DPE-7726: Fix exception on update-status. PostgreSQLUndefinedHostError: Host not set.

Exception:

> 2025-08-19 20:49:40 DEBUG unit.postgresql/2.juju-log server.go:406 cluster:API get_patroni_health: <Response [200]> (0.057417)
> 2025-08-19 20:49:40 DEBUG unit.postgresql/2.juju-log server.go:406 cluster:API cluster_status: [{'name': 'postgresql-0', 'role': 'leader', 'state': 'running', 'api_url': 'https://10.182.246.123:8008/patroni', 'host': '10.182.246.123', 'port': 5432, 'timeline': 1}, {'name': 'postgresql-1', 'role': 'sync_standby', 'state': 'running', 'api_url': 'https://10.182.246.163:8008/patroni', 'host': '10.182.246.163', 'port': 5432, 'timeline': 1, 'lag': 0}, {'name': 'postgresql-2', 'role': 'sync_standby', 'state': 'running', 'api_url': 'https://10.182.246.246:8008/patroni', 'host': '10.182.246.246', 'port': 5432, 'timeline': 1, 'lag': 0}]
> 2025-08-19 20:49:40 DEBUG unit.postgresql/2.juju-log server.go:406 __main__:Early exit primary_endpoint: Primary IP not in cached peer list
> 2025-08-19 20:49:40 ERROR unit.postgresql/2.juju-log server.go:406 root:Uncaught exception while in charm code:
> Traceback (most recent call last):
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/src/charm.py", line 2736, in <module>
>     main(PostgresqlOperatorCharm)
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/__init__.py", line 356, in __call__
>     return _main.main(charm_class=charm_class, use_juju_for_storage=use_juju_for_storage)
>            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/_main.py", line 502, in main
>     manager.run()
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/_main.py", line 486, in run
>     self._emit()
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/_main.py", line 421, in _emit
>     self._emit_charm_event(self.dispatcher.event_name)
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/_main.py", line 465, in _emit_charm_event
>     event_to_emit.emit(*args, **kwargs)
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/framework.py", line 351, in emit
>     framework._emit(event)
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/framework.py", line 924, in _emit
>     self._reemit(event_path)
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/venv/lib/python3.12/site-packages/ops/framework.py", line 1030, in _reemit
>     custom_handler(event)
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/lib/charms/tempo_coordinator_k8s/v0/charm_tracing.py", line 1116, in wrapped_function
>     return callable(*args, **kwargs)  # type: ignore
>            ^^^^^^^^^^^^^^^^^^^^^^^^^
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/src/charm.py", line 1942, in _on_update_status
>     self.postgresql_client_relation.oversee_users()
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/lib/charms/tempo_coordinator_k8s/v0/charm_tracing.py", line 1116, in wrapped_function
>     return callable(*args, **kwargs)  # type: ignore
>            ^^^^^^^^^^^^^^^^^^^^^^^^^
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/src/relations/postgresql_provider.py", line 172, in oversee_users
>     user for user in self.charm.postgresql.list_users() if user.startswith("relation-")
>                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/lib/charms/tempo_coordinator_k8s/v0/charm_tracing.py", line 1116, in wrapped_function
>     return callable(*args, **kwargs)  # type: ignore
>            ^^^^^^^^^^^^^^^^^^^^^^^^^
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/lib/charms/postgresql_k8s/v1/postgresql.py", line 959, in list_users
>     with self._connect_to_database(
>          ^^^^^^^^^^^^^^^^^^^^^^^^^^
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/lib/charms/tempo_coordinator_k8s/v0/charm_tracing.py", line 1116, in wrapped_function
>     return callable(*args, **kwargs)  # type: ignore
>            ^^^^^^^^^^^^^^^^^^^^^^^^^
>   File "/var/lib/juju/agents/unit-postgresql-2/charm/lib/charms/postgresql_k8s/v1/postgresql.py", line 273, in _connect_to_database
>     raise PostgreSQLUndefinedHostError("Host not set")
> charms.postgresql_k8s.v1.postgresql.PostgreSQLUndefinedHostError: Host not set
> 2025-08-19 20:49:40 ERROR juju.worker.uniter.operation runhook.go:180 hook "update-status" (via hook dispatching script: dispatch) failed: exit status 1

Author: taurus-forever

src/relations/postgresql_provider.py

@@ -20,6 +20,8 @@
     PostgreSQLCreateUserError,
     PostgreSQLDeleteUserError,
     PostgreSQLListUsersError,
+    PostgreSQLUndefinedHostError,
+    PostgreSQLUndefinedPasswordError,
 )
 from ops.charm import RelationBrokenEvent
 from ops.framework import Object
@@ -171,7 +173,12 @@ def oversee_users(self) -> None:
             database_users = {
                 user for user in self.charm.postgresql.list_users() if user.startswith("relation-")
             }
-        except PostgreSQLListUsersError:
+        except (
+            PostgreSQLListUsersError,
+            PostgreSQLUndefinedHostError,
+            PostgreSQLUndefinedPasswordError,
+        ) as e:
+            logger.error("Early-exit, failed to oversee users: %r", e)
             return
 
         # Retrieve the users from the active relations.