Fix scheduler code to use monitor metric objects

Per bug 1468012 we changed the monitor metric reporting
to use versioned Monitor Metric objects instead of plain
old dictionaries.

This fix addresses a code refactoring needed inside
nova/scheduler/host_manager.py - in the
_update_metrics_from_compute_node to use the monitor metric object
instead of the current non object implementation.

Further, it fixes the metrics_filter.
The metrics_filter was expecting a dict of metrics but now
it has to adapt to the MonitorMetricList object instead.

Closes-bug: 1485082
Change-Id: I4dfbea27ce6c3eecc1a8658b1f9dc0feb2298705

nova/objects/monitor_metric.py

@@ -10,6 +10,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_serialization import jsonutils
 from oslo_utils import timeutils
 
 from nova.objects import base
@@ -74,6 +75,19 @@ class MonitorMetricList(base.ObjectListBase, base.NovaObject):
         'objects': [('1.0', '1.0'), ('1.1', '1.1')],
     }
 
+    @classmethod
+    def from_json(cls, metrics):
+        """Converts a legacy json object into a list of MonitorMetric objs
+        and finally returns of MonitorMetricList
+
+        :param metrics: a string of json serialized objects
+        :returns: a MonitorMetricList Object.
+        """
+        metrics = jsonutils.loads(metrics) if metrics else []
+        metric_list = [
+            MonitorMetric(**metric) for metric in metrics]
+        return MonitorMetricList(objects=metric_list)
+
     # NOTE(jaypipes): This method exists to convert the object to the
     # format expected by the RPC notifier for metrics events.
     def to_list(self):

nova/scheduler/filters/metrics_filter.py

@@ -41,13 +41,15 @@ class MetricsFilter(filters.BaseHostFilter):
                                    sep='=',
                                    converter=float,
                                    name="metrics.weight_setting")
-        self.keys = [x[0] for x in opts]
+        self.keys = set([x[0] for x in opts])
 
     def host_passes(self, host_state, filter_properties):
-        unavail = [i for i in self.keys if i not in host_state.metrics]
+        metrics_on_host = set(m.name for m in host_state.metrics)
-        if unavail:
+        if not self.keys.issubset(metrics_on_host):
+            unavail = metrics_on_host - self.keys
             LOG.debug("%(host_state)s does not have the following "
                         "metrics: %(metrics)s",
                       {'host_state': host_state,
                        'metrics': ', '.join(unavail)})
-        return len(unavail) == 0
+            return False
+        return True

nova/scheduler/host_manager.py

@@ -28,7 +28,6 @@ except ImportError:
 import iso8601
 from oslo_config import cfg
 from oslo_log import log as logging
-from oslo_serialization import jsonutils
 from oslo_utils import timeutils
 import six
 
@@ -150,7 +149,7 @@ class HostState(object):
         self.limits = {}
 
         # Generic metrics from compute nodes
-        self.metrics = {}
+        self.metrics = None
 
         # List of aggregates the host belongs to
         self.aggregates = []
@@ -165,27 +164,6 @@ class HostState(object):
     def update_service(self, service):
         self.service = ReadOnlyDict(service)
 
-    def _update_metrics_from_compute_node(self, compute):
-        """Update metrics from a ComputeNode object."""
-        # NOTE(llu): The 'or []' is to avoid json decode failure of None
-        #            returned from compute.get, because DB schema allows
-        #            NULL in the metrics column
-        metrics = compute.metrics or []
-        if metrics:
-            metrics = jsonutils.loads(metrics)
-        for metric in metrics:
-            # 'name', 'value', 'timestamp' and 'source' are all required
-            # to be valid keys, just let KeyError happen if any one of
-            # them is missing. But we also require 'name' to be True.
-            name = metric['name']
-            item = MetricItem(value=metric['value'],
-                              timestamp=metric['timestamp'],
-                              source=metric['source'])
-            if name:
-                self.metrics[name] = item
-            else:
-                LOG.warning(_LW("Metric name unknown of %r"), item)
-
     def update_from_compute_node(self, compute):
         """Update information about a host from a ComputeNode object."""
         if (self.updated and compute.updated_at
@@ -244,7 +222,7 @@ class HostState(object):
         self.num_io_ops = int(self.stats.get('io_workload', 0))
 
         # update metrics
-        self._update_metrics_from_compute_node(compute)
+        self.metrics = objects.MonitorMetricList.from_json(compute.metrics)
 
     def consume_from_instance(self, instance):
         """Incrementally update host state from an instance."""

nova/tests/unit/scheduler/filters/test_metrics_filters.py

@@ -10,6 +10,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import datetime
+from nova import objects
 from nova.scheduler.filters import metrics_filter
 from nova import test
 from nova.tests.unit.scheduler import fakes
@@ -18,17 +20,32 @@ from nova.tests.unit.scheduler import fakes
 class TestMetricsFilter(test.NoDBTestCase):
 
     def test_metrics_filter_pass(self):
-        self.flags(weight_setting=['foo=1', 'bar=2'], group='metrics')
+        _ts_now = datetime.datetime(2015, 11, 11, 11, 0, 0)
+        obj1 = objects.MonitorMetric(name='cpu.frequency',
+                                     value=1000,
+                                     timestamp=_ts_now,
+                                     source='nova.virt.libvirt.driver')
+        obj2 = objects.MonitorMetric(name='numa.membw.current',
+                                     numa_membw_values={"0": 10, "1": 43},
+                                     timestamp=_ts_now,
+                                     source='nova.virt.libvirt.driver')
+        metrics_list = objects.MonitorMetricList(objects=[obj1, obj2])
+        self.flags(weight_setting=[
+            'cpu.frequency=1', 'numa.membw.current=2'], group='metrics')
         filt_cls = metrics_filter.MetricsFilter()
-        metrics = dict(foo=1, bar=2)
         host = fakes.FakeHostState('host1', 'node1',
-                                   attribute_dict={'metrics': metrics})
+                                   attribute_dict={'metrics': metrics_list})
         self.assertTrue(filt_cls.host_passes(host, None))
 
     def test_metrics_filter_missing_metrics(self):
+        _ts_now = datetime.datetime(2015, 11, 11, 11, 0, 0)
+        obj1 = objects.MonitorMetric(name='cpu.frequency',
+                                     value=1000,
+                                     timestamp=_ts_now,
+                                     source='nova.virt.libvirt.driver')
+        metrics_list = objects.MonitorMetricList(objects=[obj1])
         self.flags(weight_setting=['foo=1', 'bar=2'], group='metrics')
         filt_cls = metrics_filter.MetricsFilter()
-        metrics = dict(foo=1)
         host = fakes.FakeHostState('host1', 'node1',
-                                   attribute_dict={'metrics': metrics})
+                                   attribute_dict={'metrics': metrics_list})
         self.assertFalse(filt_cls.host_passes(host, None))

nova/tests/unit/scheduler/test_host_manager.py

@@ -17,6 +17,7 @@ Tests For HostManager
 """
 
 import collections
+import datetime
 
 import mock
 from oslo_config import cfg
@@ -956,15 +957,16 @@ class HostStateTestCase(test.NoDBTestCase):
         self.assertEqual(0, len(host.pci_stats.pools))
 
     def test_resources_consumption_from_compute_node(self):
+        _ts_now = datetime.datetime(2015, 11, 11, 11, 0, 0)
         metrics = [
-            dict(name='res1',
+            dict(name='cpu.frequency',
                  value=1.0,
                  source='source1',
-                 timestamp=None),
+                 timestamp=_ts_now),
-            dict(name='res2',
+            dict(name='numa.membw.current',
-                 value="string2",
+                 numa_membw_values={"0": 10, "1": 43},
                  source='source2',
-                 timestamp=None),
+                 timestamp=_ts_now),
         ]
         hyper_ver_int = utils.convert_version_to_int('6.0.0')
         compute = objects.ComputeNode(
@@ -983,9 +985,11 @@ class HostStateTestCase(test.NoDBTestCase):
         host.update_from_compute_node(compute)
 
         self.assertEqual(len(host.metrics), 2)
-        self.assertEqual(set(['res1', 'res2']), set(host.metrics.keys()))
+        self.assertEqual(1.0, host.metrics.to_list()[0]['value'])
-        self.assertEqual(1.0, host.metrics['res1'].value)
+        self.assertEqual('source1', host.metrics[0].source)
-        self.assertEqual('source1', host.metrics['res1'].source)
+        self.assertEqual('cpu.frequency', host.metrics[0].name)
-        self.assertEqual('string2', host.metrics['res2'].value)
+        self.assertEqual('numa.membw.current', host.metrics[1].name)
-        self.assertEqual('source2', host.metrics['res2'].source)
+        self.assertEqual('source2', host.metrics.to_list()[1]['source'])
+        self.assertEqual({'0': 10, '1': 43},
+                         host.metrics[1].numa_membw_values)
         self.assertIsInstance(host.numa_topology, six.string_types)