Auth0 integration

[washort]

Auth0 uses OpenID Connect, similar to Google's signin system, so much of the existing code should be adaptable.

[alison985]

After speaking with Blake last week I created my own Auth0 account for testing purposes.

[alison985]

First PR: #123

[alison985]

Here is the branch where I am working on this: https://github.com/alison985/mozilla-redash/tree/37_auth0

Current status is that going to http://localhost:5000/ takes you to http://localhost:5000/oauth/auth0?next=http%3A%2F%2Flocalhost%3A5000%2F and gives an Internal Server Error (FYI: 500). This is the error message generated in the console:

server_1 | [2017-07-21 17:46:50,354][PID:135][ERROR][redash] Exception on /oauth/auth0 [GET]
server_1 | Traceback (most recent call last):
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1988, in wsgi_app
server_1 | response = self.full_dispatch_request()
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1641, in full_dispatch_request
server_1 | rv = self.handle_user_exception(e)
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask_restful/init.py", line 271, in error_router
server_1 | return original_handler(e)
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1544, in handle_user_exception
server_1 | reraise(exc_type, exc_value, tb)
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1639, in full_dispatch_request
server_1 | rv = self.dispatch_request()
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask/app.py", line 1625, in dispatch_request
server_1 | return self.view_functionsrule.endpoint
server_1 | File "/app/redash/authentication/auth0_oauth.py", line 81, in login
server_1 | return auth0_remote_app().authorize(callback=callback, state=next_path)
server_1 | File "/app/redash/authentication/auth0_oauth.py", line 38, in auth0_remote_app
server_1 | consumer_secret=settings.AUTH0_CLIENT_SECRET
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask_oauthlib/client.py", line 71, in remote_app
server_1 | remote = OAuthRemoteApp(self, name, **kwargs)
server_1 | File "/usr/local/lib/python2.7/dist-packages/flask_oauthlib/client.py", line 276, in init
server_1 | "OAuthRemoteApp requires consumer key and secret"
server_1 | TypeError: OAuthRemoteApp requires consumer key and secret

However, the consumer_key and consumer_secret are clearly being passed here: https://github.com/alison985/mozilla-redash/blob/37_auth0/redash/authentication/auth0_oauth.py#L37-L38

This is the section of the library that is complaining:
Note it clearly refers to the variable names consumer_key and consumer_secret.

I'm at a loss. @washort any thoughts?