release 0.6.1

changelog for 0.6.1
plural add-users ids
2025-10-08 02:24:08 +00:00 · 2016-05-04 14:08:39 +02:00 · 2016-05-04 14:08:39 +02:00 · 2016-05-04 13:57:16 +02:00 · 2016-05-04 12:34:10 +02:00 · 2016-05-04 12:33:09 +02:00
49 changed files with 1958 additions and 745 deletions
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,6 +12,10 @@ before_install:
 install:
    - pip install -f travis-wheels/wheelhouse -r dev-requirements.txt .
 script:
-    - py.test --cov jupyterhub jupyterhub/tests -v
+    - travis_retry py.test --cov jupyterhub jupyterhub/tests -v
 after_success:
    - codecov
+matrix:
+  include:
+    - python: 3.5
+      env: JUPYTERHUB_TEST_SUBDOMAIN_HOST=http://127.0.0.1.xip.io:8000
--- a/43
+++ b/43
@@ -1,12 +1,27 @@
-# A base docker image that includes juptyerhub and IPython master
+# An incomplete base Docker image for running JupyterHub
 #
-# Build your own derivative images starting with
+# Add your configuration to create a complete derivative Docker image.
 #
-# FROM jupyter/jupyterhub:latest
+# Include your configuration settings by starting with one of two options:
 #
+# Option 1:
+#
+# FROM jupyterhub/jupyterhub:latest
+#
+# And put your configuration file jupyterhub_config.py in /srv/jupyterhub/jupyterhub_config.py.
+#
+# Option 2:
+#
+# Or you can create your jupyterhub config and database on the host machine, and mount it with:
+#
+# docker run -v $PWD:/srv/jupyterhub -t jupyterhub/jupyterhub
+#
+# NOTE
+# If you base on jupyterhub/jupyterhub-onbuild
+# your jupyterhub_config.py will be added automatically
+# from your docker directory.

 FROM debian:jessie
-
 MAINTAINER Jupyter Project <jupyter@googlegroups.com>

 # install nodejs, utf8 locale
@@ -22,7 +37,8 @@ RUN apt-get -y update && \
 ENV LANG C.UTF-8

 # install Python with conda
-RUN wget -q https://repo.continuum.io/miniconda/Miniconda3-3.9.1-Linux-x86_64.sh -O /tmp/miniconda.sh  && \
+RUN wget -q https://repo.continuum.io/miniconda/Miniconda3-4.0.5-Linux-x86_64.sh -O /tmp/miniconda.sh  && \
+    echo 'a7bcd0425d8b6688753946b59681572f63c2241aed77bf0ec6de4c5edc5ceeac */tmp/miniconda.sh' | shasum -a 256 -c - && \
    bash /tmp/miniconda.sh -f -b -p /opt/conda && \
    /opt/conda/bin/conda install --yes python=3.5 sqlalchemy tornado jinja2 traitlets requests pip && \
    /opt/conda/bin/pip install --upgrade pip && \
@@ -32,19 +48,16 @@ ENV PATH=/opt/conda/bin:$PATH
 # install js dependencies
 RUN npm install -g configurable-http-proxy && rm -rf ~/.npm

-WORKDIR /srv/
-ADD . /srv/jupyterhub
-WORKDIR /srv/jupyterhub/
+ADD . /src/jupyterhub
+WORKDIR /src/jupyterhub

 RUN python setup.py js && pip install . && \
-    rm -rf node_modules ~/.cache ~/.npm
+    rm -rf $PWD ~/.cache ~/.npm

+RUN mkdir -p /srv/jupyterhub/
 WORKDIR /srv/jupyterhub/
-
-# Derivative containers should add jupyterhub config,
-# which will be used when starting the application.
-
 EXPOSE 8000

-ONBUILD ADD jupyterhub_config.py /srv/jupyterhub/jupyterhub_config.py
-CMD ["jupyterhub", "-f", "/srv/jupyterhub/jupyterhub_config.py"]
+LABEL org.jupyter.service="jupyterhub"
+
+CMD ["jupyterhub"]
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -4,7 +4,9 @@ include setupegg.py
 include bower.json
 include package.json
 include *requirements.txt
+include Dockerfile

+graft onbuild
 graft jupyterhub
 graft scripts
 graft share
--- a/README.md
+++ b/README.md
@@ -3,9 +3,11 @@
 Questions, comments? Visit our Google Group:

 [![Google Group](https://img.shields.io/badge/-Google%20Group-lightgrey.svg)](https://groups.google.com/forum/#!forum/jupyter)
-[![Build Status](https://travis-ci.org/jupyter/jupyterhub.svg?branch=master)](https://travis-ci.org/jupyter/jupyterhub)
-[![Circle CI](https://circleci.com/gh/jupyter/jupyterhub.svg?style=shield&circle-token=b5b65862eb2617b9a8d39e79340b0a6b816da8cc)](https://circleci.com/gh/jupyter/jupyterhub)
+[![Build Status](https://travis-ci.org/jupyterhub/jupyterhub.svg?branch=master)](https://travis-ci.org/jupyterhub/jupyterhub)
+[![Circle CI](https://circleci.com/gh/jupyterhub/jupyterhub.svg?style=shield&circle-token=b5b65862eb2617b9a8d39e79340b0a6b816da8cc)](https://circleci.com/gh/jupyterhub/jupyterhub)
 [![Documentation Status](https://readthedocs.org/projects/jupyterhub/badge/?version=latest)](http://jupyterhub.readthedocs.org/en/latest/?badge=latest)
+[![codecov.io](https://codecov.io/github/jupyterhub/jupyterhub/coverage.svg?branch=master)](https://codecov.io/github/jupyterhub/jupyterhub?branch=master)
+

 JupyterHub, a multi-user server, manages and proxies multiple instances of the single-user <del>IPython</del> Jupyter notebook server.

@@ -25,7 +27,7 @@ Basic principles:

 ## Dependencies

-JupyterHub requires [IPython](https://ipython.org/install.html) >= 3.0 (current master) and [Python](https://www.python.org/downloads/) >= 3.3.
+JupyterHub itself requires [Python](https://www.python.org/downloads/) ≥ 3.3. To run the single-user servers (which may be on the same system as the Hub or not), [Jupyter Notebook](https://jupyter.readthedocs.org/en/latest/install.html) ≥ 4 is required.

 Install [nodejs/npm](https://www.npmjs.com/), which is available from your
 package manager. For example, install on Linux (Debian/Ubuntu) using:
@@ -50,21 +52,22 @@ Notes on the `pip` command used in the installation directions below:

 ## Installation

-JupyterHub can be installed with pip:
+JupyterHub can be installed with pip, and the proxy with npm:

+    npm install -g configurable-http-proxy
    pip3 install jupyterhub

 If you plan to run notebook servers locally, you may also need to install the
 Jupyter ~~IPython~~ notebook:

-    pip3 install notebook
+    pip3 install --upgrade notebook


 ### Development install

 For a development install, clone the repository and then install from source:

-    git clone https://github.com/jupyter/jupyterhub
+    git clone https://github.com/jupyterhub/jupyterhub
    cd jupyterhub
    pip3 install -r dev-requirements.txt -e .

@@ -90,7 +93,7 @@ and then visit `http://localhost:8000`, and sign in with your unix credentials.

 To allow multiple users to sign into the server, you will need to
 run the `jupyterhub` command as a *privileged user*, such as root.
-The [wiki](https://github.com/jupyter/jupyterhub/wiki/Using-sudo-to-run-JupyterHub-without-root-privileges)
+The [wiki](https://github.com/jupyterhub/jupyterhub/wiki/Using-sudo-to-run-JupyterHub-without-root-privileges)
 describes how to run the server as a *less privileged user*, which requires more
 configuration of the system.

@@ -113,8 +116,29 @@ The authentication and process spawning mechanisms can be replaced,
 which should allow plugging into a variety of authentication or process control environments.
 Some examples, meant as illustration and testing of this concept:

- Using GitHub OAuth instead of PAM with [OAuthenticator](https://github.com/jupyter/oauthenticator)
- Spawning single-user servers with Docker, using the [DockerSpawner](https://github.com/jupyter/dockerspawner)
+- Using GitHub OAuth instead of PAM with [OAuthenticator](https://github.com/jupyterhub/oauthenticator)
+- Spawning single-user servers with Docker, using the [DockerSpawner](https://github.com/jupyterhub/dockerspawner)
+
+### Docker
+
+There is a ready to go [docker image for JupyterHub](https://hub.docker.com/r/jupyterhub/jupyterhub/).
+[Note: This `jupyterhub/jupyterhub` docker image is only an image for running the Hub service itself.
+It does not require the other Jupyter components, which are needed by the single-user servers.
+To run the single-user servers, which may be on the same system as the Hub or not, installation of Jupyter Notebook ≥ 4 is required.]
+
+The JupyterHub docker image can be started with the following command:
+
+    docker run -d --name jupyterhub jupyter/jupyterhub jupyterhub
+
+This command will create a container named `jupyterhub` that you can stop and resume with `docker stop/start`.
+It will be listening on all interfaces at port 8000, so this is perfect to test JupyterHub on your desktop or laptop.
+If you want to run docker on a computer that has a public IP then you should (as in MUST) secure it with ssl by
+adding ssl options to your docker configuration or using a ssl enabled proxy.
+[Mounting volumes](https://docs.docker.com/engine/userguide/containers/dockervolumes/) will
+allow you to store data outside the docker image (host system) so it will be persistent, even when you start
+a new image. The command `docker exec -it jupyterhub bash` will spawn a root shell in your docker
+container. You can use it to create system users in the container. These accounts will be used for authentication
+in jupyterhub's default configuration. In order to run without SSL (for testing purposes only), you'll need to set `--no-ssl` explicitly.

 # Getting help

@@ -124,7 +148,7 @@ We encourage you to ask questions on the mailing list:

 and you may participate in development discussions or get live help on Gitter:

-[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/jupyter/jupyterhub?utm_source=badge&utm_medium=badge)
+[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/jupyterhub/jupyterhub?utm_source=badge&utm_medium=badge)

 ## Resources
 - [Project Jupyter website](https://jupyter.org)
--- a/circle.yml
+++ b/circle.yml
@@ -8,4 +8,17 @@ dependencies:

 test:
  override:
-    - docker build -t jupyter/jupyterhub .
+    - docker build -t jupyterhub/jupyterhub .
+    - docker build -t jupyterhub/jupyterhub-onbuild:${CIRCLE_TAG:-latest} onbuild
+
+deployment:
+  hub:
+    branch: master
+    commands:
+      - docker login -u $DOCKER_USER -p $DOCKER_PASS -e unused@example.com
+      - docker push jupyterhub/jupyterhub-onbuild
+  release:
+    tag: /.*/
+    commands:
+      - docker login -u $DOCKER_USER -p $DOCKER_PASS -e unused@example.com
+      - docker push jupyterhub/jupyterhub-onbuild:$CIRCLE_TAG
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,3 +1,3 @@
 -r ../requirements.txt
-sphinx
+sphinx>=1.3.6
 recommonmark==0.4.0
--- a/docs/source/authenticators.md
+++ b/docs/source/authenticators.md
@@ -77,6 +77,7 @@ For simple mappings, a configurable dict `Authenticator.username_map` is used to
 c.Authenticator.username_map  = {
  'service-name': 'localname'
 }
+```

 ### Validating usernames

--- a/docs/source/changelog.md
+++ b/docs/source/changelog.md
@@ -2,6 +2,43 @@

 See `git log` for a more detailed summary.

+## 0.6
+
+### 0.6.1
+
+Bugfixes on 0.6:
+
+- statsd is an optional dependency, only needed if in use
+- Notice more quickly when servers have crashed
+- Better error pages for proxy errors
+- Add Stop All button to admin panel for stopping all servers at once
+
+### 0.6.0
+
+- JupyterHub has moved to a new `jupyterhub` namespace on GitHub and Docker. What was `juptyer/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
+- Allow disabling PAM sessions via `c.PAMAuthenticator.open_sessions = False`. This may be needed on SELinux-enabled systems, where our PAM session logic often does not work properly
+- Add `Spawner.environment` configurable, for defining extra environment variables to load for single-user servers
+- JupyterHub API tokens can be pregenerated and loaded via `JupyterHub.api_tokens`, a dict of `token: username`.
+- JupyterHub API tokens can be requested via the REST API, with a POST request to `/api/authorizations/token`.
+  This can only be used if the Authenticator has a username and password.
+- Various fixes for user URLs and redirects
+
+
+## 0.5
+
+
+- Single-user server must be run with Jupyter Notebook ≥ 4.0
+- Require `--no-ssl` confirmation to allow the Hub to be run without SSL (e.g. behind SSL termination in nginx)
+- Add lengths to text fields for MySQL support
+- Add `Spawner.disable_user_config` for preventing user-owned configuration from modifying single-user servers.
+- Fixes for MySQL support.
+- Add ability to run each user's server on its own subdomain. Requires wildcard DNS and wildcard SSL to be feasible. Enable subdomains by setting `JupyterHub.subdomain_host = 'https://jupyterhub.domain.tld[:port]'`.
+- Use `127.0.0.1` for local communication instead of `localhost`, avoiding issues with DNS on some systems.
+- Fix race that could add users to proxy prematurely if spawning is slow.
+
 ## 0.4

 ### 0.4.1
--- a/docs/source/getting-started.md
+++ b/docs/source/getting-started.md
@@ -22,6 +22,11 @@ There are three main categories of processes run by the `jupyterhub` command lin

 ## JupyterHub's default behavior

+**IMPORTANT:** In its default configuration, JupyterHub requires SSL encryption (HTTPS) to run.
+**You should not run JupyterHub without SSL encryption on a public network.**
+See [Security documentation](#Security) for how to configure JupyterHub to use SSL, and in
+certain cases, e.g. behind SSL termination in nginx, allowing the hub to run with no SSL
+by requiring `--no-ssl` (as of [version 0.5](./changelog.html)).

 To start JupyterHub in its default configuration, type the following at the command line:

@@ -44,10 +49,6 @@ or any other public IP or domain pointing to your system.
 In their default configuration, the other services, the **Hub** and **Single-User Servers**,
 all communicate with each other on localhost only.

-**NOTE:** In its default configuration, JupyterHub runs without SSL encryption (HTTPS).
-You should not run JupyterHub without SSL encryption on a public network.
-See [Security documentation](#Security) for how to configure JupyterHub to use SSL.
-
 By default, starting JupyterHub will write two files to disk in the current working directory:

 - `jupyterhub.sqlite` is the sqlite database containing all of the state of the **Hub**.
@@ -65,23 +66,13 @@ The location of these files can be specified via configuration, discussed below.

 JupyterHub is configured in two ways:

-1. Command-line arguments
-2. Configuration files
+1. Configuration file
+2. Command-line arguments

-Type the following for brief information about the command line arguments:
-
-    jupyterhub -h
-
-or:
-
-    jupyterhub --help-all
-
-for the full command line help.
-
-By default, JupyterHub will look for a configuration file (can be missing)
+### Configuration file
+By default, JupyterHub will look for a configuration file (which may not be created yet)
 named `jupyterhub_config.py` in the current working directory.
-You can create an empty configuration file with
-
+You can create an empty configuration file with:

    jupyterhub --generate-config

@@ -93,6 +84,23 @@ values. You can load a specific config file with:
 See also: [general docs](http://ipython.org/ipython-doc/dev/development/config.html)
 on the config system Jupyter uses.

+### Command-line arguments
+Type the following for brief information about the command-line arguments:
+
+    jupyterhub -h
+
+or:
+
+    jupyterhub --help-all
+
+for the full command line help.
+
+All configurable options are technically configurable on the command-line,
+even if some are really inconvenient to type. Just replace the desired option,
+c.Class.trait, with --Class.trait. For example, to configure
+c.Spawner.notebook_dir = '~/assignments' from the command-line:
+
+    jupyterhub --Spawner.notebook_dir='~/assignments'

 ## Networking

@@ -148,6 +156,9 @@ c.JupyterHub.hub_port = 54321

 ## Security

+**IMPORTANT:** In its default configuration, JupyterHub requires SSL encryption (HTTPS) to run.
+**You should not run JupyterHub without SSL encryption on a public network.**
+
 Security is the most important aspect of configuring Jupyter. There are three main aspects of the
 security configuration:

@@ -179,6 +190,10 @@ Some cert files also contain the key, in which case only the cert is needed. It
 these files be put in a secure location on your server, where they are not readable by regular
 users.

