Stop services for goneaway events for relations

Implement stop-services function for the charm.
For relations amqp, ovsdb-cms, reset the
corresponding snap data.
Add mandatory_relations to openstack-hypervisor
charm.

Depends-On: https://review.opendev.org/c/openstack/charm-ops-sunbeam/+/899012
Change-Id: Ie6a735d4cad281c080e47208cf87f34e50d00fd1

src/charm.py

@@ -28,6 +28,8 @@ import socket
 import string
 from typing import (
     List,
+    Optional,
+    Set,
 )
 
 import charms.operator_libs_linux.v2.snap as snap
@@ -65,6 +67,8 @@ class HypervisorOperatorCharm(sunbeam_charm.OSBaseOperatorCharm):
     METADATA_SECRET_KEY = "ovn-metadata-proxy-shared-secret"
     DEFAULT_SECRET_LENGTH = 32
 
+    mandatory_relations = {"amqp", "identity-credentials", "ovsdb-cms"}
+
     def __init__(self, framework: ops.framework.Framework) -> None:
         """Run constructor."""
         super().__init__(framework)
@@ -324,6 +328,21 @@ class HypervisorOperatorCharm(sunbeam_charm.OSBaseOperatorCharm):
             self.enable_telemetry = False
             self.configure_charm(event)
 
+    def stop_services(self, relation: Optional[Set[str]]) -> None:
+        """Stop services based on relation goneaway event."""
+        snap_data = {}
+        for relation_ in relation:
+            logger.info(f"In stop_services for relation {relation_}")
+            if relation_ == "amqp":
+                logger.debug("Resetting rabbitmq url")
+                snap_data.update({"rabbitmq.url": ""})
+            elif relation_ == "ovsdb-cms":
+                logger.debug("Resetting OVN SB connection")
+                snap_data.update({"network.ovn-sb-connection": ""})
+
+        if snap_data:
+            self.set_snap_data(snap_data)
+
 
 if __name__ == "__main__":  # pragma: no cover
     main(HypervisorOperatorCharm)

tests/unit/test_charm.py

@@ -108,11 +108,11 @@ class TestCharm(test_utils.CharmTestCase):
         self.socket.getfqdn.return_value = "test.local"
         self.initial_setup()
         self.harness.set_leader()
+        test_utils.add_complete_amqp_relation(self.harness)
+        test_utils.add_complete_identity_credentials_relation(self.harness)
         hypervisor_snap_mock.ensure.assert_any_call(
             "latest", channel="essex/stable"
         )
-        test_utils.add_complete_amqp_relation(self.harness)
-        test_utils.add_complete_identity_credentials_relation(self.harness)
         metadata = self.harness.charm.metadata_secret()
         ovn_cacert = (
             test_utils.TEST_CA + "\n" + "\n".join(test_utils.TEST_CHAIN)
@@ -193,11 +193,11 @@ class TestCharm(test_utils.CharmTestCase):
         self.socket.getfqdn.return_value = "test.local"
         self.initial_setup()
         self.harness.set_leader()
+        test_utils.add_complete_amqp_relation(self.harness)
+        test_utils.add_complete_identity_credentials_relation(self.harness)
         hypervisor_snap_mock.ensure.assert_any_call(
             "latest", channel="essex/stable"
         )
-        test_utils.add_complete_amqp_relation(self.harness)
-        test_utils.add_complete_identity_credentials_relation(self.harness)
         metadata = self.harness.charm.metadata_secret()
         ovn_cacert = (
             test_utils.TEST_CA + "\n" + "\n".join(test_utils.TEST_CHAIN)