notification: Add 'status' to agent after_create/update

Make the same status information available to notification consumers
(resource==agent, event==after_create/after_update) as it was already
available where the notification is sent in class AgentDbMixin.

Change-Id: Ie74091da934c7e49fd29ae4c6f930a7eb47e14b2
Partial-Bug: #1578989
See-Also: https://review.openstack.org/502306 (nova spec)
See-Also: https://review.openstack.org/508149 (neutron spec)

neutron/db/agents_db.py

@@ -425,7 +425,7 @@ class AgentDbMixin(ext_agent.AgentPluginBase, AgentAvailabilityZoneMixin):
         agent_state['admin_state_up'] = agent.admin_state_up
         registry.notify(resources.AGENT, event_type, self, context=context,
                         host=agent_state['host'], plugin=self,
-                        agent=agent_state)
+                        agent=agent_state, status=status)
         return status, agent_state
 
     def _get_agents_considered_for_versions(self):

neutron/services/segments/db.py

@@ -252,7 +252,8 @@ def map_segment_to_hosts(context, segment_id, hosts):
 
 
 def _update_segment_host_mapping_for_agent(resource, event, trigger,
-                                           context, host, plugin, agent):
+                                           context, host, plugin, agent,
+                                           status):
     check_segment_for_agent = getattr(plugin, 'check_segment_for_agent', None)
     if not check_segment_for_agent:
         return

releasenotes/notes/agent-notification-signature-status-6a9b9dbce9cb9740.yaml

@@ -0,0 +1,12 @@
+---
+deprecations:
+  - |
+    The signature of notifications for resource ``agent`` for events
+    ``after_create`` and ``after_update`` was extended. A new keyword
+    argument was added: ``status``. This is to make the same status
+    information available to notification consumers as it was available
+    already where the notification is sent in class ``AgentDbMixin``.
+    Valid status values are defined in ``neutron_lib.agent.constants``.
+    Consuming notifications by the old signature is deprecated. Unless
+    processing arguments as ``**kwargs``, out-of-tree notification
+    consumers need to adapt.