+Note: In certain cases, e.g. behind SSL termination in nginx, allowing no SSL
+running on the hub may be desired. To run the Hub without SSL, you must opt
+in by configuring and confirming the `--no-ssl` option, added as of [version 0.5](./changelog.html).
+
 ## Cookie secret

 The cookie secret is an encryption key, used to encrypt the browser cookies used for
@@ -190,26 +205,36 @@ as follows:
 c.JupyterHub.cookie_secret_file = '/srv/jupyterhub/cookie_secret'
 ```

-The content of this file should be a long random string. An example would be to generate this
-file as:
+The content of this file should be a long random string encoded in MIME Base64. An example would be to generate this file as:

 ```bash
-openssl rand -hex 1024 > /srv/jupyterhub/cookie_secret
+openssl rand -base64 2048 > /srv/jupyterhub/cookie_secret
 ```

 In most deployments of JupyterHub, you should point this to a secure location on the file
 system, such as `/srv/jupyterhub/cookie_secret`. If the cookie secret file doesn't exist when
-the Hub starts, a new cookie secret is generated and stored in the file. The recommended
-permissions for the cookie secret file should be 600 (owner-only rw).
+the Hub starts, a new cookie secret is generated and stored in the file. The
+file must not be readable by group or other or the server won't start.
+The recommended permissions for the cookie secret file are 600 (owner-only rw).
+

 If you would like to avoid the need for files, the value can be loaded in the Hub process from
-the `JPY_COOKIE_SECRET` environment variable:
+the `JPY_COOKIE_SECRET` environment variable, which is a hex-encoded string. You
+can set it this way:

 ```bash
 export JPY_COOKIE_SECRET=`openssl rand -hex 1024`
 ```

 For security reasons, this environment variable should only be visible to the Hub.
+If you set it dynamically as above, all users will be logged out each time the
+Hub starts.
+
+You can also set the secret in the configuration file itself as a binary string:
+
+```python
+c.JupyterHub.cookie_secret = bytes.fromhex('VERY LONG SECRET HEX STRING')
+```

 ## Proxy authentication token

--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -1,22 +1,34 @@
-.. JupyterHub documentation master file, created by
-   sphinx-quickstart on Mon Jan  4 16:31:09 2016.
-   You can adapt this file completely to your liking, but it should at least
-   contain the root `toctree` directive.
-
 JupyterHub
 ==========

-.. note:: This is the official documentation for JupyterHub. This project is
-          under active development.
+JupyterHub is a server that gives multiple users access to Jupyter notebooks,
+running an independent Jupyter notebook server for each user.

-JupyterHub is a multi-user server that manages and proxies multiple instances
-of the single-user Jupyter notebook server.
+To use JupyterHub, you need a Unix server (typically Linux) running
+somewhere that is accessible to your team on the network. The JupyterHub server
+can be on an internal network at your organisation, or it can run on the public
+internet (in which case, take care with `security <getting-started.html#security>`__).
+Users access JupyterHub in a web browser, by going to the IP address or
+domain name of the server.

-Three actors:
+Different :doc:`authenticators <authenticators>` control access
+to JupyterHub. The default one (pam) uses the user accounts on the server where
+JupyterHub is running. If you use this, you will need to create a user account
+on the system for each user on your team. Using other authenticators, you can
+allow users to sign in with e.g. a Github account, or with any single-sign-on
+system your organisation has.

-* multi-user Hub (tornado process)
-* `configurable http proxy <https://github.com/jupyter/configurable-http-proxy>`_ (node-http-proxy)
-* multiple single-user IPython notebook servers (Python/IPython/tornado)
+Next, :doc:`spawners <spawners>` control how JupyterHub starts
+the individual notebook server for each user. The default spawner will
+start a notebook server on the same machine running under their system username.
+The other main option is to start each server in a separate container, often
+using Docker.
+
+JupyterHub runs as three separate parts:
+
+* The multi-user Hub (Python & Tornado)
+* A `configurable http proxy <https://github.com/jupyter/configurable-http-proxy>`_ (NodeJS)
+* Multiple single-user Jupyter notebook servers (Python & Tornado)

 Basic principles:

@@ -34,6 +46,7 @@ Contents:

   getting-started
   howitworks
+   websecurity

 .. toctree::
   :maxdepth: 2
--- a/docs/source/troubleshooting.md
+++ b/docs/source/troubleshooting.md
@@ -2,10 +2,98 @@

 This document is under active development.

-## Networking
+When troubleshooting, you may see unexpected behaviors or receive an error
+message. These two lists provide links to identifying the cause of the
+problem and how to resolve it.

-If JupyterHub proxy fails to start:
+## Behavior problems
+- [JupyterHub proxy fails to start](#jupyterhub-proxy-fails-to-start)
+
+## Errors
+- [500 error after spawning a single-user server](#500-error-after-spawning-my-single-user-server)
+
+----
+
+## JupyterHub proxy fails to start
+
+If you have tried to start the JupyterHub proxy and it fails to start:

 - check if the JupyterHub IP configuration setting is
  ``c.JupyterHub.ip = '*'``; if it is, try ``c.JupyterHub.ip = ''``
- Try starting with ``jupyterhub --ip=0.0.0.0``
+- Try starting with ``jupyterhub --ip=0.0.0.0``
+
+----
+
+## 500 error after spawning my single-user server
+
+
+You receive a 500 error when accessing the URL `/user/you/...`. This is often
+seen when your single-user server cannot check your cookies with the Hub.
+
+There are two likely reasons for this:
+
+1. The single-user server cannot connect to the Hub's API (networking
+   configuration problems)
+2. The single-user server cannot *authenticate* its requests (invalid token)
+
+### Symptoms:
+
+The main symptom is a failure to load *any* page served by the single-user
+server, met with a 500 error. This is typically the first page at `/user/you`
+after logging in or clicking "Start my server". When a single-user server
+receives a request, it makes an API request to the Hub to check if the cookie
+corresponds to the right user. This request is logged.
+
+If everything is working, it will look like this:
+
+```
+200 GET /hub/api/authorizations/cookie/jupyter-hub-token-name/[secret] (@10.0.1.4) 6.10ms
+```
+
+You should see a similar 200 message, as above, in the Hub log when you first
+visit your single-user server. If you don't see this message in the log, it
+may mean that your single-user server isn't connecting to your Hub.
+
+If you see 403 (forbidden) like this, it's a token problem:
+
+```
+403 GET /hub/api/authorizations/cookie/jupyter-hub-token-name/[secret] (@10.0.1.4) 4.14ms
+```
+
+Check the logs of the single-user server, which may have more detailed
+information on the cause.
+
+### Causes and resolutions:
+
+#### No authorization request
+
+If you make an API request and it is not received by the server, you likely
+have a network configuration issue. Often, this happens when the Hub is only
+listening on 127.0.0.1 (default) and the single-user servers are not on the
+same 'machine' (can be physically remote, or in a docker container or VM). The
+fix for this case is to make sure that `c.JupyterHub.hub_ip` is an address
+that all single-user servers can connect to, e.g.:
+
+```python
+c.JupyterHub.hub_ip = '10.0.0.1'
+```
+
+#### 403 GET /hub/api/authorizations/cookie
+
+If you receive a 403 error, the API token for the single-user server is likely
+invalid. Commonly, the 403 error is caused by resetting the JupyterHub
+database (either removing jupyterhub.sqlite or some other action) while
+leaving single-user servers running. This happens most frequently when using
+DockerSpawner, because Docker's default behavior is to stop/start containers
+which resets the JupyterHub database, rather than destroying and recreating
+the container every time. This means that the same API token is used by the
+server for its whole life, until the container is rebuilt.
+
+The fix for this Docker case is to remove any Docker containers seeing this
+issue (typicaly all containers created before a certain point in time):
+
+    docker rm -f jupyter-name
+
+After this, when you start your server via JupyterHub, it will build a
+new container. If this was the underlying cause of the issue, you should see
+your server again.
--- a/docs/source/websecurity.md
+++ b/docs/source/websecurity.md
@@ -0,0 +1,63 @@
+# Web Security in JupyterHub
+
+JupyterHub is designed to be a simple multi-user server for modestly sized groups of semi-trusted users.
+While the design reflects serving semi-trusted users,
+JupyterHub is not necessarily unsuitable for serving untrusted users.
+Using JupyterHub with untrusted users does mean more work and much care is required to secure a Hub against untrusted users,
+with extra caution on protecting users from each other as the Hub is serving untrusted users.
+
+One aspect of JupyterHub's design simplicity for semi-trusted users is that the Hub and single-user servers are placed in a single domain, behind a [proxy][configurable-http-proxy].
+As a result, if the Hub is serving untrusted users,
+many of the web's cross-site protections are not applied between single-user servers and the Hub,
+or between single-user servers and each other,
+since browsers see the whole thing (proxy, Hub, and single user servers) as a single website.
+
+To protect users from each other, a user must never be able to write arbitrary HTML and serve it to another user on the Hub's domain.
+JupyterHub's authentication setup prevents this because only the owner of a given single-user server is allowed to view user-authored pages served by their server.
+To protect all users from each other, JupyterHub administrators must ensure that:
+
+* A user does not have permission to modify their single-user server:
+  - A user may not install new packages in the Python environment that runs their server.
+  - If the PATH is used to resolve the single-user executable (instead of an absolute path), a user may not create new files in any PATH directory that precedes the directory containing jupyterhub-singleuser.
+  - A user may not modify environment variables (e.g. PATH, PYTHONPATH) for their single-user server.
+* A user may not modify the configuration of the notebook server (the ~/.jupyter or JUPYTER_CONFIG_DIR directory).
+
+If any additional services are run on the same domain as the Hub, the services must never display user-authored HTML that is neither sanitized nor sandboxed (e.g. IFramed) to any user that lacks authentication as the author of a file.
+
+
+## Mitigations
+
+There are two main configuration options provided by JupyterHub to mitigate these issues:
+
+### Subdomains
+
+JupyterHub 0.5 adds the ability to run single-user servers on their own subdomains,
+which means the cross-origin protections between servers has the desired effect,
+and user servers and the Hub are protected from each other.
+A user's server will be at `username.jupyter.mydomain.com`, etc.
+This requires all user subdomains to point to the same address,
+which is most easily accomplished with wildcard DNS.
+Since this spreads the service across multiple domains, you will need wildcard SSL, as well.
+Unfortunately, for many institutional domains, wildcard DNS and SSL are not available,
+but if you do plan to serve untrusted users, enabling subdomains is highly encouraged,
+as it resolves all of the cross-site issues.
+
+### Disabling user config
+
+If subdomains are not available or not desirable,
+0.5 also adds an option `Spawner.disable_user_config`,
+which you can set to prevent the user-owned configuration files from being loaded.
+This leaves only package installation and PATHs as things the admin must enforce.
+
+For most Spawners, PATH is not something users an influence,
+but care should be taken to ensure that the Spawn does *not* evaluate shell configuration files prior to launching the server.
+
+Package isolation is most easily handled by running the single-user server in a virtualenv with disabled system-site-packages.
+
+## Extra notes
+
+It is important to note that the control over the environment only affects the single-user server,
+and not the environment(s) in which the user's kernel(s) may run.
+Installing additional packages in the kernel environment does not pose additional risk to the web application's security.
+
+[configurable-http-proxy]: https://github.com/jupyterhub/configurable-http-proxy
--- a/examples/postgres/hub/Dockerfile
+++ b/examples/postgres/hub/Dockerfile
@@ -1,4 +1,4 @@
-FROM jupyter/jupyterhub
+FROM jupyter/jupyterhub-onbuild

 MAINTAINER Jupyter Project <jupyter@googlegroups.com>

--- a/examples/spawn-form/jupyterhub_config.py
+++ b/examples/spawn-form/jupyterhub_config.py
@@ -1,5 +1,5 @@
 """
-Example JuptyerHub config allowing users to specify environment variables and notebook-server args
+Example JupyterHub config allowing users to specify environment variables and notebook-server args
 """
 import shlex

--- a/jupyterhub/apihandlers/auth.py
+++ b/jupyterhub/apihandlers/auth.py
@@ -6,7 +6,7 @@
 import json
 from urllib.parse import quote

-from tornado import web
+from tornado import web, gen
 from .. import orm
 from ..utils import token_authenticated
 from .base import APIHandler
@@ -20,13 +20,25 @@ class TokenAPIHandler(APIHandler):
            raise web.HTTPError(404)
        self.write(json.dumps(self.user_model(self.users[orm_token.user])))

+    @gen.coroutine
+    def post(self):
+        if self.authenticator is not None:
+          data = self.get_json_body()
+          username = yield self.authenticator.authenticate(self, data)
+          if username is None:
+            raise web.HTTPError(403)
+          user = self.find_user(username)
+          api_token = user.new_api_token()
+          self.write(json.dumps({"Authentication":api_token}))
+        else:
+          raise web.HTTPError(404)

 class CookieAPIHandler(APIHandler):
    @token_authenticated
    def get(self, cookie_name, cookie_value=None):
        cookie_name = quote(cookie_name, safe='')
        if cookie_value is None:
-            self.log.warn("Cookie values in request body is deprecated, use `/cookie_name/cookie_value`")
+            self.log.warning("Cookie values in request body is deprecated, use `/cookie_name/cookie_value`")
            cookie_value = self.request.body
        else:
            cookie_value = cookie_value.encode('utf8')
@@ -39,4 +51,5 @@ class CookieAPIHandler(APIHandler):
 default_handlers = [
    (r"/api/authorizations/cookie/([^/]+)(?:/([^/]+))?", CookieAPIHandler),
    (r"/api/authorizations/token/([^/]+)", TokenAPIHandler),
+    (r"/api/authorizations/token", TokenAPIHandler),
 ]
--- a/jupyterhub/apihandlers/base.py
+++ b/jupyterhub/apihandlers/base.py
@@ -26,25 +26,29 @@ class APIHandler(BaseHandler):
        # If no header is provided, assume it comes from a script/curl.
        # We are only concerned with cross-site browser stuff here.
        if not host:
-            self.log.warn("Blocking API request with no host")
+            self.log.warning("Blocking API request with no host")
            return False
        if not referer:
-            self.log.warn("Blocking API request with no referer")
+            self.log.warning("Blocking API request with no referer")
            return False
        
        host_path = url_path_join(host, self.hub.server.base_url)
        referer_path = referer.split('://', 1)[-1]
        if not (referer_path + '/').startswith(host_path):
-            self.log.warn("Blocking Cross Origin API request.  Referer: %s, Host: %s",
+            self.log.warning("Blocking Cross Origin API request.  Referer: %s, Host: %s",
                referer, host_path)
            return False
        return True
    
    def get_current_user_cookie(self):
        """Override get_user_cookie to check Referer header"""
-        if not self.check_referer():
+        cookie_user = super().get_current_user_cookie()
+        # check referer only if there is a cookie user,
+        # avoiding misleading "Blocking Cross Origin" messages
+        # when there's no cookie set anyway.
+        if cookie_user and not self.check_referer():
            return None
-        return super().get_current_user_cookie()
+        return cookie_user

    def get_json_body(self):
        """Return the body of the request as JSON data."""
@@ -86,7 +90,7 @@ class APIHandler(BaseHandler):
        model = {
            'name': user.name,
            'admin': user.admin,
-            'server': user.server.base_url if user.running else None,
+            'server': user.url if user.running else None,
            'pending': None,
            'last_activity': user.last_activity.isoformat(),
        }
--- a/jupyterhub/apihandlers/proxy.py
+++ b/jupyterhub/apihandlers/proxy.py
@@ -28,7 +28,7 @@ class ProxyAPIHandler(APIHandler):
    @gen.coroutine
    def post(self):
        """POST checks the proxy to ensure"""
-        yield self.proxy.check_routes()
+        yield self.proxy.check_routes(self.users)
        
    
    @admin_only
@@ -59,7 +59,7 @@ class ProxyAPIHandler(APIHandler):
            self.proxy.auth_token = model['auth_token']
        self.db.commit()
        self.log.info("Updated proxy at %s", server.bind_url)
-        yield self.proxy.check_routes()
+        yield self.proxy.check_routes(self.users)
        


--- a/jupyterhub/apihandlers/users.py
+++ b/jupyterhub/apihandlers/users.py
@@ -41,7 +41,7 @@ class UserListAPIHandler(APIHandler):
                continue
            user = self.find_user(name)
            if user is not None:
-                self.log.warn("User %s already exists" % name)
+                self.log.warning("User %s already exists" % name)
            else:
                to_create.append(name)
        
@@ -161,8 +161,9 @@ class UserServerAPIHandler(APIHandler):
    @admin_or_self
    def post(self, name):
        user = self.find_user(name)
-        if user.spawner:
-            state = yield user.spawner.poll()
+        if user.running:
+            # include notify, so that a server that died is noticed immediately
+            state = yield user.spawner.poll_and_notify()
            if state is None:
                raise web.HTTPError(400, "%s's server is already running" % name)

@@ -180,7 +181,8 @@ class UserServerAPIHandler(APIHandler):
            return
        if not user.running:
            raise web.HTTPError(400, "%s's server is not running" % name)
-        status = yield user.spawner.poll()
+        # include notify, so that a server that died is noticed immediately
+        status = yield user.spawner.poll_and_notify()
        if status is not None:
            raise web.HTTPError(400, "%s's server is not running" % name)
        yield self.stop_single_user(user)
@@ -195,7 +197,7 @@ class UserAdminAccessAPIHandler(APIHandler):
    @admin_only
    def post(self, name):
        current = self.get_current_user()
-        self.log.warn("Admin user %s has requested access to %s's server",
+        self.log.warning("Admin user %s has requested access to %s's server",
            current.name, name,
        )
        if not self.settings.get('admin_access', False):
--- a/jupyterhub/app.py
+++ b/jupyterhub/app.py
--- a/jupyterhub/auth.py
+++ b/jupyterhub/auth.py
@@ -15,7 +15,7 @@ from tornado import gen
 import pamela

 from traitlets.config import LoggingConfigurable
-from traitlets import Bool, Set, Unicode, Dict, Any
+from traitlets import Bool, Set, Unicode, Dict, Any, default, observe

 from .handlers.login import LoginHandler
 from .utils import url_path_join
@@ -29,19 +29,19 @@ class Authenticator(LoggingConfigurable):
    """
    
    db = Any()
-    admin_users = Set(config=True,
+    admin_users = Set(
        help="""set of usernames of admin users

        If unspecified, only the user that launches the server will be admin.
        """
-    )
-    whitelist = Set(config=True,
+    ).tag(config=True)
+    whitelist = Set(
        help="""Username whitelist.
        
        Use this to restrict which users can login.
        If empty, allow any user to attempt login.
        """
-    )
+    ).tag(config=True)
    custom_html = Unicode('',
        help="""HTML login form for custom handlers.
        Override in form-based custom authenticators
@@ -55,16 +55,17 @@ class Authenticator(LoggingConfigurable):
        """
    )
    
-    username_pattern = Unicode(config=True,
+    username_pattern = Unicode(
        help="""Regular expression pattern for validating usernames.
        
        If not defined: allow any username.
        """
-    )
-    def _username_pattern_changed(self, name, old, new):
-        if not new:
+    ).tag(config=True)
+    @observe('username_pattern')
+    def _username_pattern_changed(self, change):
+        if not change['new']:
            self.username_regex = None
-        self.username_regex = re.compile(new)
+        self.username_regex = re.compile(change['new'])
    
    username_regex = Any()
    
@@ -77,14 +78,14 @@ class Authenticator(LoggingConfigurable):
            return True
        return bool(self.username_regex.match(username))
    
-    username_map = Dict(config=True,
+    username_map = Dict(
        help="""Dictionary mapping authenticator usernames to JupyterHub users.
        
        Can be used to map OAuth service names to local users, for instance.
        
        Used in normalize_username.
        """
-    )
+    ).tag(config=True)
    
    def normalize_username(self, username):
        """Normalize a username.
@@ -246,12 +247,12 @@ class LocalAuthenticator(Authenticator):
    Checks for local users, and can attempt to create them if they exist.
    """
    
-    create_system_users = Bool(False, config=True,
+    create_system_users = Bool(False,
        help="""If a user is added that doesn't exist on the system,
        should I try to create the system user?
        """
-    )
-    add_user_cmd = Command(config=True,
+    ).tag(config=True)
+    add_user_cmd = Command(
        help="""The command to use for creating users as a list of strings.
        
        For each element in the list, the string USERNAME will be replaced with
@@ -271,7 +272,9 @@ class LocalAuthenticator(Authenticator):
        
        when the user 'river' is created.
        """
-    )
+    ).tag(config=True)
+    
+    @default('add_user_cmd')
    def _add_user_cmd_default(self):
        if sys.platform == 'darwin':
            raise ValueError("I don't know how to create users on OS X")
@@ -283,13 +286,12 @@ class LocalAuthenticator(Authenticator):
            return ['adduser', '-q', '--gecos', '""', '--disabled-password']

    group_whitelist = Set(
-        config=True,
        help="Automatically whitelist anyone in this group.",
-    )
-
-    def _group_whitelist_changed(self, name, old, new):
+    ).tag(config=True)
+    @observe('group_whitelist')
+    def _group_whitelist_changed(self, change):
        if self.whitelist:
-            self.log.warn(
+            self.log.warning(
                "Ignoring username whitelist because group whitelist supplied!"
            )

@@ -351,12 +353,24 @@ class LocalAuthenticator(Authenticator):

 class PAMAuthenticator(LocalAuthenticator):
    """Authenticate local Linux/UNIX users with PAM"""
-    encoding = Unicode('utf8', config=True,
+    encoding = Unicode('utf8',
        help="""The encoding to use for PAM"""
-    )
-    service = Unicode('login', config=True,
+    ).tag(config=True)
+    service = Unicode('login',
        help="""The PAM service to use for authentication."""
-    )
+    ).tag(config=True)
+    open_sessions = Bool(True,
+        help="""Whether to open PAM sessions when spawners are started.
+        
+        This may trigger things like mounting shared filsystems,
+        loading credentials, etc. depending on system configuration,
+        but it does not always work.
+        
+        It can be disabled with::
+        
+            c.PAMAuthenticator.open_sessions = False
+        """
+    ).tag(config=True)
    
    @gen.coroutine
    def authenticate(self, handler, data):
@@ -369,23 +383,31 @@ class PAMAuthenticator(LocalAuthenticator):
            pamela.authenticate(username, data['password'], service=self.service)
        except pamela.PAMError as e:
            if handler is not None:
-                self.log.warn("PAM Authentication failed (@%s): %s", handler.request.remote_ip, e)
+                self.log.warning("PAM Authentication failed (%s@%s): %s", username, handler.request.remote_ip, e)
            else:
-                self.log.warn("PAM Authentication failed: %s", e)
+                self.log.warning("PAM Authentication failed: %s", e)
        else:
            return username
    
    def pre_spawn_start(self, user, spawner):
        """Open PAM session for user"""
+        if not self.open_sessions:
+            return
        try:
            pamela.open_session(user.name, service=self.service)
        except pamela.PAMError as e:
-            self.log.warn("Failed to open PAM session for %s: %s", user.name, e)
+            self.log.warning("Failed to open PAM session for %s: %s", user.name, e)
+            self.log.warning("Disabling PAM sessions from now on.")
+            self.open_sessions = False
    
    def post_spawn_stop(self, user, spawner):
        """Close PAM session for user"""
+        if not self.open_sessions:
+            return
        try:
            pamela.close_session(user.name, service=self.service)
        except pamela.PAMError as e:
-            self.log.warn("Failed to close PAM session for %s: %s", user.name, e)
+            self.log.warning("Failed to close PAM session for %s: %s", user.name, e)
+            self.log.warning("Disabling PAM sessions from now on.")
+            self.open_sessions = False
    
--- a/jupyterhub/emptyclass.py
+++ b/jupyterhub/emptyclass.py
@@ -0,0 +1,13 @@
+"""
+Simple empty class that returns itself for all functions called on it.
+This allows us to call any method of any name on this, and it'll return another
+instance of itself that'll allow any method to be called on it.
+
+Primarily used to mock out the statsd client when statsd is not being used
+"""
+class EmptyClass:
+    def empty_function(self, *args, **kwargs):
+        return self
+
+    def __getattr__(self, attr):
+        return self.empty_function
--- a/jupyterhub/handlers/base.py
+++ b/jupyterhub/handlers/base.py
@@ -46,27 +46,39 @@ class BaseHandler(RequestHandler):
    @property
    def base_url(self):
        return self.settings.get('base_url', '/')
-    
+
    @property
    def version_hash(self):
        return self.settings.get('version_hash', '')
-    
+
+    @property
+    def subdomain_host(self):
+        return self.settings.get('subdomain_host', '')
+
+    @property
+    def domain(self):
+        return self.settings['domain']
+
    @property
    def db(self):
        return self.settings['db']
-    
+
    @property
    def users(self):
        return self.settings.setdefault('users', {})
-    
+
    @property
    def hub(self):
        return self.settings['hub']
-    
+
    @property
    def proxy(self):
        return self.settings['proxy']
-    
+
+    @property
+    def statsd(self):
+        return self.settings['statsd']
+
    @property
    def authenticator(self):
        return self.settings.get('authenticator', None)
@@ -75,28 +87,28 @@ class BaseHandler(RequestHandler):
        """Roll back any uncommitted transactions from the handler."""
        self.db.rollback()
        super().finish(*args, **kwargs)
-    
+
    #---------------------------------------------------------------
    # Security policies
    #---------------------------------------------------------------
-    
+
    @property
    def csp_report_uri(self):
        return self.settings.get('csp_report_uri',
            url_path_join(self.hub.server.base_url, 'security/csp-report')
        )
-    
+
    @property
    def content_security_policy(self):
        """The default Content-Security-Policy header
-        
+
        Can be overridden by defining Content-Security-Policy in settings['headers']
        """
        return '; '.join([
            "frame-ancestors 'self'",
            "report-uri " + self.csp_report_uri,
        ])
-    
+
    def set_default_headers(self):
        """
        Set any headers passed as tornado_settings['headers'].
@@ -105,7 +117,7 @@ class BaseHandler(RequestHandler):
        """
        headers = self.settings.get('headers', {})
        headers.setdefault("Content-Security-Policy", self.content_security_policy)
-        
+
        for header_name, header_content in headers.items():
            self.set_header(header_name, header_content)

@@ -116,7 +128,7 @@ class BaseHandler(RequestHandler):
    @property
    def admin_users(self):
        return self.settings.setdefault('admin_users', set())
-    
+
    @property
    def cookie_max_age_days(self):
        return self.settings.get('cookie_max_age_days', None)
@@ -133,7 +145,7 @@ class BaseHandler(RequestHandler):
            return None
        else:
            return orm_token.user
-    
+
    def _user_for_cookie(self, cookie_name, cookie_value=None):
        """Get the User for a given cookie, if there is one"""
        cookie_id = self.get_secure_cookie(
@@ -143,41 +155,41 @@ class BaseHandler(RequestHandler):
        )
        def clear():
            self.clear_cookie(cookie_name, path=self.hub.server.base_url)
-        
+
        if cookie_id is None:
            if self.get_cookie(cookie_name):
-                self.log.warn("Invalid or expired cookie token")
+                self.log.warning("Invalid or expired cookie token")
                clear()
            return
        cookie_id = cookie_id.decode('utf8', 'replace')
        u = self.db.query(orm.User).filter(orm.User.cookie_id==cookie_id).first()
        user = self._user_from_orm(u)
        if user is None:
-            self.log.warn("Invalid cookie token")
+            self.log.warning("Invalid cookie token")
            # have cookie, but it's not valid. Clear it and start over.
            clear()
        return user
-    
+
    def _user_from_orm(self, orm_user):
        """return User wrapper from orm.User object"""
        if orm_user is None:
            return
        return self.users[orm_user]
-    
+
    def get_current_user_cookie(self):
        """get_current_user from a cookie token"""
        return self._user_for_cookie(self.hub.server.cookie_name)
-    
+
    def get_current_user(self):
        """get current username"""
        user = self.get_current_user_token()
        if user is not None:
            return user
        return self.get_current_user_cookie()
-    
+
    def find_user(self, name):
        """Get a user by name
-        
+
        return None if no such user
        """
        orm_user = orm.User.find(db=self.db, name=name)
@@ -192,57 +204,60 @@ class BaseHandler(RequestHandler):
            self.db.add(u)
            self.db.commit()
            user = self._user_from_orm(u)
+            self.authenticator.add_user(user)
        return user
-    
+
    def clear_login_cookie(self, name=None):
        if name is None:
            user = self.get_current_user()
        else:
            user = self.find_user(name)
+        kwargs = {}
+        if self.subdomain_host:
+            kwargs['domain'] = self.domain
        if user and user.server:
-            self.clear_cookie(user.server.cookie_name, path=user.server.base_url)
-        self.clear_cookie(self.hub.server.cookie_name, path=self.hub.server.base_url)
-    
+            self.clear_cookie(user.server.cookie_name, path=user.server.base_url, **kwargs)
+        self.clear_cookie(self.hub.server.cookie_name, path=self.hub.server.base_url, **kwargs)
+
+    def _set_user_cookie(self, user, server):
+        # tornado <4.2 have a bug that consider secure==True as soon as
+        # 'secure' kwarg is passed to set_secure_cookie
+        if  self.request.protocol == 'https':
+            kwargs = {'secure': True}
+        else:
+            kwargs = {}
+        if self.subdomain_host:
+            kwargs['domain'] = self.domain
+        self.log.debug("Setting cookie for %s: %s, %s", user.name, server.cookie_name, kwargs)
+        self.set_secure_cookie(
+            server.cookie_name,
+            user.cookie_id,
+            path=server.base_url,
+            **kwargs
+        )
+
    def set_server_cookie(self, user):
        """set the login cookie for the single-user server"""
-        # tornado <4.2 have a bug that consider secure==True as soon as
-        # 'secure' kwarg is passed to set_secure_cookie
-        if  self.request.protocol == 'https':
-            kwargs = {'secure':True}
-        else:
-            kwargs = {}
-        self.set_secure_cookie(
-            user.server.cookie_name,
-            user.cookie_id,
-            path=user.server.base_url,
-            **kwargs
-        )
-    
+        self._set_user_cookie(user, user.server)
+
    def set_hub_cookie(self, user):
        """set the login cookie for the Hub"""
-        # tornado <4.2 have a bug that consider secure==True as soon as
-        # 'secure' kwarg is passed to set_secure_cookie
-        if  self.request.protocol == 'https':
-            kwargs = {'secure':True}
-        else:
-            kwargs = {}
-        self.set_secure_cookie(
-            self.hub.server.cookie_name,
-            user.cookie_id,
-            path=self.hub.server.base_url,
-            **kwargs
-        )
-    
+        self._set_user_cookie(user, self.hub.server)
+
    def set_login_cookie(self, user):
        """Set login cookies for the Hub and single-user server."""
+        if self.subdomain_host and not self.request.host.startswith(self.domain):
+            self.log.warning(
+                "Possibly setting cookie on wrong domain: %s != %s",
+                self.request.host, self.domain)
        # create and set a new cookie token for the single-user server
        if user.server:
            self.set_server_cookie(user)
-        
+
        # create and set a new cookie token for the hub
        if not self.get_current_user_cookie():
            self.set_hub_cookie(user)
-    
+
    @gen.coroutine
    def authenticate(self, data):
        auth = self.authenticator
@@ -268,7 +283,7 @@ class BaseHandler(RequestHandler):
    @property
    def spawner_class(self):
        return self.settings.get('spawner_class', LocalProcessSpawner)
-    
+
    @gen.coroutine
    def spawn_single_user(self, user, options=None):
        if user.spawn_pending:
@@ -280,7 +295,7 @@ class BaseHandler(RequestHandler):
        @gen.coroutine
        def finish_user_spawn(f=None):
            """Finish the user spawn by registering listeners and notifying the proxy.
-            
+
            If the spawner is slow to start, this is passed as an async callback,
            otherwise it is called immediately.
            """
@@ -289,38 +304,48 @@ class BaseHandler(RequestHandler):
                return
            toc = IOLoop.current().time()
            self.log.info("User %s server took %.3f seconds to start", user.name, toc-tic)
+            self.statsd.timing('spawner.success', (toc - tic) * 1000)
            yield self.proxy.add_user(user)
            user.spawner.add_poll_callback(self.user_stopped, user)
-        
+
        try:
            yield gen.with_timeout(timedelta(seconds=self.slow_spawn_timeout), f)
        except gen.TimeoutError:
            if user.spawn_pending:
+                # still in Spawner.start, which is taking a long time
+                # we shouldn't poll while spawn_pending is True
+                self.log.warning("User %s server is slow to start", user.name)
+                # schedule finish for when the user finishes spawning
+                IOLoop.current().add_future(f, finish_user_spawn)
+            else:
+                # start has finished, but the server hasn't come up
+                # check if the server died while we were waiting
                status = yield user.spawner.poll()
                if status is None:
-                    # hit timeout, but spawn is still pending
-                    self.log.warn("User %s server is slow to start", user.name)
+                    # hit timeout, but server's running. Hope that it'll show up soon enough,
+                    # though it's possible that it started at the wrong URL
+                    self.log.warning("User %s server is slow to become responsive", user.name)
                    # schedule finish for when the user finishes spawning
                    IOLoop.current().add_future(f, finish_user_spawn)
                else:
+                    toc = IOLoop.current().time()
+                    self.statsd.timing('spawner.failure', (toc - tic) * 1000)
                    raise web.HTTPError(500, "Spawner failed to start [status=%s]" % status)
-            else:
-                raise
        else:
            yield finish_user_spawn()
-    
+
    @gen.coroutine
    def user_stopped(self, user):
        """Callback that fires when the spawner has stopped"""
        status = yield user.spawner.poll()
        if status is None:
            status = 'unknown'
-        self.log.warn("User %s server stopped, with exit code: %s",
+        self.log.warning("User %s server stopped, with exit code: %s",
            user.name, status,
        )
        yield self.proxy.delete_user(user)
        yield user.stop()
-    
+
    @gen.coroutine
    def stop_single_user(self, user):
        if user.stop_pending:
@@ -331,7 +356,7 @@ class BaseHandler(RequestHandler):
        @gen.coroutine
        def finish_stop(f=None):
            """Finish the stop action by noticing that the user is stopped.
-            
+
            If the spawner is slow to stop, this is passed as an async callback,
            otherwise it is called immediately.
            """
@@ -340,13 +365,13 @@ class BaseHandler(RequestHandler):
                return
            toc = IOLoop.current().time()
            self.log.info("User %s server took %.3f seconds to stop", user.name, toc-tic)
-        
+
        try:
            yield gen.with_timeout(timedelta(seconds=self.slow_stop_timeout), f)
        except gen.TimeoutError:
            if user.stop_pending:
                # hit timeout, but stop is still pending
-                self.log.warn("User %s server is slow to stop", user.name)
+                self.log.warning("User %s server is slow to stop", user.name)
                # schedule finish for when the server finishes stopping
                IOLoop.current().add_future(f, finish_stop)
            else:
@@ -385,6 +410,7 @@ class BaseHandler(RequestHandler):
        """render custom error pages"""
        exc_info = kwargs.get('exc_info')
        message = ''
+        exception = None
        status_message = responses.get(status_code, 'Unknown HTTP Error')
        if exc_info:
            exception = exc_info[1]
@@ -426,7 +452,7 @@ class Template404(BaseHandler):

 class PrefixRedirectHandler(BaseHandler):
    """Redirect anything outside a prefix inside.
-    
+
    Redirects /foo to /prefix/foo, etc.
    """
    def get(self):
@@ -437,22 +463,27 @@ class PrefixRedirectHandler(BaseHandler):


 class UserSpawnHandler(BaseHandler):
-    """Requests to /user/name handled by the Hub
-    should result in spawning the single-user server and
-    being redirected to the original.
+    """Redirect requests to /user/name/* handled by the Hub.
+
+    If logged in, spawn a single-user server and redirect request.
+    If a user, alice, requests /user/bob/notebooks/mynotebook.ipynb,
+    redirect her to /user/alice/notebooks/mynotebook.ipynb, which should
+    in turn call this function.
    """
+
    @gen.coroutine
-    def get(self, name):
+    def get(self, name, user_path):
        current_user = self.get_current_user()
        if current_user and current_user.name == name:
-            # logged in, spawn the server
+            # logged in as correct user, spawn the server
            if current_user.spawner:
                if current_user.spawn_pending:
                    # spawn has started, but not finished
+                    self.statsd.incr('redirects.user_spawn_pending', 1)
                    html = self.render_template("spawn_pending.html", user=current_user)
                    self.finish(html)
                    return
-                
+
                # spawn has supposedly finished, check on the status
                status = yield current_user.spawner.poll()
                if status is not None:
@@ -465,25 +496,38 @@ class UserSpawnHandler(BaseHandler):
            self.set_login_cookie(current_user)
            without_prefix = self.request.uri[len(self.hub.server.base_url):]
            target = url_path_join(self.base_url, without_prefix)
+            if self.subdomain_host:
+                target = current_user.host + target
+            self.redirect(target)
+            self.statsd.incr('redirects.user_after_login')
+        elif current_user:
+            # logged in as a different user, redirect
+            self.statsd.incr('redirects.user_to_user', 1)
+            target = url_path_join(current_user.url, user_path or '')
            self.redirect(target)
        else:
-            # not logged in to the right user,
-            # clear any cookies and reload (will redirect to login)
+            # not logged in, clear any cookies and reload
+            self.statsd.incr('redirects.user_to_login', 1)
            self.clear_login_cookie()
            self.redirect(url_concat(
                self.settings['login_url'],
-                {'next': self.request.uri,
-            }))
+                {'next': self.request.uri},
+            ))
+

 class CSPReportHandler(BaseHandler):
    '''Accepts a content security policy violation report'''
    @web.authenticated
    def post(self):
        '''Log a content security policy violation report'''
-        self.log.warn("Content security violation: %s",
-                      self.request.body.decode('utf8', 'replace'))
+        self.log.warning(
+            "Content security violation: %s",
+            self.request.body.decode('utf8', 'replace')
+        )
+        # Report it to statsd as well
+        self.statsd.incr('csp_report')

 default_handlers = [
-    (r'/user/([^/]+)/?.*', UserSpawnHandler),
+    (r'/user/([^/]+)(/.*)?', UserSpawnHandler),
    (r'/security/csp-report', CSPReportHandler),
 ]
--- a/jupyterhub/handlers/login.py
+++ b/jupyterhub/handlers/login.py
@@ -15,10 +15,11 @@ class LogoutHandler(BaseHandler):
        user = self.get_current_user()
        if user:
            self.log.info("User logged out: %s", user.name)
-        self.clear_login_cookie()
-        for name in user.other_user_cookies:
-            self.clear_login_cookie(name)
-        user.other_user_cookies = set([])
+            self.clear_login_cookie()
+            for name in user.other_user_cookies:
+                self.clear_login_cookie(name)
+            user.other_user_cookies = set([])
+            self.statsd.incr('logout')
        self.redirect(self.hub.server.base_url, permanent=False)


@@ -35,6 +36,7 @@ class LoginHandler(BaseHandler):
        )

    def get(self):
+        self.statsd.incr('login.request')
        next_url = self.get_argument('next', '')
        if not next_url.startswith('/'):
            # disallow non-absolute next URLs (e.g. full URLs)
@@ -43,7 +45,7 @@ class LoginHandler(BaseHandler):
        if user:
            if not next_url:
                if user.running:
-                    next_url = user.server.base_url
+                    next_url = user.url
                else:
                    next_url = self.hub.server.base_url
            # set new login cookie
@@ -61,8 +63,13 @@ class LoginHandler(BaseHandler):
        for arg in self.request.arguments:
            data[arg] = self.get_argument(arg)

