Technical Reference

Authenticators

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Authenticators

The Authenticator is the mechanism for authorizing users to use the Hub and single user notebook servers.

The default PAM Authenticator

JupyterHub ships only with the default PAM-based Authenticator, for logging in with local user accounts via a username and password.

The OAuthenticator

Some login mechanisms, such as OAuth, don't map onto username and password authentication, and instead use tokens. When using these mechanisms, you can override the login handlers.

You can see an example implementation of an Authenticator that uses GitHub OAuth at OAuthenticator.

JupyterHub's OAuthenticator currently supports the following popular services:

  • Auth0
  • Bitbucket
  • CILogon
  • GitHub
  • GitLab
  • Globus
  • Google
  • MediaWiki
  • Okpy
  • OpenShift

A generic implementation, which you can use for OAuth authentication with any provider, is also available.

Additional Authenticators

  • ldapauthenticator for LDAP
  • tmpauthenticator for temporary accounts

Technical Overview of Authentication

How the Base Authenticator works

The base authenticator uses simple username and password authentication.

The base Authenticator has one central method:

Authenticator.authenticate method

Authenticator.authenticate(handler, data)

This method is passed the Tornado RequestHandler and the POST data from JupyterHub's login form. Unless the login form has been customized, data will have two keys:

  • username
  • password

The authenticate method's job is simple:

  • return the username (non-empty str) of the authenticated user if authentication is successful
  • return None otherwise

Writing an Authenticator that looks up passwords in a dictionary requires only overriding this one method:

from tornado import gen
from IPython.utils.traitlets import Dict
from jupyterhub.auth import Authenticator

class DictionaryAuthenticator(Authenticator):

    passwords = Dict(config=True,
        help="""dict of username:password for authentication"""
    )

    @gen.coroutine
    def authenticate(self, handler, data):
        if self.passwords.get(data['username']) == data['password']:
            return data['username']

Normalize usernames

Since the Authenticator and Spawner both use the same username, sometimes you want to transform the name coming from the authentication service (e.g. turning email addresses into local system usernames) before adding them to the Hub service. Authenticators can define normalize_username, which takes a username. The default normalization is to cast names to lowercase

For simple mappings, a configurable dict Authenticator.username_map is used to turn one name into another:

c.Authenticator.username_map  = {
  'service-name': 'localname'
}

Validate usernames

In most cases, there is a very limited set of acceptable usernames. Authenticators can define validate_username(username), which should return True for a valid username and False for an invalid one. The primary effect this has is improving error messages during user creation.

The default behavior is to use configurable Authenticator.username_pattern, which is a regular expression string for validation.

To only allow usernames that start with 'w':

c.Authenticator.username_pattern = r'w.*'

How to write a custom authenticator

You can use custom Authenticator subclasses to enable authentication via other mechanisms. One such example is using GitHub OAuth.

Because the username is passed from the Authenticator to the Spawner, a custom Authenticator and Spawner are often used together.

See a list of custom Authenticators on the wiki.

If you are interested in writing a custom authenticator, you can read this tutorial.

JupyterHub as an OAuth provider

Beginning with version 0.8, JupyterHub is an OAuth provider.