Merge "Cleanup scheduler" into stable/wallaby

6 files changed, 54 insertions, 55 deletions

diff --git a/designate/scheduler/base.py b/designate/scheduler/base.py
index b288548d..934f646a 100644
--- a/designate/scheduler/base.py
+++ b/designate/scheduler/base.py
@@ -27,28 +27,29 @@ class Scheduler(object):
 
     :raises: NoFiltersConfigured
     """
-
     filters = []
     """The list of filters enabled on this scheduler"""
 
     def __init__(self, storage):
-
         enabled_filters = cfg.CONF['service:central'].scheduler_filters
-        # Get a storage connection
+        self.filters = list()
         self.storage = storage
-        if len(enabled_filters) > 0:
-            filters = named.NamedExtensionManager(
-                namespace='designate.scheduler.filters',
-                names=enabled_filters,
-                name_order=True)
 
-            self.filters = [x.plugin(storage=self.storage) for x in filters]
-            for filter in self.filters:
-                LOG.info("Loaded Scheduler Filter: %s", filter.name)
+        if not enabled_filters:
+            raise exceptions.NoFiltersConfigured(
+                'There are no scheduling filters configured'
+            )
 
-        else:
-            raise exceptions.NoFiltersConfigured('There are no scheduling '
-                                                 'filters configured')
+        extensions = named.NamedExtensionManager(
+            namespace='designate.scheduler.filters',
+            names=enabled_filters,
+            name_order=True,
+        )
+
+        for extension in extensions:
+            plugin = extension.plugin(storage=self.storage)
+            LOG.info('Loaded Scheduler Filter: %s', plugin.name)
+            self.filters.append(plugin)
 
     def schedule_zone(self, context, zone):
         """Get a pool to create the new zone in.
@@ -61,21 +62,24 @@ class Scheduler(object):
         """
         pools = self.storage.find_pools(context)
 
-        if len(self.filters) == 0:
+        if not self.filters:
             raise exceptions.NoFiltersConfigured('There are no scheduling '
                                                  'filters configured')
 
-        for f in self.filters:
-            LOG.debug("Running %s filter with %d pools", f.name, len(pools))
-            pools = f.filter(context, pools, zone)
+        for plugin in self.filters:
+            LOG.debug(
+                'Running %s filter with %d pools', plugin.name, len(pools)
+            )
+            pools = plugin.filter(context, pools, zone)
             LOG.debug(
-                "%d candidate pools remaining after %s filter",
-                len(pools),
-                f.name)
+                '%d candidate pools remaining after %s filter',
+                len(pools), plugin.name
+            )
 
         if len(pools) > 1:
             raise exceptions.MultiplePoolsFound()
-        if len(pools) == 0:
-            raise exceptions.NoValidPoolFound('There are no pools that '
-                                              'matched your request')
+        if not pools:
+            raise exceptions.NoValidPoolFound(
+                'There are no pools that matched your request'
+            )
         return pools[0].id
diff --git a/designate/scheduler/filters/attribute_filter.py b/designate/scheduler/filters/attribute_filter.py
index 8751fc24..a53333e6 100644
--- a/designate/scheduler/filters/attribute_filter.py
+++ b/designate/scheduler/filters/attribute_filter.py
@@ -74,7 +74,7 @@ class AttributeFilter(base.Filter):
             # fine, we should just continue.
             pool_attributes.pop('pool_id', None)
 
-            if pool_attributes == {}:
+            if not pool_attributes:
                 # If we did not send any attribute to filter on, we should
                 # not filter the pools based on an empty set, as this will
                 # return no pools.
@@ -83,12 +83,10 @@ class AttributeFilter(base.Filter):
             # Check if the keys requested exist in this pool
             if not {key for key in six.iterkeys(pool_attributes)}.issuperset(
                     zone_attributes):
-                msg = "%(pool)s did not match list of requested attribute "\
-                      "keys - removing from list. Requested: %(r_key)s. Pool:"\
-                      "%(p_key)s"
-
                 LOG.debug(
-                    msg,
+                    '%(pool)s did not match list of requested attribute '
+                    'keys - removing from list. Requested: %(r_key)s. Pool:'
+                    '%(p_key)s',
                     {
                         'pool': pool,
                         'r_key': zone_attributes,
@@ -98,8 +96,8 @@ class AttributeFilter(base.Filter):
                 # Missing required keys - remove from the list
                 return False
 