+        auth_timer = self.statsd.timer('login.authenticate').start()
        username = yield self.authenticate(data)
+        auth_timer.stop(send=False)
+
        if username:
+            self.statsd.incr('login.success')
+            self.statsd.timing('login.authenticate.success', auth_timer.ms)
            user = self.user_from_username(username)
            already_running = False
            if user.spawner:
@@ -78,7 +85,9 @@ class LoginHandler(BaseHandler):
            self.redirect(next_url)
            self.log.info("User logged in: %s", username)
        else:
-            self.log.debug("Failed login for %s", username)
+            self.statsd.incr('login.failure')
+            self.statsd.timing('login.authenticate.failure', auth_timer.ms)
+            self.log.debug("Failed login for %s", data.get('username', 'unknown user'))
            html = self._render(
                login_error='Invalid username or password',
                username=username,
--- a/jupyterhub/handlers/pages.py
+++ b/jupyterhub/handlers/pages.py
@@ -3,30 +3,33 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.

+from http.client import responses
+
+from jinja2 import TemplateNotFound
 from tornado import web, gen

 from .. import orm
 from ..utils import admin_only, url_path_join
 from .base import BaseHandler
-from .login import LoginHandler


 class RootHandler(BaseHandler):
    """Render the Hub root page.
-    
+
    If logged in, redirects to:
-    
+
    - single-user server if running
    - hub home, otherwise
-    
+
    Otherwise, renders login page.
    """
    def get(self):
        user = self.get_current_user()
        if user:
            if user.running:
-                url = user.server.base_url
+                url = user.url
                self.log.debug("User is running: %s", url)
+                self.set_login_cookie(user) # set cookie
            else:
                url = url_path_join(self.hub.server.base_url, 'home')
                self.log.debug("User is not running: %s", url)
@@ -40,18 +43,23 @@ class HomeHandler(BaseHandler):
    """Render the user's home page."""

    @web.authenticated
+    @gen.coroutine
    def get(self):
+        user = self.get_current_user()
+        if user.running:
+            # trigger poll_and_notify event in case of a server that died
+            yield user.spawner.poll_and_notify()
        html = self.render_template('home.html',
-            user=self.get_current_user(),
+            user=user,
        )
        self.finish(html)


 class SpawnHandler(BaseHandler):
    """Handle spawning of single-user servers via form.
-    
+
    GET renders the form, POST handles form submission.
-    
+
    Only enabled when Spawner.options_form is defined.
    """
    def _render_form(self, message=''):
@@ -67,7 +75,7 @@ class SpawnHandler(BaseHandler):
        """GET renders form for spawning with user-specified options"""
        user = self.get_current_user()
        if user.running:
-            url = user.server.base_url
+            url = user.url
            self.log.debug("User is running: %s", url)
            self.redirect(url)
            return
@@ -75,16 +83,15 @@ class SpawnHandler(BaseHandler):
            self.finish(self._render_form())
        else:
            # not running, no form. Trigger spawn.
-            url = url_path_join(self.base_url, 'user', user.name)
-            self.redirect(url)
-    
+            self.redirect(user.url)
+
    @web.authenticated
    @gen.coroutine
    def post(self):
        """POST spawns with user-specified options"""
        user = self.get_current_user()
        if user.running:
-            url = user.server.base_url
+            url = user.url
            self.log.warning("User is already running: %s", url)
            self.redirect(url)
            return
@@ -93,15 +100,15 @@ class SpawnHandler(BaseHandler):
            form_options[key] = [ bs.decode('utf8') for bs in byte_list ]
        for key, byte_list in self.request.files.items():
            form_options["%s_file"%key] = byte_list
-        options = user.spawner.options_from_form(form_options)
        try:
+            options = user.spawner.options_from_form(form_options)
            yield self.spawn_single_user(user, options=options)
        except Exception as e:
            self.log.error("Failed to spawn single-user server with form", exc_info=True)
            self.finish(self._render_form(str(e)))
            return
        self.set_login_cookie(user)
-        url = user.server.base_url
+        url = user.url
        self.redirect(url)

 class AdminHandler(BaseHandler):
@@ -122,14 +129,14 @@ class AdminHandler(BaseHandler):
        }
        sorts = self.get_arguments('sort') or default_sort
        orders = self.get_arguments('order')
-        
+
        for bad in set(sorts).difference(available):
-            self.log.warn("ignoring invalid sort: %r", bad)
+            self.log.warning("ignoring invalid sort: %r", bad)
            sorts.remove(bad)
        for bad in set(orders).difference({'asc', 'desc'}):
-            self.log.warn("ignoring invalid order: %r", bad)
+            self.log.warning("ignoring invalid order: %r", bad)
            orders.remove(bad)
-        
+
        # add default sort as secondary
        for s in default_sort:
            if s not in sorts:
@@ -139,17 +146,17 @@ class AdminHandler(BaseHandler):
                orders.append(default_order[col])
        else:
            orders = orders[:len(sorts)]
-        
+
        # this could be one incomprehensible nested list comprehension
        # get User columns
        cols = [ getattr(orm.User, mapping.get(c, c)) for c in sorts ]
        # get User.col.desc() order objects
        ordered = [ getattr(c, o)() for c, o in zip(cols, orders) ]
-        
+
        users = self.db.query(orm.User).order_by(*ordered)
        users = [ self._user_from_orm(u) for u in users ]
        running = [ u for u in users if u.running ]
-        
+
        html = self.render_template('admin.html',
            user=self.get_current_user(),
            admin_access=self.settings.get('admin_access', False),
@@ -160,9 +167,43 @@ class AdminHandler(BaseHandler):
        self.finish(html)


+class ProxyErrorHandler(BaseHandler):
+    """Handler for rendering proxy error pages"""
+    
+    def get(self, status_code_s):
+        status_code = int(status_code_s)
+        status_message = responses.get(status_code, 'Unknown HTTP Error')
+        # build template namespace
+        
+        hub_home = url_path_join(self.hub.server.base_url, 'home')
+        message_html = ''
+        if status_code == 503:
+            message_html = ' '.join([
+                "Your server appears to be down.",
+                "Try restarting it <a href='%s'>from the hub</a>" % hub_home
+            ])
+        ns = dict(
+            status_code=status_code,
+            status_message=status_message,
+            message_html=message_html,
+            logo_url=hub_home,
+        )
+
+        self.set_header('Content-Type', 'text/html')
+        # render the template
+        try:
+            html = self.render_template('%s.html' % status_code, **ns)
+        except TemplateNotFound:
+            self.log.debug("No template for %d", status_code)
+            html = self.render_template('error.html', **ns)
+
+        self.write(html)
+
+
 default_handlers = [
    (r'/', RootHandler),
    (r'/home', HomeHandler),
    (r'/admin', AdminHandler),
    (r'/spawn', SpawnHandler),
+    (r'/error/(\d+)', ProxyErrorHandler),
 ]
--- a/jupyterhub/handlers/static.py
+++ b/jupyterhub/handlers/static.py
@@ -1,6 +1,7 @@
 # Copyright (c) Jupyter Development Team.
 # Distributed under the terms of the Modified BSD License.

+import os
 from tornado.web import StaticFileHandler

 class CacheControlStaticFilesHandler(StaticFileHandler):
@@ -14,4 +15,14 @@ class CacheControlStaticFilesHandler(StaticFileHandler):
    def set_extra_headers(self, path):
        if "v" not in self.request.arguments:
            self.add_header("Cache-Control", "no-cache")
-    
+
+class LogoHandler(StaticFileHandler):
+    """A singular handler for serving the logo."""
+    def get(self):
+        return super().get('')
+
+    @classmethod
+    def get_absolute_path(cls, root, path):
+        """We only serve one file, ignore relative path"""
+        return os.path.abspath(root)
+
--- a/jupyterhub/orm.py
+++ b/jupyterhub/orm.py
@@ -4,15 +4,13 @@
 # Distributed under the terms of the Modified BSD License.

 from datetime import datetime
-import errno
 import json
-import socket

 from tornado import gen
 from tornado.log import app_log
 from tornado.httpclient import HTTPRequest, AsyncHTTPClient

-from sqlalchemy.types import TypeDecorator, VARCHAR
+from sqlalchemy.types import TypeDecorator, TEXT
 from sqlalchemy import (
    inspect,
    Column, Integer, ForeignKey, Unicode, Boolean,
@@ -26,7 +24,7 @@ from sqlalchemy import create_engine

 from .utils import (
    random_port, url_path_join, wait_for_server, wait_for_http_server,
-    new_token, hash_token, compare_token, localhost,
+    new_token, hash_token, compare_token, can_connect,
 )


@@ -39,7 +37,7 @@ class JSONDict(TypeDecorator):

    """

-    impl = VARCHAR
+    impl = TEXT

    def process_bind_param(self, value, dialect):
        if value is not None:
@@ -59,26 +57,26 @@ Base.log = app_log

 class Server(Base):
    """The basic state of a server
-    
+
    connection and cookie info
    """
    __tablename__ = 'servers'
    id = Column(Integer, primary_key=True)
-    proto = Column(Unicode, default='http')
-    ip = Column(Unicode, default='')
+    proto = Column(Unicode(15), default='http')
+    ip = Column(Unicode(255), default='')  # could also be a DNS name
    port = Column(Integer, default=random_port)
-    base_url = Column(Unicode, default='/')
-    cookie_name = Column(Unicode, default='cookie')
-    
+    base_url = Column(Unicode(255), default='/')
+    cookie_name = Column(Unicode(255), default='cookie')
+
    def __repr__(self):
        return "<Server(%s:%s)>" % (self.ip, self.port)
-    
+
    @property
    def host(self):
        ip = self.ip
        if ip in {'', '0.0.0.0'}:
            # when listening on all interfaces, connect to localhost
-            ip = localhost()
+            ip = '127.0.0.1'
        return "{proto}://{ip}:{port}".format(
            proto=self.proto,
            ip=ip,
@@ -91,52 +89,34 @@ class Server(Base):
            host=self.host,
            uri=self.base_url,
        )
-    
+
    @property
    def bind_url(self):
        """representation of URL used for binding
-        
+
        Never used in APIs, only logging,
        since it can be non-connectable value, such as '', meaning all interfaces.
        """
        if self.ip in {'', '0.0.0.0'}:
-            return self.url.replace('localhost', self.ip or '*', 1)
+            return self.url.replace('127.0.0.1', self.ip or '*', 1)
        return self.url
-    
+
    @gen.coroutine
    def wait_up(self, timeout=10, http=False):
        """Wait for this server to come up"""
        if http:
            yield wait_for_http_server(self.url, timeout=timeout)
        else:
-            yield wait_for_server(self.ip or localhost(), self.port, timeout=timeout)
-    
+            yield wait_for_server(self.ip or '127.0.0.1', self.port, timeout=timeout)
+
    def is_up(self):
        """Is the server accepting connections?"""
-        try:
-            socket.create_connection((self.ip or localhost(), self.port))
-        except socket.error as e:
-            if e.errno == errno.ENETUNREACH:
-                try:
-                    socket.create_connection((self.ip or '127.0.0.1', self.port))
-                except socket.error as e:
-                    if e.errno == errno.ECONNREFUSED:
-                        return False
-                    else:
-                        raise
-                else:
-                    return True
-            elif e.errno == errno.ECONNREFUSED:
-                return False
-            else:
-                raise
-        else:
-            return True
+        return can_connect(self.ip or '127.0.0.1', self.port)


 class Proxy(Base):
    """A configurable-http-proxy instance.
-    
+
    A proxy consists of the API server info and the public-facing server info,
    plus an auth token for configuring the proxy table.
    """
@@ -147,7 +127,7 @@ class Proxy(Base):
    public_server = relationship(Server, primaryjoin=_public_server_id == Server.id)
    _api_server_id = Column(Integer, ForeignKey('servers.id'))
    api_server = relationship(Server, primaryjoin=_api_server_id == Server.id)
-    
+
    def __repr__(self):
        if self.public_server:
            return "<%s %s:%s>" % (
@@ -155,7 +135,7 @@ class Proxy(Base):
            )
        else:
            return "<%s [unconfigured]>" % self.__class__.__name__
-    
+
    def api_request(self, path, method='GET', body=None, client=None):
        """Make an authenticated API request of the proxy"""
        client = client or AsyncHTTPClient()
@@ -176,10 +156,14 @@ class Proxy(Base):
    def add_user(self, user, client=None):
        """Add a user's server to the proxy table."""
        self.log.info("Adding user %s to proxy %s => %s",
-            user.name, user.server.base_url, user.server.host,
+            user.name, user.proxy_path, user.server.host,
        )
-        
-        yield self.api_request(user.server.base_url,
+
+        if user.spawn_pending:
+            raise RuntimeError(
+                "User %s's spawn is pending, shouldn't be added to the proxy yet!", user.name)
+
+        yield self.api_request(user.proxy_path,
            method='POST',
            body=dict(
                target=user.server.host,
@@ -187,30 +171,15 @@ class Proxy(Base):
            ),
            client=client,
        )
-    
+
    @gen.coroutine
    def delete_user(self, user, client=None):
        """Remove a user's server to the proxy table."""
        self.log.info("Removing user %s from proxy", user.name)
-        yield self.api_request(user.server.base_url,
+        yield self.api_request(user.proxy_path,
            method='DELETE',
            client=client,
        )
-    
-    @gen.coroutine
-    def add_all_users(self):
-        """Update the proxy table from the database.
-        
-        Used when loading up a new proxy.
-        """
-        db = inspect(self).session
-        futures = []
-        for user in db.query(User):
-            if (user.server):
-                futures.append(self.add_user(user))
-        # wait after submitting them all
-        for f in futures:
-            yield f

    @gen.coroutine
    def get_routes(self, client=None):
@@ -219,17 +188,42 @@ class Proxy(Base):
        return json.loads(resp.body.decode('utf8', 'replace'))

    @gen.coroutine
-    def check_routes(self, routes=None):
-        """Check that all users are properly"""
+    def add_all_users(self, user_dict):
+        """Update the proxy table from the database.
+
+        Used when loading up a new proxy.
+        """
+        db = inspect(self).session
+        futures = []
+        for orm_user in db.query(User):
+            user = user_dict[orm_user]
+            if user.running:
+                futures.append(self.add_user(user))
+        # wait after submitting them all
+        for f in futures:
+            yield f
+
+    @gen.coroutine
+    def check_routes(self, user_dict, routes=None):
+        """Check that all users are properly routed on the proxy"""
        if not routes:
            routes = yield self.get_routes()

        have_routes = { r['user'] for r in routes.values() if 'user' in r }
        futures = []
        db = inspect(self).session
-        for user in db.query(User).filter(User.server != None):
+        for orm_user in db.query(User).filter(User.server != None):
+            user = user_dict[orm_user]
+            if not user.running:
+                # Don't add users to the proxy that haven't finished starting
+                continue
+            if user.server is None:
+                # This should never be True, but seems to be on rare occasion.
+                # catch filter bug, either in sqlalchemy or my understanding of its behavior
+                self.log.error("User %s has no server, but wasn't filtered out.", user)
+                continue
            if user.name not in have_routes:
-                self.log.warn("Adding missing route for %s", user.name)
+                self.log.warning("Adding missing route for %s (%s)", user.name, user.server)
                futures.append(self.add_user(user))
        for f in futures:
            yield f
@@ -238,9 +232,9 @@ class Proxy(Base):

 class Hub(Base):
    """Bring it all together at the hub.
-    
+
    The Hub is a server, plus its API path suffix
-    
+
    the api_url is the full URL plus the api_path suffix on the end
    of the server base_url.
    """
@@ -248,12 +242,13 @@ class Hub(Base):
    id = Column(Integer, primary_key=True)
    _server_id = Column(Integer, ForeignKey('servers.id'))
    server = relationship(Server, primaryjoin=_server_id == Server.id)
-    
+    host = ''
+
    @property
    def api_url(self):
        """return the full API url (with proto://host...)"""
        return url_path_join(self.server.url, 'api')
-    
+
    def __repr__(self):
        if self.server:
            return "<%s %s:%s>" % (
@@ -265,31 +260,31 @@ class Hub(Base):

 class User(Base):
    """The User table
-    
+
    Each user has a single server,
    and multiple tokens used for authorization.
-    
+
    API tokens grant access to the Hub's REST API.
    These are used by single-user servers to authenticate requests,
    and external services to manipulate the Hub.
-    
+
    Cookies are set with a single ID.
    Resetting the Cookie ID invalidates all cookies, forcing user to login again.
-    
+
    A `state` column contains a JSON dict,
    used for restoring state of a Spawner.
    """
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True, autoincrement=True)
-    name = Column(Unicode)
+    name = Column(Unicode(1023))
    # should we allow multiple servers per user?
    _server_id = Column(Integer, ForeignKey('servers.id'))
    server = relationship(Server, primaryjoin=_server_id == Server.id)
    admin = Column(Boolean, default=False)
    last_activity = Column(DateTime, default=datetime.utcnow)
-    
+
    api_tokens = relationship("APIToken", backref="user")
-    cookie_id = Column(Unicode, default=new_token)
+    cookie_id = Column(Unicode(1023), default=new_token)
    state = Column(JSONDict)

    other_user_cookies = set([])
@@ -307,12 +302,22 @@ class User(Base):
                cls=self.__class__.__name__,
                name=self.name,
            )
-    
-    def new_api_token(self):
-        """Create a new API token"""
+
+    def new_api_token(self, token=None):
+        """Create a new API token
+        
+        If `token` is given, load that token.
+        """
        assert self.id is not None
        db = inspect(self).session
-        token = new_token()
+        if token is None:
+            token = new_token()
+        else:
+            if len(token) < 8:
+                raise ValueError("Tokens must be at least 8 characters, got %r" % token)
+            found = APIToken.find(db, token)
+            if found:
+                raise ValueError("Collision on token: %s..." % token[:4])
        orm_token = APIToken(user_id=self.id)
        orm_token.token = token
        db.add(orm_token)
@@ -330,29 +335,29 @@ class User(Base):
 class APIToken(Base):
    """An API token"""
    __tablename__ = 'api_tokens'
-    
+
    @declared_attr
    def user_id(cls):
        return Column(Integer, ForeignKey('users.id'))

    id = Column(Integer, primary_key=True)
-    hashed = Column(Unicode)
-    prefix = Column(Unicode)
+    hashed = Column(Unicode(1023))
+    prefix = Column(Unicode(1023))
    prefix_length = 4
    algorithm = "sha512"
    rounds = 16384
    salt_bytes = 8
-    
+
    @property
    def token(self):
        raise AttributeError("token is write-only")
-    
+
    @token.setter
    def token(self, token):
        """Store the hashed value and prefix for a token"""
        self.prefix = token[:self.prefix_length]
        self.hashed = hash_token(token, rounds=self.rounds, salt=self.salt_bytes, algorithm=self.algorithm)
-    
+
    def __repr__(self):
        return "<{cls}('{pre}...', user='{u}')>".format(
            cls=self.__class__.__name__,
@@ -373,7 +378,7 @@ class APIToken(Base):
        for orm_token in prefix_match:
            if orm_token.match(token):
                return orm_token
-    
+
    def match(self, token):
        """Is this my token?"""
        return compare_token(self.hashed, token)
@@ -383,6 +388,8 @@ def new_session_factory(url="sqlite:///:memory:", reset=False, **kwargs):
    """Create a new session at url"""
    if url.startswith('sqlite'):
        kwargs.setdefault('connect_args', {'check_same_thread': False})
+    elif url.startswith('mysql'):
+        kwargs.setdefault('pool_recycle', 60)

    if url.endswith(':memory:'):
        # If we're using an in-memory database, ensure that only one connection
--- a/jupyterhub/spawner.py
