MultiAuthenticator for jupyterhub

multiauthenticator.py

from urllib.parse import urlsplit

from tornado import gen
from tornado.escape import url_escape
from tornado.httputil import url_concat

from traitlets import (
    Unicode, Integer, Dict, TraitError, List, Bool, Any,
    Type, Set, Instance, Bytes, Float,
    observe, default,
)

from jupyterhub.auth import Authenticator
from jupyterhub.handlers.login import LoginHandler, LogoutHandler

from oauthenticator.google import GoogleOAuthenticator, GoogleLoginHandler, GoogleOAuthHandler
from oauthenticator.github import GitHubOAuthenticator, GitHubLoginHandler
from jhub_cas_authenticator.cas_auth import CASAuthenticator, CASLoginHandler
import pdb


class MultiLoginHandler(LoginHandler):

    def _render(self, login_error=None):
        """
        Mainly changes the template, also simplify a bit
        """
        context = {
            'google': {
                'enabled': self.authenticator.enable_google,
            },
            'github': {
                'enabled': self.authenticator.enable_github,
            },
            'nih': {
                'enabled': self.authenticator.enable_nih,
            },
        }
        nextval = self.get_argument('next', default='')
        return self.render_template('nlm/login.html',
            next=url_escape(nextval),
            multiauth=context,
            login_error=login_error,
            authenticator_login_url=url_concat(
                self.authenticator.login_url(self.hub.base_url),
                {'next': nextval},
            ),
        )

    @gen.coroutine
    def get(self):
        """
        Simplify rendering as there is no username
        """
        self.statsd.incr('login.request')
        user = self.get_current_user()
        if user:
            # set new login cookie
            # because single-user cookie may have been cleared or incorrect
            self.set_login_cookie(self.get_current_user())
            self.redirect(self.get_next_url(user), permanent=False)
        else:
            self.finish(self._render())

    @gen.coroutine
    def post(self):
        """
        Redirect to the handler for the appropriate oauth selected
        """
        concat_data = {
            'next': self.get_argument('next', ''),
        }
        if self.authenticator.enable_google and self.get_argument('login_google', None):
            login_url = '{}://{}{}google/login'.format(self.request.protocol, self.request.host, self.hub.base_url)
            self.redirect(url_concat(login_url, concat_data))
        elif self.authenticator.enable_github and self.get_argument('login_github', None):
            login_url = '{}://{}{}github/login'.format(self.request.protocol, self.request.host, self.hub.base_url)
            self.redirect(url_concat(login_url, concat_data))
        elif self.authenticator.enable_nih and self.get_argument('login_nih', None):
            login_url = '{}://{}{}nih/login'.format(self.request.protocol, self.request.host, self.hub.base_url)
            self.redirect(url_concat(login_url, concat_data))
        else:
            html = self._render(login_error='Unknown or missing authenticator')
            self.finish(html)


class MultiLogoutHandler(LogoutHandler):
    pass


class MultiAuthenticator(Authenticator):

    enable_google = Bool(True, help='Enable oauth2 authorization to google').tag(config=True)
    enable_github = Bool(True, help='Enable oauth2 authorization to github').tag(config=True)
    enable_nih = Bool(True, help='Enable CAS/SAML authentication to NIH Login').tag(config=True)

    google_class = Type(GoogleOAuthenticator, Authenticator, help='Must be an authenticator').tag(config=True)
    github_class = Type(GitHubOAuthenticator, Authenticator, help='Must be an authenticator').tag(config=True)
    nih_class = Type(CASAuthenticator, Authenticator, help='Must be an authenticator').tag(config=True)

    google_authenticator = Instance(Authenticator)
    github_authenticator = Instance(Authenticator)
    nih_authenticator = Instance(Authenticator)

    @default('google_authenticator')
    def _default_google_authenticator(self):
        return self.google_class()

    @default('github_authenticator')
    def _default_github_authenticator(self):
        return self.github_class()

