svc_monitor scheduling does not handle empty azs

The change handles cases where either the entire nova az is diabled
or few hosts in the az are disabled or nova-commpute is not
running on any of the hosts.

Change-Id: I117e841ab1d56aa1df57d48c315d2988830f52cf
Closes-Bug: #1561609

src/config/svc-monitor/svc_monitor/scheduler/vrouter_scheduler.py

@@ -63,7 +63,22 @@ def _get_az_vrouter_list(self):
         for az in az_list:
             if self._args.netns_availability_zone not in str(az):
                 continue
-            az_vr_list.extend(az.hosts.keys())
+            try:
+                # check if the az is available
+                if not az.zoneState['available']:
+                    continue
+                # check if there are any hosts
+                if not az.hosts:
+                    continue
+                # check if hosts are active & enabled
+                for host,host_status in az.hosts.iteritems():
+                    if (('nova-compute' in host_status) and \
+                        host_status['nova-compute']['available'] and \
+                        host_status['nova-compute']['active']):
+                        az_vr_list.append(host)
+            except Exception as e:
+                self._logger.log_error(str(e))
+                continue
 
         return az_vr_list
 

src/config/svc-monitor/svc_monitor/tests/scheduler/test_vrouter_schedulers.py

@@ -19,7 +19,7 @@
 
 import mock
 import unittest
-
+import six
 import cfgm_common.analytics_client as analytics
 import cfgm_common.svc_info as svc_info
 from sandesh_common.vns import constants
@@ -145,3 +145,54 @@ def side_effect(seq):
             self.assertEqual(chosen_vrouter, 'vrouter1')
 
         random_patch.stop()
+
+    def test_disabled_azs(self):
+        class FakeAvailabilityZone(object):
+            def __repr__(self):
+                return "<AvailabilityZone: %s>" % self.zoneName
+            def __init__(self, info):
+                self._info = info
+                self._add_details(info)
+
+            def _add_details(self, info):
+                for (k, v) in six.iteritems(info):
+                    try:
+                        setattr(self, k, v)
+                        self._info[k] = v
+                    except AttributeError:
+                        pass
+
+        def get_fake_azs():
+            az1_info = {"zoneState":{"available":True},
+                        "hosts":{"compute1":{"nova-compute":
+                                            {"available":True,"active":True}},
+                                 "compute2":{"nova-compute":
+                                            {"available":False,"active":True}},
+                                 "compute3":{"nova-compute":
+                                            {"available":True,"active":True}}},
+                        "zoneName":"fake_az1"}
+
+            az2_info = {"zoneState":{"available":False},
+                        "hosts":{"compute4":{"nova-compute":
+                                            {"available":True,"active":True}}},
+                        "zoneName":"fake_az2"}
+
+            az3_info = {"zoneState":{"available":True},
+                        "hosts":{"compute5":{"nova-compute":
+                                            {"available":True,"active":True}}},
+                        "zoneName":"fake_az3"}
+
+            return [FakeAvailabilityZone(az1_info),
+                    FakeAvailabilityZone(az2_info),
+                    FakeAvailabilityZone(az3_info)]
+
+        self.mock_nc = mock.MagicMock()
+        self.mock_nc.oper = mock.Mock(return_value=get_fake_azs())
+
+        self.scheduler2 = \
+            scheduler.RandomScheduler(vnc_lib=self.vnc_mock, nova_client=self.mock_nc,
+                disc=mock.MagicMock(), logger=mock.MagicMock(),
+                args=mock.MagicMock(netns_availability_zone="fake_az1"))
+
+        az_vr_list = self.scheduler2._get_az_vrouter_list()
+        self.assertEqual(az_vr_list, ['compute1', 'compute3'])