Add config option to override hardcoded service username

'manila' username is hardcoded and cannot be overridden. At
the moment the main purpose of this is to allow operator to
configure an username that can match manila charm's service
credential, which may be "manila", "manila_manilav2" or
"<prefix>-manila".

Related-bug: #2043588
Change-Id: I7bcdcd361b633481bd401209a1df614132d34139
(cherry picked from commit ed1b52e)
(cherry picked from commit 537992c)
(cherry picked from commit 35aa466)
(cherry picked from commit 46be288)

src/config.yaml

@@ -14,6 +14,10 @@ options:
       Note that updating this setting to a source that is known to
       provide a later version of OpenStack will trigger a software
       upgrade.
+  service-user:
+    default: manila
+    type: string
+    description: Username used for keystone's service credential.
   rabbit-user:
     default: manila
     type: string

src/reactive/manila_ganesha.py

@@ -7,7 +7,10 @@
 import charms.reactive.relations as relations
 
 import charmhelpers.core as ch_core
-from charmhelpers.core.hookenv import log
+from charmhelpers.core.hookenv import (
+    log,
+    config,
+)
 
 
 charms_openstack.bus.discover()
@@ -42,12 +45,18 @@ def setup_manila():
     }
 
 
+@reactive.when('config.changed.service-user')
+@reactive.when('identity-service.connected')
+def update_ident_username(keystone):
+    """Updates the user to the Identity Service"""
+    configure_ident_username(keystone)
+
+
 @reactive.when_not('identity-service.available')
 @reactive.when('identity-service.connected')
 def configure_ident_username(keystone):
-    """Requests a user to the Identity Service
-    """
-    username = 'manila'
+    """Requests a user to the Identity Service"""
+    username = config().get('service-user')
     keystone.request_credentials(username)
 
 

unit_tests/test_manila_ganesha_handlers.py

@@ -49,6 +49,8 @@ def test_hooks(self):
                 'enable_services_in_non_ha': ('config.rendered',
                                               'ganesha-pool-configured',),
                 'disable_services': ('cluster.connected',),
+                'update_ident_username': ('config.changed.service-user',
+                                          'identity-service.connected',),
             },
             'when_not': {
                 'ceph_connected': ('ganesha-pool-configured',),