    @default('nih_authenticator')
    def _default_nih_authenticator(self):
        return self.nih_class()

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.__client_id = None
        self.__client_secret = None
        self.__scope = None

    @property
    def client_id(self):
        return self.__client_id

    @property
    def client_secret(self):
        return self.__client_secret

    @property
    def scope(self):
        return self.__scope

    def set_oauth_tokens(self, subauth):
        """
        Caches configured information from the subauthenticator in properties
        """
        self.__client_id = subauth.client_id
        self.__client_secret = subauth.client_secret
        self.__scope = subauth.scope

    def get_callback_url(self, handler=None):
        """
        This is called by oauth2, it thinks that there will just be one 
        """
        pdb.set_trace()
        if handler is None:
            raise ValueError("MultiAuthenticator only works with a handler")
        if isinstance(handler, GoogleLoginHandler):
            self.set_oauth_tokens(self.google_authenticator)
            if self.google_authenticator.oauth_callback_url:
                return self.google_authenticator.oauth_callback_url
        if isinstance(handler, GitHubLoginHandler):
            self.set_oauth_tokens(self.github_authenticator)
            if self.config.github_authenticator.oauth_callback_url:
                return self.config.github_authenticator.oauth_callback_url
        parts = urlsplit(handler.request.uri)
        callback_url = '{}://{}{}'.format(
            handler.request.protocol,
            handler.request.host,
            parts.path.replace('/login', '/callback')
        )
        return callback_url

    def validate_username(self, username):
        return super().validate_username(username)

    def normalize_username(self, username):
        return super().normalize_username(username)

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)


    def get_handlers(self, app):
        h = [
            ('/login', MultiLoginHandler),
            ('/logout', MultiLogoutHandler),
        ]
        if self.enable_google:
            handlers = dict(self.google_authenticator.get_handlers(app))
            h.extend([
                ('/google/login', handlers['/oauth_login']),
                ('/google/callback', handlers['/oauth_callback'])
            ])
        if self.enable_github:
            handlers = dict(self.github_authenticator.get_handlers(app))
            h.extend([
                ('/github/login', handlers['/oauth_login']),
                ('/github/callback', handlers['/oauth_callback']),
            ])
        if self.enable_nih:
            handlers = dict(self.nih_authenticator.get_handlers(app))
            h.extend([
                ('/nih/login', handlers['/login']),
            ])
        return h

    @gen.coroutine
    def authenticate(self, handler, data):
        """
        Delegate authentication to the appropriate authenticator
        """
        pdb.set_trace()
        if isinstance(handler, GoogleOAuthHandler):
            return self.google_authenticator.authenticate(handler, data)
        elif isinstance(handler, CASLoginHandler):
            return self.nih_authenticator.authenticate(handler, data)
        else:
            return self.github_authenticator.authenticate(handler, data)

Hi @danizen! How do I combine LDAP authentication with local /etc/password accounts in Jupyterhub? Is there a solution out there, do you know? Thank you!

@danizen how do you configure this in the JupyterHub config file?

@MRichards99
we extended this a bit, hope this helps
https://github.com/zhiyuli/oauthenticator/blob/hydroshare/examples/multi_oauth/jupyterhub_config.py
https://github.com/zhiyuli/oauthenticator/tree/hydroshare/examples/multi_oauth

@danizen how do you configure this in the JupyterHub config file?

I don't remember exactly, but you need to create an App registration for whichever OAuth authenticators you want to create, and copy the application client id and secret into the config file.

Hi @danizen! How do I combine LDAP authentication with local /etc/password accounts in Jupyterhub? Is there a solution out there, do you know? Thank you!

A better solution will be to use the LDAP authentication indirectly, through some sort of OAuth2 or Saml configuration. LDAP Authentication directly is no longer considered as secure.

I would avoid combining local /etc/passwd authentication with anything else - if you are going to do that, then you are going to be adding the other things through PAM (Pluggable Authentication Module) at the Linux system admin. level, and that is not what I would recommend here.