Allow for manual setting of default service region in config

In case DEFAULT_SERVICE_REGIONS setting in Horizon config is specified
(on a per-endpoint basis), use it instead of a value stored in
cookies. This value is still checked for sanity, i.e. it should be
present in Keystone service catalog.

Change-Id: Ia4787b56db7ce7787bd8aac21b5c0ec8a95a6f09
Related-Bug: #1506825
Closes-Bug: #1703390

3 files changed, 29 insertions, 4 deletions

diff --git a/doc/source/configuration/index.rst b/doc/source/configuration/index.rst
index 26c272b..5b581b0 100644
--- a/doc/source/configuration/index.rst
+++ b/doc/source/configuration/index.rst
@@ -37,6 +37,28 @@ the site header when logged in.
 You should also define ``OPENSTACK_KEYSTONE_URL`` to indicate which of
 the regions is the default one.
 
+
+``DEFAULT_SERVICE_REGIONS``
+---------------------------
+
+Default: ``{}``
+
+The default service region is set on a per-endpoint basis, meaning that once
+the user logs into some Keystone endpoint, if a default service region is
+defined for it in this setting and exists within Keystone catalog, it will be
+set as the initial service region in this endpoint. By default it is an empty
+dictionary because upstream can neither predict service region names in a
+specific deployment, nor tell whether this behavior is desired. The key of the
+dictionary is a full url of a Keystone endpoint with version suffix, the value
+is a region name.
+
+Example::
+
+    DEFAULT_SERVICE_REGIONS = {
+        OPENSTACK_KEYSTONE_URL: 'RegionOne'
+    }
+
+
 ``OPENSTACK_API_VERSIONS``
 --------------------------
 
diff --git a/openstack_auth/user.py b/openstack_auth/user.py
index 3edb204..063648b 100644
--- a/openstack_auth/user.py
+++ b/openstack_auth/user.py
@@ -43,8 +43,11 @@ def set_session_from_user(request, user):
 
 def create_user_from_token(request, token, endpoint, services_region=None):
     # if the region is provided, use that, otherwise use the preferred region
+    default_service_regions = getattr(settings, 'DEFAULT_SERVICE_REGIONS', {})
+    default_service_region = default_service_regions.get(endpoint)
     svc_region = services_region or \
-        utils.default_services_region(token.serviceCatalog, request)
+        utils.default_services_region(token.serviceCatalog, request,
+                                      selected_region=default_service_region)
     return User(id=token.user['id'],
                 token=token,
                 user=token.user['name'],
diff --git a/openstack_auth/utils.py b/openstack_auth/utils.py
index 3d49b7a..39ced4a 100644
--- a/openstack_auth/utils.py
+++ b/openstack_auth/utils.py
@@ -372,7 +372,8 @@ def get_project_list(*args, **kwargs):
     return projects
 
 
-def default_services_region(service_catalog, request=None):
+def default_services_region(service_catalog, request=None,
+                            selected_region=None):
     """Returns the first endpoint region for first non-identity service.
 
     Extracted from the service catalog.
@@ -396,8 +397,7 @@ def default_services_region(service_catalog, request=None):
                 LOG.error('No regions can be found in the service catalog.')
                 return None
 
-        selected_region = None
-        if request:
+        if request and selected_region is None:
             selected_region = request.COOKIES.get('services_region',
                                                   available_regions[0])
         if selected_region not in available_regions: