use callback payloads for BEFORE_READ events

This patch switches callbacks over to the payload object style events
[1] for BEFORE_READ based notifications. To do so an EventPayload object
is used with the publish() method to pass along the API related data.
In addition a few UTs are updated to work with the changes.

NeutronLibImpact

[1] https://docs.openstack.org/neutron-lib/latest/contributor/callbacks.html#event-payloads

Change-Id: Iff3e96c56867b4bf4272fed676f39cd6796d756c

neutron/plugins/ml2/drivers/openvswitch/mech_driver/mech_openvswitch.py

@@ -121,9 +121,9 @@ class OpenvswitchMechanismDriver(mech_agent.SimpleAgentMechanismDriverBase):
         def set_bridge_name_inner(bridge_name):
             vif_details[portbindings.VIF_DETAILS_BRIDGE_NAME] = bridge_name
 
-        registry.notify(
-            a_const.OVS_BRIDGE_NAME, events.BEFORE_READ,
-            set_bridge_name_inner, port=port)
+        registry.publish(a_const.OVS_BRIDGE_NAME, events.BEFORE_READ,
+            set_bridge_name_inner, payload=events.EventPayload(
+                None, metadata={'port': port}))
 
     def _pre_get_vif_details(self, agent, context):
         a_config = agent['configurations']

neutron/services/trunk/drivers/openvswitch/driver.py

@@ -68,8 +68,9 @@ def register():
     LOG.debug('Open vSwitch trunk driver registered')
 
 
-def vif_details_bridge_name_handler(resource, event, set_br_name, **kwargs):
+def vif_details_bridge_name_handler(resource, event, set_br_name,
+                                    payload=None):
     """If port is a trunk port, generate a bridge_name for its vif_details."""
-    port = kwargs['port']
+    port = payload.metadata['port']
     if 'trunk_details' in port:
         set_br_name(utils.gen_trunk_br_name(port['trunk_details']['trunk_id']))

neutron/tests/unit/plugins/ml2/drivers/openvswitch/mech_driver/test_mech_openvswitch.py

@@ -67,7 +67,7 @@ class OpenvswitchMechanismBaseTestCase(base.AgentMechanismBaseTestCase):
 
     def test__set_bridge_name_notify(self):
 
-        def fake_callback(resource, event, trigger, **kwargs):
+        def fake_callback(resource, event, trigger, payload=None):
             trigger('fake-br-name')
 
         registry.subscribe(fake_callback, a_const.OVS_BRIDGE_NAME,

neutron/tests/unit/services/trunk/drivers/openvswitch/test_driver.py

@@ -60,7 +60,14 @@ class OVSDriverTestCase(base.BaseTestCase):
         driver.register()
         mock_gen_br_name.return_value = 'fake-trunk-br-name'
         test_trigger = mock.Mock()
-        registry.notify(agent_consts.OVS_BRIDGE_NAME, events.BEFORE_READ,
-                        test_trigger, **{'port': {'trunk_details':
-                                                  {'trunk_id': 'foo'}}})
+        registry.publish(agent_consts.OVS_BRIDGE_NAME, events.BEFORE_READ,
+                         test_trigger,
+                         payload=events.EventPayload(
+                             None, metadata={
+                                 'port': {
+                                     'trunk_details': {
+                                         'trunk_id': 'foo'
+                                     }
+                                 }
+                             }))
         test_trigger.assert_called_once_with('fake-trunk-br-name')