Use cached volumes in REST API extensions

This patch caches db volumes in the core volumes API so that they can be
used in the host and tenant attribute API extensions in order to lower
the response time by avoiding costly individual db queries for each
volume in the REST API contributions.

Change-Id: Ie0cbe929379df32fddbdce1953f13b6f26208bff
Partial-Bug: #1197612
(cherry picked from commit 9ed0f39)

cinder/api/contrib/volume_host_attribute.py

@@ -29,29 +29,26 @@ def __init__(self, *args, **kwargs):
         super(VolumeHostAttributeController, self).__init__(*args, **kwargs)
         self.volume_api = volume.API()
 
-    def _add_volume_host_attribute(self, context, resp_volume):
-        try:
-            db_volume = self.volume_api.get(context, resp_volume['id'])
-        except Exception:
-            return
-        else:
-            key = "%s:host" % Volume_host_attribute.alias
-            resp_volume[key] = db_volume['host']
+    def _add_volume_host_attribute(self, context, req, resp_volume):
+        db_volume = req.cached_resource_by_id(resp_volume['id'])
+        key = "%s:host" % Volume_host_attribute.alias
+        resp_volume[key] = db_volume['host']
 
     @wsgi.extends
     def show(self, req, resp_obj, id):
         context = req.environ['cinder.context']
         if authorize(context):
             resp_obj.attach(xml=VolumeHostAttributeTemplate())
-            self._add_volume_host_attribute(context, resp_obj.obj['volume'])
+            volume = resp_obj.obj['volume']
+            self._add_volume_host_attribute(context, req, volume)
 
     @wsgi.extends
     def detail(self, req, resp_obj):
         context = req.environ['cinder.context']
         if authorize(context):
             resp_obj.attach(xml=VolumeListHostAttributeTemplate())
             for volume in list(resp_obj.obj['volumes']):
-                self._add_volume_host_attribute(context, volume)
+                self._add_volume_host_attribute(context, req, volume)
 
 
 class Volume_host_attribute(extensions.ExtensionDescriptor):

cinder/api/contrib/volume_tenant_attribute.py

@@ -27,29 +27,26 @@ def __init__(self, *args, **kwargs):
         super(VolumeTenantAttributeController, self).__init__(*args, **kwargs)
         self.volume_api = volume.API()
 
-    def _add_volume_tenant_attribute(self, context, resp_volume):
-        try:
-            db_volume = self.volume_api.get(context, resp_volume['id'])
-        except Exception:
-            return
-        else:
-            key = "%s:tenant_id" % Volume_tenant_attribute.alias
-            resp_volume[key] = db_volume['project_id']
+    def _add_volume_tenant_attribute(self, context, req, resp_volume):
+        db_volume = req.cached_resource_by_id(resp_volume['id'])
+        key = "%s:tenant_id" % Volume_tenant_attribute.alias
+        resp_volume[key] = db_volume['project_id']
 
     @wsgi.extends
     def show(self, req, resp_obj, id):
         context = req.environ['cinder.context']
         if authorize(context):
             resp_obj.attach(xml=VolumeTenantAttributeTemplate())
-            self._add_volume_tenant_attribute(context, resp_obj.obj['volume'])
+            volume = resp_obj.obj['volume']
+            self._add_volume_tenant_attribute(context, req, volume)
 
     @wsgi.extends
     def detail(self, req, resp_obj):
         context = req.environ['cinder.context']
         if authorize(context):
             resp_obj.attach(xml=VolumeListTenantAttributeTemplate())
             for volume in list(resp_obj.obj['volumes']):
-                self._add_volume_tenant_attribute(context, volume)
+                self._add_volume_tenant_attribute(context, req, volume)
 
 
 class Volume_tenant_attribute(extensions.ExtensionDescriptor):

cinder/api/v1/volumes.py

@@ -275,6 +275,7 @@ def show(self, req, id):
 
         try:
             vol = self.volume_api.get(context, id)
+            req.cache_resource(vol)
         except exception.NotFound:
             raise exc.HTTPNotFound()
 
