add service_enabled to glance_utils.py

hooks/glance_utils.py

@@ -141,3 +141,15 @@ def set_ceph_env_variables(service):
             out.write('CEPH_ARGS="--id %s"\n' % service)
     with open('/etc/init/glance.override', 'w') as out:
             out.write('env CEPH_ARGS="--id %s"\n' % service)
+
+
+def service_enabled(service):
+    '''
+    Determine if a specific cinder service is enabled in charm configuration.
+
+    :returns: boolean: True if service is enabled in config, False if not.
+    '''
+    enabled = config()['enabled-services']
+    if enabled == 'all':
+        return True
+    return service in enabled