Merge "Stop looping all filters if no objects return"

openstack/common/scheduler/base_filter.py

@@ -17,8 +17,12 @@
 Filter support
 """
 
+from openstack.common.gettextutils import _
+from openstack.common import log as logging
 from openstack.common.scheduler import base_handler
 
+LOG = logging.getLogger(__name__)
+
 
 class BaseFilter(object):
     """Base class for all filter classes."""
@@ -48,6 +52,22 @@ class BaseFilterHandler(base_handler.BaseHandler):
 
     def get_filtered_objects(self, filter_classes, objs,
                              filter_properties):
+        list_objs = list(objs)
+        LOG.debug(_("Starting with %d host(s)"), len(list_objs))
         for filter_cls in filter_classes:
-            objs = filter_cls().filter_all(objs, filter_properties)
-        return list(objs)
+            cls_name = filter_cls.__name__
+            filter_class = filter_cls()
+
+            objs = filter_class.filter_all(list_objs, filter_properties)
+            if objs is None:
+                LOG.debug(_("Filter %(cls_name)s says to stop filtering"),
+                          {'cls_name': cls_name})
+                return
+            list_objs = list(objs)
+            msg = (_("Filter %(cls_name)s returned %(obj_len)d host(s)")
+                   % {'cls_name': cls_name, 'obj_len': len(list_objs)})
+            if not list_objs:
+                LOG.info(msg)
+                break
+            LOG.debug(msg)
+        return list_objs

tests/unit/scheduler/test_base_filter.py

@@ -13,6 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import contextlib
+
+import mock
+
 from openstack.common.fixture import moxstubout
 from openstack.common.scheduler import base_filter
 from openstack.common import test
@@ -121,3 +125,27 @@ class TestBaseFilterHandler(test.BaseTestCase):
         expected = [FakeFilter1, FakeFilter4]
         result = self.handler.get_all_classes()
         self.assertEqual(expected, result)
+
+    def _get_filtered_objects(self):
+        filter_objs_initial = [1, 2, 3, 4]
+        filter_properties = {'x': 'y'}
+        filter_classes = [FakeFilter1, FakeFilter2, FakeFilter3, FakeFilter4]
+        return self.handler.get_filtered_objects(filter_classes,
+                                                 filter_objs_initial,
+                                                 filter_properties)
+
+    def test_get_filtered_objects_return_none(self):
+        def fake_filter_all(self, list_objs, filter_properties):
+            return
+        with contextlib.nested(
+            mock.patch.object(FakeFilter3, 'filter_all', fake_filter_all),
+            mock.patch.object(FakeFilter4, 'filter_all')
+        ) as (fake3_filter_all, fake4_filter_all):
+            result = self._get_filtered_objects()
+            self.assertIsNone(result)
+            self.assertFalse(fake4_filter_all.called)
+
+    def test_get_filtered_objects(self):
+        filter_objs_expected = [1, 2, 3, 4]
+        result = self._get_filtered_objects()
+        self.assertEqual(filter_objs_expected, result)