@@ -330,6 +331,7 @@ def _items(self, req, entity_maker):
             self._add_visible_admin_metadata(context, volume)
 
         limited_list = common.limited(volumes, req)
+        req.cache_resource(limited_list)
         res = [entity_maker(context, vol) for vol in limited_list]
         return {'volumes': res}
 

cinder/api/v2/volumes.py

@@ -212,6 +212,7 @@ def show(self, req, id):
 
         try:
             vol = self.volume_api.get(context, id)
+            req.cache_resource(vol)
         except exception.NotFound:
             msg = _("Volume could not be found")
             raise exc.HTTPNotFound(explanation=msg)
@@ -285,6 +286,7 @@ def _get_volumes(self, req, is_detail):
             volumes = self._view_builder.detail_list(req, limited_list)
         else:
             volumes = self._view_builder.summary_list(req, limited_list)
+        req.cache_resource(limited_list)
         return volumes
 
     def _image_uuid_from_href(self, image_href):

cinder/tests/api/fakes.py

@@ -137,7 +137,7 @@ class HTTPRequest(webob.Request):
     def blank(cls, *args, **kwargs):
         kwargs['base_url'] = 'http://localhost/v1'
         use_admin_context = kwargs.pop('use_admin_context', False)
-        out = webob.Request.blank(*args, **kwargs)
+        out = os_wsgi.Request.blank(*args, **kwargs)
         out.environ['cinder.context'] = FakeRequestContext(
             'fake_user',
             'fake',

cinder/tests/api/v1/test_volumes.py

@@ -386,6 +386,8 @@ def test_volume_list(self):
                                                                  1, 1, 1),
                                  'size': 1}]}
         self.assertEqual(res_dict, expected)
+        # Finally test that we cached the returned volumes
+        self.assertEqual(1, len(req.cached_resource()))
 
     def test_volume_list_with_admin_metadata(self):
         volume = stubs.stub_volume("1")
@@ -451,6 +453,8 @@ def test_volume_list_detail(self):
                                                                  1, 1, 1),
                                  'size': 1}]}
         self.assertEqual(res_dict, expected)
+        # Finally test that we cached the returned volumes
+        self.assertEqual(1, len(req.cached_resource()))
 
     def test_volume_list_detail_with_admin_metadata(self):
         volume = stubs.stub_volume("1")
@@ -638,6 +642,8 @@ def test_volume_show(self):
                                                                1, 1, 1),
                                'size': 1}}
         self.assertEqual(res_dict, expected)
+        # Finally test that we cached the returned volume
+        self.assertIsNotNone(req.cached_resource_by_id('1'))
 
     def test_volume_show_no_attachments(self):
         def stub_volume_get(self, context, volume_id):
@@ -701,6 +707,8 @@ def test_volume_show_no_volume(self):
                           self.controller.show,
                           req,
                           1)
+        # Finally test that we did not cache anything
+        self.assertIsNone(req.cached_resource_by_id('1'))
 
     def test_volume_detail_limit_offset(self):
         def volume_detail_limit_offset(is_admin):

cinder/tests/api/v2/test_volumes.py

@@ -435,6 +435,8 @@ def test_volume_list_summary(self):
             ]
         }
         self.assertEqual(res_dict, expected)
+        # Finally test that we cached the returned volumes
+        self.assertEqual(1, len(req.cached_resource()))
 
     def test_volume_list_detail(self):
         self.stubs.Set(volume_api.API, 'get_all',
@@ -482,6 +484,8 @@ def test_volume_list_detail(self):
             ]
         }
         self.assertEqual(res_dict, expected)
+        # Finally test that we cached the returned volumes
+        self.assertEqual(1, len(req.cached_resource()))
 
     def test_volume_list_detail_with_admin_metadata(self):
         volume = stubs.stub_volume("1")
@@ -869,6 +873,8 @@ def test_volume_show(self):
             }
         }
         self.assertEqual(res_dict, expected)
+        # Finally test that we cached the returned volume
+        self.assertIsNotNone(req.cached_resource_by_id('1'))
 
     def test_volume_show_no_attachments(self):
         def stub_volume_get(self, context, volume_id):
@@ -915,6 +921,8 @@ def test_volume_show_no_volume(self):
         req = fakes.HTTPRequest.blank('/v2/volumes/1')
         self.assertRaises(webob.exc.HTTPNotFound, self.controller.show,
                           req, 1)
+        # Finally test that nothing was cached
+        self.assertIsNone(req.cached_resource_by_id('1'))
 
     def test_volume_show_with_admin_metadata(self):
         volume = stubs.stub_volume("1")