[OVN] Add ``ProviderResourceAssociation`` to any ML2/OVN router

Since [1], any Neutron router created with ML2/OVN will have an
associated ``ProviderResourceAssociation`` register. The routers
created before this feature won't have any and it won't be possible
to delete them. This patch adds a temporary maintenance task to
create the needed register for these Neutron routers.

[1]https://review.opendev.org/c/openstack/neutron/+/883988

Closes-Bug: #2053122
Related-Bug: #2020823
Change-Id: Iecd5c7a66b16e25e9888dbd1e305586b2be2011e

neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/maintenance.py

@@ -41,6 +41,7 @@ from neutron.db import ovn_hash_ring_db as hash_ring_db
 from neutron.db import ovn_revision_numbers_db as revision_numbers_db
 from neutron.objects import ports as ports_obj
 from neutron.objects import router as router_obj
+from neutron.objects import servicetype as servicetype_obj
 from neutron import service
 from neutron.services.logapi.drivers.ovn import driver as log_driver
 
@@ -1184,6 +1185,25 @@ class DBInconsistenciesPeriodics(SchemaAwarePeriodicsBase):
                     txn.add(cmd)
         raise periodics.NeverAgain()
 
+    # TODO(ralonsoh): Remove this method in the C+2 cycle (next SLURP release)
+    @has_lock_periodic(spacing=600, run_immediately=True)
+    def add_provider_resource_association_to_routers(self):
+        """Add the ``ProviderResourceAssociation`` register to all routers"""
+        provider_name = 'ovn'
+        context = n_context.get_admin_context()
+        pra_list = servicetype_obj.ProviderResourceAssociation.get_objects(
+            context, provider_name=provider_name)
+        pra_res_ids = set(pra.resource_id for pra in pra_list)
+        with db_api.CONTEXT_WRITER.using(context):
+            for lr in self._nb_idl.lr_list().execute(check_error=True):
+                router_id = lr.name.replace('neutron-', '')
+                if router_id not in pra_res_ids:
+                    servicetype_obj.ProviderResourceAssociation(
+                        context, provider_name=provider_name,
+                        resource_id=router_id).create()
+
+        raise periodics.NeverAgain()
+
 
 class HashRingHealthCheckPeriodics(object):
 

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

@@ -26,11 +26,13 @@ from neutron_lib.callbacks import registry
 from neutron_lib import constants as n_const
 from neutron_lib import context as n_context
 from neutron_lib.exceptions import l3 as lib_l3_exc
+from oslo_utils import uuidutils
 
 from neutron.common.ovn import constants as ovn_const
 from neutron.common.ovn import utils
 from neutron.conf.plugins.ml2.drivers.ovn import ovn_conf as ovn_config
 from neutron.db import ovn_revision_numbers_db as db_rev
+from neutron.objects import servicetype as servicetype_obj
 from neutron.plugins.ml2.drivers.ovn.mech_driver.ovsdb import maintenance
 from neutron.services.portforwarding import constants as pf_consts
 from neutron.tests.functional import base
@@ -1162,6 +1164,32 @@ class TestMaintenance(_TestMaintenanceHelper):
         else:
             self.assertNotIn('gateway_port', fip_rule)
 
+    def test_add_provider_resource_association_to_routers(self):
+        provider_name = 'ovn'
+        router1 = self._create_router(uuidutils.generate_uuid())
+        router2 = self._create_router(uuidutils.generate_uuid())
+
+        # NOTE(ralonsoh): now each Neutron router will create a
+        # ``ProviderResourceAssociation`` register. In order to be able to test
+        # the maintenance method, the router2 ``ProviderResourceAssociation``
+        # register is deleted.
+        servicetype_obj.ProviderResourceAssociation.delete_objects(
+            self.context, resource_id=router2['id'])
+        pra_list = servicetype_obj.ProviderResourceAssociation.get_objects(
+            self.context, provider_name=provider_name)
+        pra_res_ids = set(pra.resource_id for pra in pra_list)
+        self.assertIn(router1['id'], pra_res_ids)
+        self.assertNotIn(router2['id'], pra_res_ids)
+
+        self.assertRaises(
+            periodics.NeverAgain,
+            self.maint.add_provider_resource_association_to_routers)
+        pra_list = servicetype_obj.ProviderResourceAssociation.get_objects(
+            self.context, provider_name=provider_name)
+        pra_res_ids = set(pra.resource_id for pra in pra_list)
+        self.assertIn(router1['id'], pra_res_ids)
+        self.assertIn(router2['id'], pra_res_ids)
+
 
 class TestLogMaintenance(_TestMaintenanceHelper,
                          test_log_driver.LogApiTestCaseBase):