Comment 7 for bug 1764622

Reviewed: https://review.openstack.org/619001
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=6ae1f5e21d87ba3e11bd124eb1268823a1641205
Submitter: Zuul
Branch: stable/queens

commit 6ae1f5e21d87ba3e11bd124eb1268823a1641205
Author: Mathieu Gagné <email address hidden>
Date: Wed Oct 31 22:24:31 2018 -0400

    Fix django.contrib.auth.middleware monkey patching

    The "request" attribute is not available in
    openstack_auth.backend.KeystoneBackend.get_user when session data is restored
    and it's the first request to happen after a server restart.

    As stated by the function document, the "request" attribute needs to be
    monkey-patched by openstack_auth.utils.patch_middleware_get_user
    for this function to work properly.

    This should happen in openstack_auth.urls at import time. But there is nowhere
    in Horizon where this module is imported at startup. It's only introspected
    by openstack_dashboard.urls due to AUTHENTICATION_URLS setting.

    Without this monkey-patching, the whole authentication mechanism falls back
    to "AnonymousUser" and you will get redirected to the login page due
    to horizon.exceptions.NotAuthenticated being raised by
    horizon.decorators.require_auth as request.user.is_authenticated will be False.

    But if a user requests a page under auth/, it will have the side-effect of
    monkey-patching django.contrib.auth.middleware as expected. This means that
    once this request is completed, all following requests to pages other than
    the ones under auth/ will have there sessions properly restored and
    you will be properly authenticated.

    Therefore this change introduces a dummy middleware which sole purpose is
    to perform this monkey-patching as early as possible.

    There is also some cleanup to get rid of the previous attempts at
    monkeypatching.

    Closes-bug: #1764622

    [backport specific notice]
    Queens horizon supports Django 1.8 and 1.11.
    The key point is Django 2.0 is not supported.
    Django 2.0 dropped the legacy Django middleware interface and
    the new interface is not supported in Django 1.8.
    Thus, this backport changes OpenstackAuthMonkeyPatchMiddleware in
    openstack_auth/middlware.py to use the legacy middleware interface.

    Conflicts:
     openstack_dashboard/settings.py
     openstack_dashboard/test/helpers.py

    Change-Id: Ib9912090a87b716e7f5710f6f360b0df168ec2e3
    (cherry picked from commit 0d163613265e036818fe567793a4fc88fe140d4a)
    (cherry picked from commit 8851866aad5b3826f0a3d569405707bffa593c80)