-            for key in six.iterkeys(zone_attributes):
-                LOG.debug("Checking value of %s for %s", key, pool)
+            for key in zone_attributes.keys():
+                LOG.debug('Checking value of %s for %s', key, pool)
 
                 pool_attr = bool_from_string(pool_attributes[key],
                                              default=pool_attributes[key])
@@ -108,8 +106,8 @@ class AttributeFilter(base.Filter):
 
                 if not pool_attr == zone_attr:
                     LOG.debug(
-                        "%(pool)s did not match requested value of %(key)s. "
-                        "Requested: %(r_val)s. Pool: %(p_val)s",
+                        '%(pool)s did not match requested value of %(key)s. '
+                        'Requested: %(r_val)s. Pool: %(p_val)s',
                         {
                             'pool': pool,
                             'key': key,
@@ -123,7 +121,5 @@ class AttributeFilter(base.Filter):
             return True
 
         pool_list = [pool for pool in pools if evaluate_pool(pool)]
-
         pools = PoolList(objects=pool_list)
-
         return pools
diff --git a/designate/scheduler/filters/fallback_filter.py b/designate/scheduler/filters/fallback_filter.py
index cbb31ac3..bacb0d33 100644
--- a/designate/scheduler/filters/fallback_filter.py
+++ b/designate/scheduler/filters/fallback_filter.py
@@ -40,10 +40,9 @@ class FallbackFilter(base.Filter):
     """
 
     def filter(self, context, pools, zone):
-        if len(pools) == 0:
+        if not pools:
             pools = objects.PoolList()
             pools.append(
-                objects.Pool(id=cfg.CONF['service:central'].default_pool_id))
-            return pools
-        else:
-            return pools
+                objects.Pool(id=cfg.CONF['service:central'].default_pool_id)
+            )
+        return pools
diff --git a/designate/scheduler/filters/random_filter.py b/designate/scheduler/filters/random_filter.py
index 578695db..494a1fad 100644
--- a/designate/scheduler/filters/random_filter.py
+++ b/designate/scheduler/filters/random_filter.py
@@ -22,7 +22,8 @@ LOG = logging.getLogger(__name__)
 
 
 class RandomFilter(base.Filter):
-    """Randomly chooses one of the input pools if there is multiple supplied.
+    """Randomly chooses one of the input pools if there are multiple
+    ones supplied.
 
     .. note::
 
@@ -35,9 +36,8 @@ class RandomFilter(base.Filter):
     """
 
     def filter(self, context, pools, zone):
-        new_list = PoolList()
-        if len(pools):
-            new_list.append(random.choice(pools))
-            return new_list
-        else:
-            return pools
+        if pools:
+            new_pool_list = PoolList()
+            new_pool_list.append(random.choice(pools))
+            return new_pool_list
+        return pools
diff --git a/designate/tests/unit/scheduler/test_basic.py b/designate/tests/unit/scheduler/test_basic.py
index 49531e81..156a29ad 100644
--- a/designate/tests/unit/scheduler/test_basic.py
+++ b/designate/tests/unit/scheduler/test_basic.py
@@ -11,7 +11,7 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-from unittest.mock import Mock
+from unittest import mock
 
 from designate import exceptions
 from designate import objects
@@ -35,7 +35,7 @@ class SchedulerTest(tests.TestCase):
             'find_pools.return_value': objects.PoolList.from_list(
                 [{"id": "794ccc2c-d751-44fe-b57f-8894c9f5c842"}])
         }
-        mock_storage = Mock(**attrs)
+        mock_storage = mock.Mock(**attrs)
 
         test_scheduler = scheduler.get_scheduler(storage=mock_storage)
 
@@ -55,7 +55,7 @@ class SchedulerTest(tests.TestCase):
             )
         }
 
-        mock_storage = Mock(**attrs)
+        mock_storage = mock.Mock(**attrs)
 
         test_scheduler = scheduler.get_scheduler(storage=mock_storage)
 
@@ -74,7 +74,7 @@ class SchedulerTest(tests.TestCase):
         attrs = {
             'find_pools.return_value': objects.PoolList()
         }
-        mock_storage = Mock(**attrs)
+        mock_storage = mock.Mock(**attrs)
 
         self.CONF.set_override(
             'scheduler_filters', ['random'], 'service:central'
@@ -96,7 +96,7 @@ class SchedulerTest(tests.TestCase):
         attrs = {
             'find_pools.return_value': objects.PoolList()
         }
-        mock_storage = Mock(**attrs)
+        mock_storage = mock.Mock(**attrs)
 
         self.assertRaisesRegex(
             exceptions.NoFiltersConfigured,
diff --git a/designate/tests/unit/scheduler/test_filters.py b/designate/tests/unit/scheduler/test_filters.py
index da718914..78570e80 100644
--- a/designate/tests/unit/scheduler/test_filters.py
+++ b/designate/tests/unit/scheduler/test_filters.py
@@ -11,7 +11,7 @@
 # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 # License for the specific language governing permissions and limitations
 # under the License.
-from unittest.mock import Mock
+from unittest import mock
 
 import fixtures
 
@@ -41,7 +41,7 @@ class SchedulerFilterTest(tests.TestCase):
                 id="6c346011-e581-429b-a7a2-6cdf0aba91c3")
         }
 
-        mock_storage = Mock(**attrs)
+        mock_storage = mock.Mock(**attrs)
         self.test_filter = self.FILTER(storage=mock_storage)