 +2,7 @@

 When working with JupyterHub, a **Service** is defined as a process
 that interacts with the Hub's REST API. A Service may perform a specific
-or action or task. For example, shutting down individuals' single user
+action or task. For example, shutting down individuals' single user
 notebook servers that have been idle for some time is a good example of
 a task that could be automated by a Service. Let's look at how the
 [jupyterhub_idle_culler][] script can be used as a Service.
@@ -114,7 +114,7 @@ interact with it.
 This will run the idle culler service manually. It can be run as a standalone
 script anywhere with access to the Hub, and will periodically check for idle
 servers and shut them down via the Hub's REST API. In order to shutdown the
-servers, the token given to cull-idle must have admin privileges.
+servers, the token given to `cull-idle` must have admin privileges.

 Generate an API token and store it in the `JUPYTERHUB_API_TOKEN` environment
 variable. Run `jupyterhub_idle_culler` manually.
--- a/docs/source/getting-started/spawners-basics.md
+++ b/docs/source/getting-started/spawners-basics.md
@@ -1,8 +1,8 @@
 # Spawners and single-user notebook servers

 Since the single-user server is an instance of `jupyter notebook`, an entire separate
-multi-process application, there are many aspect of that server can configure, and a lot of ways
-to express that configuration.
+multi-process application, there are many aspects of that server that can be configured, and a lot
+of ways to express that configuration.

 At the JupyterHub level, you can set some values on the Spawner. The simplest of these is
 `Spawner.notebook_dir`, which lets you set the root directory for a user's server. This root
@@ -14,7 +14,7 @@ expanded to the user's home directory.
 c.Spawner.notebook_dir = '~/notebooks'
 ```

-You can also specify extra command-line arguments to the notebook server with:
+You can also specify extra command line arguments to the notebook server with:

 ```python
 c.Spawner.args = ['--debug', '--profile=PHYS131']
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -123,8 +123,8 @@ We want you to contribute to JupyterHub in ways that are most exciting
 & useful to you. We value documentation, testing, bug reporting & code equally,
 and are glad to have your contributions in whatever form you wish :)

-Our `Code of Conduct <https://github.com/jupyter/governance/blob/master/conduct/code_of_conduct.md>`_
-(`reporting guidelines <https://github.com/jupyter/governance/blob/master/conduct/reporting_online.md>`_)
+Our `Code of Conduct <https://github.com/jupyter/governance/blob/HEAD/conduct/code_of_conduct.md>`_
+(`reporting guidelines <https://github.com/jupyter/governance/blob/HEAD/conduct/reporting_online.md>`_)
 helps keep our community welcoming to as many people as possible.

 .. toctree::
@@ -155,4 +155,4 @@ Questions? Suggestions?

 .. _JupyterHub: https://github.com/jupyterhub/jupyterhub
 .. _Jupyter notebook: https://jupyter-notebook.readthedocs.io/en/latest/
-.. _REST API: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default
+.. _REST API: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/HEAD/docs/rest-api.yml#!/default
--- a/docs/source/installation-guide-hard.rst
+++ b/docs/source/installation-guide-hard.rst
@@ -3,4 +3,4 @@
 JupyterHub the hard way
 =======================

-This guide has moved to https://github.com/jupyterhub/jupyterhub-the-hard-way/blob/master/docs/installation-guide-hard.md
+This guide has moved to https://github.com/jupyterhub/jupyterhub-the-hard-way/blob/HEAD/docs/installation-guide-hard.md
--- a/docs/source/reference/authenticators.md
+++ b/docs/source/reference/authenticators.md
@@ -37,7 +37,7 @@ with any provider, is also available.
 ## The Dummy Authenticator

 When testing, it may be helpful to use the
-:class:`~jupyterhub.auth.DummyAuthenticator`. This allows for any username and
+{class}`jupyterhub.auth.DummyAuthenticator`. This allows for any username and
 password unless if a global password has been set. Once set, any username will
 still be accepted but the correct password will need to be provided.

@@ -259,7 +259,7 @@ PAM session.

 Beginning with version 0.8, JupyterHub is an OAuth provider.

-[authenticator]: https://github.com/jupyterhub/jupyterhub/blob/master/jupyterhub/auth.py
+[authenticator]: https://github.com/jupyterhub/jupyterhub/blob/HEAD/jupyterhub/auth.py
 [pam]: https://en.wikipedia.org/wiki/Pluggable_authentication_module
 [oauth]: https://en.wikipedia.org/wiki/OAuth
 [github oauth]: https://developer.github.com/v3/oauth/
--- a/docs/source/reference/rest.md
+++ b/docs/source/reference/rest.md
@@ -158,6 +158,27 @@ provided by notebook servers managed by JupyterHub if one of the following is tr
 1. The token is for the same user as the owner of the notebook
 2. The token is tied to an admin user or service **and** `c.JupyterHub.admin_access` is set to `True`

+## Paginating API requests
+
+Pagination is available through the `offset` and `limit` query parameters on
+certain endpoints, which can be used to return ideally sized windows of results.
+Here's example code demonstrating pagination on the `GET /users`
+endpoint to fetch the first 20 records.
+
+```python
+import requests
+
+api_url = 'http://127.0.0.1:8081/hub/api'
+
+r = requests.get(api_url + '/users?offset=0&limit=20')
+r.raise_for_status()
+r.json()
+```
+
+By default, pagination limit will be specified by the `JupyterHub.api_page_default_limit` config variable.
+
+Pagination is enabled on the `GET /users`, `GET /groups`, and `GET /proxy` REST endpoints.
+
 ## Enabling users to spawn multiple named-servers via the API

 With JupyterHub version 0.8, support for multiple servers per user has landed.
@@ -209,7 +230,7 @@ be viewed in a more [interactive style on swagger's petstore][].
 Both resources contain the same information and differ only in its display.
 Note: The Swagger specification is being renamed the [OpenAPI Initiative][].

-[interactive style on swagger's petstore]: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/master/docs/rest-api.yml#!/default
+[interactive style on swagger's petstore]: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyterhub/jupyterhub/HEAD/docs/rest-api.yml#!/default
 [openapi initiative]: https://www.openapis.org/
 [jupyterhub rest api]: ./rest-api
-[jupyter notebook rest api]: http://petstore.swagger.io/?url=https://raw.githubusercontent.com/jupyter/notebook/master/notebook/services/api/api.yaml
+[jupyter notebook rest api]: https://petstore3.swagger.io/?url=https://raw.githubusercontent.com/jupyter/notebook/HEAD/notebook/services/api/api.yaml
--- a/docs/source/reference/services.md
+++ b/docs/source/reference/services.md
@@ -203,8 +203,6 @@ To use HubAuth, you must set the `.api_token`, either programmatically when cons
 or via the `JUPYTERHUB_API_TOKEN` environment variable.

 Most of the logic for authentication implementation is found in the
-[`HubAuth.user_for_cookie`][hubauth.user_for_cookie]
-and in the
 [`HubAuth.user_for_token`][hubauth.user_for_token]
 methods, which makes a request of the Hub, and returns:

@@ -230,7 +228,7 @@ configurable by the `cookie_cache_max_age` setting (default: five minutes).
 For example, you have a Flask service that returns information about a user.
 JupyterHub's HubAuth class can be used to authenticate requests to the Flask
 service. See the `service-whoami-flask` example in the
-[JupyterHub GitHub repo](https://github.com/jupyterhub/jupyterhub/tree/master/examples/service-whoami-flask)
+[JupyterHub GitHub repo](https://github.com/jupyterhub/jupyterhub/tree/HEAD/examples/service-whoami-flask)
 for more details.

 ```python
@@ -241,11 +239,11 @@ from urllib.parse import quote

 from flask import Flask, redirect, request, Response

-from jupyterhub.services.auth import HubAuth
+from jupyterhub.services.auth import HubOAuth

 prefix = os.environ.get('JUPYTERHUB_SERVICE_PREFIX', '/')

-auth = HubAuth(
+auth = HubOAuth(
    api_token=os.environ['JUPYTERHUB_API_TOKEN'],
    cache_max_age=60,
 )
@@ -257,11 +255,8 @@ def authenticated(f):
    """Decorator for authenticating with the Hub"""
    @wraps(f)
    def decorated(*args, **kwargs):
-        cookie = request.cookies.get(auth.cookie_name)
        token = request.headers.get(auth.auth_header_name)
-        if cookie:
-            user = auth.user_for_cookie(cookie)
-        elif token:
+        if token:
            user = auth.user_for_token(token)
        else:
            user = None
--- a/docs/source/reference/spawners.md
+++ b/docs/source/reference/spawners.md
@@ -37,14 +37,13 @@ Some examples include:
 Information about the user can be retrieved from `self.user`,
 an object encapsulating the user's name, authentication, and server info.

-The return value of `Spawner.start` should be the (ip, port) of the running server.
-
-**NOTE:** When writing coroutines, _never_ `yield` in between a database change and a commit.
+The return value of `Spawner.start` should be the `(ip, port)` of the running server,
+or a full URL as a string.

 Most `Spawner.start` functions will look similar to this example:

 ```python
-def start(self):
+async def start(self):
    self.ip = '127.0.0.1'
    self.port = random_port()
    # get environment variables,
@@ -56,8 +55,10 @@ def start(self):
    cmd.extend(self.cmd)
    cmd.extend(self.get_args())

