use payloads for AGENT BEFORE_DELETE callbacks

This patch switches BEFORE_DELETE callback events for AGENT resources
over to the payload style args use a DBEventPayload object. In addition,
the _delete_mac_associated_with_agent is now refactored into it's own
method to allow the context parameter to be parsed by
retry_if_session_inactive.

NeutronLibImpact

Change-Id: I0af951f4346f9290c2eba6aad17f772fbf27bb2f

neutron/db/agents_db.py

@@ -266,8 +266,9 @@ class AgentDbMixin(ext_agent.AgentPluginBase, AgentAvailabilityZoneMixin):
     @db_api.retry_if_session_inactive()
     def delete_agent(self, context, id):
         agent = self._get_agent(context, id)
-        registry.notify(resources.AGENT, events.BEFORE_DELETE, self,
-                        context=context, agent=agent)
+        registry.publish(resources.AGENT, events.BEFORE_DELETE, self,
+                         payload=events.DBEventPayload(
+                             context, states=(agent,), resource_id=id))
         agent.delete()
 
     @db_api.retry_if_session_inactive()

neutron/db/dvr_mac_db.py

@@ -59,10 +59,8 @@ class DVRDbMixin(ext_dvr.DVRMacAddressPluginBase):
         return self._plugin
 
     @staticmethod
-    @registry.receives(resources.AGENT, [events.BEFORE_DELETE])
     @db_api.retry_if_session_inactive()
-    def _delete_mac_associated_with_agent(resource, event, trigger, context,
-                                          agent, **kwargs):
+    def _db_delete_mac_associated_with_agent(context, agent):
         host = agent['host']
         plugin = directory.get_plugin()
         if [a for a in plugin.get_agents(context, filters={'host': [host]})
@@ -78,6 +76,14 @@ class DVRDbMixin(ext_dvr.DVRMacAddressPluginBase):
         dvr_macs = plugin.get_dvr_mac_address_list(context)
         plugin.notifier.dvr_mac_address_update(context, dvr_macs)
 
+    @staticmethod
+    @registry.receives(resources.AGENT, [events.BEFORE_DELETE])
+    def _delete_mac_associated_with_agent(resource, event,
+                                          trigger, payload=None):
+
+        DVRDbMixin._db_delete_mac_associated_with_agent(
+            payload.context, payload.latest_state)
+
     @db_api.context_manager.reader
     def _get_dvr_mac_address_by_host(self, context, host):
         dvr_obj = router.DVRMacAddress.get_object(context, host=host)

neutron/tests/unit/db/test_dvr_mac_db.py

@@ -94,8 +94,9 @@ class DvrDbMixinTestCase(test_plugin.Ml2PluginV2TestCase):
         agent2 = {'host': 'host_1', 'id': 'a2'}
         with mock.patch.object(plugin, 'get_agents', return_value=[agent2]):
             with mock.patch.object(plugin, 'notifier') as notifier:
-                registry.notify(resources.AGENT, events.BEFORE_DELETE, self,
-                                context=self.ctx, agent=agent1)
+                registry.publish(resources.AGENT, events.BEFORE_DELETE, self,
+                                 payload=events.DBEventPayload(
+                                     self.ctx, states=(agent1,)))
         mac_list = self.mixin.get_dvr_mac_address_list(self.ctx)
         for mac in mac_list:
             self.assertIsInstance(mac, dict)
@@ -110,8 +111,9 @@ class DvrDbMixinTestCase(test_plugin.Ml2PluginV2TestCase):
         self._create_dvr_mac_entry('host_2', mac_2)
         agent = {'host': 'host_1', 'id': 'a1'}
         with mock.patch.object(plugin, 'notifier') as notifier:
-            registry.notify(resources.AGENT, events.BEFORE_DELETE, self,
-                            context=self.ctx, agent=agent)
+            registry.publish(resources.AGENT, events.BEFORE_DELETE, self,
+                             payload=events.DBEventPayload(
+                                 self.ctx, states=(agent,)))
         mac_list = self.mixin.get_dvr_mac_address_list(self.ctx)
         self.assertEqual(1, len(mac_list))
         for mac in mac_list: