Fix performance glitch while sorting image locations

Some of the available glance stores like file, cinder etc has
capability to reuse already initiated driver (DRIVER_REUSABLE = 0b01000000). In
Caracal we have added a feature to sort image locations based on store
weight. As RBD driver of glance does not have this reuse capability, during
image list API call it initializes the RBD driver for each of the available
image which is causing noticable delay in list call.

To avoid this, using new interface added in glance_store which will directly
get the weight of the store from memory and return it back to user.

Depends-On: https://review.opendev.org/c/openstack/glance_store/+/940531
Closes-Bug: #2086675
Change-Id: I662ba19697e03917ca999920ea7be93a0b2a8296
(cherry picked from commit ce537e073b2e7efb332d719bb45bf20c403c140a)

glance/common/utils.py

@@ -724,13 +724,12 @@ def get_store_weight(location):
         if not store_id:
             return 0
         try:
-            store = glance_store.get_store_from_store_identifier(store_id)
+            return glance_store.get_store_weight(store_id)
         except glance_store.exceptions.UnknownScheme:
             msg = (_LW("Unable to find store '%s', returning "
                        "default weight '0'") % store_id)
             LOG.warning(msg)
             return 0
-        return store.weight if store is not None else 0
 
     sorted_locations = sorted(locations, key=get_store_weight, reverse=True)
     LOG.debug(('Sorted locations: %s'), sorted_locations)

glance/tests/unit/common/test_utils.py

@@ -189,7 +189,7 @@ def test_sort_image_locations_multistore_disabled(self):
             'url': 'rbd://cccccccc/images/id',
             'metadata': {'store': 'rbd3'}
         }]
-        mp = "glance.common.utils.glance_store.get_store_from_store_identifier"
+        mp = "glance.common.utils.glance_store.get_store_weight"
         with mock.patch(mp) as mock_get_store:
             utils.sort_image_locations(locations)
 
@@ -215,10 +215,9 @@ def test_sort_image_locations(self):
             'url': 'rbd://cccccccc/images/id',
             'metadata': {'store': 'rbd3'}
         }]
-        mp = "glance.common.utils.glance_store.get_store_from_store_identifier"
+        mp = "glance.common.utils.glance_store.get_store_weight"
         with mock.patch(mp) as mock_get_store:
-            mock_store = mock_get_store.return_value
-            mock_store.weight = 100
+            mock_get_store.return_value = 100
             utils.sort_image_locations(locations)
 
         # Since 3 stores are configured, internal method will be called 3 times
@@ -243,7 +242,7 @@ def test_sort_image_locations_without_metadata(self):
             'url': 'rbd://cccccccc/images/id',
             'metadata': {}
         }]
-        mp = "glance.common.utils.glance_store.get_store_from_store_identifier"
+        mp = "glance.common.utils.glance_store.get_store_weight"
         with mock.patch(mp) as mock_get_store:
             utils.sort_image_locations(locations)
 
@@ -270,10 +269,9 @@ def test_sort_image_locations_with_partial_metadata(self):
             'url': 'rbd://cccccccc/images/id',
             'metadata': {}
         }]
-        mp = "glance.common.utils.glance_store.get_store_from_store_identifier"
+        mp = "glance.common.utils.glance_store.get_store_weight"
         with mock.patch(mp) as mock_get_store:
-            mock_store = mock_get_store.return_value
-            mock_store.weight = 100
+            mock_get_store.return_value = 100
             utils.sort_image_locations(locations)
 
         # Since 3 stores are configured, but only one location has
@@ -300,7 +298,7 @@ def test_sort_image_locations_unknownscheme(self):
             'url': 'rbd://cccccccc/images/id',
             'metadata': {'store': 'rbd3'}
         }]
-        mp = "glance.common.utils.glance_store.get_store_from_store_identifier"
+        mp = "glance.common.utils.glance_store.get_store_weight"
         with mock.patch(mp) as mock_get_store:
             mock_get_store.side_effect = store.UnknownScheme()
             sorted_locations = utils.sort_image_locations(locations)