Added variable to allow for arbitrary HORIZON_CONFIG

A new variable has been added to allow a deployer to set arbitrary
configuration options.

Closes-Bug: #1598143
Change-Id: Ic2d83d5b581046314145ecd0201087cc1682716b
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

defaults/main.yml

@@ -191,3 +191,6 @@ horizon_pip_packages:
   - pycrypto
   - python-memcached
   - python-keystoneclient
+
+# Set arbitrary horizon configuration options
+horizon_config_overrides: {}

releasenotes/notes/horizon-arbitrary-config-8a36e4bd6818afe1.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - Horizon now has the ability to set arbitrary configuration options using
+    global option ``horizon_config_overrides`` in YAML format. The overrides
+    follow the same pattern found within the other OpenStack service
+    overrides. `General documentation on overrides can be found here <http://docs.openstack.org/developer/openstack-ansible/install-guide/configure-openstack.html#overriding-openstack-configuration-defaults>`_.

templates/horizon_local_settings.py.j2

@@ -728,3 +728,7 @@ SITE_BRANDING = '{{ horizon_site_name }}'
 #custom python module with horizon dashboard theme overrides
 HORIZON_CONFIG["customization_module"] = 'horizon_customization.overrides'
 {% endif %}
+
+
+# Set arbitrary horizon configuration options
+HORIZON_CONFIG.update({{ horizon_config_overrides }})

tests/test-vars.yml

@@ -84,3 +84,5 @@ tempest_plugins:
   - name: tempest-horizon
     repo: https://git.openstack.org/openstack/tempest-horizon
     branch: master
+horizon_config_overrides:
+  X_TEST_OPTION: True