+++ b/jupyterhub/spawner.py
@@ -10,11 +10,12 @@ import pwd
 import signal
 import sys
 import grp
+import warnings
 from subprocess import Popen
-from tempfile import TemporaryDirectory
+from tempfile import mkdtemp

 from tornado import gen
-from tornado.ioloop import IOLoop, PeriodicCallback
+from tornado.ioloop import PeriodicCallback

 from traitlets.config import LoggingConfigurable
 from traitlets import (
@@ -22,7 +23,7 @@ from traitlets import (
 )

 from .traitlets import Command
-from .utils import random_port, localhost
+from .utils import random_port

 class Spawner(LoggingConfigurable):
    """Base class for spawning single-user notebook servers.
@@ -41,39 +42,38 @@ class Spawner(LoggingConfigurable):
    hub = Any()
    authenticator = Any()
    api_token = Unicode()
-    ip = Unicode(localhost(), config=True,
+    ip = Unicode('127.0.0.1',
        help="The IP address (or hostname) the single-user server should listen on"
-    )
-    start_timeout = Integer(60, config=True,
+    ).tag(config=True)
+    start_timeout = Integer(60,
        help="""Timeout (in seconds) before giving up on the spawner.
        
        This is the timeout for start to return, not the timeout for the server to respond.
        Callers of spawner.start will assume that startup has failed if it takes longer than this.
        start should return when the server process is started and its location is known.
        """
-    )
+    ).tag(config=True)

-    http_timeout = Integer(
-        30, config=True,
+    http_timeout = Integer(30,
        help="""Timeout (in seconds) before giving up on a spawned HTTP server

        Once a server has successfully been spawned, this is the amount of time
        we wait before assuming that the server is unable to accept
        connections.
        """
-    )
+    ).tag(config=True)

-    poll_interval = Integer(30, config=True,
+    poll_interval = Integer(30,
        help="""Interval (in seconds) on which to poll the spawner."""
-    )
+    ).tag(config=True)
    _callbacks = List()
    _poll_callback = Any()
    
-    debug = Bool(False, config=True,
+    debug = Bool(False,
        help="Enable debug-logging of the single-user server"
-    )
+    ).tag(config=True)
    
-    options_form = Unicode("", config=True, help="""
+    options_form = Unicode("", help="""
        An HTML form for options a user can specify on launching their server.
        The surrounding `<form>` element and the submit button are already provided.
        
@@ -87,7 +87,7 @@ class Spawner(LoggingConfigurable):
              <option value="A">The letter A</option>
              <option value="B">The letter B</option>
            </select>
-    """)
+    """).tag(config=True)

    def options_from_form(self, form_data):
        """Interpret HTTP form data
@@ -113,32 +113,58 @@ class Spawner(LoggingConfigurable):
        'VIRTUAL_ENV',
        'LANG',
        'LC_ALL',
-    ], config=True,
+    ],
        help="Whitelist of environment variables for the subprocess to inherit"
-    )
-    env = Dict()
-    def _env_default(self):
-        env = {}
-        for key in self.env_keep:
-            if key in os.environ:
-                env[key] = os.environ[key]
-        env['JPY_API_TOKEN'] = self.api_token
-        return env
+    ).tag(config=True)
+    env = Dict(help="""Deprecated: use Spawner.get_env or Spawner.environment
    
-    cmd = Command(['jupyterhub-singleuser'], config=True,
+    - extend Spawner.get_env for adding required env in Spawner subclasses
+    - Spawner.environment for config-specified env
+    """)
+    
+    environment = Dict(
+        help="""Environment variables to load for the Spawner.
+
+        Value could be a string or a callable. If it is a callable, it will
+        be called with one parameter, which will be the instance of the spawner
+        in use. It should quickly (without doing much blocking operations) return
+        a string that will be used as the value for the environment variable.
+        """
+    ).tag(config=True)
+    
+    cmd = Command(['jupyterhub-singleuser'],
        help="""The command used for starting notebooks."""
-    )
-    args = List(Unicode, config=True,
+    ).tag(config=True)
+    args = List(Unicode(),
        help="""Extra arguments to be passed to the single-user server"""
-    )
+    ).tag(config=True)
    
-    notebook_dir = Unicode('', config=True,
+    notebook_dir = Unicode('',
        help="""The notebook directory for the single-user server
        
        `~` will be expanded to the user's home directory
        `%U` will be expanded to the user's username
        """
-    )
+    ).tag(config=True)
+
+    default_url = Unicode('',
+        help="""The default URL for the single-user server. 
+
+        Can be used in conjunction with --notebook-dir=/ to enable 
+        full filesystem traversal, while preserving user's homedir as
+        landing page for notebook
+
+        `%U` will be expanded to the user's username
+        """
+    ).tag(config=True)
+    
+    disable_user_config = Bool(False,
+        help="""Disable per-user configuration of single-user servers.
+        
+        This prevents any config in users' $HOME directories
+        from having an effect on their server.
+        """
+    ).tag(config=True)
    
    def __init__(self, **kwargs):
        super(Spawner, self).__init__(**kwargs)
@@ -185,12 +211,34 @@ class Spawner(LoggingConfigurable):
        self.api_token = ''
    
    def get_env(self):
-        """Return the environment we should use
-        
-        Default returns a copy of self.env.
+        """Return the environment dict to use for the Spawner.
+
+        This applies things like `env_keep`, anything defined in `Spawner.environment`,
+        and adds the API token to the env.
+
        Use this to access the env in Spawner.start to allow extension in subclasses.
        """
-        return self.env.copy()
+        env = {}
+        if self.env:
+            warnings.warn("Spawner.env is deprecated, found %s" % self.env, DeprecationWarning)
+            env.update(self.env)
+        
+        for key in self.env_keep:
+            if key in os.environ:
+                env[key] = os.environ[key]
+
+        # config overrides. 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
+        # spawn time.
+        for key, value in self.environment.items():
+            if callable(value):
+                env[key] = value(self)
+            else:
+                env[key] = value
+
+        env['JPY_API_TOKEN'] = self.api_token
+        return env
    
    def get_args(self):
        """Return the arguments to be passed after self.cmd"""
@@ -199,6 +247,7 @@ class Spawner(LoggingConfigurable):
            '--port=%i' % self.user.server.port,
            '--cookie-name=%s' % self.user.server.cookie_name,
            '--base-url=%s' % self.user.server.base_url,
+            '--hub-host=%s' % self.hub.host,
            '--hub-prefix=%s' % self.hub.server.base_url,
            '--hub-api-url=%s' % self.hub.api_url,
            ]
@@ -207,8 +256,14 @@ class Spawner(LoggingConfigurable):
        if self.notebook_dir:
            self.notebook_dir = self.notebook_dir.replace("%U",self.user.name)
            args.append('--notebook-dir=%s' % self.notebook_dir)
+        if self.default_url:
+            self.default_url = self.default_url.replace("%U",self.user.name)
+            args.append('--NotebookApp.default_url=%s' % self.default_url)
+
        if self.debug:
            args.append('--debug')
+        if self.disable_user_config:
+            args.append('--disable-user-config')
        args.extend(self.args)
        return args
    
@@ -280,15 +335,17 @@ class Spawner(LoggingConfigurable):
        
        self.stop_polling()
        
-        add_callback = IOLoop.current().add_callback
        for callback in self._callbacks:
-            add_callback(callback)
+            try:
+                yield gen.maybe_future(callback())
+            except Exception:
+                self.log.exception("Unhandled error in poll callback for %s", self)
+        return status
    
    death_interval = Float(0.1)
    @gen.coroutine
    def wait_for_death(self, timeout=10):
        """wait for the process to die, up to timeout seconds"""
-        loop = IOLoop.current()
        for i in range(int(timeout / self.death_interval)):
            status = yield self.poll()
            if status is not None:
@@ -302,12 +359,13 @@ def _try_setcwd(path):
        try:
            os.chdir(path)
        except OSError as e:
+            exc = e # break exception instance out of except scope
            print("Couldn't set CWD to %s (%s)" % (path, e), file=sys.stderr)
            path, _ = os.path.split(path)
        else:
            return
-    print("Couldn't set CWD at all (%s), using temp dir" % e, file=sys.stderr)
-    td = TemporaryDirectory().name
+    print("Couldn't set CWD at all (%s), using temp dir" % exc, file=sys.stderr)
+    td = mkdtemp()
    os.chdir(td)


@@ -342,15 +400,15 @@ class LocalProcessSpawner(Spawner):
    This is the default spawner for JupyterHub.
    """
    
-    INTERRUPT_TIMEOUT = Integer(10, config=True,
+    INTERRUPT_TIMEOUT = Integer(10,
        help="Seconds to wait for process to halt after SIGINT before proceeding to SIGTERM"
-    )
-    TERM_TIMEOUT = Integer(5, config=True,
+    ).tag(config=True)
+    TERM_TIMEOUT = Integer(5,
        help="Seconds to wait for process to halt after SIGTERM before proceeding to SIGKILL"
-    )
-    KILL_TIMEOUT = Integer(5, config=True,
+    ).tag(config=True)
+    KILL_TIMEOUT = Integer(5,
        help="Seconds to wait for process to halt after SIGKILL before giving up"
-    )
+    ).tag(config=True)
    
    proc = Instance(Popen, allow_none=True)
    pid = Integer(0)
@@ -486,5 +544,5 @@ class LocalProcessSpawner(Spawner):
        status = yield self.poll()
        if status is None:
            # it all failed, zombie process
-            self.log.warn("Process %i never died", self.pid)
+            self.log.warning("Process %i never died", self.pid)
    
--- a/jupyterhub/tests/mocking.py
+++ b/jupyterhub/tests/mocking.py
@@ -1,7 +1,7 @@
 """mock utilities for testing"""

+import os
 import sys
-from datetime import timedelta
 from tempfile import NamedTemporaryFile
 import threading

@@ -13,11 +13,13 @@ from tornado import gen
 from tornado.concurrent import Future
 from tornado.ioloop import IOLoop

-from ..spawner import LocalProcessSpawner
+from traitlets import default
+
 from ..app import JupyterHub
 from ..auth import PAMAuthenticator
 from .. import orm
-from ..utils import localhost
+from ..spawner import LocalProcessSpawner
+from ..utils import url_path_join

 from pamela import PAMError

@@ -44,7 +46,7 @@ class MockSpawner(LocalProcessSpawner):
    
    def user_env(self, env):
        return env
-    
+    @default('cmd')
    def _cmd_default(self):
        return [sys.executable, '-m', 'jupyterhub.tests.mocksu']

@@ -66,6 +68,7 @@ class SlowSpawner(MockSpawner):
 class NeverSpawner(MockSpawner):
    """A spawner that will never start"""
    
+    @default('start_timeout')
    def _start_timeout_default(self):
        return 1
    
@@ -90,6 +93,7 @@ class FormSpawner(MockSpawner):


 class MockPAMAuthenticator(PAMAuthenticator):
+    @default('admin_users')
    def _admin_users_default(self):
        return {'admin'}
    
@@ -109,13 +113,23 @@ class MockHub(JupyterHub):
    """Hub with various mock bits"""

    db_file = None
+    confirm_no_ssl = True
    
+    last_activity_interval = 2
+    
+    @default('subdomain_host')
+    def _subdomain_host_default(self):
+        return os.environ.get('JUPYTERHUB_TEST_SUBDOMAIN_HOST', '')
+    
+    @default('ip')
    def _ip_default(self):
-        return localhost()
+        return '127.0.0.1'
    
+    @default('authenticator_class')
    def _authenticator_class_default(self):
        return MockPAMAuthenticator
    
+    @default('spawner_class')
    def _spawner_class_default(self):
        return MockSpawner
    
@@ -124,7 +138,8 @@ class MockHub(JupyterHub):
    
    def start(self, argv=None):
        self.db_file = NamedTemporaryFile()
-        self.db_url = 'sqlite:///' + self.db_file.name
+        self.pid_file = NamedTemporaryFile(delete=False).name
+        self.db_url = self.db_file.name
        
        evt = threading.Event()
        
@@ -161,13 +176,33 @@ class MockHub(JupyterHub):
        self.db_file.close()
    
    def login_user(self, name):
-        r = requests.post(self.proxy.public_server.url + 'hub/login',
+        base_url = public_url(self)
+        r = requests.post(base_url + 'hub/login',
            data={
                'username': name,
                'password': name,
            },
            allow_redirects=False,
        )
+        r.raise_for_status()
        assert r.cookies
        return r.cookies

+
+def public_host(app):
+    if app.subdomain_host:
+        return app.subdomain_host
+    else:
+        return app.proxy.public_server.host
+
+
+def public_url(app):
+    return public_host(app) + app.proxy.public_server.base_url
+
+
+def user_url(user, app):
+    if app.subdomain_host:
+        host = user.host
+    else:
+        host = public_host(app)
+    return host + user.server.base_url
--- a/jupyterhub/tests/test_api.py
+++ b/jupyterhub/tests/test_api.py
@@ -2,9 +2,8 @@

 import json
 import time
-from datetime import timedelta
 from queue import Queue
-from urllib.parse import urlparse
+from urllib.parse import urlparse, quote

 import requests

@@ -14,6 +13,7 @@ from .. import orm
 from ..user import User
 from ..utils import url_path_join as ujoin
 from . import mocking
+from .mocking import public_url, user_url


 def check_db_locks(func):
@@ -41,7 +41,7 @@ def check_db_locks(func):

 def find_user(db, name):
    return db.query(orm.User).filter(orm.User.name==name).first()
-    
+
 def add_user(db, app=None, **kwargs):
    orm_user = orm.User(**kwargs)
    db.add(orm_user)
@@ -81,17 +81,17 @@ def test_auth_api(app):
    db = app.db
    r = api_request(app, 'authorizations', 'gobbledygook')
    assert r.status_code == 404
-    
+
    # make a new cookie token
    user = db.query(orm.User).first()
    api_token = user.new_api_token()
-    
+
    # check success:
    r = api_request(app, 'authorizations/token', api_token)
    assert r.status_code == 200
    reply = r.json()
    assert reply['name'] == user.name
-    
+
    # check fail
    r = api_request(app, 'authorizations/token', api_token,
        headers={'Authorization': 'no sir'},
@@ -105,7 +105,7 @@ def test_auth_api(app):


 def test_referer_check(app, io_loop):
-    url = app.hub.server.url
+    url = ujoin(public_url(app), app.hub.server.base_url)
    host = urlparse(url).netloc
    user = find_user(app.db, 'admin')
    if user is None:
@@ -115,7 +115,7 @@ def test_referer_check(app, io_loop):
    # stop the admin's server so we don't mess up future tests
    io_loop.run_sync(lambda : app.proxy.delete_user(app_user))
    io_loop.run_sync(app_user.stop)
-    
+
    r = api_request(app, 'users',
        headers={
            'Authorization': '',
@@ -152,7 +152,7 @@ def test_get_users(app):
    db = app.db
    r = api_request(app, 'users')
    assert r.status_code == 200
-    
+
    users = sorted(r.json(), key=lambda d: d['name'])
    for u in users:
        u.pop('last_activity')
@@ -230,21 +230,21 @@ def test_add_multi_user(app):
    reply = r.json()
    r_names = [ user['name'] for user in reply ]
    assert names == r_names
-    
+
    for name in names:
        user = find_user(db, name)
        assert user is not None
        assert user.name == name
        assert not user.admin
-    
+
    # try to create the same users again
    r = api_request(app, 'users', method='post',
        data=json.dumps({'usernames': names}),
    )
    assert r.status_code == 400
-    
+
    names = ['a', 'b', 'ab']
-    
+
    # try to create the same users again
    r = api_request(app, 'users', method='post',
        data=json.dumps({'usernames': names}),
@@ -265,7 +265,7 @@ def test_add_multi_user_admin(app):
    reply = r.json()
    r_names = [ user['name'] for user in reply ]
    assert names == r_names
-    
+
    for name in names:
        user = find_user(db, name)
        assert user is not None
@@ -298,7 +298,7 @@ def test_delete_user(app):
    mal = add_user(db, name='mal')
    r = api_request(app, 'users', 'mal', method='delete')
    assert r.status_code == 204
-    
+

 def test_make_admin(app):
    db = app.db
@@ -321,7 +321,7 @@ def test_make_admin(app):

 def get_app_user(app, name):
    """Get the User object from the main thread
-    
+
    Needed for access to the Spawner.
    No ORM methods should be called on the result.
    """
@@ -350,21 +350,25 @@ def test_spawn(app, io_loop):
    assert not app_user.spawn_pending
    status = io_loop.run_sync(app_user.spawner.poll)
    assert status is None
-    
+
    assert user.server.base_url == '/user/%s' % name
-    r = requests.get(ujoin(app.proxy.public_server.url, user.server.base_url))
+    url = user_url(user, app)
+    print(url)
+    r = requests.get(url)
    assert r.status_code == 200
    assert r.text == user.server.base_url

-    r = requests.get(ujoin(app.proxy.public_server.url, user.server.base_url, 'args'))
+    r = requests.get(ujoin(url, 'args'))
    assert r.status_code == 200
    argv = r.json()
    for expected in ['--user=%s' % name, '--base-url=%s' % user.server.base_url]:
        assert expected in argv
-    
+    if app.subdomain_host:
+        assert '--hub-host=%s' % app.subdomain_host in argv
+
    r = api_request(app, 'users', name, 'server', method='delete')
    assert r.status_code == 204
-    
+
    assert 'pid' not in user.state
    status = io_loop.run_sync(app_user.spawner.poll)
    assert status == 0
@@ -379,18 +383,19 @@ def test_slow_spawn(app, io_loop):
    name = 'zoe'
    user = add_user(db, app=app, name=name)
    r = api_request(app, 'users', name, 'server', method='post')
+    app.tornado_settings['spawner_class'] = mocking.MockSpawner
    r.raise_for_status()
    assert r.status_code == 202
    app_user = get_app_user(app, name)
    assert app_user.spawner is not None
    assert app_user.spawn_pending
    assert not app_user.stop_pending
-    
+
    @gen.coroutine
    def wait_spawn():
        while app_user.spawn_pending:
            yield gen.sleep(0.1)
-    
+
    io_loop.run_sync(wait_spawn)
    assert not app_user.spawn_pending
    status = io_loop.run_sync(app_user.spawner.poll)
@@ -412,13 +417,13 @@ def test_slow_spawn(app, io_loop):
    assert r.status_code == 202
    assert app_user.spawner is not None
    assert app_user.stop_pending
-    
+
    io_loop.run_sync(wait_stop)
    assert not app_user.stop_pending
    assert app_user.spawner is not None
    r = api_request(app, 'users', name, 'server', method='delete')
    assert r.status_code == 400
-    
+

 def test_never_spawn(app, io_loop):
    app.tornado_settings['spawner_class'] = mocking.NeverSpawner
@@ -428,15 +433,16 @@ def test_never_spawn(app, io_loop):
    name = 'badger'
    user = add_user(db, app=app, name=name)
    r = api_request(app, 'users', name, 'server', method='post')
+    app.tornado_settings['spawner_class'] = mocking.MockSpawner
    app_user = get_app_user(app, name)
    assert app_user.spawner is not None
    assert app_user.spawn_pending
-    
+
    @gen.coroutine
    def wait_pending():
        while app_user.spawn_pending:
            yield gen.sleep(0.1)
-    
+
    io_loop.run_sync(wait_pending)
    assert not app_user.spawn_pending
    status = io_loop.run_sync(app_user.spawner.poll)
@@ -450,6 +456,76 @@ def test_get_proxy(app, io_loop):
    assert list(reply.keys()) == ['/']


+def test_cookie(app):
+    db = app.db
+    name = 'patience'
+    user = add_user(db, app=app, name=name)
+    r = api_request(app, 'users', name, 'server', method='post')
+    assert r.status_code == 201
+    assert 'pid' in user.state
+    app_user = get_app_user(app, name)
+
+    cookies = app.login_user(name)
+    # cookie jar gives '"cookie-value"', we want 'cookie-value'
+    cookie = cookies[user.server.cookie_name][1:-1]
+    r = api_request(app, 'authorizations/cookie', user.server.cookie_name, "nothintoseehere")
+    assert r.status_code == 404
+
+    r = api_request(app, 'authorizations/cookie', user.server.cookie_name, quote(cookie, safe=''))
+    r.raise_for_status()
+    reply = r.json()
+    assert reply['name'] == name
+
+    # deprecated cookie in body:
+    r = api_request(app, 'authorizations/cookie', user.server.cookie_name, data=cookie)
+    r.raise_for_status()
+    reply = r.json()
+    assert reply['name'] == name
+
+def test_token(app):
+    name = 'book'
+    user = add_user(app.db, app=app, name=name)
+    token = user.new_api_token()
+    r = api_request(app, 'authorizations/token', token)
+    r.raise_for_status()
+    user_model = r.json()
+    assert user_model['name'] == name
+    r = api_request(app, 'authorizations/token', 'notauthorized')
+    assert r.status_code == 404
+
+def test_get_token(app):
+    name = 'user'
+    user = add_user(app.db, app=app, name=name)
+    r = api_request(app, 'authorizations/token', method='post', data=json.dumps({
+        'username': name,
