Ensure that load balancer is added to logical switch

Add logic to handle cases where a race between logical router port and
load balancer creation renders the affected logical switch without the
proper load balancer in its attribute.

This change adds _get_subnet() to the helper module, so obtaining the
subnet is done from a shared location.

Closes-bug: #1931639
Change-Id: Ie4a843fc5dd98fc25f8cecf91997e275c36f121d
(cherry picked from commit b2a862fdb3)

ovn_octavia_provider/helper.py

@@ -1472,9 +1472,31 @@ class OvnProviderHelper(object):
 
         external_ids[pool_key] = pool_data[pool_key]
         commands.extend(self._refresh_lb_vips(ovn_lb.uuid, external_ids))
+        subnet_id = member[constants.SUBNET_ID]
         commands.extend(
             self._update_lb_to_ls_association(
-                ovn_lb, subnet_id=member[constants.SUBNET_ID], associate=True))
+                ovn_lb, subnet_id=subnet_id, associate=True))
+
+        # Make sure that all logical switches related to logical router
+        # are associated with the load balancer. This is needed to handle
+        # potential race that happens when lrp and lb are created at the
+        # same time.
+        neutron_client = clients.get_neutron_client()
+        try:
+            subnet = neutron_client.show_subnet(subnet_id)
+            ls_name = utils.ovn_name(subnet['subnet']['network_id'])
+            ovn_ls = self.ovn_nbdb_api.ls_get(ls_name).execute(
+                check_error=True)
+            ovn_lr = self._find_lr_of_ls(ovn_ls)
+            if ovn_lr:
+                for net in self._find_ls_for_lr(ovn_lr):
+                    commands.append(self.ovn_nbdb_api.ls_lb_add(
+                        net, ovn_lb.uuid, may_exist=True))
+        except n_exc.NotFound:
+            pass
+        except idlutils.RowNotFound:
+            pass
+
         self._execute_commands(commands)
 
     def member_create(self, member):

ovn_octavia_provider/tests/unit/test_helper.py

@@ -1117,7 +1117,10 @@ class TestOvnProviderHelper(ovn_base.TestOvnOctaviaBase):
         self.helper.ovn_nbdb_api.lb_del.assert_called_once_with(
             self.ovn_lb.uuid)
 
-    def test_member_create(self):
+    @mock.patch('ovn_octavia_provider.common.clients.get_neutron_client')
+    def test_member_create(self, net_cli):
+        net_cli.return_value.show_subnet.side_effect = [
+            idlutils.RowNotFound, idlutils.RowNotFound]
         self.ovn_lb.external_ids = mock.MagicMock()
         status = self.helper.member_create(self.member)
         self.assertEqual(status['loadbalancers'][0]['provisioning_status'],
@@ -1137,6 +1140,38 @@ class TestOvnProviderHelper(ovn_base.TestOvnOctaviaBase):
         self.assertEqual(status['members'][0]['operating_status'],
                          constants.OFFLINE)
 
+    @mock.patch.object(ovn_helper.OvnProviderHelper, '_find_ls_for_lr')
+    @mock.patch.object(ovn_helper.OvnProviderHelper, '_find_lr_of_ls')
+    @mock.patch('ovn_octavia_provider.common.clients.get_neutron_client')
+    def test_member_create_lb_add_from_lr(self, net_cli, f_lr, f_ls):
+        fake_subnet = fakes.FakeSubnet.create_one_subnet()
+        net_cli.return_value.show_subnet.return_value = {'subnet': fake_subnet}
+        f_lr.return_value = self.router
+        f_ls.return_value = [self.network]
+        self.ovn_lb.external_ids = mock.MagicMock()
+        status = self.helper.member_create(self.member)
+        self.assertEqual(status['loadbalancers'][0]['provisioning_status'],
+                         constants.ACTIVE)
+        f_lr.assert_called_once_with(self.network)
+        f_ls.assert_called_once_with(self.router)
+
+    @mock.patch.object(ovn_helper.OvnProviderHelper, '_find_ls_for_lr')
+    @mock.patch.object(ovn_helper.OvnProviderHelper, '_find_lr_of_ls')
+    @mock.patch('ovn_octavia_provider.common.clients.get_neutron_client')
+    def test_member_create_lb_add_from_lr_no_ls(self, net_cli, f_lr, f_ls):
+        fake_subnet = fakes.FakeSubnet.create_one_subnet()
+        net_cli.return_value.show_subnet.return_value = {'subnet': fake_subnet}
+        self.ovn_lb.external_ids = mock.MagicMock()
+        (self.helper.ovn_nbdb_api.ls_get.return_value.
+            execute.side_effect) = [n_exc.NotFound]
+        status = self.helper.member_create(self.member)
+        self.assertEqual(status['loadbalancers'][0]['provisioning_status'],
+                         constants.ACTIVE)
+        (self.helper.ovn_nbdb_api.ls_get.return_value.execute.
+            assert_called_once_with(check_error=True))
+        f_lr.assert_not_called()
+        f_ls.assert_not_called()
+
     @mock.patch.object(ovn_helper.OvnProviderHelper, '_add_member')
     def test_member_create_exception(self, mock_add_member):
         mock_add_member.side_effect = [RuntimeError]
@@ -1152,7 +1187,9 @@ class TestOvnProviderHelper(ovn_base.TestOvnOctaviaBase):
             [mock.call('pool_%s' % self.pool_id),
              mock.call('pool_%s%s' % (self.pool_id, ':D'))])
 
-    def test_member_create_listener(self):
+    @mock.patch('ovn_octavia_provider.common.clients.get_neutron_client')
+    def test_member_create_listener(self, net_cli):
+        net_cli.return_value.show_subnet.side_effect = [idlutils.RowNotFound]
         self.ovn_lb.external_ids = mock.MagicMock()
         self.helper._get_pool_listeners.return_value = ['listener1']
         status = self.helper.member_create(self.member)