-    yield self._actually_start_server_somehow(cmd, env)
-    return (self.ip, self.port)
+    await self._actually_start_server_somehow(cmd, env)
+    # url may not match self.ip:self.port, but it could!
+    url = self._get_connectable_url()
+    return url
 ```

 When `Spawner.start` returns, the single-user server process should actually be running,
@@ -65,6 +66,48 @@ not just requested. JupyterHub can handle `Spawner.start` being very slow
 (such as PBS-style batch queues, or instantiating whole AWS instances)
 via relaxing the `Spawner.start_timeout` config value.

+#### Note on IPs and ports
+
+`Spawner.ip` and `Spawner.port` attributes set the _bind_ url,
+which the single-user server should listen on
+(passed to the single-user process via the `JUPYTERHUB_SERVICE_URL` environment variable).
+The _return_ value is the ip and port (or full url) the Hub should _connect to_.
+These are not necessarily the same, and usually won't be in any Spawner that works with remote resources or containers.
+
+The default for Spawner.ip, and Spawner.port is `127.0.0.1:{random}`,
+which is appropriate for Spawners that launch local processes,
+where everything is on localhost and each server needs its own port.
+For remote or container Spawners, it will often make sense to use a different value,
+such as `ip = '0.0.0.0'` and a fixed port, e.g. `8888`.
+The defaults can be changed in the class,
+preserving configuration with traitlets:
+
+```python
+from traitlets import default
+from jupyterhub.spawner import Spawner
+
+class MySpawner(Spawner):
+    @default("ip")
+    def _default_ip(self):
+        return '0.0.0.0'
+
+    @default("port")
+    def _default_port(self):
+        return 8888
+
+    async def start(self):
+        env = self.get_env()
+        cmd = []
+        # get jupyterhub command to run,
+        # typically ['jupyterhub-singleuser']
+        cmd.extend(self.cmd)
+        cmd.extend(self.get_args())
+
+        remote_server_info = await self._actually_start_server_somehow(cmd, env)
+        url = self.get_public_url_from(remote_server_info)
+        return url
+```
+
 ### Spawner.poll

 `Spawner.poll` should check if the spawner is still running.
@@ -125,7 +168,7 @@ If the `Spawner.options_form` is defined, when a user tries to start their serve

 If `Spawner.options_form` is undefined, the user's server is spawned directly, and no spawn page is rendered.

-See [this example](https://github.com/jupyterhub/jupyterhub/blob/master/examples/spawn-form/jupyterhub_config.py) for a form that allows custom CLI args for the local spawner.
+See [this example](https://github.com/jupyterhub/jupyterhub/blob/HEAD/examples/spawn-form/jupyterhub_config.py) for a form that allows custom CLI args for the local spawner.

 ### `Spawner.options_from_form`

@@ -166,7 +209,7 @@ which would return:

 When `Spawner.start` is called, this dictionary is accessible as `self.user_options`.

-[spawner]: https://github.com/jupyterhub/jupyterhub/blob/master/jupyterhub/spawner.py
+[spawner]: https://github.com/jupyterhub/jupyterhub/blob/HEAD/jupyterhub/spawner.py

 ## Writing a custom spawner

@@ -207,6 +250,73 @@ Additionally, configurable attributes for your spawner will
 appear in jupyterhub help output and auto-generated configuration files
 via `jupyterhub --generate-config`.

+## Environment variables and command-line arguments
+
+Spawners mainly do one thing: launch a command in an environment.
+
+The command-line is constructed from user configuration:
+
+- Spawner.cmd (default: `['jupterhub-singleuser']`)
+- Spawner.args (cli args to pass to the cmd, default: empty)
+
+where the configuration:
+
+```python
+c.Spawner.cmd = ["my-singleuser-wrapper"]
+c.Spawner.args = ["--debug", "--flag"]
+```
+
+would result in spawning the command:
+
+```bash
+my-singleuser-wrapper --debug --flag
+```
+
+The `Spawner.get_args()` method is how Spawner.args is accessed,
+and can be used by Spawners to customize/extend user-provided arguments.
+
+Prior to 2.0, JupyterHub unconditionally added certain options _if specified_ to the command-line,
+such as `--ip={Spawner.ip}` and `--port={Spawner.port}`.
+These have now all been moved to environment variables,
+and from JupyterHub 2.0,
+the command-line launched by JupyterHub is fully specified by overridable configuration `Spawner.cmd + Spawner.args`.
+
+Most process configuration is passed via environment variables.
+Additional variables can be specified via the `Spawner.environment` configuration.
+
+The process environment is returned by `Spawner.get_env`, which specifies the following environment variables:
+
+- JUPYTERHUB*SERVICE_URL - the \_bind* url where the server should launch its http server (`http://127.0.0.1:12345`).
+  This includes Spawner.ip and Spawner.port; _new in 2.0, prior to 2.0 ip,port were on the command-line and only if specified_
+- JUPYTERHUB_SERVICE_PREFIX - the URL prefix the service will run on (e.g. `/user/name/`)
+- JUPYTERHUB_USER - the JupyterHub user's username
+- JUPYTERHUB_SERVER_NAME - the server's name, if using named servers (default server has an empty name)
+- JUPYTERHUB_API_URL - the full url for the JupyterHub API (http://17.0.0.1:8001/hub/api)
+- JUPYTERHUB_BASE_URL - the base url of the whole jupyterhub deployment, i.e. the bit before `hub/` or `user/`,
+  as set by c.JupyterHub.base_url (default: `/`)
+- JUPYTERHUB_API_TOKEN - the API token the server can use to make requests to the Hub.
+  This is also the OAuth client secret.
+- JUPYTERHUB_CLIENT_ID - the OAuth client ID for authenticating visitors.
+- JUPYTERHUB_OAUTH_CALLBACK_URL - the callback URL to use in oauth, typically `/user/:name/oauth_callback`
+
+Optional environment variables, depending on configuration:
+
+- JUPYTERHUB*SSL*[KEYFILE|CERTFILE|CLIENT_CI] - SSL configuration, when internal_ssl is enabled
+- JUPYTERHUB_ROOT_DIR - the root directory of the server (notebook directory), when Spawner.notebook_dir is defined (new in 2.0)
+- JUPYTERHUB_DEFAULT_URL - the default URL for the server (for redirects from /user/:name/),
+  if Spawner.default_url is defined
+  (new in 2.0, previously passed via cli)
+- JUPYTERHUB_DEBUG=1 - generic debug flag, sets maximum log level when Spawner.debug is True
+  (new in 2.0, previously passed via cli)
+- JUPYTERHUB_DISABLE_USER_CONFIG=1 - disable loading user config,
+  sets maximum log level when Spawner.debug is True (new in 2.0,
+  previously passed via cli)
+
+- JUPYTERHUB*[MEM|CPU]*[LIMIT_GUARANTEE] - the values of cpu and memory limits and guarantees.
+  These are not expected to be enforced by the process,
+  but are made available as a hint,
+  e.g. for resource monitoring extensions.
+
 ## Spawners, resource limits, and guarantees (Optional)

 Some spawners of the single-user notebook servers allow setting limits or
--- a/docs/source/reference/templates.md
+++ b/docs/source/reference/templates.md
@@ -10,7 +10,7 @@ appearance.

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

--- a/docs/source/troubleshooting.md
+++ b/docs/source/troubleshooting.md
@@ -234,7 +234,7 @@ With a docker container, pass in the environment variable with the run command:
      -e JUPYTERHUB_API_TOKEN=my_secret_token \
      jupyter/datascience-notebook:latest

-[This example](https://github.com/jupyterhub/jupyterhub/tree/master/examples/service-notebook/external) demonstrates how to combine the use of the `jupyterhub-singleuser` environment variables when launching a Notebook as an externally managed service.
+[This example](https://github.com/jupyterhub/jupyterhub/tree/HEAD/examples/service-notebook/external) demonstrates how to combine the use of the `jupyterhub-singleuser` environment variables when launching a Notebook as an externally managed service.

 ## How do I...?

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

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

 exit 0
--- a/examples/external-oauth/jupyterhub_config.py
+++ b/examples/external-oauth/jupyterhub_config.py
@@ -13,7 +13,7 @@ if not api_token:
 c.JupyterHub.services = [
    {
        'name': 'external-oauth',
-        'oauth_client_id': "whoami-oauth-client-test",
+        'oauth_client_id': "service-oauth-client-test",
        'api_token': api_token,
        'oauth_redirect_uri': 'http://127.0.0.1:5555/oauth_callback',
    }
--- a/examples/external-oauth/launch-service-basic.sh
+++ b/examples/external-oauth/launch-service-basic.sh
@@ -9,7 +9,7 @@ if [[ -z "${JUPYTERHUB_API_TOKEN}" ]]; then
 fi

 # 2. oauth client ID
-export JUPYTERHUB_CLIENT_ID='whoami-oauth-client-test'
+export JUPYTERHUB_CLIENT_ID='service-oauth-client-test'
 # 3. where the Hub is
 export JUPYTERHUB_URL='http://127.0.0.1:8000'

--- a/examples/external-oauth/launch-service.sh
+++ b/examples/external-oauth/launch-service.sh
@@ -9,7 +9,7 @@ if [[ -z "${JUPYTERHUB_API_TOKEN}" ]]; then
 fi

 # 2. oauth client ID
-export JUPYTERHUB_CLIENT_ID="whoami-oauth-client-test"
+export JUPYTERHUB_CLIENT_ID="service-oauth-client-test"
 # 3. what URL to run on
 export JUPYTERHUB_SERVICE_PREFIX='/'
 export JUPYTERHUB_SERVICE_URL='http://127.0.0.1:5555'
--- a/examples/service-whoami-flask/README.md
+++ b/examples/service-whoami-flask/README.md
@@ -1,6 +1,6 @@
 # Authenticating a flask service with JupyterHub

-Uses `jupyterhub.services.HubAuth` to authenticate requests with the Hub in a [flask][] application.
+Uses `jupyterhub.services.HubOAuth` to authenticate requests with the Hub in a [flask][] application.

 ## Run

@@ -8,7 +8,7 @@ Uses `jupyterhub.services.HubAuth` to authenticate requests with the Hub in a [f

        jupyterhub --ip=127.0.0.1

-2.  Visit http://127.0.0.1:8000/services/whoami/ or http://127.0.0.1:8000/services/whoami-oauth/
+2.  Visit http://127.0.0.1:8000/services/whoami/

 After logging in with your local-system credentials, you should see a JSON dump of your user info:

--- a/examples/service-whoami-flask/jupyterhub_config.py
+++ b/examples/service-whoami-flask/jupyterhub_config.py
@@ -5,10 +5,12 @@ c.JupyterHub.services = [
        'command': ['flask', 'run', '--port=10101'],
        'environment': {'FLASK_APP': 'whoami-flask.py'},
    },
-    {
-        'name': 'whoami-oauth',
-        'url': 'http://127.0.0.1:10201',
-        'command': ['flask', 'run', '--port=10201'],
-        'environment': {'FLASK_APP': 'whoami-oauth.py'},
-    },
 ]
+
+# dummy auth and simple spawner for testing
+# any username and password will work
+c.JupyterHub.spawner_class = 'simple'
+c.JupyterHub.authenticator_class = 'dummy'
+
+# listen only on localhost while testing with wide-open auth
+c.JupyterHub.ip = '127.0.0.1'
--- a/examples/service-whoami-flask/whoami-flask.py
+++ b/examples/service-whoami-flask/whoami-flask.py
@@ -4,42 +4,48 @@ whoami service authentication with the Hub
 """
 import json
 import os
+import secrets
 from functools import wraps
-from urllib.parse import quote

 from flask import Flask
+from flask import make_response
 from flask import redirect
 from flask import request
 from flask import Response
+from flask import session

-from jupyterhub.services.auth import HubAuth
+from jupyterhub.services.auth import HubOAuth


 prefix = os.environ.get('JUPYTERHUB_SERVICE_PREFIX', '/')

-auth = HubAuth(api_token=os.environ['JUPYTERHUB_API_TOKEN'], cache_max_age=60)
+auth = HubOAuth(api_token=os.environ['JUPYTERHUB_API_TOKEN'], cache_max_age=60)

 app = Flask(__name__)
+# encryption key for session cookies
+app.secret_key = secrets.token_bytes(32)


 def authenticated(f):
-    """Decorator for authenticating with the Hub"""
+    """Decorator for authenticating with the Hub via OAuth"""

    @wraps(f)
    def decorated(*args, **kwargs):
-        cookie = request.cookies.get(auth.cookie_name)
-        token = request.headers.get(auth.auth_header_name)
-        if cookie:
-            user = auth.user_for_cookie(cookie)
-        elif token:
+        token = session.get("token")
+
+        if token:
            user = auth.user_for_token(token)
        else:
            user = None
+
        if user:
            return f(user, *args, **kwargs)
        else:
            # redirect to login url on failed auth
-            return redirect(auth.login_url + '?next=%s' % quote(request.path))
+            state = auth.generate_state(next_url=request.path)
+            response = make_response(redirect(auth.login_url + '&state=%s' % state))
+            response.set_cookie(auth.state_cookie_name, state)
+            return response

    return decorated

@@ -50,3 +56,24 @@ def whoami(user):
    return Response(
        json.dumps(user, indent=1, sort_keys=True), mimetype='application/json'
    )
+
+
+@app.route(prefix + 'oauth_callback')
+def oauth_callback():
+    code = request.args.get('code', None)
+    if code is None:
+        return 403
+
+    # validate state field
+    arg_state = request.args.get('state', None)
+    cookie_state = request.cookies.get(auth.state_cookie_name)
+    if arg_state is None or arg_state != cookie_state:
+        # state doesn't match
+        return 403
+
+    token = auth.token_for_code(code)
+    # store token in session cookie
+    session["token"] = token
+    next_url = auth.get_next_url(cookie_state) or prefix
+    response = make_response(redirect(next_url))
+    return response
--- a/examples/service-whoami-flask/whoami-oauth.py
+++ b/examples/service-whoami-flask/whoami-oauth.py
@@ -1,72 +0,0 @@
-#!/usr/bin/env python3
-"""
-whoami service authentication with the Hub
-"""
-import json
-import os
-from functools import wraps
-
-from flask import Flask
-from flask import make_response
-from flask import redirect
-from flask import request
-from flask import Response
-
-from jupyterhub.services.auth import HubOAuth
-
-
-prefix = os.environ.get('JUPYTERHUB_SERVICE_PREFIX', '/')
-
-auth = HubOAuth(api_token=os.environ['JUPYTERHUB_API_TOKEN'], cache_max_age=60)
-
-app = Flask(__name__)
-
-
-def authenticated(f):
-    """Decorator for authenticating with the Hub via OAuth"""
-
-    @wraps(f)
-    def decorated(*args, **kwargs):
-        token = request.cookies.get(auth.cookie_name)
-        if token:
-            user = auth.user_for_token(token)
-        else:
-            user = None
-        if user:
-            return f(user, *args, **kwargs)
-        else:
-            # redirect to login url on failed auth
-            state = auth.generate_state(next_url=request.path)
-            response = make_response(redirect(auth.login_url + '&state=%s' % state))
-            response.set_cookie(auth.state_cookie_name, state)
-            return response
-
-    return decorated
-
-
-@app.route(prefix)
-@authenticated
-def whoami(user):
-    return Response(
-        json.dumps(user, indent=1, sort_keys=True), mimetype='application/json'
-    )
-
-
-@app.route(prefix + 'oauth_callback')
-def oauth_callback():
-    code = request.args.get('code', None)
-    if code is None:
-        return 403
-
-    # validate state field
-    arg_state = request.args.get('state', None)
-    cookie_state = request.cookies.get(auth.state_cookie_name)
-    if arg_state is None or arg_state != cookie_state:
-        # state doesn't match
-        return 403
-
-    token = auth.token_for_code(code)
-    next_url = auth.get_next_url(cookie_state) or prefix
-    response = make_response(redirect(next_url))
-    response.set_cookie(auth.cookie_name, token)
-    return response
--- a/jupyterhub/apihandlers/auth.py
+++ b/jupyterhub/apihandlers/auth.py
@@ -14,7 +14,6 @@ from tornado import web

 from .. import orm
 from .. import scopes
-from ..user import User
 from ..utils import token_authenticated
 from .base import APIHandler
 from .base import BaseHandler
@@ -24,7 +23,7 @@ class TokenAPIHandler(APIHandler):
    @token_authenticated
    def get(self, token):
        # FIXME: deprecate this API for oauth token resolution, in favor of using /api/user
-        # TODO: require specific scope for this deprecated API, applied to oauth client secrets only?
+        # TODO: require specific scope for this deprecated API, applied to service tokens only?
        self.log.warning(
            "/authorizations/token/:token endpoint is deprecated in JupyterHub 2.0. Use /api/user"
        )
@@ -55,53 +54,20 @@ class TokenAPIHandler(APIHandler):
        self.write(json.dumps(model))

    async def post(self):
-        warn_msg = (
-            "Using deprecated token creation endpoint %s."
-            " Use /hub/api/users/:user/tokens instead."
-        ) % self.request.uri
-        self.log.warning(warn_msg)
-        requester = user = self.current_user
-        if user is None:
-            # allow requesting a token with username and password
-            # for authenticators where that's possible
-            data = self.get_json_body()
-            try:
-                requester = user = await self.login_user(data)
-            except Exception as e:
-                self.log.error("Failure trying to authenticate with form data: %s" % e)
-                user = None
-            if user is None:
-                raise web.HTTPError(403)
-        else:
-            data = self.get_json_body()
-            # admin users can request tokens for other users
-            if data and data.get('username'):
-                user = self.find_user(data['username'])
-                if user is not requester and not requester.admin:
-                    raise web.HTTPError(
-                        403, "Only admins can request tokens for other users."
-                    )
-                if requester.admin and user is None:
-                    raise web.HTTPError(400, "No such user '%s'" % data['username'])
-
-        note = (data or {}).get('note')
-        if not note:
-            note = "Requested via deprecated api"
-            if requester is not user:
-                kind = 'user' if isinstance(user, User) else 'service'
-                note += " by %s %s" % (kind, requester.name)
-
-        api_token = user.new_api_token(note=note)
-        self.write(
-            json.dumps(
-                {'token': api_token, 'warning': warn_msg, 'user': self.user_model(user)}
-            )
+        raise web.HTTPError(
+            404,
+            "Deprecated endpoint /hub/api/authorizations/token is removed in JupyterHub 2.0."
+            " Use /hub/api/users/:user/tokens instead.",
        )


 class CookieAPIHandler(APIHandler):
    @token_authenticated
    def get(self, cookie_name, cookie_value=None):
+        self.log.warning(
+            "/authorizations/cookie endpoint is deprecated in JupyterHub 2.0. Use /api/user with OAuth tokens."
+        )
+
        cookie_name = quote(cookie_name, safe='')
        if cookie_value is None:
            self.log.warning(
--- a/jupyterhub/apihandlers/base.py
+++ b/jupyterhub/apihandlers/base.py
@@ -368,6 +368,22 @@ class APIHandler(BaseHandler):
                    400, ("group names must be str, not %r", type(groupname))
                )

+    def get_api_pagination(self):
+        default_limit = self.settings["app"].api_page_default_limit
+        max_limit = self.settings["app"].api_page_max_limit
+        offset = self.get_argument("offset", None)
+        limit = self.get_argument("limit", default_limit)
+        try:
+            offset = abs(int(offset)) if offset is not None else 0
+            limit = abs(int(limit))
+            if limit > max_limit:
+                limit = max_limit
+        except Exception as e:
+            raise web.HTTPError(
+                400, "Invalid argument type, offset and limit must be integers"
+            )
+        return offset, limit
+
    def options(self, *args, **kwargs):
        self.finish()

--- a/jupyterhub/apihandlers/groups.py
+++ b/jupyterhub/apihandlers/groups.py
@@ -37,9 +37,11 @@ class GroupListAPIHandler(_GroupAPIHandler):
    @needs_scope('read:groups')
    def get(self):
        """List groups"""
-        groups = self.db.query(orm.Group)
+        query = self.db.query(orm.Group)
+        offset, limit = self.get_api_pagination()
+        query = query.offset(offset).limit(limit)
        scope_filter = self.get_scope_filter('read:groups')
-        data = [self.group_model(g) for g in groups if scope_filter(g, kind='group')]
+        data = [self.group_model(g) for g in query if scope_filter(g, kind='group')]
        self.write(json.dumps(data))

    @needs_scope('admin:groups')
--- a/jupyterhub/apihandlers/proxy.py
+++ b/jupyterhub/apihandlers/proxy.py
@@ -17,7 +17,16 @@ class ProxyAPIHandler(APIHandler):
        This is the same as fetching the routing table directly from the proxy,
        but without clients needing to maintain separate
        """
+        offset, limit = self.get_api_pagination()
+
        routes = await self.proxy.get_all_routes()
+
+        routes = {
+            key: routes[key]
+            for key in list(routes.keys())[offset:limit]
+            if key in routes
+        }
+
        self.write(json.dumps(routes))

    @needs_scope('proxy')
--- a/jupyterhub/apihandlers/users.py
+++ b/jupyterhub/apihandlers/users.py
@@ -44,6 +44,11 @@ class SelfAPIHandler(APIHandler):
            self.raw_scopes.update(scopes.identify_scopes(user.orm_user))
            self.parsed_scopes = scopes.parse_scopes(self.raw_scopes)
            model = self.user_model(user)
+        # validate return, should have at least kind and name,
+        # otherwise our filters did something wrong
+        for key in ("kind", "name"):
+            if key not in model:
+                raise ValueError(f"Missing identify model for {user}: {model}")
        self.write(json.dumps(model))


@@ -66,6 +71,7 @@ class UserListAPIHandler(APIHandler):
    )
    def get(self):
        state_filter = self.get_argument("state", None)
+        offset, limit = self.get_api_pagination()

        # post_filter
        post_filter = None
@@ -105,12 +111,16 @@ class UserListAPIHandler(APIHandler):
        else:
            # no filter, return all users
            query = self.db.query(orm.User)
+
+        query = query.offset(offset).limit(limit)
+
        data = []
        for u in query:
            if post_filter is None or post_filter(u):
                user_model = self.user_model(u)
                if user_model:
                    data.append(user_model)
+
        self.write(json.dumps(data))

    @needs_scope('admin:users')
@@ -239,11 +249,7 @@ class UserAPIHandler(APIHandler):

        await maybe_future(self.authenticator.delete_user(user))

-        # allow the spawner to cleanup any persistent resources associated with the user
-        try:
-            await user.spawner.delete_forever()
-        except Exception as e:
-            self.log.error("Error cleaning up persistent resources: %s" % e)
+        await user.delete_spawners()

        # remove from registry
        self.users.delete(user)
@@ -485,10 +491,18 @@ class UserServerAPIHandler(APIHandler):
        options = self.get_json_body()
        remove = (options or {}).get('remove', False)

-        def _remove_spawner(f=None):
-            if f and f.exception():
-                return
+        async def _remove_spawner(f=None):
+            """Remove the spawner object
+
+            only called after it stops successfully
+            """
+            if f:
+                # await f, stop on error,
+                # leaving resources in the db in case of failure to stop
+                await f
            self.log.info("Deleting spawner %s", spawner._log_name)
+            await maybe_future(user._delete_spawner(spawner))
+
            self.db.delete(spawner.orm_spawner)
            user.spawners.pop(server_name, None)
            self.db.commit()
@@ -509,7 +523,8 @@ class UserServerAPIHandler(APIHandler):
            self.set_header('Content-Type', 'text/plain')
            self.set_status(202)
            if remove:
-                spawner._stop_future.add_done_callback(_remove_spawner)
+                # schedule remove when stop completes
+                asyncio.ensure_future(_remove_spawner(spawner._stop_future))
            return

        if spawner.pending:
@@ -527,9 +542,10 @@ class UserServerAPIHandler(APIHandler):

        if remove:
