Fix glance-api if cache is disabled

This patch fixes glance when cache is disabled.

Change-Id: I3c3560ba9c87c7098d75173a095642bdd1d7c687

Author: keuko

glance/sqlite_migration.py

@@ -33,15 +33,18 @@
 
 
 def can_migrate_to_central_db():
+    # Return immediately if cache is disabled
+    if not (CONF.paste_deploy.flavor and 'cache' in CONF.paste_deploy.flavor):
+        return False
+
+    is_centralized_db_driver = CONF.image_cache_driver == "centralized_db"
     # Check worker_self_reference_url is set if cache is enabled and
     # cache driver is centralized_db
-    is_centralized_db_driver = CONF.image_cache_driver == "centralized_db"
-    if CONF.paste_deploy.flavor and 'cache' in CONF.paste_deploy.flavor:
-        if is_centralized_db_driver and not CONF.worker_self_reference_url:
-            msg = _("'worker_self_reference_url' needs to be set "
-                    "if `centralized_db` is defined as cache driver "
-                    "for image_cache_driver config option.")
-            raise RuntimeError(msg)
+    if is_centralized_db_driver and not CONF.worker_self_reference_url:
+        msg = _("'worker_self_reference_url' needs to be set "
+                "if `centralized_db` is defined as cache driver "
+                "for image_cache_driver config option.")
+        raise RuntimeError(msg)
 
     return is_centralized_db_driver
 

glance/tests/unit/test_sqlite_migration.py

@@ -101,10 +101,16 @@ def test_migrate_if_required_false(self):
         self.config(image_cache_driver="sqlite")
         self.assertFalse(sqlite_migration.migrate_if_required())
 
+    def test_migrate_if_required_cache_disabled(self):
+        self.config(flavor="keystone", group="paste_deploy")
+        self.config(image_cache_driver="centralized_db")
+        self.assertFalse(sqlite_migration.migrate_if_required())
+
     @mock.patch('os.path.exists')
     @mock.patch('os.path.join', new=mock.MagicMock())
     def test_migrate_if_required_db_not_found(self, mock_exists):
         mock_exists.return_value = False
+        self.config(flavor="keystone+cache", group="paste_deploy")
         self.config(image_cache_driver="centralized_db")
         with mock.patch.object(sqlite_migration, 'LOG') as mock_log:
             sqlite_migration.migrate_if_required()