Add a new method ha_state_change to L3 agent extension

This is needed by VPNaaS agent extension and other advanced
services in case they support L3 HA router.

Change-Id: Ice1b1c2ca97f47312e37379106ed5a6580f100dc
Needed-By: I0b86c432e4b2210e5f2a73a7e3ba16d10467f0f2
Related-Bug: #1692128

neutron/agent/l3/ha.py

@@ -109,9 +109,9 @@ class AgentMixin(object):
         return self.conf.ha_vrrp_advert_int
 
     def enqueue_state_change(self, router_id, state):
+        state_change_data = {"router_id": router_id, "state": state}
         LOG.info('Router %(router_id)s transitioned to %(state)s',
-                 {'router_id': router_id,
-                  'state': state})
+                 state_change_data)
 
         ri = self._get_router_info(router_id)
         if ri is None:
@@ -127,6 +127,7 @@ class AgentMixin(object):
         self._update_radvd_daemon(ri, state)
         self.pd.process_ha_state(router_id, state == 'master')
         self.state_change_notifier.queue_event((router_id, state))
+        self.l3_ext_manager.ha_state_change(self.context, state_change_data)
 
     def _configure_ipv6_params_on_ext_gw_port_if_necessary(self, ri, state):
         # If ipv6 is enabled on the platform, ipv6_gateway config flag is

neutron/agent/l3/l3_agent_extension.py

@@ -53,3 +53,13 @@ class L3AgentCoreResourceExtension(agent_extension.AgentExtension):
         :param context: rpc context
         :param data: router data
         """
+
+    @abc.abstractmethod
+    def ha_state_change(self, context, data):
+        """Change router state from agent extension.
+
+        Called on HA router state change.
+
+        :param context: rpc context
+        :param data: dict of router_id and new state
+        """

neutron/agent/l3/l3_agent_extensions_manager.py

@@ -70,3 +70,15 @@ class L3AgentExtensionsManager(agent_ext_manager.AgentExtensionsManager):
                     "implement method delete_router",
                     {'name': extension.name}
                 )
+
+    def ha_state_change(self, context, data):
+        """Notify all agent extensions for HA router state change."""
+        for extension in self:
+            if hasattr(extension.obj, 'ha_state_change'):
+                extension.obj.ha_state_change(context, data)
+            else:
+                LOG.warning(
+                    "Agent Extension '%(name)s' does not "
+                    "implement method ha_state_change",
+                    {'name': extension.name}
+                )

neutron/tests/unit/agent/l3/test_agent.py

@@ -211,6 +211,17 @@ class TestBasicRouterOperations(BasicRouterOperationsFramework):
         agent.enqueue_state_change(router.id, 'master')
         self.assertFalse(agent._update_metadata_proxy.call_count)
 
+    def test_enqueue_state_change_l3_extension(self):
+        agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)
+        router = mock.Mock()
+        router_info = mock.MagicMock()
+        agent.router_info[router.id] = router_info
+        agent.l3_ext_manager.ha_state_change = mock.Mock()
+        agent.enqueue_state_change(router.id, 'master')
+        agent.l3_ext_manager.ha_state_change.assert_called_once_with(
+            agent.context,
+            {'router_id': router.id, 'state': 'master'})
+
     def _test__configure_ipv6_params_on_ext_gw_port_if_necessary_helper(
             self, state, enable_expected):
         agent = l3_agent.L3NATAgent(HOSTNAME, self.conf)

releasenotes/notes/l3-agent-extensions-ha-state-change-f50ae363a53b0f18.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    A new method ``ha_state_change`` has been added to
+    ``L3AgentExtensionsManager``.