            if stop_future:
-                stop_future.add_done_callback(_remove_spawner)
+                # schedule remove when stop completes
+                asyncio.ensure_future(_remove_spawner(spawner._stop_future))
            else:
-                _remove_spawner()
+                await _remove_spawner()

        status = 202 if spawner._stop_pending else 204
        self.set_header('Content-Type', 'text/plain')
--- a/jupyterhub/app.py
+++ b/jupyterhub/app.py
@@ -1021,6 +1021,15 @@ class JupyterHub(Application):
        """,
    ).tag(config=True)

+    api_page_default_limit = Integer(
+        50,
+        help="The default amount of records returned by a paginated endpoint",
+    ).tag(config=True)
+
+    api_page_max_limit = Integer(
+        200, help="The maximum amount of records that can be returned at once"
+    )
+
    authenticate_prometheus = Bool(
        True, help="Authentication for prometheus metrics"
    ).tag(config=True)
@@ -2386,10 +2395,6 @@ class JupyterHub(Application):
        for user in self.users.values():
            for spawner in user.spawners.values():
                oauth_client_ids.add(spawner.oauth_client_id)
-                # avoid deleting clients created by 0.8
-                # 0.9 uses `jupyterhub-user-...` for the client id, while
-                # 0.8 uses just `user-...`
-                oauth_client_ids.add(spawner.oauth_client_id.split('-', 1)[1])

        for i, oauth_client in enumerate(self.db.query(orm.OAuthClient)):
            if oauth_client.identifier not in oauth_client_ids:
--- a/jupyterhub/orm.py
+++ b/jupyterhub/orm.py
@@ -3,6 +3,7 @@
 # Distributed under the terms of the Modified BSD License.
 import enum
 import json
+import warnings
 from base64 import decodebytes
 from base64 import encodebytes
 from datetime import datetime
@@ -674,18 +675,29 @@ class APIToken(Hashed, Base):
            orm_token.service = service
        if expires_in is not None:
            orm_token.expires_at = cls.now() + timedelta(seconds=expires_in)
+
        db.add(orm_token)
-        # load default roles if they haven't been initiated
-        # correct to have this here? otherwise some tests fail
        token_role = Role.find(db, 'token')
        if not token_role:
+            # FIXME: remove this.
+            # Creating a token before the db has roles defined should raise an error.
+            # PR #3460 should let us fix it by ensuring default roles are defined
+
+            warnings.warn(
+                "Token created before default roles!", RuntimeWarning, stacklevel=2
+            )
            default_roles = get_default_roles()
            for role in default_roles:
                create_role(db, role)
-        if roles is not None:
-            update_roles(db, entity=orm_token, roles=roles)
-        else:
-            assign_default_roles(db, entity=orm_token)
+        try:
+            if roles is not None:
+                update_roles(db, entity=orm_token, roles=roles)
+            else:
+                assign_default_roles(db, entity=orm_token)
+        except Exception:
+            db.delete(orm_token)
+            db.commit()
+            raise

        db.commit()
        return token
--- a/jupyterhub/proxy.py
+++ b/jupyterhub/proxy.py
@@ -24,6 +24,7 @@ import time
 from functools import wraps
 from subprocess import Popen
 from urllib.parse import quote
+from weakref import WeakKeyDictionary

 from tornado.httpclient import AsyncHTTPClient
 from tornado.httpclient import HTTPError
@@ -44,7 +45,6 @@ from .metrics import CHECK_ROUTES_DURATION_SECONDS
 from .metrics import PROXY_POLL_DURATION_SECONDS
 from .objects import Server
 from .utils import exponential_backoff
-from .utils import make_ssl_context
 from .utils import url_path_join
 from jupyterhub.traitlets import Command

@@ -55,11 +55,18 @@ def _one_at_a_time(method):
    If multiple concurrent calls to this method are made,
    queue them instead of allowing them to be concurrently outstanding.
    """
-    method._lock = asyncio.Lock()
+    # use weak dict for locks
+    # so that the lock is always acquired within the current asyncio loop
+    # should only be relevant in testing, where eventloops are created and destroyed often
+    method._locks = WeakKeyDictionary()

    @wraps(method)
    async def locked_method(*args, **kwargs):
-        async with method._lock:
+        loop = asyncio.get_event_loop()
+        lock = method._locks.get(loop, None)
+        if lock is None:
+            lock = method._locks[loop] = asyncio.Lock()
+        async with lock:
            return await method(*args, **kwargs)

    return locked_method
@@ -123,7 +130,7 @@ class Proxy(LoggingConfigurable):
        a URL as target. The hub will ensure this route is present
        in the proxy.

-        If the hub is running in host based mode (with 
+        If the hub is running in host based mode (with
        JupyterHub.subdomain_host set), the routespec *must*
        have a domain component (example.com/my-url/). If the
        hub is not running in host based mode, the routespec
--- a/jupyterhub/roles.py
+++ b/jupyterhub/roles.py
@@ -437,11 +437,11 @@ def assign_default_roles(db, entity):
    """Assigns the default roles to an entity:
    users and services get 'user' role, or admin role if they have admin flag
    Tokens get 'token' role"""
-    default_token_role = orm.Role.find(db, 'token')
    if isinstance(entity, orm.Group):
        pass
    elif isinstance(entity, orm.APIToken):
        app_log.debug('Assigning default roles to tokens')
+        default_token_role = orm.Role.find(db, 'token')
        if not entity.roles and (entity.user or entity.service) is not None:
            default_token_role.tokens.append(entity)
            app_log.info('Added role %s to token %s', default_token_role.name, entity)
--- a/jupyterhub/scopes.py
+++ b/jupyterhub/scopes.py
@@ -1,5 +1,7 @@
+"""General scope definitions and utilities"""
 import functools
 import inspect
+import warnings
 from enum import Enum

 from tornado import web
@@ -13,60 +15,85 @@ class Scope(Enum):
    ALL = True


-def _intersect_scopes(token_scopes, owner_scopes):
-    """Compares the permissions of token and its owner including horizontal filters
-    Returns the intersection of the two sets of scopes
+def _intersect_scopes(scopes_a, scopes_b):
+    """Intersect two sets of scopes
+
+    Compares the permissions of two sets of scopes,
+    including horizontal filters,
+    and returns the intersected scopes.

    Note: Intersects correctly with ALL and exact filter matches
          (i.e. users!user=x & read:users:name -> read:users:name!user=x)

          Does not currently intersect with containing filters
-          (i.e. users!group=x & users!user=y even if user y is in group x,
-          same for users:servers!user=x & users:servers!server=y)
+          (i.e. users!group=x & users!user=y even if user y is in group x)
    """
-    owner_parsed_scopes = parse_scopes(owner_scopes)
-    token_parsed_scopes = parse_scopes(token_scopes)
+    parsed_scopes_a = parse_scopes(scopes_a)
+    parsed_scopes_b = parse_scopes(scopes_b)

-    common_bases = owner_parsed_scopes.keys() & token_parsed_scopes.keys()
+    common_bases = parsed_scopes_a.keys() & parsed_scopes_b.keys()

    common_filters = {}
-    warn = False
+    warned = False
    for base in common_bases:
-        if owner_parsed_scopes[base] == Scope.ALL:
-            common_filters[base] = token_parsed_scopes[base]
-        elif token_parsed_scopes[base] == Scope.ALL:
-            common_filters[base] = owner_parsed_scopes[base]
+        filters_a = parsed_scopes_a[base]
+        filters_b = parsed_scopes_b[base]
+        if filters_a == Scope.ALL:
+            common_filters[base] = filters_b
+        elif filters_b == Scope.ALL:
+            common_filters[base] = filters_a
        else:
-            common_entities = (
-                owner_parsed_scopes[base].keys() & token_parsed_scopes[base].keys()
-            )
-            all_entities = (
-                owner_parsed_scopes[base].keys() | token_parsed_scopes[base].keys()
-            )
-            if 'user' in all_entities and ('group' or 'server' in all_entities):
-                warn = True
+            # warn *if* there are non-overlapping user= and group= filters
+            common_entities = filters_a.keys() & filters_b.keys()
+            all_entities = filters_a.keys() | filters_b.keys()
+            if (
+                not warned
+                and 'group' in all_entities
+                and ('user' in all_entities or 'server' in all_entities)
+            ):
+                # this could resolve wrong if there's a user or server only on one side and a group only on the other
+                # check both directions: A has group X not in B group list AND B has user Y not in A user list
+                for a, b in [(filters_a, filters_b), (filters_b, filters_a)]:
+                    for b_key in ('user', 'server'):
+                        if (
+                            not warned
+                            and "group" in a
+                            and b_key in b
+                            and set(a["group"]).difference(b.get("group", []))
+                            and set(b[b_key]).difference(a.get(b_key, []))
+                        ):
+                            warnings.warn(
+                                f"{base}[!{b_key}={b[b_key]}, !group={a['group']}] combinations of filters present,"
+                                " intersection between not considered. May result in lower than intended permissions.",
+                                UserWarning,
+                            )
+                            warned = True

            common_filters[base] = {
-                entity: set(owner_parsed_scopes[base][entity])
-                & set(token_parsed_scopes[base][entity])
+                entity: set(parsed_scopes_a[base][entity])
+                & set(parsed_scopes_b[base][entity])
                for entity in common_entities
            }

-    if warn:
-        app_log.warning(
-            "[!user=, !group=] or [!user=, !server=] combinations of filters present, intersection between not considered. May result in lower than intended permissions."
-        )
+            if 'server' in all_entities and 'user' in all_entities:
+                if filters_a.get('server') == filters_b.get('server'):
+                    continue

-    scopes = set()
-    for base in common_filters:
-        if common_filters[base] == Scope.ALL:
-            scopes.add(base)
-        else:
-            for entity, names_list in common_filters[base].items():
-                for name in names_list:
-                    scopes.add(f'{base}!{entity}={name}')
+                additional_servers = set()
+                # resolve user/server hierarchy in both directions
+                for a, b in [(filters_a, filters_b), (filters_b, filters_a)]:
+                    if 'server' in a and 'user' in b:
+                        for server in a['server']:
+                            username, _, servername = server.partition("/")
+                            if username in b['user']:
+                                additional_servers.add(server)

-    return scopes
+                if additional_servers:
+                    if "server" not in common_filters[base]:
+                        common_filters[base]["server"] = set()
+                    common_filters[base]["server"].update(additional_servers)
+
+    return unparse_scopes(common_filters)


 def get_scopes_for(orm_object):
@@ -176,7 +203,7 @@ def parse_scopes(scope_list):
    """
    Parses scopes and filters in something akin to JSON style

-    For instance, scope list ["users", "groups!group=foo", "users:servers!server=bar", "users:servers!server=baz"]
+    For instance, scope list ["users", "groups!group=foo", "users:servers!server=user/bar", "users:servers!server=user/baz"]
    would lead to scope model
    {
       "users":scope.ALL,
@@ -187,8 +214,8 @@ def parse_scopes(scope_list):
       },
       "users:servers":{
          "server":[
-             "bar",
-             "baz"
+             "user/bar",
+             "user/baz"
          ]
       }
    }
@@ -208,6 +235,19 @@ def parse_scopes(scope_list):
    return parsed_scopes


+def unparse_scopes(parsed_scopes):
+    """Turn a parsed_scopes dictionary back into a scopes set"""
+    scopes = set()
+    for base, filters in parsed_scopes.items():
+        if filters == Scope.ALL:
+            scopes.add(base)
+        else:
+            for entity, names_list in filters.items():
+                for name in names_list:
+                    scopes.add(f'{base}!{entity}={name}')
+    return scopes
+
+
 def needs_scope(*scopes):
    """Decorator to restrict access to users or services with the required scope"""

@@ -269,6 +309,9 @@ def identify_scopes(obj):
            for field in {"name", "roles", "groups"}
        }
    elif isinstance(obj, orm.Service):
+        # FIXME: need sub-scopes for services
+        # until then, we have just one service scope:
+        return {f"read:services!service={obj.name}"}
        return {
            f"read:services:{field}!service={obj.name}" for field in {"name", "roles"}
        }
--- a/jupyterhub/services/auth.py
+++ b/jupyterhub/services/auth.py
@@ -1,7 +1,7 @@
 """Authenticating services with JupyterHub.

-Cookies are sent to the Hub for verification. The Hub replies with a JSON
-model describing the authenticated user.
+Tokens are sent to the Hub for verification.
+The Hub replies with a JSON model describing the authenticated user.

 ``HubAuth`` can be used in any application, even outside tornado.

@@ -10,6 +10,7 @@ authenticate with the Hub.

 """
 import base64
+import hashlib
 import json
 import os
 import random
@@ -20,7 +21,6 @@ import time
 import uuid
 import warnings
 from unittest import mock
-from urllib.parse import quote
 from urllib.parse import urlencode

 import requests
@@ -113,9 +113,15 @@ class HubAuth(SingletonConfigurable):

    This can be used by any application.

+    Use this base class only for direct, token-authenticated applications
+    (web APIs).
+    For applications that support direct visits from browsers,
+    use HubOAuth to enable OAuth redirect-based authentication.
+
+
    If using tornado, use via :class:`HubAuthenticated` mixin.
-    If using manually, use the ``.user_for_cookie(cookie_value)`` method
-    to identify the user corresponding to a given cookie value.
+    If using manually, use the ``.user_for_token(token_value)`` method
+    to identify the user owning a given token.

    The following config must be set:

@@ -129,15 +135,12 @@ class HubAuth(SingletonConfigurable):
    - cookie_cache_max_age: the number of seconds responses
      from the Hub should be cached.
    - login_url (the *public* ``/hub/login`` URL of the Hub).
-    - cookie_name: the name of the cookie I should be using,
-      if different from the default (unlikely).
-
    """

    hub_host = Unicode(
        '',
        help="""The public host of JupyterHub
-        
+
        Only used if JupyterHub is spreading servers across subdomains.
        """,
    ).tag(config=True)
@@ -239,10 +242,6 @@ class HubAuth(SingletonConfigurable):
        """,
    ).tag(config=True)

-    cookie_name = Unicode(
-        'jupyterhub-services', help="""The name of the cookie I should be looking for"""
-    ).tag(config=True)
-
    cookie_options = Dict(
        help="""Additional options to pass when setting cookies.

@@ -286,12 +285,12 @@ class HubAuth(SingletonConfigurable):
    def _default_cache(self):
        return _ExpiringDict(self.cache_max_age)

-    def _check_hub_authorization(self, url, cache_key=None, use_cache=True):
+    def _check_hub_authorization(self, url, api_token, cache_key=None, use_cache=True):
        """Identify a user with the Hub

        Args:
            url (str): The API URL to check the Hub for authorization
-                       (e.g. http://127.0.0.1:8081/hub/api/authorizations/token/abc-def)
+                       (e.g. http://127.0.0.1:8081/hub/api/user)
            cache_key (str): The key for checking the cache
            use_cache (bool): Specify use_cache=False to skip cached cookie values (default: True)

@@ -309,7 +308,12 @@ class HubAuth(SingletonConfigurable):
            except KeyError:
                app_log.debug("HubAuth cache miss: %s", cache_key)

-        data = self._api_request('GET', url, allow_404=True)
+        data = self._api_request(
+            'GET',
+            url,
+            headers={"Authorization": "token " + api_token},
+            allow_403=True,
+        )
        if data is None:
            app_log.warning("No Hub user identified for request")
        else:
@@ -321,7 +325,7 @@ class HubAuth(SingletonConfigurable):

    def _api_request(self, method, url, **kwargs):
        """Make an API request"""
-        allow_404 = kwargs.pop('allow_404', False)
+        allow_403 = kwargs.pop('allow_403', False)
        headers = kwargs.setdefault('headers', {})
        headers.setdefault('Authorization', 'token %s' % self.api_token)
        if "cert" not in kwargs and self.certfile and self.keyfile:
@@ -345,7 +349,7 @@ class HubAuth(SingletonConfigurable):
            raise HTTPError(500, msg)

        data = None
-        if r.status_code == 404 and allow_404:
+        if r.status_code == 403 and allow_403:
            pass
        elif r.status_code == 403:
            app_log.error(
@@ -389,26 +393,9 @@ class HubAuth(SingletonConfigurable):
        return data

    def user_for_cookie(self, encrypted_cookie, use_cache=True, session_id=''):
-        """Ask the Hub to identify the user for a given cookie.
-
-        Args:
-            encrypted_cookie (str): the cookie value (not decrypted, the Hub will do that)
-            use_cache (bool): Specify use_cache=False to skip cached cookie values (default: True)
-
-        Returns:
-            user_model (dict): The user model, if a user is identified, None if authentication fails.
-
-            The 'name' field contains the user's name.
-        """
-        return self._check_hub_authorization(
-            url=url_path_join(
-                self.api_url,
-                "authorizations/cookie",
-                self.cookie_name,
-                quote(encrypted_cookie, safe=''),
-            ),
-            cache_key='cookie:{}:{}'.format(session_id, encrypted_cookie),
-            use_cache=use_cache,
+        """Deprecated and removed. Use HubOAuth to authenticate browsers."""
+        raise RuntimeError(
+            "Identifying users by shared cookie is removed in JupyterHub 2.0. Use OAuth tokens."
        )

    def user_for_token(self, token, use_cache=True, session_id=''):
@@ -425,14 +412,19 @@ class HubAuth(SingletonConfigurable):
        """
        return self._check_hub_authorization(
            url=url_path_join(
-                self.api_url, "authorizations/token", quote(token, safe='')
+                self.api_url,
+                "user",
+            ),
+            api_token=token,
+            cache_key='token:{}:{}'.format(
+                session_id,
+                hashlib.sha256(token.encode("utf8", "replace")).hexdigest(),
            ),
-            cache_key='token:{}:{}'.format(session_id, token),
            use_cache=use_cache,
        )

    auth_header_name = 'Authorization'
-    auth_header_pat = re.compile(r'token\s+(.+)', re.IGNORECASE)
+    auth_header_pat = re.compile(r'(?:token|bearer)\s+(.+)', re.IGNORECASE)

    def get_token(self, handler):
        """Get the user token from a request
@@ -453,10 +445,8 @@ class HubAuth(SingletonConfigurable):

    def _get_user_cookie(self, handler):
        """Get the user model from a cookie"""
-        encrypted_cookie = handler.get_cookie(self.cookie_name)
-        session_id = self.get_session_id(handler)
-        if encrypted_cookie:
-            return self.user_for_cookie(encrypted_cookie, session_id=session_id)
+        # overridden in HubOAuth to store the access token after oauth
+        return None

    def get_session_id(self, handler):
        """Get the jupyterhub session id
@@ -509,6 +499,9 @@ class HubAuth(SingletonConfigurable):
 class HubOAuth(HubAuth):
    """HubAuth using OAuth for login instead of cookies set by the Hub.

+    Use this class if you want users to be able to visit your service with a browser.
+    They will be authenticated via OAuth with the Hub.
+
    .. versionadded: 0.8
    """

@@ -557,7 +550,7 @@ class HubOAuth(HubAuth):

    oauth_client_id = Unicode(
        help="""The OAuth client ID for this application.
-        
+
        Use JUPYTERHUB_CLIENT_ID by default.
        """
    ).tag(config=True)
@@ -574,7 +567,7 @@ class HubOAuth(HubAuth):

    oauth_redirect_uri = Unicode(
        help="""OAuth redirect URI
-        
+
        Should generally be /base_url/oauth_callback
        """
    ).tag(config=True)
--- a/jupyterhub/singleuser/mixins.py
+++ b/jupyterhub/singleuser/mixins.py
@@ -10,9 +10,11 @@ with JupyterHub authentication mixins enabled.
 # Distributed under the terms of the Modified BSD License.
 import asyncio
 import json
+import logging
 import os
 import random
 import secrets
+import sys
 import warnings
 from datetime import datetime
 from datetime import timezone
@@ -50,6 +52,17 @@ from ..utils import make_ssl_context
 from ..utils import url_path_join


+def _bool_env(key):
+    """Cast an environment variable to bool
+
+    0, empty, or unset is False; All other values are True.
+    """
+    if os.environ.get(key, "") in {"", "0"}:
+        return False
+    else:
+        return True
+
+
 # Authenticate requests with the Hub


@@ -99,19 +112,26 @@ class JupyterHubLoginHandlerMixin:
        Thus shouldn't be called anymore because HubAuthenticatedHandler
        should have already overridden get_current_user().

-        Keep here to prevent unlikely circumstance from losing auth.
+        Keep here to protect uncommon circumstance of multiple BaseHandlers
+        from missing auth.
+
+        e.g. when multiple BaseHandler classes are used.
        """
        if HubAuthenticatedHandler not in handler.__class__.mro():
            warnings.warn(
-                f"Expected to see HubAuthenticatedHandler in {handler.__class__}.mro()",
+                f"Expected to see HubAuthenticatedHandler in {handler.__class__}.mro(),"
+                " patching in at call time. Hub authentication is still applied.",
                RuntimeWarning,
                stacklevel=2,
            )
+            # patch HubAuthenticated into the instance
            handler.__class__ = type(
                handler.__class__.__name__,
                (HubAuthenticatedHandler, handler.__class__),
                {},
            )
+            # patch into the class itself so this doesn't happen again for the same class
+            patch_base_handler(handler.__class__)
        return handler.get_current_user()

    @classmethod
@@ -141,7 +161,6 @@ class OAuthCallbackHandlerMixin(HubOAuthCallbackHandler):
 aliases = {
    'user': 'SingleUserNotebookApp.user',
    'group': 'SingleUserNotebookApp.group',
-    'cookie-name': 'HubAuth.cookie_name',
    'hub-prefix': 'SingleUserNotebookApp.hub_prefix',
    'hub-host': 'SingleUserNotebookApp.hub_host',
    'hub-api-url': 'SingleUserNotebookApp.hub_api_url',
@@ -270,6 +289,10 @@ class SingleUserNotebookAppMixin(Configurable):
    def _user_changed(self, change):
        self.log.name = change.new

+    @default("default_url")
+    def _default_url(self):
+        return os.environ.get("JUPYTERHUB_DEFAULT_URL", "/tree/")
+
    hub_host = Unicode().tag(config=True)

    hub_prefix = Unicode('/hub/').tag(config=True)
@@ -352,7 +375,26 @@ class SingleUserNotebookAppMixin(Configurable):
        """,
    ).tag(config=True)

-    @validate('notebook_dir')
+    @default("disable_user_config")
+    def _default_disable_user_config(self):
+        return _bool_env("JUPYTERHUB_DISABLE_USER_CONFIG")
+
+    @default("root_dir")
+    def _default_root_dir(self):
+        if os.environ.get("JUPYTERHUB_ROOT_DIR"):
+            proposal = {"value": os.environ["JUPYTERHUB_ROOT_DIR"]}
+            # explicitly call validator, not called on default values
+            return self._notebook_dir_validate(proposal)
+        else:
+            return os.getcwd()
+
+    # notebook_dir is used by the classic notebook server
+    # root_dir is the future in jupyter server
+    @default("notebook_dir")
+    def _default_notebook_dir(self):
+        return self._default_root_dir()
+
+    @validate("notebook_dir", "root_dir")
    def _notebook_dir_validate(self, proposal):
        value = os.path.expanduser(proposal['value'])
        # Strip any trailing slashes
@@ -368,6 +410,13 @@ class SingleUserNotebookAppMixin(Configurable):
            raise TraitError("No such notebook dir: %r" % value)
        return value

+    @default('log_level')
+    def _log_level_default(self):
+        if _bool_env("JUPYTERHUB_DEBUG"):
+            return logging.DEBUG
+        else:
+            return logging.INFO
+
    @default('log_datefmt')
    def _log_datefmt_default(self):
        """Exclude date from default date format"""
@@ -683,6 +732,97 @@ def detect_base_package(App):
    return None


+def _nice_cls_repr(cls):
+    """Nice repr of classes, e.g. 'module.submod.Class'
+
+    Also accepts tuples of classes
+    """
+    return f"{cls.__module__}.{cls.__name__}"
+
+
+def patch_base_handler(BaseHandler, log=None):
+    """Patch HubAuthenticated into a base handler class
+
+    so anything inheriting from BaseHandler uses Hub authentication.
+    This works *even after* subclasses have imported and inherited from BaseHandler.
+
+    .. versionadded: 1.5
+        Made available as an importable utility
+    """
+    if log is None:
+        log = logging.getLogger()
+
+    if HubAuthenticatedHandler not in BaseHandler.__bases__:
+        new_bases = (HubAuthenticatedHandler,) + BaseHandler.__bases__
+        log.info(
+            "Patching auth into {mod}.{name}({old_bases}) -> {name}({new_bases})".format(
+                mod=BaseHandler.__module__,
+                name=BaseHandler.__name__,
+                old_bases=', '.join(
+                    _nice_cls_repr(cls) for cls in BaseHandler.__bases__
+                ),
+                new_bases=', '.join(_nice_cls_repr(cls) for cls in new_bases),
+            )
+        )
+        BaseHandler.__bases__ = new_bases
+        # We've now inserted our class as a parent of BaseHandler,
+        # but we also need to ensure BaseHandler *itself* doesn't
+        # override the public tornado API methods we have inserted.
+        # If they are defined in BaseHandler, explicitly replace them with our methods.
+        for name in ("get_current_user", "get_login_url"):
+            if name in BaseHandler.__dict__:
+                log.debug(
+                    f"Overriding {BaseHandler}.{name} with HubAuthenticatedHandler.{name}"
+                )
+                method = getattr(HubAuthenticatedHandler, name)
+                setattr(BaseHandler, name, method)
+    return BaseHandler
+
+
+def _patch_app_base_handlers(app):
+    """Patch Hub Authentication into the base handlers of an app
+
+    Patches HubAuthenticatedHandler into:
+
+    - App.base_handler_class (if defined)
+    - jupyter_server's JupyterHandler (if already imported)
+    - notebook's IPythonHandler (if already imported)
+    """
+    BaseHandler = app_base_handler = getattr(app, "base_handler_class", None)
+
+    base_handlers = []
+    if BaseHandler is not None:
+        base_handlers.append(BaseHandler)
+
+    # patch juptyer_server and notebook handlers if they have been imported
+    for base_handler_name in [
+        "jupyter_server.base.handlers.JupyterHandler",
+        "notebook.base.handlers.IPythonHandler",
+    ]:
+        modname, _ = base_handler_name.rsplit(".", 1)
+        if modname in sys.modules:
+            base_handlers.append(import_item(base_handler_name))
+
+    if not base_handlers:
+        pkg = detect_base_package(app.__class__)
+        if pkg == "jupyter_server":
+            BaseHandler = import_item("jupyter_server.base.handlers.JupyterHandler")
+        elif pkg == "notebook":
+            BaseHandler = import_item("notebook.base.handlers.IPythonHandler")
+        else:
+            raise ValueError(
+                "{}.base_handler_class must be defined".format(app.__class__.__name__)
+            )
+        base_handlers.append(BaseHandler)
+
+    # patch-in HubAuthenticatedHandler to base handler classes
+    for BaseHandler in base_handlers:
+        patch_base_handler(BaseHandler)
+
+    # return the first entry
+    return base_handlers[0]
+
+
 def make_singleuser_app(App):
    """Make and return a singleuser notebook app

@@ -706,37 +846,7 @@ def make_singleuser_app(App):
    # detect base classes
    LoginHandler = empty_parent_app.login_handler_class
    LogoutHandler = empty_parent_app.logout_handler_class
-    BaseHandler = getattr(empty_parent_app, "base_handler_class", None)
-    if BaseHandler is None:
-        pkg = detect_base_package(App)
-        if pkg == "jupyter_server":
-            BaseHandler = import_item("jupyter_server.base.handlers.JupyterHandler")
-        elif pkg == "notebook":
-            BaseHandler = import_item("notebook.base.handlers.IPythonHandler")
-        else:
-            raise ValueError(
-                "{}.base_handler_class must be defined".format(App.__name__)
-            )
-
-    # patch-in HubAuthenticatedHandler to BaseHandler,
-    # so anything inheriting from BaseHandler uses Hub authentication
-    if HubAuthenticatedHandler not in BaseHandler.__bases__:
-        new_bases = (HubAuthenticatedHandler,) + BaseHandler.__bases__
-        log.debug(
-            f"Patching {BaseHandler}{BaseHandler.__bases__} -> {BaseHandler}{new_bases}"
-        )
-        BaseHandler.__bases__ = new_bases
-        # We've now inserted our class as a parent of BaseHandler,
-        # but we also need to ensure BaseHandler *itself* doesn't
-        # override the public tornado API methods we have inserted.
-        # If they are defined in BaseHandler, explicitly replace them with our methods.
-        for name in ("get_current_user", "get_login_url"):
-            if name in BaseHandler.__dict__:
-                log.debug(
-                    f"Overriding {BaseHandler}.{name} with HubAuthenticatedHandler.{name}"
-                )
-                method = getattr(HubAuthenticatedHandler, name)
-                setattr(BaseHandler, name, method)
+    BaseHandler = _patch_app_base_handlers(empty_parent_app)

    # create Handler classes from mixins + bases
    class JupyterHubLoginHandler(JupyterHubLoginHandlerMixin, LoginHandler):
@@ -766,4 +876,11 @@ def make_singleuser_app(App):
        logout_handler_class = JupyterHubLogoutHandler
        oauth_callback_handler_class = OAuthCallbackHandler

+        def initialize(self, *args, **kwargs):
+            result = super().initialize(*args, **kwargs)
+            # run patch again after initialize, so extensions have already been loaded
+            # probably a no-op most of the time
+            _patch_app_base_handlers(self)
+            return result
+
    return SingleUserNotebookApp
--- a/jupyterhub/spawner.py
+++ b/jupyterhub/spawner.py
@@ -39,7 +39,6 @@ from .traitlets import ByteSpecification
 from .traitlets import Callable
 from .traitlets import Command
 from .utils import exponential_backoff
-from .utils import iterate_until
 from .utils import maybe_future
 from .utils import random_port
 from .utils import url_path_join
@@ -246,11 +245,22 @@ class Spawner(LoggingConfigurable):
    )

    ip = Unicode(
-        '',
+        '127.0.0.1',
        help="""
        The IP address (or hostname) the single-user server should listen on.

+        Usually either '127.0.0.1' (default) or '0.0.0.0'.
+
        The JupyterHub proxy implementation should be able to send packets to this interface.
+
+        Subclasses which launch remotely or in containers
+        should override the default to '0.0.0.0'.
+
+        .. versionchanged:: 2.0
+            Default changed to '127.0.0.1', from ''.
+            In most cases, this does not result in a change in behavior,
+            as '' was interpreted as 'unspecified',
+            which used the subprocesses' own default, itself usually '127.0.0.1'.
        """,
    ).tag(config=True)

@@ -811,8 +821,20 @@ class Spawner(LoggingConfigurable):
            'activity',
        )
        env['JUPYTERHUB_BASE_URL'] = self.hub.base_url[:-4]
+
        if self.server:
+            base_url = self.server.base_url
+            if self.ip or self.port:
+                self.server.ip = self.ip
+                self.server.port = self.port
            env['JUPYTERHUB_SERVICE_PREFIX'] = self.server.base_url
+        else:
+            # this should only occur in mock/testing scenarios
+            base_url = '/'
+
+        proto = 'https' if self.internal_ssl else 'http'
+        bind_url = f"{proto}://{self.ip}:{self.port}{base_url}"
+        env["JUPYTERHUB_SERVICE_URL"] = bind_url

        # Put in limit and guarantee info if they exist.
        # Note that this is for use by the humans / notebook extensions in the
@@ -832,6 +854,20 @@ class Spawner(LoggingConfigurable):
            env['JUPYTERHUB_SSL_CERTFILE'] = self.cert_paths['certfile']
            env['JUPYTERHUB_SSL_CLIENT_CA'] = self.cert_paths['cafile']

+        if self.notebook_dir:
+            notebook_dir = self.format_string(self.notebook_dir)
+            env["JUPYTERHUB_ROOT_DIR"] = notebook_dir
+
+        if self.default_url:
+            default_url = self.format_string(self.default_url)
+            env["JUPYTERHUB_DEFAULT_URL"] = default_url
+
+        if self.debug:
+            env["JUPYTERHUB_DEBUG"] = "1"
+
+        if self.disable_user_config:
+            env["JUPYTERHUB_DISABLE_USER_CONFIG"] = "1"
+
        # env overrides from config. If the value is a callable, it will be called with
        # one parameter - the current spawner instance - and the return value
        # will be assigned to the environment variable. This will be called at
@@ -843,7 +879,6 @@ class Spawner(LoggingConfigurable):
                env[key] = value(self)
            else:
                env[key] = value
-
        return env

    async def get_url(self):
@@ -1010,35 +1045,16 @@ class Spawner(LoggingConfigurable):
        """Return the arguments to be passed after self.cmd

        Doesn't expect shell expansion to happen.
+
+        .. versionchanged:: 2.0
+            Prior to 2.0, JupyterHub passed some options such as
+            ip, port, and default_url to the command-line.
+            JupyterHub 2.0 no longer builds any CLI args
+            other than `Spawner.cmd` and `Spawner.args`.
+            All values that come from jupyterhub itself
+            will be passed via environment variables.
        """
-        args = []
-
-        if self.ip:
-            args.append('--ip=%s' % _quote_safe(self.ip))
-
-        if self.port:
-            args.append('--port=%i' % self.port)
-        elif self.server and self.server.port:
-            self.log.warning(
-                "Setting port from user.server is deprecated as of JupyterHub 0.7."
-            )
-            args.append('--port=%i' % self.server.port)
-
-        if self.notebook_dir:
-            notebook_dir = self.format_string(self.notebook_dir)
-            args.append('--notebook-dir=%s' % _quote_safe(notebook_dir))
-        if self.default_url:
-            default_url = self.format_string(self.default_url)
-            args.append(
-                '--SingleUserNotebookApp.default_url=%s' % _quote_safe(default_url)
-            )
-
-        if self.debug:
-            args.append('--debug')
-        if self.disable_user_config:
-            args.append('--disable-user-config')
-        args.extend(self.args)
-        return args
+        return self.args

    def run_pre_spawn_hook(self):
        """Run the pre_spawn_hook if defined"""
@@ -1155,6 +1171,18 @@ class Spawner(LoggingConfigurable):
        """
        raise NotImplementedError("Override in subclass. Must be a coroutine.")

+    def delete_forever(self):
+        """Called when a user or server is deleted.
+
+        This can do things like request removal of resources such as persistent storage.
+        Only called on stopped spawners, and is usually the last action ever taken for the user.
+
+        Will only be called once on each Spawner, immediately prior to removal.
+
+        Stopping a server does *not* call this method.
+        """
+        pass
+
    def add_poll_callback(self, callback, *args, **kwargs):
        """Add a callback to fire when the single-user server stops"""
        if args or kwargs:
@@ -1470,7 +1498,8 @@ class LocalProcessSpawner(Spawner):

    async def start(self):
        """Start the single-user server."""
-        self.port = random_port()
+        if self.port == 0:
+            self.port = random_port()
        cmd = []
        env = self.get_env()

--- a/jupyterhub/tests/mocking.py
+++ b/jupyterhub/tests/mocking.py
@@ -94,16 +94,6 @@ class MockSpawner(SimpleLocalProcessSpawner):
    def _cmd_default(self):
        return [sys.executable, '-m', 'jupyterhub.tests.mocksu']

-    async def delete_forever(self):
-        """Called when a user is deleted.
-
-        This can do things like request removal of resources such as persistent storage.
-        Only called on stopped spawners, and is likely the last action ever taken for the user.
-
-        Will only be called once on the user's default Spawner.
-        """
-        pass
-
    use_this_api_token = None

    def start(self):
--- a/jupyterhub/tests/mocksu.py
+++ b/jupyterhub/tests/mocksu.py
@@ -11,10 +11,10 @@ Handlers and their purpose include:
 - ArgsHandler: allowing retrieval of `sys.argv`.

 """
-import argparse
 import json
 import os
 import sys
+from urllib.parse import urlparse

 from tornado import httpserver
 from tornado import ioloop
@@ -36,7 +36,8 @@ class ArgsHandler(web.RequestHandler):
        self.write(json.dumps(sys.argv))


-def main(args):
+def main():
+    url = urlparse(os.environ["JUPYTERHUB_SERVICE_URL"])
    options.logging = 'debug'
    log.enable_pretty_logging()
    app = web.Application(
@@ -50,10 +51,11 @@ def main(args):

    if key and cert and ca:
        ssl_context = make_ssl_context(key, cert, cafile=ca, check_hostname=False)
+        assert url.scheme == "https"

    server = httpserver.HTTPServer(app, ssl_options=ssl_context)
-    log.app_log.info("Starting mock singleuser server at 127.0.0.1:%s", args.port)
-    server.listen(args.port, '127.0.0.1')
+    log.app_log.info(f"Starting mock singleuser server at {url.hostname}:{url.port}")
+    server.listen(url.port, url.hostname)
    try:
        ioloop.IOLoop.instance().start()
    except KeyboardInterrupt:
@@ -61,7 +63,4 @@ def main(args):


 if __name__ == '__main__':
-    parser = argparse.ArgumentParser()
-    parser.add_argument('--port', type=int)
-    args, extra = parser.parse_known_args()
-    main(args)
+    main()
--- a/jupyterhub/tests/test_api.py
+++ b/jupyterhub/tests/test_api.py
@@ -192,6 +192,38 @@ async def test_get_users(app):
    r_user_model = r.json()[0]
    assert r_user_model['name'] == user_model['name']

+    # Tests offset for pagination
+    r = await api_request(app, 'users?offset=1')
+    assert r.status_code == 200
+
+    users = sorted(r.json(), key=lambda d: d['name'])
+    users = [normalize_user(u) for u in users]
+    assert users == [
+        fill_user(
+            {'name': 'user', 'admin': False, 'auth_state': None, 'roles': ['user']}
+        )
+    ]
+
+    r = await api_request(app, 'users?offset=20')
+    assert r.status_code == 200
+    assert r.json() == []
+
+    # Test limit for pagination
+    r = await api_request(app, 'users?limit=1')
+    assert r.status_code == 200
+
+    users = sorted(r.json(), key=lambda d: d['name'])
+    users = [normalize_user(u) for u in users]
+    assert users == [
+        fill_user(
+            {'name': 'admin', 'admin': True, 'auth_state': None, 'roles': ['admin']}
+        )
+    ]
+
+    r = await api_request(app, 'users?limit=0')
+    assert r.status_code == 200
+    assert r.json() == []
+

@mark.user
@mark.parametrize(
@@ -611,10 +643,17 @@ async def test_spawn(app):
    r = await async_requests.get(ujoin(url, 'args'), **kwargs)
    assert r.status_code == 200
    argv = r.json()
-    assert '--port' in ' '.join(argv)
+    assert '--port' not in ' '.join(argv)
+    # we pass no CLI args anymore:
+    assert len(argv) == 1
    r = await async_requests.get(ujoin(url, 'env'), **kwargs)
    env = r.json()
-    for expected in ['JUPYTERHUB_USER', 'JUPYTERHUB_BASE_URL', 'JUPYTERHUB_API_TOKEN']:
+    for expected in [
+        'JUPYTERHUB_USER',
+        'JUPYTERHUB_BASE_URL',
+        'JUPYTERHUB_API_TOKEN',
+        'JUPYTERHUB_SERVICE_URL',
+    ]:
        assert expected in env
    if app.subdomain_host:
        assert env['JUPYTERHUB_HOST'] == app.subdomain_host
@@ -1176,76 +1215,13 @@ async def test_check_token(app):
    assert r.status_code == 404


-@mark.parametrize("headers, status", [({}, 200), ({'Authorization': 'token bad'}, 403)])
+@mark.parametrize("headers, status", [({}, 404), ({'Authorization': 'token bad'}, 404)])
 async def test_get_new_token_deprecated(app, headers, status):
    # request a new token
    r = await api_request(
        app, 'authorizations', 'token', method='post', headers=headers
    )
    assert r.status_code == status
-    if status != 200:
-        return
-    reply = r.json()
-    assert 'token' in reply
-    r = await api_request(app, 'authorizations', 'token', reply['token'])
-    r.raise_for_status()
-    reply = r.json()
-    assert reply['name'] == 'admin'
-
-
-async def test_token_formdata_deprecated(app):
-    """Create a token for a user with formdata and no auth header"""
-    data = {'username': 'fake', 'password': 'fake'}
-    r = await api_request(
-        app,
-        'authorizations',
-        'token',
-        method='post',
-        data=json.dumps(data) if data else None,
-        noauth=True,
-    )
-    assert r.status_code == 200
-    reply = r.json()
-    assert 'token' in reply
-    r = await api_request(app, 'authorizations', 'token', reply['token'])
-    r.raise_for_status()
-    reply = r.json()
-    assert reply['name'] == data['username']
-
-
-@mark.parametrize(
-    "as_user, for_user, status",
-    [
-        ('admin', 'other', 200),
-        ('admin', 'missing', 400),
-        ('user', 'other', 403),
-        ('user', 'user', 200),
-    ],
-)
-async def test_token_as_user_deprecated(app, as_user, for_user, status):
-    # ensure both users exist
-    u = add_user(app.db, app, name=as_user)
-    if for_user != 'missing':
-        for_user_obj = add_user(app.db, app, name=for_user)
-    data = {'username': for_user}
-    headers = {'Authorization': 'token %s' % u.new_api_token()}
-    r = await api_request(
-        app,
-        'authorizations',
-        'token',
-        method='post',
-        data=json.dumps(data),
-        headers=headers,
-    )
-    assert r.status_code == status
-    reply = r.json()
-    if status != 200:
-        return
-    assert 'token' in reply
-    r = await api_request(app, 'authorizations', 'token', reply['token'])
-    r.raise_for_status()
-    reply = r.json()
-    assert reply['name'] == data['username']


@mark.parametrize(
@@ -1447,16 +1423,45 @@ async def test_groups_list(app):
    reply = r.json()
    assert reply == []

-    # create a group
+    # create two groups
    group = orm.Group(name='alphaflight')
+    group_2 = orm.Group(name='betaflight')
    app.db.add(group)
+    app.db.add(group_2)
    app.db.commit()

    r = await api_request(app, 'groups')
    r.raise_for_status()
    reply = r.json()
+    assert reply == [
+        {'kind': 'group', 'name': 'alphaflight', 'users': [], 'roles': []},
+        {'kind': 'group', 'name': 'betaflight', 'users': [], 'roles': []},
+    ]
+
+    # Test offset for pagination
+    r = await api_request(app, "groups?offset=1")
+    r.raise_for_status()
+    reply = r.json()
+    assert r.status_code == 200
+    assert reply == [{'kind': 'group', 'name': 'betaflight', 'users': [], 'roles': []}]
+
+    r = await api_request(app, "groups?offset=10")
+    r.raise_for_status()
+    reply = r.json()
+    assert reply == []
+
+    # Test limit for pagination
+    r = await api_request(app, "groups?limit=1")
+    r.raise_for_status()
+    reply = r.json()
+    assert r.status_code == 200
    assert reply == [{'kind': 'group', 'name': 'alphaflight', 'users': [], 'roles': []}]

+    r = await api_request(app, "groups?limit=0")
+    r.raise_for_status()
+    reply = r.json()
+    assert reply == []
+

@mark.group
 async def test_add_multi_group(app):
--- a/jupyterhub/tests/test_scopes.py
+++ b/jupyterhub/tests/test_scopes.py
@@ -1,5 +1,4 @@
 """Test scopes for API handlers"""
-import json
 from unittest import mock

 import pytest
@@ -11,6 +10,7 @@ from .. import orm
 from .. import roles
 from ..handlers import BaseHandler
 from ..scopes import _check_scope
+from ..scopes import _intersect_scopes
 from ..scopes import get_scopes_for
 from ..scopes import needs_scope
 from ..scopes import parse_scopes
@@ -806,3 +806,81 @@ async def test_roles_access(app, create_service_with_scopes, create_user_with_sc
    assert r.status_code == 200
    model_keys = {'kind', 'name', 'roles'}
    assert model_keys == r.json().keys()
+
+
+@pytest.mark.parametrize(
+    "left, right, expected, should_warn",
+    [
+        (set(), set(), set(), False),
+        (set(), set(["users"]), set(), False),
+        # no warning if users and groups only on the same side
+        (
+            set(["users!user=x", "users!group=y"]),
+            set([]),
+            set([]),
+            False,
+        ),
+        # no warning if users are on both sizes
+        (
+            set(["users!user=x", "users!user=y", "users!group=y"]),
+            set(["users!user=x"]),
+            set(["users!user=x"]),
+            False,
+        ),
+        # no warning if users and groups are both defined
+        # on both sides
+        (
+            set(["users!user=x", "users!group=y"]),
+            set(["users!user=x", "users!group=y", "users!user=z"]),
+            set(["users!user=x", "users!group=y"]),
+            False,
+        ),
+        # warn if there's a user on one side and a group on the other
+        # which *may* intersect
+        (
+            set(["users!group=y", "users!user=z"]),
+            set(["users!user=x"]),
+            set([]),
+            True,
+        ),
+        # same for group->server
+        (
+            set(["users!group=y", "users!user=z"]),
+            set(["users!server=x/y"]),
+            set([]),
+            True,
+        ),
+        # this one actually shouldn't warn because server=x/y is under user=x,
+        # but we don't need to overcomplicate things just for a warning
+        (
+            set(["users!group=y", "users!user=x"]),
+            set(["users!server=x/y"]),
+            set(["users!server=x/y"]),
+            True,
+        ),
+        # resolves server under user, without warning
+        (
+            set(["read:users:servers!user=abc"]),
+            set(["read:users:servers!server=abc/xyz"]),
+            set(["read:users:servers!server=abc/xyz"]),
+            False,
+        ),
+        # user->server, no match
+        (
+            set(["read:users:servers!user=abc"]),
+            set(["read:users:servers!server=abcd/xyz"]),
+            set([]),
+            False,
+        ),
+    ],
+)
+def test_intersect_scopes(left, right, expected, should_warn, recwarn):
+    # run every test in both directions, to ensure symmetry of the inputs
+    for a, b in [(left, right), (right, left)]:
+        intersection = _intersect_scopes(set(left), set(right))
+        assert intersection == set(expected)
+
+    if should_warn:
+        assert len(recwarn) == 1