+        'password': name,
+    }))
+    assert r.status_code == 200
+    data = r.content.decode("utf-8")
+    token = json.loads(data)
+    assert not token['Authentication'] is None
+
+def test_bad_get_token(app):
+    name = 'user'
+    password = 'fake'
+    user = add_user(app.db, app=app, name=name)
+    r = api_request(app, 'authorizations/token', method='post', data=json.dumps({
+        'username': name,
+        'password': password,
+    }))
+    assert r.status_code == 403
+
+def test_options(app):
+    r = api_request(app, 'users', method='options')
+    r.raise_for_status()
+    assert 'Access-Control-Allow-Headers' in r.headers
+
+
+def test_bad_json_body(app):
+    r = api_request(app, 'users', method='post', data='notjson')
+    assert r.status_code == 400
+
+
 def test_shutdown(app):
    r = api_request(app, 'shutdown', method='post', data=json.dumps({
        'servers': True,
--- a/jupyterhub/tests/test_app.py
+++ b/jupyterhub/tests/test_app.py
@@ -1,10 +1,17 @@
 """Test the JupyterHub entry point"""

+import binascii
 import os
 import re
 import sys
-from subprocess import check_output
+from subprocess import check_output, Popen, PIPE
 from tempfile import NamedTemporaryFile, TemporaryDirectory
+from unittest.mock import patch
+
+import pytest
+
+from .mocking import MockHub
+from .. import orm

 def test_help_all():
    out = check_output([sys.executable, '-m', 'jupyterhub', '--help-all']).decode('utf8', 'replace')
@@ -23,10 +30,23 @@ def test_token_app():
 def test_generate_config():
    with NamedTemporaryFile(prefix='jupyterhub_config', suffix='.py') as tf:
        cfg_file = tf.name
-    
-    out = check_output([sys.executable, '-m', 'jupyterhub',
-        '--generate-config', '-f', cfg_file]
-    ).decode('utf8', 'replace')
+    with open(cfg_file, 'w') as f:
+        f.write("c.A = 5")
+    p = Popen([sys.executable, '-m', 'jupyterhub',
+        '--generate-config', '-f', cfg_file],
+        stdout=PIPE, stdin=PIPE)
+    out, _ = p.communicate(b'n')
+    out = out.decode('utf8', 'replace')
+    assert os.path.exists(cfg_file)
+    with open(cfg_file) as f:
+        cfg_text = f.read()
+    assert cfg_text == 'c.A = 5'
+
+    p = Popen([sys.executable, '-m', 'jupyterhub',
+        '--generate-config', '-f', cfg_file],
+        stdout=PIPE, stdin=PIPE)
+    out, _ = p.communicate(b'x\ny')
+    out = out.decode('utf8', 'replace')
    assert os.path.exists(cfg_file)
    with open(cfg_file) as f:
        cfg_text = f.read()
@@ -34,3 +54,89 @@ def test_generate_config():
    assert cfg_file in out
    assert 'Spawner.cmd' in cfg_text
    assert 'Authenticator.whitelist' in cfg_text
+
+
+def test_init_tokens():
+    with TemporaryDirectory() as td:
+        db_file = os.path.join(td, 'jupyterhub.sqlite')
+        tokens = {
+            'super-secret-token': 'alyx',
+            'also-super-secret': 'gordon',
+            'boagasdfasdf': 'chell',
+        }
+        app = MockHub(db_file=db_file, api_tokens=tokens)
+        app.initialize([])
+        db = app.db
+        for token, username in tokens.items():
+            api_token = orm.APIToken.find(db, token)
+            assert api_token is not None
+            user = api_token.user
+            assert user.name == username
+        
+        # simulate second startup, reloading same tokens:
+        app = MockHub(db_file=db_file, api_tokens=tokens)
+        app.initialize([])
+        db = app.db
+        for token, username in tokens.items():
+            api_token = orm.APIToken.find(db, token)
+            assert api_token is not None
+            user = api_token.user
+            assert user.name == username
+        
+        # don't allow failed token insertion to create users:
+        tokens['short'] = 'gman'
+        app = MockHub(db_file=db_file, api_tokens=tokens)
+        # with pytest.raises(ValueError):
+        app.initialize([])
+        assert orm.User.find(app.db, 'gman') is None
+
+
+def test_write_cookie_secret(tmpdir):
+    secret_path = str(tmpdir.join('cookie_secret'))
+    hub = MockHub(cookie_secret_file=secret_path)
+    hub.init_secrets()
+    assert os.path.exists(secret_path)
+    assert os.stat(secret_path).st_mode & 0o600
+    assert not os.stat(secret_path).st_mode & 0o177
+
+
+def test_cookie_secret_permissions(tmpdir):
+    secret_file = tmpdir.join('cookie_secret')
+    secret_path = str(secret_file)
+    secret = os.urandom(1024)
+    secret_file.write(binascii.b2a_base64(secret))
+    hub = MockHub(cookie_secret_file=secret_path)
+
+    # raise with public secret file
+    os.chmod(secret_path, 0o664)
+    with pytest.raises(SystemExit):
+        hub.init_secrets()
+
+    # ok with same file, proper permissions
+    os.chmod(secret_path, 0o660)
+    hub.init_secrets()
+    assert hub.cookie_secret == secret
+
+
+def test_cookie_secret_content(tmpdir):
+    secret_file = tmpdir.join('cookie_secret')
+    secret_file.write('not base 64: uñiço∂e')
+    secret_path = str(secret_file)
+    os.chmod(secret_path, 0o660)
+    hub = MockHub(cookie_secret_file=secret_path)
+    with pytest.raises(SystemExit):
+        hub.init_secrets()
+
+
+def test_cookie_secret_env(tmpdir):
+    hub = MockHub(cookie_secret_file=str(tmpdir.join('cookie_secret')))
+
+    with patch.dict(os.environ, {'JPY_COOKIE_SECRET': 'not hex'}):
+        with pytest.raises(ValueError):
+            hub.init_secrets()
+
+    with patch.dict(os.environ, {'JPY_COOKIE_SECRET': 'abc123'}):
+        hub.init_secrets()
+    assert hub.cookie_secret == binascii.a2b_hex('abc123')
+    assert not os.path.exists(hub.cookie_secret_file)
+
--- a/jupyterhub/tests/test_orm.py
+++ b/jupyterhub/tests/test_orm.py
@@ -20,7 +20,7 @@ def test_server(db):
    assert server.proto == 'http'
    assert isinstance(server.port, int)
    assert isinstance(server.cookie_name, str)
-    assert server.host == 'http://localhost:%i' % server.port
+    assert server.host == 'http://127.0.0.1:%i' % server.port
    assert server.url == server.host + '/'
    assert server.bind_url == 'http://*:%i/' % server.port
    server.ip = '127.0.0.1'
@@ -93,6 +93,16 @@ def test_tokens(db):
    found = orm.APIToken.find(db, 'something else')
    assert found is None

+    secret = 'super-secret-preload-token'
+    token = user.new_api_token(secret)
+    assert token == secret
+    assert len(user.api_tokens) == 3
+
+    # raise ValueError on collision
+    with pytest.raises(ValueError):
+        user.new_api_token(token)
+    assert len(user.api_tokens) == 3
+

 def test_spawn_fails(db, io_loop):
    orm_user = orm.User(name='aeofel')
--- a/jupyterhub/tests/test_pages.py
+++ b/jupyterhub/tests/test_pages.py
@@ -1,6 +1,6 @@
 """Tests for HTML pages"""

-from urllib.parse import urlparse
+from urllib.parse import urlencode, urlparse

 import requests

@@ -8,12 +8,11 @@ from ..utils import url_path_join as ujoin
 from .. import orm

 import mock
-from .mocking import FormSpawner
+from .mocking import FormSpawner, public_url, public_host, user_url
 from .test_api import api_request

-
 def get_page(path, app, **kw):
-    base_url = ujoin(app.proxy.public_server.host, app.hub.server.base_url)
+    base_url = ujoin(public_url(app), app.hub.server.base_url)
    print(base_url)
    return requests.get(ujoin(base_url, path), **kw)

@@ -22,15 +21,17 @@ def test_root_no_auth(app, io_loop):
    routes = io_loop.run_sync(app.proxy.get_routes)
    print(routes)
    print(app.hub.server)
-    r = requests.get(app.proxy.public_server.host)
+    url = public_url(app)
+    print(url)
+    r = requests.get(url)
    r.raise_for_status()
-    assert r.url == ujoin(app.proxy.public_server.host, app.hub.server.base_url, 'login')
+    assert r.url == ujoin(url, app.hub.server.base_url, 'login')

 def test_root_auth(app):
    cookies = app.login_user('river')
-    r = requests.get(app.proxy.public_server.host, cookies=cookies)
+    r = requests.get(public_url(app), cookies=cookies)
    r.raise_for_status()
-    assert r.url == ujoin(app.proxy.public_server.host, '/user/river')
+    assert r.url == user_url(app.users['river'], app)

 def test_home_no_auth(app):
    r = get_page('home', app, allow_redirects=False)
@@ -62,6 +63,7 @@ def test_admin(app):
    r.raise_for_status()
    assert r.url.endswith('/admin')

+
 def test_spawn_redirect(app, io_loop):
    name = 'wash'
    cookies = app.login_user(name)
@@ -100,7 +102,7 @@ def test_spawn_page(app):

 def test_spawn_form(app, io_loop):
    with mock.patch.dict(app.users.settings, {'spawner_class': FormSpawner}):
-        base_url = ujoin(app.proxy.public_server.host, app.hub.server.base_url)
+        base_url = ujoin(public_url(app), app.hub.server.base_url)
        cookies = app.login_user('jones')
        orm_u = orm.User.find(app.db, 'jones')
        u = app.users[orm_u]
@@ -121,7 +123,7 @@ def test_spawn_form(app, io_loop):

 def test_spawn_form_with_file(app, io_loop):
    with mock.patch.dict(app.users.settings, {'spawner_class': FormSpawner}):
-        base_url = ujoin(app.proxy.public_server.host, app.hub.server.base_url)
+        base_url = ujoin(public_url(app), app.hub.server.base_url)
        cookies = app.login_user('jones')
        orm_u = orm.User.find(app.db, 'jones')
        u = app.users[orm_u]
@@ -147,3 +149,98 @@ def test_spawn_form_with_file(app, io_loop):
                      'content_type': 'application/unknown'},
        }

+
+def test_user_redirect(app):
+    name = 'wash'
+    cookies = app.login_user(name)
+
+    r = get_page('/user/baduser', app, cookies=cookies)
+    r.raise_for_status()
+    print(urlparse(r.url))
+    path = urlparse(r.url).path
+    assert path == '/user/%s' % name
+
+    r = get_page('/user/baduser/test.ipynb', app, cookies=cookies)
+    r.raise_for_status()
+    print(urlparse(r.url))
+    path = urlparse(r.url).path
+    assert path == '/user/%s/test.ipynb' % name
+
+    r = get_page('/user/baduser/test.ipynb', app)
+    r.raise_for_status()
+    print(urlparse(r.url))
+    path = urlparse(r.url).path
+    assert path == '/hub/login'
+    query = urlparse(r.url).query
+    assert query == urlencode({'next': '/hub/user/baduser/test.ipynb'})
+
+
+def test_login_fail(app):
+    name = 'wash'
+    base_url = public_url(app)
+    r = requests.post(base_url + 'hub/login',
+        data={
+            'username': name,
+            'password': 'wrong',
+        },
+        allow_redirects=False,
+    )
+    assert not r.cookies
+
+
+def test_login_redirect(app, io_loop):
+    cookies = app.login_user('river')
+    user = app.users['river']
+    # no next_url, server running
+    io_loop.run_sync(user.spawn)
+    r = get_page('login', app, cookies=cookies, allow_redirects=False)
+    r.raise_for_status()
+    assert r.status_code == 302
+    assert '/user/river' in r.headers['Location']
+    
+    # no next_url, server not running
+    io_loop.run_sync(user.stop)
+    r = get_page('login', app, cookies=cookies, allow_redirects=False)
+    r.raise_for_status()
+    assert r.status_code == 302
+    assert '/hub/' in r.headers['Location']
+    
+    # next URL given, use it
+    r = get_page('login?next=/hub/admin', app, cookies=cookies, allow_redirects=False)
+    r.raise_for_status()
+    assert r.status_code == 302
+    assert r.headers['Location'].endswith('/hub/admin')
+
+
+def test_logout(app):
+    name = 'wash'
+    cookies = app.login_user(name)
+    r = requests.get(public_host(app) + app.tornado_settings['logout_url'], cookies=cookies)
+    r.raise_for_status()
+    login_url = public_host(app) + app.tornado_settings['login_url']
+    assert r.url == login_url
+    assert r.cookies == {}
+
+
+def test_login_no_whitelist_adds_user(app):
+    auth = app.authenticator
+    mock_add_user = mock.Mock()
+    with mock.patch.object(auth, 'add_user', mock_add_user):
+        cookies = app.login_user('jubal')
+
+    user = app.users['jubal']
+    assert mock_add_user.mock_calls == [mock.call(user)]
+
+
+def test_static_files(app):
+    base_url = ujoin(public_url(app), app.hub.server.base_url)
+    print(base_url)
+    r = requests.get(ujoin(base_url, 'logo'))
+    r.raise_for_status()
+    assert r.headers['content-type'] == 'image/png'
+    r = requests.get(ujoin(base_url, 'static', 'images', 'jupyter.png'))
+    r.raise_for_status()
+    assert r.headers['content-type'] == 'image/png'
+    r = requests.get(ujoin(base_url, 'static', 'css', 'style.min.css'))
+    r.raise_for_status()
+    assert r.headers['content-type'] == 'text/css'
--- a/jupyterhub/tests/test_proxy.py
+++ b/jupyterhub/tests/test_proxy.py
@@ -4,6 +4,7 @@ import json
 import os
 from queue import Queue
 from subprocess import Popen
+from urllib.parse import urlparse

 from .. import orm
 from .mocking import MockHub
@@ -34,6 +35,8 @@ def test_external_proxy(request, io_loop):
        '--api-port', str(proxy_port),
        '--default-target', 'http://%s:%i' % (app.hub_ip, app.hub_port),
    ]
+    if app.subdomain_host:
+        cmd.append('--host-routing')
    proxy = Popen(cmd, env=env)
    def _cleanup_proxy():
        if proxy.poll() is None:
@@ -60,7 +63,11 @@ def test_external_proxy(request, io_loop):
    r.raise_for_status()
    
    routes = io_loop.run_sync(app.proxy.get_routes)
-    assert sorted(routes.keys()) == ['/', '/user/river']
+    user_path = '/user/river'
+    if app.subdomain_host:
+        domain = urlparse(app.subdomain_host).hostname
+        user_path = '/%s.%s' % (name, domain) + user_path
+    assert sorted(routes.keys()) == ['/', user_path]
    
    # teardown the proxy and start a new one in the same place
    proxy.terminate()
@@ -76,7 +83,7 @@ def test_external_proxy(request, io_loop):
    
    # check that the routes are correct
    routes = io_loop.run_sync(app.proxy.get_routes)
-    assert sorted(routes.keys()) == ['/', '/user/river']
+    assert sorted(routes.keys()) == ['/', user_path]
    
    # teardown the proxy again, and start a new one with different auth and port
    proxy.terminate()
@@ -90,13 +97,16 @@ def test_external_proxy(request, io_loop):
        '--api-port', str(proxy_port),
        '--default-target', 'http://%s:%i' % (app.hub_ip, app.hub_port),
    ]
-    
+    if app.subdomain_host:
+        cmd.append('--host-routing')
    proxy = Popen(cmd, env=env)
    wait_for_proxy()
    
    # tell the hub where the new proxy is
    r = api_request(app, 'proxy', method='patch', data=json.dumps({
        'port': proxy_port,
+        'protocol': 'http',
+        'ip': app.ip,
        'auth_token': new_auth_token,
    }))
    r.raise_for_status()
@@ -113,7 +123,8 @@ def test_external_proxy(request, io_loop):
    
    # check that the routes are correct
    routes = io_loop.run_sync(app.proxy.get_routes)
-    assert sorted(routes.keys()) == ['/', '/user/river']
+    assert sorted(routes.keys()) == ['/', user_path]
+

 def test_check_routes(app, io_loop):
    proxy = app.proxy
@@ -123,13 +134,24 @@ def test_check_routes(app, io_loop):
    r.raise_for_status()
    zoe = orm.User.find(app.db, 'zoe')
    assert zoe is not None
+    zoe = app.users[zoe]
    before = sorted(io_loop.run_sync(app.proxy.get_routes))
-    assert '/user/zoe' in before
-    io_loop.run_sync(app.proxy.check_routes)
+    assert zoe.proxy_path in before
+    io_loop.run_sync(lambda : app.proxy.check_routes(app.users))
    io_loop.run_sync(lambda : proxy.delete_user(zoe))
    during = sorted(io_loop.run_sync(app.proxy.get_routes))
-    assert '/user/zoe' not in during
-    io_loop.run_sync(app.proxy.check_routes)
+    assert zoe.proxy_path not in during
+    io_loop.run_sync(lambda : app.proxy.check_routes(app.users))
    after = sorted(io_loop.run_sync(app.proxy.get_routes))
-    assert '/user/zoe' in after
+    assert zoe.proxy_path in after
    assert before == after
+
+
+def test_patch_proxy_bad_req(app):
+    r = api_request(app, 'proxy', method='patch')
+    assert r.status_code == 400
+    r = api_request(app, 'proxy', method='patch', data='notjson')
+    assert r.status_code == 400
+    r = api_request(app, 'proxy', method='patch', data=json.dumps([]))
+    assert r.status_code == 400
+    
--- a/jupyterhub/tests/test_spawner.py
+++ b/jupyterhub/tests/test_spawner.py
@@ -4,9 +4,14 @@
 # Distributed under the terms of the Modified BSD License.

 import logging
+import os
 import signal
 import sys
+import tempfile
 import time
+from unittest import mock
+
+from tornado import gen

 from .. import spawner as spawnermod
 from ..spawner import LocalProcessSpawner
@@ -39,13 +44,14 @@ def new_spawner(db, **kwargs):
    kwargs.setdefault('INTERRUPT_TIMEOUT', 1)
    kwargs.setdefault('TERM_TIMEOUT', 1)
    kwargs.setdefault('KILL_TIMEOUT', 1)
+    kwargs.setdefault('poll_interval', 1)
    return LocalProcessSpawner(db=db, **kwargs)


 def test_spawner(db, io_loop):
    spawner = new_spawner(db)
    io_loop.run_sync(spawner.start)
-    assert spawner.user.server.ip == 'localhost'
+    assert spawner.user.server.ip == '127.0.0.1'
    
    # wait for the process to get to the while True: loop
    time.sleep(1)
@@ -59,7 +65,7 @@ def test_spawner(db, io_loop):
 def test_single_user_spawner(db, io_loop):
    spawner = new_spawner(db, cmd=['jupyterhub-singleuser'])
    io_loop.run_sync(spawner.start)
-    assert spawner.user.server.ip == 'localhost'
+    assert spawner.user.server.ip == '127.0.0.1'
    # wait for http server to come up,
    # checking for early termination every 1s
    def wait():
@@ -110,3 +116,53 @@ def test_stop_spawner_stop_now(db, io_loop):
    status = io_loop.run_sync(spawner.poll)
    assert status == -signal.SIGTERM

+def test_spawner_poll(db, io_loop):
+    first_spawner = new_spawner(db)
+    user = first_spawner.user
+    io_loop.run_sync(first_spawner.start)
+    proc = first_spawner.proc
+    status = io_loop.run_sync(first_spawner.poll)
+    assert status is None
+    user.state = first_spawner.get_state()
+    assert 'pid' in user.state
+    
+    # create a new Spawner, loading from state of previous
+    spawner = new_spawner(db, user=first_spawner.user)
+    spawner.start_polling()
+    
+    # wait for the process to get to the while True: loop
+    io_loop.run_sync(lambda : gen.sleep(1))
+    status = io_loop.run_sync(spawner.poll)
+    assert status is None
+    
+    # kill the process
+    proc.terminate()
+    for i in range(10):
+        if proc.poll() is None:
+            time.sleep(1)
+        else:
+            break
+    assert proc.poll() is not None
+
+    io_loop.run_sync(lambda : gen.sleep(2))
+    status = io_loop.run_sync(spawner.poll)
+    assert status is not None
+
+def test_setcwd():
+    cwd = os.getcwd()
+    with tempfile.TemporaryDirectory() as td:
+        td = os.path.realpath(os.path.abspath(td))
+        spawnermod._try_setcwd(td)
+        assert os.path.samefile(os.getcwd(), td)
+    os.chdir(cwd)
+    chdir = os.chdir
+    temp_root = os.path.realpath(os.path.abspath(tempfile.gettempdir()))
+    def raiser(path):
+        path = os.path.realpath(os.path.abspath(path))
+        if not path.startswith(temp_root):
+            raise OSError(path)
+        chdir(path)
+    with mock.patch('os.chdir', raiser):
+        spawnermod._try_setcwd(cwd)
+        assert os.getcwd().startswith(temp_root)
+    os.chdir(cwd)
--- a/jupyterhub/traitlets.py
+++ b/jupyterhub/traitlets.py
@@ -21,7 +21,7 @@ class Command(List):
        kwargs.setdefault('minlen', 1)
        if isinstance(default_value, str):
            default_value = [default_value]
-        super().__init__(Unicode, default_value, **kwargs)
+        super().__init__(Unicode(), default_value, **kwargs)
        
    def validate(self, obj, value):
        if isinstance(value, str):
--- a/jupyterhub/user.py
+++ b/jupyterhub/user.py
@@ -2,7 +2,7 @@
 # Distributed under the terms of the Modified BSD License.

 from datetime import datetime, timedelta
-from urllib.parse import quote
+from urllib.parse import quote, urlparse

 from tornado import gen
 from tornado.log import app_log
@@ -12,7 +12,7 @@ from sqlalchemy import inspect
 from .utils import url_path_join

 from . import orm
-from traitlets import HasTraits, Any, Dict
+from traitlets import HasTraits, Any, Dict, observe, default
 from .spawner import LocalProcessSpawner


@@ -38,6 +38,12 @@ class UserDict(dict):
    def __getitem__(self, key):
        if isinstance(key, User):
            key = key.id
+        elif isinstance(key, str):
+            orm_user = self.db.query(orm.User).filter(orm.User.name==key).first()
+            if orm_user is None:
+                raise KeyError("No such user: %s" % key)
+            else:
+                key = orm_user
        if isinstance(key, orm.User):
            # users[orm_user] returns User(orm_user)
            orm_user = key
@@ -69,22 +75,24 @@ class UserDict(dict):

 class User(HasTraits):
    
+    @default('log')
    def _log_default(self):
        return app_log
    
    settings = Dict()
    
    db = Any(allow_none=True)
+    @default('db')
    def _db_default(self):
        if self.orm_user:
            return inspect(self.orm_user).session
-    
-    def _db_changed(self, name, old, new):
+    @observe('db')
+    def _db_changed(self, change):
        """Changing db session reacquires ORM User object"""
        # db session changed, re-get orm User
        if self.orm_user:
            id = self.orm_user.id
