[ovn]support read chassis update time from nb_cfg_timestamp

nb_cfg_timestamp: The timestamp when ovn-controller finishes
processing the change corresponding to nb_cfg[1]. it can better
reflect the status of chassis.

This patch updated some unit tests. ensure mock 'time.time' is
stopped after test. if not stop, may affect "timeutils.utcnow_ts"
to obtain the real time, cause test case
'test_agent_with_nb_cfg_timestamp_not_timeout' failure.

Partial-bug: #1938478
[1] https://www.ovn.org/support/dist-docs/ovn-sb.5.html

Conflicts:
  neutron/plugins/ml2/drivers/ovn/agent/neutron_agent.py
  neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/test_mech_driver.py
  neutron/tests/unit/agent/l2/extensions/dhcp/test_ipv6.py

Change-Id: Ia74a9404411862dc88b48c4a198d5c53f5f52704
(cherry picked from commit 9e263dcf00)
(cherry picked from commit cfc0678caf)
(cherry picked from commit 538712635c)

neutron/plugins/ml2/drivers/ovn/agent/neutron_agent.py

@@ -14,6 +14,7 @@
 
 import abc
 import copy
+import datetime
 
 from oslo_config import cfg
 from oslo_utils import timeutils
@@ -44,7 +45,21 @@ class NeutronAgent(abc.ABC):
 
     def update(self, chassis_private, updated_at=None, clear_down=False):
         self.chassis_private = chassis_private
-        self.updated_at = updated_at or timeutils.utcnow(with_timezone=True)
+        if not updated_at:
+            # When use the Chassis_Private table for agents health check,
+            # chassis_private has attribute nb_cfg_timestamp.
+            # nb_cfg_timestamp: the timestamp when ovn-controller finishes
+            # processing the change corresponding to nb_cfg(
+            # https://www.ovn.org/support/dist-docs/ovn-sb.5.html).
+            # it can better reflect the status of chassis.
+            # nb_cfg_timestamp is milliseconds, need to convert to datetime.
+            if hasattr(chassis_private, 'nb_cfg_timestamp'):
+                updated_at = datetime.datetime.fromtimestamp(
+                    chassis_private.nb_cfg_timestamp / 1000,
+                    datetime.timezone.utc)
+            else:
+                updated_at = timeutils.utcnow(with_timezone=True)
+        self.updated_at = updated_at
         if clear_down:
             self.set_down = False
 

neutron/tests/functional/base.py

@@ -29,6 +29,7 @@ from oslo_config import cfg
 from oslo_db import exception as os_db_exc
 from oslo_db.sqlalchemy import provision
 from oslo_log import log
+from oslo_utils import timeutils
 from oslo_utils import uuidutils
 
 from neutron.agent.linux import utils
@@ -439,9 +440,11 @@ class TestOVNFunctionalBase(test_plugin.Ml2PluginV2TestCase,
             name, ['geneve'], '172.24.4.%d' % self._counter,
             external_ids=external_ids, hostname=host).execute(check_error=True)
         if self.sb_api.is_table_present('Chassis_Private'):
+            nb_cfg_timestamp = timeutils.utcnow_ts() * 1000
             self.sb_api.db_create(
                 'Chassis_Private', name=name, external_ids=external_ids,
-                chassis=chassis.uuid).execute(check_error=True)
+                chassis=chassis.uuid, nb_cfg_timestamp=nb_cfg_timestamp
+            ).execute(check_error=True)
         return name
 
     def del_fake_chassis(self, chassis, if_exists=True):

neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_ovsdb_monitor.py

@@ -11,7 +11,7 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-
+import datetime
 import functools
 from unittest import mock
 
@@ -22,6 +22,7 @@ from neutron_lib.api.definitions import portbindings
 from neutron_lib.plugins import constants as plugin_constants
 from neutron_lib.plugins import directory
 from oslo_concurrency import processutils
+from oslo_utils import timeutils
 from oslo_utils import uuidutils
 from ovsdbapp.backend.ovs_idl import event
 from ovsdbapp.backend.ovs_idl import idlutils
@@ -461,6 +462,21 @@ class TestAgentMonitor(base.TestOVNFunctionalBase):
         self.assertEqual(neutron_agent.ControllerAgent,
                 type(neutron_agent.AgentCache()[self.chassis_name]))
 
+    def test_agent_updated_at_use_nb_cfg_timestamp(self):
+        if not self.sb_api.is_table_present('Chassis_Private'):
+            self.skipTest('Ovn sb not support Chassis_Private')
+        timestamp = timeutils.utcnow_ts()
+        nb_cfg_timestamp = timestamp * 1000
+        updated_at = datetime.datetime.fromtimestamp(
+            timestamp, datetime.timezone.utc)
+        self.sb_api.db_set('Chassis_Private', self.chassis_name, (
+            'nb_cfg_timestamp', nb_cfg_timestamp)).execute(check_error=True)
+        n_utils.wait_until_true(lambda:
+                neutron_agent.AgentCache()[self.chassis_name].
+                chassis_private.nb_cfg_timestamp == nb_cfg_timestamp)
+        agent = neutron_agent.AgentCache()[self.chassis_name]
+        self.assertEqual(updated_at, agent.updated_at)
+
 
 class TestOvnIdlProbeInterval(base.TestOVNFunctionalBase):
     def setUp(self):

neutron/tests/unit/plugins/ml2/drivers/ovn/mech_driver/test_mech_driver.py

@@ -2056,9 +2056,11 @@ class TestOVNMechanismDriver(TestOVNMechanismDriverBase):
                            updated_at=None):
         updated_at = updated_at or timeutils.utcnow(with_timezone=True)
         chassis_private = chassis_private or self._add_chassis(nb_cfg)
-        chassis_private.external_ids = {
-            ovn_const.OVN_LIVENESS_CHECK_EXT_ID_KEY:
-                datetime.datetime.isoformat(updated_at)}
+
+        if hasattr(chassis_private, 'nb_cfg_timestamp') and isinstance(
+                chassis_private.nb_cfg_timestamp, mock.Mock):
+            del chassis_private.nb_cfg_timestamp
+        chassis_private.external_ids = {}
         if agent_type == ovn_const.OVN_METADATA_AGENT:
             chassis_private.external_ids.update({
                 ovn_const.OVN_AGENT_METADATA_SB_CFG_KEY: nb_cfg,
@@ -2115,6 +2117,35 @@ class TestOVNMechanismDriver(TestOVNMechanismDriverBase):
             self.assertFalse(agent.alive, "Agent of type %s alive=%s" %
                              (agent.agent_type, agent.alive))
 
+    def test_agent_with_nb_cfg_timestamp_timeout(self):
+        nb_cfg = 3
+        chassis_private = self._add_chassis(nb_cfg)
+
+        self.mech_driver.nb_ovn.nb_global.nb_cfg = nb_cfg + 2
+        updated_at = (timeutils.utcnow_ts() - cfg.CONF.agent_down_time - 1
+                      ) * 1000
+        chassis_private.nb_cfg_timestamp = updated_at
+        agent_type = ovn_const.OVN_CONTROLLER_AGENT
+        updated_at = (timeutils.utcnow(with_timezone=True) -
+                      datetime.timedelta(minutes=10))
+        agent = self._add_chassis_agent(nb_cfg, agent_type, chassis_private,
+                                        updated_at=updated_at)
+        self.assertFalse(agent.alive, "Agent of type %s alive=%s" %
+                         (agent.agent_type, agent.alive))
+
+    def test_agent_with_nb_cfg_timestamp_not_timeout(self):
+        nb_cfg = 3
+        chassis_private = self._add_chassis(nb_cfg)
+
+        self.mech_driver.nb_ovn.nb_global.nb_cfg = nb_cfg + 2
+        updated_at = timeutils.utcnow_ts() * 1000
+        chassis_private.nb_cfg_timestamp = updated_at
+        agent_type = ovn_const.OVN_CONTROLLER_AGENT
+        agent = self._add_chassis_agent(nb_cfg, agent_type,
+                                        chassis_private)
+        self.assertTrue(agent.alive, "Agent of type %s alive=%s" % (
+            agent.agent_type, agent.alive))
+
     def _test__update_dnat_entry_if_needed(self, up=True):
         ovn_conf.cfg.CONF.set_override(
             'enable_distributed_floating_ip', True, group='ovn')