Respect CONF.scheduler_use_baremetal_filters

This fixes an issue where the default filters are loaded before
IronicHostManager overrides the default, which is the intended behavior
when CONF.scheduler_use_baremetal_filters is True.

Creates a _load_filters method on the base HostManager class that
returns a list of filters to be loaded at initialization, and overrides
it in IronicHostManager to return the default baremetal filters when
scheduler_use_baremetal_filters is set.

Change-Id: I1801c62d85665a6a3423428e91e1aeeb546613d7
Closes-Bug: #1439868

nova/scheduler/host_manager.py

@@ -310,8 +310,7 @@ class HostManager(object):
                 CONF.scheduler_available_filters)
         self.filter_cls_map = {cls.__name__: cls for cls in filter_classes}
         self.filter_obj_map = {}
-        self.default_filters = self._choose_host_filters(
-                CONF.scheduler_default_filters)
+        self.default_filters = self._choose_host_filters(self._load_filters())
         self.weight_handler = weights.HostWeightHandler()
         weigher_classes = self.weight_handler.get_matching_classes(
                 CONF.scheduler_weight_classes)
@@ -328,6 +327,9 @@ class HostManager(object):
         if self.tracks_instance_changes:
             self._init_instance_info()
 
+    def _load_filters(self):
+        return CONF.scheduler_default_filters
+
     def _init_aggregates(self):
         elevated = context_module.get_admin_context()
         aggs = objects.AggregateList.get_all(elevated)

nova/scheduler/ironic_host_manager.py

@@ -98,11 +98,10 @@ class IronicNodeState(host_manager.HostState):
 class IronicHostManager(host_manager.HostManager):
     """Ironic HostManager class."""
 
-    def __init__(self):
-        super(IronicHostManager, self).__init__()
+    def _load_filters(self):
         if CONF.scheduler_use_baremetal_filters:
-            baremetal_default = CONF.baremetal_scheduler_default_filters
-            CONF.scheduler_default_filters = baremetal_default
+            return CONF.baremetal_scheduler_default_filters
+        return super(IronicHostManager, self)._load_filters()
 
     def host_state_cls(self, host, node, **kwargs):
         """Factory function/property to create a new HostState."""

nova/tests/unit/scheduler/test_host_manager.py

@@ -69,6 +69,10 @@ class HostManagerTestCase(test.NoDBTestCase):
         self.fake_hosts += [host_manager.HostState('fake_multihost',
                 'fake-node%s' % x) for x in xrange(1, 5)]
 
+    def test_load_filters(self):
+        filters = self.host_manager._load_filters()
+        self.assertEqual(filters, ['FakeFilterClass1'])
+
     @mock.patch.object(nova.objects.InstanceList, 'get_by_filters')
     @mock.patch.object(nova.objects.ComputeNodeList, 'get_all')
     @mock.patch('nova.utils.spawn_n')

nova/tests/unit/scheduler/test_ironic_host_manager.py

@@ -242,6 +242,7 @@ class IronicHostManagerTestFilters(test.NoDBTestCase):
                                                 cls in ['FakeFilterClass1',
                                                         'FakeFilterClass2']])
         self.flags(scheduler_default_filters=['FakeFilterClass1'])
+        self.flags(baremetal_scheduler_default_filters=['FakeFilterClass2'])
         self.host_manager = ironic_host_manager.IronicHostManager()
         self.fake_hosts = [ironic_host_manager.IronicNodeState(
                 'fake_host%s' % x, 'fake-node') for x in range(1, 5)]
@@ -270,6 +271,30 @@ class IronicHostManagerTestFilters(test.NoDBTestCase):
         self.assertEqual(1, len(default_filters))
         self.assertIsInstance(default_filters[0], FakeFilterClass1)
 
+    @mock.patch.object(host_manager.HostManager, '_init_instance_info')
+    @mock.patch.object(host_manager.HostManager, '_init_aggregates')
+    def test_host_manager_default_filters_uses_baremetal(self, mock_init_agg,
+                                                         mock_init_inst):
+        self.flags(scheduler_use_baremetal_filters=True)
+        host_manager = ironic_host_manager.IronicHostManager()
+
+        # ensure the defaults come from baremetal_scheduler_default_filters
+        # and not scheduler_default_filters
+        default_filters = host_manager.default_filters
+        self.assertEqual(1, len(default_filters))
+        self.assertIsInstance(default_filters[0], FakeFilterClass2)
+
+    def test_load_filters(self):
+        # without scheduler_use_baremetal_filters
+        filters = self.host_manager._load_filters()
+        self.assertEqual(['FakeFilterClass1'], filters)
+
+    def test_load_filters_baremetal(self):
+        # with scheduler_use_baremetal_filters
+        self.flags(scheduler_use_baremetal_filters=True)
+        filters = self.host_manager._load_filters()
+        self.assertEqual(['FakeFilterClass2'], filters)
+
     def _mock_get_filtered_hosts(self, info):
         info['got_objs'] = []
         info['got_fprops'] = []