+    else:
+        assert len(recwarn) == 0
--- a/jupyterhub/tests/test_services_auth.py
+++ b/jupyterhub/tests/test_services_auth.py
@@ -26,8 +26,8 @@ from tornado.web import RequestHandler

 from .. import orm
 from ..services.auth import _ExpiringDict
-from ..services.auth import HubAuth
-from ..services.auth import HubAuthenticated
+from ..services.auth import HubOAuth
+from ..services.auth import HubOAuthenticated
 from ..utils import url_path_join
 from .mocking import public_host
 from .mocking import public_url
@@ -76,178 +76,6 @@ def test_expiring_dict():
        assert cache.get('key', 'default') == 'cached value'


-def test_hub_auth():
-    auth = HubAuth(cookie_name='foo')
-    mock_model = {'name': 'onyxia'}
-    url = url_path_join(auth.api_url, "authorizations/cookie/foo/bar")
-    with requests_mock.Mocker() as m:
-        m.get(url, text=json.dumps(mock_model))
-        user_model = auth.user_for_cookie('bar')
-    assert user_model == mock_model
-    # check cache
-    user_model = auth.user_for_cookie('bar')
-    assert user_model == mock_model
-
-    with requests_mock.Mocker() as m:
-        m.get(url, status_code=404)
-        user_model = auth.user_for_cookie('bar', use_cache=False)
-    assert user_model is None
-
-    # invalidate cache with timer
-    mock_model = {'name': 'willow'}
-    with monotonic_future, requests_mock.Mocker() as m:
-        m.get(url, text=json.dumps(mock_model))
-        user_model = auth.user_for_cookie('bar')
-    assert user_model == mock_model
-
-    with requests_mock.Mocker() as m:
-        m.get(url, status_code=500)
-        with raises(HTTPError) as exc_info:
-            user_model = auth.user_for_cookie('bar', use_cache=False)
-    assert exc_info.value.status_code == 502
-
-    with requests_mock.Mocker() as m:
-        m.get(url, status_code=400)
-        with raises(HTTPError) as exc_info:
-            user_model = auth.user_for_cookie('bar', use_cache=False)
-    assert exc_info.value.status_code == 500
-
-
-def test_hub_authenticated(request):
-    auth = HubAuth(cookie_name='jubal')
-    mock_model = {'name': 'jubalearly', 'groups': ['lions']}
-    cookie_url = url_path_join(auth.api_url, "authorizations/cookie", auth.cookie_name)
-    good_url = url_path_join(cookie_url, "early")
-    bad_url = url_path_join(cookie_url, "late")
-
-    class TestHandler(HubAuthenticated, RequestHandler):
-        hub_auth = auth
-
-        @authenticated
-        def get(self):
-            self.finish(self.get_current_user())
-
-    # start hub-authenticated service in a thread:
-    port = 50505
-    q = Queue()
-
-    def run():
-        asyncio.set_event_loop(asyncio.new_event_loop())
-        app = Application([('/*', TestHandler)], login_url=auth.login_url)
-
-        http_server = HTTPServer(app)
-        http_server.listen(port)
-        loop = IOLoop.current()
-        loop.add_callback(lambda: q.put(loop))
-        loop.start()
-
-    t = Thread(target=run)
-    t.start()
-
-    def finish_thread():
-        loop.add_callback(loop.stop)
-        t.join(timeout=30)
-        assert not t.is_alive()
-
-    request.addfinalizer(finish_thread)
-
-    # wait for thread to start
-    loop = q.get(timeout=10)
-
-    with requests_mock.Mocker(real_http=True) as m:
-        # no cookie
-        r = requests.get('http://127.0.0.1:%i' % port, allow_redirects=False)
-        r.raise_for_status()
-        assert r.status_code == 302
-        assert auth.login_url in r.headers['Location']
-
-        # wrong cookie
-        m.get(bad_url, status_code=404)
-        r = requests.get(
-            'http://127.0.0.1:%i' % port,
-            cookies={'jubal': 'late'},
-            allow_redirects=False,
-        )
-        r.raise_for_status()
-        assert r.status_code == 302
-        assert auth.login_url in r.headers['Location']
-
-        # clear the cache because we are going to request
-        # the same url again with a different result
-        auth.cache.clear()
-
-        # upstream 403
-        m.get(bad_url, status_code=403)
-        r = requests.get(
-            'http://127.0.0.1:%i' % port,
-            cookies={'jubal': 'late'},
-            allow_redirects=False,
-        )
-        assert r.status_code == 500
-
-        m.get(good_url, text=json.dumps(mock_model))
-
-        # no specific allowed user
-        r = requests.get(
-            'http://127.0.0.1:%i' % port,
-            cookies={'jubal': 'early'},
-            allow_redirects=False,
-        )
-        r.raise_for_status()
-        assert r.status_code == 200
-
-        # pass allowed user
-        TestHandler.hub_users = {'jubalearly'}
-        r = requests.get(
-            'http://127.0.0.1:%i' % port,
-            cookies={'jubal': 'early'},
-            allow_redirects=False,
-        )
-        r.raise_for_status()
-        assert r.status_code == 200
-
-        # no pass allowed ser
-        TestHandler.hub_users = {'kaylee'}
-        r = requests.get(
-            'http://127.0.0.1:%i' % port,
-            cookies={'jubal': 'early'},
-            allow_redirects=False,
-        )
-        assert r.status_code == 403
-
-        # pass allowed group
-        TestHandler.hub_groups = {'lions'}
-        r = requests.get(
-            'http://127.0.0.1:%i' % port,
-            cookies={'jubal': 'early'},
-            allow_redirects=False,
-        )
-        r.raise_for_status()
-        assert r.status_code == 200
-
-        # no pass allowed group
-        TestHandler.hub_groups = {'tigers'}
-        r = requests.get(
-            'http://127.0.0.1:%i' % port,
-            cookies={'jubal': 'early'},
-            allow_redirects=False,
-        )
-        assert r.status_code == 403
-
-
-async def test_hubauth_cookie(app, mockservice_url):
-    """Test HubAuthenticated service with user cookies"""
-    cookies = await app.login_user('badger')
-    r = await async_requests.get(
-        public_url(app, mockservice_url) + '/whoami/', cookies=cookies
-    )
-    r.raise_for_status()
-    print(r.text)
-    reply = r.json()
-    sub_reply = {key: reply.get(key, 'missing') for key in ['name', 'admin']}
-    assert sub_reply == {'name': 'badger', 'admin': False}
-
-
 async def test_hubauth_token(app, mockservice_url):
    """Test HubAuthenticated service with user API tokens"""
    u = add_user(app.db, name='river')
@@ -295,8 +123,10 @@ async def test_hubauth_service_token(app, mockservice_url):
    r = await async_requests.get(
        public_url(app, mockservice_url) + '/whoami/',
        headers={'Authorization': 'token %s' % token},
+        allow_redirects=False,
    )
    r.raise_for_status()
+    assert r.status_code == 200
    reply = r.json()
    service_model = {'kind': 'service', 'name': name, 'admin': False, 'roles': []}
    assert service_model.items() <= reply.items()
--- a/jupyterhub/tests/utils.py
+++ b/jupyterhub/tests/utils.py
@@ -1,4 +1,5 @@
 import asyncio
+import inspect
 import os
 from concurrent.futures import ThreadPoolExecutor

@@ -80,14 +81,26 @@ def check_db_locks(func):
    """

    def new_func(app, *args, **kwargs):
-        retval = func(app, *args, **kwargs)
+        maybe_future = func(app, *args, **kwargs)

-        temp_session = app.session_factory()
-        temp_session.execute('CREATE TABLE dummy (foo INT)')
-        temp_session.execute('DROP TABLE dummy')
-        temp_session.close()
+        def _check(_=None):
+            temp_session = app.session_factory()
+            try:
+                temp_session.execute('CREATE TABLE dummy (foo INT)')
+                temp_session.execute('DROP TABLE dummy')
+            finally:
+                temp_session.close()

-        return retval
+        async def await_then_check():
+            result = await maybe_future
+            _check()
+            return result
+
+        if inspect.isawaitable(maybe_future):
+            return await_then_check()
+        else:
+            _check()
+            return maybe_future

    return new_func

--- a/jupyterhub/user.py
+++ b/jupyterhub/user.py
@@ -252,6 +252,35 @@ class User:
                await self.save_auth_state(auth_state)
        return auth_state

+    async def delete_spawners(self):
+        """Call spawner cleanup methods
+
+        Allows the spawner to cleanup persistent resources
+        """
+        for name in self.orm_user.orm_spawners.keys():
+            await self._delete_spawner(name)
+
+    async def _delete_spawner(self, name_or_spawner):
+        """Delete a single spawner"""
+        # always ensure full Spawner
+        # this may instantiate the Spawner if it wasn't already running,
+        # just to delete it
+        if isinstance(name_or_spawner, str):
+            spawner = self.spawners[name_or_spawner]
+        else:
+            spawner = name_or_spawner
+
+        if spawner.active:
+            raise RuntimeError(
+                f"Spawner {spawner._log_name} is active and cannot be deleted."
+            )
+        try:
+            await maybe_future(spawner.delete_forever())
+        except Exception as e:
+            self.log.exception(
+                f"Error cleaning up persistent resources on {spawner._log_name}"
+            )
+
    def all_spawners(self, include_default=True):
        """Generator yielding all my spawners

@@ -810,14 +839,8 @@ class User:
                if orm_token:
                    self.db.delete(orm_token)
                # remove oauth client as well
-                # handle upgrades from 0.8, where client id will be `user-USERNAME`,
-                # not just `jupyterhub-user-USERNAME`
-                client_ids = (
-                    spawner.oauth_client_id,
-                    spawner.oauth_client_id.split('-', 1)[1],
-                )
-                for oauth_client in self.db.query(orm.OAuthClient).filter(
-                    orm.OAuthClient.identifier.in_(client_ids)
+                for oauth_client in self.db.query(orm.OAuthClient).filter_by(
+                    identifier=spawner.oauth_client_id,
                ):
                    self.log.debug("Deleting oauth client %s", oauth_client.identifier)
                    self.db.delete(oauth_client)
--- a/singleuser/Dockerfile
+++ b/singleuser/Dockerfile
@@ -6,7 +6,7 @@ FROM $BASE_IMAGE
 MAINTAINER Project Jupyter <jupyter@googlegroups.com>

 ADD install_jupyterhub /tmp/install_jupyterhub
-ARG JUPYTERHUB_VERSION=master
+ARG JUPYTERHUB_VERSION=main
 # install pinned jupyterhub and ensure notebook is installed
 RUN python3 /tmp/install_jupyterhub && \
    python3 -m pip install notebook
--- a/singleuser/README.md
+++ b/singleuser/README.md
@@ -5,7 +5,7 @@ Built from the `jupyter/base-notebook` base image.
 This image contains a single user notebook server for use with
 [JupyterHub](https://github.com/jupyterhub/jupyterhub). In particular, it is meant
 to be used with the
-[DockerSpawner](https://github.com/jupyterhub/dockerspawner/blob/master/dockerspawner/dockerspawner.py)
+[DockerSpawner](https://github.com/jupyterhub/dockerspawner/blob/HEAD/dockerspawner/dockerspawner.py)
 class to launch user notebook servers within docker containers.

 The only thing this image accomplishes is pinning the jupyterhub version on top of base-notebook.
--- a/singleuser/hooks/post_push
+++ b/singleuser/hooks/post_push
@@ -13,7 +13,7 @@ function get_hub_version() {
    hub_xy="${hub_xy}.${split[3]}"
  fi
 }
-# tag e.g. 0.9 with master
+# tag e.g. 0.9 with main
 get_hub_version
 docker tag $DOCKER_REPO:$DOCKER_TAG $DOCKER_REPO:$hub_xy
 docker push $DOCKER_REPO:$hub_xy
--- a/singleuser/install_jupyterhub
+++ b/singleuser/install_jupyterhub
@@ -9,8 +9,8 @@ pip_install = [
    sys.executable, '-m', 'pip', 'install', '--no-cache', '--upgrade',
    '--upgrade-strategy', 'only-if-needed',
 ]
-if V == 'master':
-    req = 'https://github.com/jupyterhub/jupyterhub/archive/master.tar.gz'
+if V in {'main', 'HEAD'}:
+    req = 'https://github.com/jupyterhub/jupyterhub/archive/HEAD.tar.gz'
 else:
    version_info = [ int(part) for part in V.split('.') ]
    version_info[-1] += 1