Allow specifying authentication URLs from settings

To allow us to have authentication mechanisms that live out of tree as
AUTHENTICATION_BACKENDS do we need to have a way to load the views that
service those backends.

Provide a means via settings that we can add new routes to the /auth
urls.

Closes-Bug: #1433358
Change-Id: I1ffc8a4e0bbfa58c7b50351432668d49d3a7dab1

doc/source/topics/settings.rst

@@ -280,6 +280,18 @@ Most of the following settings are defined in
  ``openstack_dashboard/local/local_settings.py``, which should be copied from
  ``openstack_dashboard/local/local_settings.py.example``.
 
+``AUTHENTICATION_URLS``
+-----------------------
+
+.. versionadded:: 2015.1(Kilo)
+
+Default: ``['openstack_auth.urls']``
+
+A list of modules from which to collate authentication URLs from. The default
+option adds URLs from the django-openstack-auth module however others will be
+required for additional authentication mechanisms.
+
+
 ``API_RESULT_LIMIT``
 --------------------
 

openstack_dashboard/local/local_settings.py.example

@@ -296,6 +296,13 @@ TIME_ZONE = "UTC"
 # the password.
 # ENFORCE_PASSWORD_CHECK = False
 
+# Modules that provide /auth routes that can be used to handle different types
+# of user authentication. Add auth plugins that require extra route handling to
+# this list.
+#AUTHENTICATION_URLS = [
+#    'openstack_auth.urls',
+#]
+
 # The Horizon Policy Enforcement engine uses these values to load per service
 # policy rule files. The content of these files should match the files the
 # OpenStack services are using to determine role based access control in the

openstack_dashboard/settings.py

@@ -164,6 +164,7 @@ INSTALLED_APPS = [
 
 TEST_RUNNER = 'django_nose.NoseTestSuiteRunner'
 AUTHENTICATION_BACKENDS = ('openstack_auth.backend.KeystoneBackend',)
+AUTHENTICATION_URLS = ['openstack_auth.urls']
 MESSAGE_STORAGE = 'django.contrib.messages.storage.fallback.FallbackStorage'
 
 SESSION_ENGINE = 'django.contrib.sessions.backends.signed_cookies'

openstack_dashboard/urls.py

@@ -32,11 +32,16 @@ import horizon
 urlpatterns = patterns(
     '',
     url(r'^$', 'openstack_dashboard.views.splash', name='splash'),
-    url(r'^auth/', include('openstack_auth.urls')),
     url(r'^api/', include('openstack_dashboard.api.rest.urls')),
     url(r'', include(horizon.urls)),
 )
 
+for u in getattr(settings, 'AUTHENTICATION_URLS', ['openstack_auth.urls']):
+    urlpatterns += patterns(
+        '',
+        url(r'^auth/', include(u))
+    )
+
 # Development static app and project media serving using the staticfiles app.
 urlpatterns += staticfiles_urlpatterns()