-            self.orm_user = new.query(orm.User).filter(orm.User.id==id).first()
+            self.orm_user = change['new'].query(orm.User).filter(orm.User.id==id).first()
        self.spawner.db = self.db
    
    orm_user = None
@@ -139,6 +147,8 @@ class User(HasTraits):
    @property
    def running(self):
        """property for whether a user has a running server"""
+        if self.spawn_pending or self.stop_pending:
+            return False # server is not running if spawn or stop is still pending
        if self.server is None:
            return False
        return True
@@ -148,6 +158,41 @@ class User(HasTraits):
        """My name, escaped for use in URLs, cookies, etc."""
        return quote(self.name, safe='@')
    
+    @property
+    def proxy_path(self):
+        if self.settings.get('subdomain_host'):
+            return url_path_join('/' + self.domain, self.server.base_url)
+        else:
+            return self.server.base_url
+    
+    @property
+    def domain(self):
+        """Get the domain for my server."""
+        # FIXME: escaped_name probably isn't escaped enough in general for a domain fragment
+        return self.escaped_name + '.' + self.settings['domain']
+    
+    @property
+    def host(self):
+        """Get the *host* for my server (domain[:port])"""
+        # FIXME: escaped_name probably isn't escaped enough in general for a domain fragment
+        parsed = urlparse(self.settings['subdomain_host'])
+        h = '%s://%s.%s' % (parsed.scheme, self.escaped_name, parsed.netloc)
+        return h
+    
+    @property
+    def url(self):
+        """My URL
+        
+        Full name.domain/path if using subdomains, otherwise just my /base/url
+        """
+        if self.settings.get('subdomain_host'):
+            return '{host}{path}'.format(
+                host=self.host,
+                path=self.base_url,
+            )
+        else:
+            return self.base_url
+    
    @gen.coroutine
    def spawn(self, options=None):
        """Start the user's spawner"""
@@ -183,7 +228,7 @@ class User(HasTraits):
            yield gen.with_timeout(timedelta(seconds=spawner.start_timeout), f)
        except Exception as e:
            if isinstance(e, gen.TimeoutError):
-                self.log.warn("{user}'s server failed to start in {s} seconds, giving up".format(
+                self.log.warning("{user}'s server failed to start in {s} seconds, giving up".format(
                    user=self.name, s=spawner.start_timeout,
                ))
                e.reason = 'timeout'
@@ -206,11 +251,12 @@ class User(HasTraits):
        self.state = spawner.get_state()
        self.last_activity = datetime.utcnow()
        db.commit()
+        self.spawn_pending = False
        try:
            yield self.server.wait_up(http=True, timeout=spawner.http_timeout)
        except Exception as e:
            if isinstance(e, TimeoutError):
-                self.log.warn(
+                self.log.warning(
                    "{user}'s server never showed up at {url} "
                    "after {http_timeout} seconds. Giving up".format(
                        user=self.name,
@@ -232,7 +278,6 @@ class User(HasTraits):
                ), exc_info=True)
            # raise original TimeoutError
            raise e
-        self.spawn_pending = False
        return self

    @gen.coroutine
--- a/jupyterhub/utils.py
+++ b/jupyterhub/utils.py
@@ -30,22 +30,32 @@ def random_port():
 ISO8601_ms = '%Y-%m-%dT%H:%M:%S.%fZ'
 ISO8601_s = '%Y-%m-%dT%H:%M:%SZ'

+def can_connect(ip, port):
+    """Check if we can connect to an ip:port
+    
+    return True if we can connect, False otherwise.
+    """
+    try:
+        socket.create_connection((ip, port))
+    except socket.error as e:
+        if e.errno not in {errno.ECONNREFUSED, errno.ETIMEDOUT}:
+            app_log.error("Unexpected error connecting to %s:%i %s",
+                ip, port, e
+            )
+        return False
+    else:
+        return True
+
@gen.coroutine
 def wait_for_server(ip, port, timeout=10):
    """wait for any server to show up at ip:port"""
    loop = ioloop.IOLoop.current()
    tic = loop.time()
    while loop.time() - tic < timeout:
-        try:
-            socket.create_connection((ip, port))
-        except socket.error as e:
-            if e.errno != errno.ECONNREFUSED:
-                app_log.error("Unexpected error waiting for %s:%i %s",
-                    ip, port, e
-                )
-            yield gen.sleep(0.1)
-        else:
+        if can_connect(ip, port):
            return
+        else:
+            yield gen.sleep(0.1)
    raise TimeoutError("Server at {ip}:{port} didn't respond in {timeout} seconds".format(
        **locals()
    ))
@@ -68,14 +78,14 @@ def wait_for_http_server(url, timeout=10):
                if e.code != 599:
                    # we expect 599 for no connection,
                    # but 502 or other proxy error is conceivable
-                    app_log.warn("Server at %s responded with error: %s", url, e.code)
+                    app_log.warning("Server at %s responded with error: %s", url, e.code)
                yield gen.sleep(0.1)
            else:
                app_log.debug("Server at %s responded with %s", url, e.code)
                return
        except (OSError, socket.error) as e:
            if e.errno not in {errno.ECONNABORTED, errno.ECONNREFUSED, errno.ECONNRESET}:
-                app_log.warn("Failed to connect to %s (%s)", url, e)
+                app_log.warning("Failed to connect to %s (%s)", url, e)
            yield gen.sleep(0.1)
        else:
            return
@@ -195,35 +205,3 @@ def url_path_join(*pieces):

    return result

-def localhost():
-    """Return localhost or 127.0.0.1"""
-    if hasattr(localhost, '_localhost'):
-        return localhost._localhost
-    binder = connector = None
-    try:
-        binder = socket.socket()
-        binder.bind(('localhost', 0))
-        binder.listen(1)
-        port = binder.getsockname()[1]
-        def accept():
-            try:
-                conn, addr = binder.accept()
-            except ConnectionAbortedError:
-                pass
-            else:
-                conn.close()
-        t = Thread(target=accept)
-        t.start()
-        connector = socket.create_connection(('localhost', port), timeout=10)
-        t.join(timeout=10)
-    except (socket.error, socket.gaierror) as e:
-        warnings.warn("localhost doesn't appear to work, using 127.0.0.1\n%s" % e, RuntimeWarning)
-        localhost._localhost = '127.0.0.1'
-    else:
-        localhost._localhost = 'localhost'
-    finally:
-        if binder:
-            binder.close()
-        if connector:
-            connector.close()
-    return localhost._localhost
--- a/jupyterhub/version.py
+++ b/jupyterhub/version.py
@@ -5,8 +5,9 @@

 version_info = (
    0,
-    4,
+    6,
    1,
+    # 'dev',
 )

 __version__ = '.'.join(map(str, version_info))
--- a/onbuild/Dockerfile
+++ b/onbuild/Dockerfile
@@ -0,0 +1,11 @@
+# JupyterHub Dockerfile that loads your jupyterhub_config.py
+#
+# Adds ONBUILD step to jupyter/jupyterhub to load your juptyerhub_config.py into the image
+#
+# Derivative images must have jupyterhub_config.py next to the Dockerfile.
+
+FROM jupyterhub/jupyterhub
+
+ONBUILD ADD jupyterhub_config.py /srv/jupyterhub/jupyterhub_config.py
+
+CMD ["jupyterhub", "-f", "/srv/jupyterhub/jupyterhub_config.py"]
--- a/onbuild/README.md
+++ b/onbuild/README.md
@@ -0,0 +1,10 @@
+# JupyterHub onbuild image
+
+If you base a Dockerfile on this image:
+
+    FROM juptyerhub/jupyterhub-onbuild:0.6
+    ...
+
+then your `jupyterhub_config.py` adjacent to your Dockerfile will be loaded into the image and used by JupyterHub.
+
+This is how the `jupyter/jupyterhub` docker image behaved prior to 0.6.
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-traitlets>=4
+traitlets>=4.1
 tornado>=4.1
 jinja2
 pamela
--- a/scripts/jupyterhub-singleuser
+++ b/scripts/jupyterhub-singleuser
@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python
 """Extend regular notebook server to be aware of multiuser things."""

 # Copyright (c) Jupyter Development Team.
@@ -17,34 +17,27 @@ from jinja2 import ChoiceLoader, FunctionLoader
 from tornado import ioloop
 from tornado.web import HTTPError

+try:
+    import notebook
+except ImportError:
+    raise ImportError("JupyterHub single-user server requires notebook >= 4.0")

-from IPython.utils.traitlets import (
+from traitlets import (
+    Bool,
    Integer,
    Unicode,
    CUnicode,
 )

-try:
-    import notebook
-    # 4.x
-except ImportError:
-    from IPython.html.notebookapp import NotebookApp, aliases as notebook_aliases
-    from IPython.html.auth.login import LoginHandler
-    from IPython.html.auth.logout import LogoutHandler
+from notebook.notebookapp import (
+    NotebookApp,
+    aliases as notebook_aliases,
+    flags as notebook_flags,
+)
+from notebook.auth.login import LoginHandler
+from notebook.auth.logout import LogoutHandler

-    from IPython.html.utils import url_path_join
-
-    from distutils.version import LooseVersion as V
-
-    import IPython
-    if V(IPython.__version__) < V('3.0'):
-        raise ImportError("JupyterHub Requires IPython >= 3.0, found %s" % IPython.__version__)
-else:
-    from notebook.notebookapp import NotebookApp, aliases as notebook_aliases
-    from notebook.auth.login import LoginHandler
-    from notebook.auth.logout import LogoutHandler
-
-    from notebook.utils import url_path_join
+from notebook.utils import url_path_join


 # Define two methods to attach to AuthenticatedHandler,
@@ -54,7 +47,7 @@ class JupyterHubLoginHandler(LoginHandler):
    @staticmethod
    def login_available(settings):
        return True
-    
+
    @staticmethod
    def verify_token(self, cookie_name, encrypted_cookie):
        """method for token verification"""
@@ -62,7 +55,7 @@ class JupyterHubLoginHandler(LoginHandler):
        if encrypted_cookie in cookie_cache:
            # we've seen this token before, don't ask upstream again
            return cookie_cache[encrypted_cookie]
-    
+
        hub_api_url = self.settings['hub_api_url']
        hub_api_key = self.settings['hub_api_key']
        r = requests.get(url_path_join(
@@ -85,7 +78,7 @@ class JupyterHubLoginHandler(LoginHandler):
            data = r.json()
        cookie_cache[encrypted_cookie] = data
        return data
-    
+
    @staticmethod
    def get_user(self):
        """alternative get_current_user to query the central server"""
@@ -94,7 +87,7 @@ class JupyterHubLoginHandler(LoginHandler):
        # since this may be called again when trying to render the error page
        if hasattr(self, '_cached_user'):
            return self._cached_user
-        
+
        self._cached_user = None
        my_user = self.settings['user']
        encrypted_cookie = self.get_cookie(self.cookie_name)
@@ -116,7 +109,9 @@ class JupyterHubLoginHandler(LoginHandler):

 class JupyterHubLogoutHandler(LogoutHandler):
    def get(self):
-        self.redirect(url_path_join(self.settings['hub_prefix'], 'logout'))
+        self.redirect(
+            self.settings['hub_host'] +
+            url_path_join(self.settings['hub_prefix'], 'logout'))


 # register new hub related command-line aliases
@@ -125,9 +120,18 @@ aliases.update({
    'user' : 'SingleUserNotebookApp.user',
    'cookie-name': 'SingleUserNotebookApp.cookie_name',
    'hub-prefix': 'SingleUserNotebookApp.hub_prefix',
+    'hub-host': 'SingleUserNotebookApp.hub_host',
    'hub-api-url': 'SingleUserNotebookApp.hub_api_url',
    'base-url': 'SingleUserNotebookApp.base_url',
 })
+flags = dict(notebook_flags)
+flags.update({
+    'disable-user-config': ({
+        'SingleUserNotebookApp': {
+            'disable_user_config': True
+        }
+    }, "Disable user-controlled configuration of the notebook server.")
+})

 page_template = """
 {% extends "templates/page.html" %}
@@ -141,8 +145,21 @@ page_template = """
 >
 Control Panel</a>
 {% endblock %}
+{% block logo %}
+<img src='{{logo_url}}' alt='Jupyter Notebook'/>
+{% endblock logo %}
 """

+def _exclude_home(path_list):
+    """Filter out any entries in a path list that are in my home directory.
+
+    Used to disable per-user configuration.
+    """
+    home = os.path.expanduser('~')
+    for p in path_list:
+        if not p.startswith(home):
+            yield p
+
 class SingleUserNotebookApp(NotebookApp):
    """A Subclass of the regular NotebookApp that is aware of the parent multiuser context."""
    user = CUnicode(config=True)
@@ -150,12 +167,23 @@ class SingleUserNotebookApp(NotebookApp):
        self.log.name = new
    cookie_name = Unicode(config=True)
    hub_prefix = Unicode(config=True)
+    hub_host = Unicode(config=True)
    hub_api_url = Unicode(config=True)
    aliases = aliases
+    flags = flags
    open_browser = False
    trust_xheaders = True
    login_handler_class = JupyterHubLoginHandler
    logout_handler_class = JupyterHubLogoutHandler
+    port_retries = 0 # disable port-retries, since the Spawner will tell us what port to use
+
+    disable_user_config = Bool(False, config=True,
+        help="""Disable user configuration of single-user server.
+
+        Prevents user-writable files that normally configure the single-user server
+        from being loaded, ensuring admins have full control of configuration.
+        """
+    )

    cookie_cache_lifetime = Integer(
        config=True,
@@ -182,7 +210,37 @@ class SingleUserNotebookApp(NotebookApp):
    def _clear_cookie_cache(self):
        self.log.debug("Clearing cookie cache")
        self.tornado_settings['cookie_cache'].clear()
-    
+
+    def migrate_config(self):
+        if self.disable_user_config:
+            # disable config-migration when user config is disabled
+            return
+        else:
+            super(SingleUserNotebookApp, self).migrate_config()
+
+    @property
+    def config_file_paths(self):
+        path = super(SingleUserNotebookApp, self).config_file_paths
+
+        if self.disable_user_config:
+            # filter out user-writable config dirs if user config is disabled
+            path = list(_exclude_home(path))
+        return path
+
+    @property
+    def nbextensions_path(self):
+        path = super(SingleUserNotebookApp, self).nbextensions_path
+
+        if self.disable_user_config:
+            path = list(_exclude_home(path))
+        return path
+
+    def _static_custom_path_default(self):
+        path = super(SingleUserNotebookApp, self)._static_custom_path_default()
+        if self.disable_user_config:
+            path = list(_exclude_home(path))
+        return path
+
    def start(self):
        # Start a PeriodicCallback to clear cached cookies.  This forces us to
        # revalidate our user with the Hub at least every
@@ -193,7 +251,7 @@ class SingleUserNotebookApp(NotebookApp):
                self.cookie_cache_lifetime * 1e3,
            ).start()
        super(SingleUserNotebookApp, self).start()
-    
+
    def init_webapp(self):
        # load the hub related settings into the tornado settings dict
        env = os.environ
@@ -202,26 +260,28 @@ class SingleUserNotebookApp(NotebookApp):
        s['user'] = self.user
        s['hub_api_key'] = env.pop('JPY_API_TOKEN')
        s['hub_prefix'] = self.hub_prefix
+        s['hub_host'] = self.hub_host
        s['cookie_name'] = self.cookie_name
-        s['login_url'] = self.hub_prefix
+        s['login_url'] = self.hub_host + self.hub_prefix
        s['hub_api_url'] = self.hub_api_url
-        s['csp_report_uri'] = url_path_join(self.hub_prefix, 'security/csp-report')
-        
+        s['csp_report_uri'] = self.hub_host + url_path_join(self.hub_prefix, 'security/csp-report')
        super(SingleUserNotebookApp, self).init_webapp()
        self.patch_templates()
-    
+
    def patch_templates(self):
        """Patch page templates to add Hub-related buttons"""
+
+        self.jinja_template_vars['logo_url'] = self.hub_host + url_path_join(self.hub_prefix, 'logo')
        env = self.web_app.settings['jinja2_env']
-        
+
        env.globals['hub_control_panel_url'] = \
-            url_path_join(self.hub_prefix, 'home')
-        
+            self.hub_host + url_path_join(self.hub_prefix, 'home')
+
        # patch jinja env loading to modify page template
        def get_page(name):
            if name == 'page.html':
                return page_template
-        
+
        orig_loader = env.loader
        env.loader = ChoiceLoader([
            FunctionLoader(get_page),
--- a/setup.py
+++ b/setup.py
@@ -166,7 +166,7 @@ class Bower(BaseCommand):
        
        if self.should_run_npm():
            print("installing build dependencies with npm")
-            check_call(['npm', 'install'], cwd=here)
+            check_call(['npm', 'install', '--progress=false'], cwd=here)
            os.utime(self.node_modules)
        
        env = os.environ.copy()
--- a/share/jupyter/hub/static/js/admin.js
+++ b/share/jupyter/hub/static/js/admin.js
@@ -152,15 +152,15 @@ require(["jquery", "bootstrap", "moment", "jhapi", "utils"], function ($, bs, mo
        });
    });
    
-    $("#add-user").click(function () {
-        var dialog = $("#add-user-dialog");
+    $("#add-users").click(function () {
+        var dialog = $("#add-users-dialog");
        dialog.find(".username-input").val('');
        dialog.find(".admin-checkbox").prop("checked", false);
        dialog.modal();
    });

-    $("#add-user-dialog").find(".save-button").click(function () {
-        var dialog = $("#add-user-dialog");
+    $("#add-users-dialog").find(".save-button").click(function () {
+        var dialog = $("#add-users-dialog");
        var lines = dialog.find(".username-input").val().split('\n');
        var admin = dialog.find(".admin-checkbox").prop("checked");
        var usernames = [];
@@ -178,6 +178,15 @@ require(["jquery", "bootstrap", "moment", "jhapi", "utils"], function ($, bs, mo
        });
    });

+    $("#stop-all-servers").click(function () {
+        $("#stop-all-servers-dialog").modal();
+    });
+
+    $("#stop-all-servers-dialog").find(".stop-all-button").click(function () {
+        // stop all clicks all the active stop buttons
+        $('.stop-server').not('.hidden').click();
+    });
+
    $("#shutdown-hub").click(function () {
        var dialog = $("#shutdown-hub-dialog");
        dialog.find("input[type=checkbox]").prop("checked", true);
--- a/share/jupyter/hub/templates/admin.html
+++ b/share/jupyter/hub/templates/admin.html
@@ -32,8 +32,9 @@
    <tbody>
      <tr class="user-row add-user-row">
        <td colspan="12">
-          <a id="add-user" class="col-xs-5 btn btn-default">Add User</a>
-          <a id="shutdown-hub" class="col-xs-5 col-xs-offset-2 btn btn-danger">Shutdown Hub</a>
+          <a id="add-users" class="col-xs-2 btn btn-default">Add Users</a>
+          <a id="stop-all-servers" class="col-xs-2 col-xs-offset-5 btn btn-danger">Stop All</a>
+          <a id="shutdown-hub" class="col-xs-2 col-xs-offset-1 btn btn-danger">Shutdown Hub</a>
        </td>
      </tr>
  {% for u in users %}
@@ -71,6 +72,10 @@
  This operation cannot be undone.
 {% endcall %}

+{% call modal('Stop All Servers', btn_label='Stop All', btn_class='btn-danger stop-all-button') %}
+  Are you sure you want to stop all your users' servers? Kernels will be shutdown and unsaved data may be lost.
+{% endcall %}
+
 {% call modal('Shutdown Hub', btn_label='Shutdown', btn_class='btn-danger shutdown-button') %}
  Are you sure you want to shutdown the Hub?
  You can choose to leave the proxy and/or single-user servers running by unchecking the boxes below:
@@ -108,7 +113,7 @@

 {{ user_modal('Edit User') }}

-{{ user_modal('Add User', multi=True) }}
+{{ user_modal('Add Users', multi=True) }}

 {% endblock %}

--- a/share/jupyter/hub/templates/error.html
+++ b/share/jupyter/hub/templates/error.html
@@ -17,6 +17,11 @@
    {{message}}
  </p>
  {% endif %}
+  {% if message_html %}
+  <p>
+    {{message_html | safe}}
+  </p>
+  {% endif %}
  {% endblock error_detail %}
 </div>

--- a/share/jupyter/hub/templates/home.html
+++ b/share/jupyter/hub/templates/home.html
@@ -10,7 +10,7 @@
      {% endif %}
      <a id="start" class="btn btn-lg btn-success"
      {% if user.running %}
-        href="{{base_url}}user/{{user.name}}/"
+        href="{{ user.url }}"
      {% else %}
        href="{{base_url}}spawn"
      {% endif %}
--- a/share/jupyter/hub/templates/page.html
+++ b/share/jupyter/hub/templates/page.html
@@ -82,7 +82,7 @@

 <div id="header" class="navbar navbar-static-top">
  <div class="container">
-  <span id="jupyterhub-logo" class="pull-left"><a href="{{base_url}}"><img src='{{static_url("images/jupyter.png") }}' alt='JupyterHub' class='jpy-logo' title='Home'/></a></span>
+  <span id="jupyterhub-logo" class="pull-left"><a href="{{logo_url or base_url}}"><img src='{{base_url}}logo' alt='JupyterHub' class='jpy-logo' title='Home'/></a></span>

  {% block login_widget %}

--- a/tools/tasks.py
+++ b/tools/tasks.py
@@ -133,6 +133,7 @@ def untag(vs, push=False):
    v2 = parse_vs(vs)
    v2.append('dev')
    v2[1] += 1
+    v2[2] = 0
    vs2 = unparse_vs(v2)
    patch_version(vs2, repo_root)
    with cd(repo_root):