From f9e267fa42f5b8a024edaafd872eeeb9eb9f9b43 Mon Sep 17 00:00:00 2001
From: licanwei <li.canwei2@zte.com.cn>
Date: Thu, 6 Jun 2019 11:13:34 +0800
Subject: [PATCH] check instance state for instance.update

In the process of creating an instance, Nova will emit an
instance.update notification with 'building' state.
This will cause a KeyError exception because this instance
isn't in Watcher datamodel.
So we should ignore the notification instance.update with
'building' state.

Closes-Bug: #1832154

Change-Id: I950eec50d2cee38bd22c47a70ae6f88bbf049080
---
 .../model/notification/nova.py                |  5 ++++
 .../notification/test_nova_notifications.py   | 25 +++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/watcher/decision_engine/model/notification/nova.py b/watcher/decision_engine/model/notification/nova.py
index f4dee54ae..77cfb07b0 100644
--- a/watcher/decision_engine/model/notification/nova.py
+++ b/watcher/decision_engine/model/notification/nova.py
@@ -216,7 +216,12 @@ class VersionedNotification(NovaNotification):
     def instance_updated(self, payload):
         instance_data = payload['nova_object.data']
         instance_uuid = instance_data['uuid']
+        instance_state = instance_data['state']
         node_uuid = instance_data.get('host')
+        # if instance state is building, don't update data model
+        if instance_state == 'building':
+            return
+
         instance = self.get_or_create_instance(instance_uuid, node_uuid)
 
         self.update_instance(instance, payload)
diff --git a/watcher/tests/decision_engine/model/notification/test_nova_notifications.py b/watcher/tests/decision_engine/model/notification/test_nova_notifications.py
index 95f793e70..ab7d5fdd4 100644
--- a/watcher/tests/decision_engine/model/notification/test_nova_notifications.py
+++ b/watcher/tests/decision_engine/model/notification/test_nova_notifications.py
@@ -245,6 +245,31 @@ class TestNovaNotifications(NotificationTestCase):
 
         self.assertEqual(element.InstanceState.PAUSED.value, instance0.state)
 
+    def test_nova_instance_state_building(self):
+        compute_model = self.fake_cdmc.generate_scenario_3_with_2_nodes()
+        self.fake_cdmc.cluster_data_model = compute_model
+        handler = novanotification.VersionedNotification(self.fake_cdmc)
+
+        instance0_uuid = '73b09e16-35b7-4922-804e-e8f5d9b740fc'
+        instance0 = compute_model.get_instance_by_uuid(instance0_uuid)
+        self.assertEqual(element.InstanceState.ACTIVE.value, instance0.state)
+
+        message = self.load_message('instance-update.json')
+
+        message['payload']['nova_object.data']['state'] = 'building'
+
+        handler.info(
+            ctxt=self.context,
+            publisher_id=message['publisher_id'],
+            event_type=message['event_type'],
+            payload=message['payload'],
+            metadata=self.FAKE_METADATA,
+        )
+
+        # Assert that the instance state in the model is unchanged
+        # since the 'building' state is ignored.
+        self.assertEqual(element.InstanceState.ACTIVE.value, instance0.state)
+
     @mock.patch.object(nova_helper, "NovaHelper")
     def test_nova_instance_update_notfound_still_creates(
             self, m_nova_helper_cls):