[MISC] Define charm utility properties (#749)

Author: sinclert-canonical

src/backups.py

@@ -745,7 +745,7 @@ def _is_primary_pgbackrest_service_running(self) -> bool:
 
     def _on_s3_credential_changed(self, event: CredentialsChangedEvent):
         """Call the stanza initialization when the credentials or the connection info change."""
-        if "cluster_initialised" not in self.charm.app_peer_data:
+        if not self.charm.is_cluster_initialised:
             logger.debug("Cannot set pgBackRest configurations, PostgreSQL has not yet started.")
             event.defer()
             return
@@ -757,10 +757,7 @@ def _on_s3_credential_changed(self, event: CredentialsChangedEvent):
             return
 
         # Prevents S3 change in the middle of restoring backup and patroni / pgbackrest errors caused by that.
-        if (
-            "restoring-backup" in self.charm.app_peer_data
-            or "restore-to-time" in self.charm.app_peer_data
-        ):
+        if self.charm.is_cluster_restoring_backup or self.charm.is_cluster_restoring_to_time:
             logger.info("Cannot change S3 configuration during restore")
             event.defer()
             return

src/charm.py

@@ -345,6 +345,26 @@ def is_cluster_initialised(self) -> bool:
         """Returns whether the cluster is already initialised."""
         return "cluster_initialised" in self.app_peer_data
 
+    @property
+    def is_cluster_restoring_backup(self) -> bool:
+        """Returns whether the cluster is restoring a backup."""
+        return "restoring-backup" in self.app_peer_data
+
+    @property
+    def is_cluster_restoring_to_time(self) -> bool:
+        """Returns whether the cluster is restoring a backup to a specific time."""
+        return "restore-to-time" in self.app_peer_data
+
+    @property
+    def is_unit_departing(self) -> bool:
+        """Returns whether the unit is departing."""
+        return "departing" in self.unit_peer_data
+
+    @property
+    def is_unit_stopped(self) -> bool:
+        """Returns whether the unit is stopped."""
+        return "stopped" in self.unit_peer_data
+
     @property
     def postgresql(self) -> PostgreSQL:
         """Returns an instance of the object used to interact with the database."""
@@ -452,9 +472,9 @@ def _on_peer_relation_departed(self, event: RelationDepartedEvent) -> None:
         if not self.unit.is_leader():
             return
 
-        if "cluster_initialised" not in self._peers.data[
-            self.app
-        ] or not self._updated_synchronous_node_count(len(self._units_ips)):
+        if not self.is_cluster_initialised or not self._updated_synchronous_node_count(
+            len(self._units_ips)
+        ):
             logger.debug("Deferring on_peer_relation_departed: cluster not initialized")
             event.defer()
             return
@@ -662,7 +682,7 @@ def has_raft_keys(self):
     def _peer_relation_changed_checks(self, event: HookEvent) -> bool:
         """Split of to reduce complexity."""
         # Prevents the cluster to be reconfigured before it's bootstrapped in the leader.
-        if "cluster_initialised" not in self._peers.data[self.app]:
+        if not self.is_cluster_initialised:
             logger.debug("Deferring on_peer_relation_changed: cluster not initialized")
             event.defer()
             return False
@@ -710,7 +730,7 @@ def _on_peer_relation_changed(self, event: HookEvent):
             return
 
         if (
-            "restoring-backup" in self.app_peer_data or "restore-to-time" in self.app_peer_data
+            self.is_cluster_restoring_backup or self.is_cluster_restoring_to_time
         ) and not self._was_restore_successful():
             logger.debug("on_peer_relation_changed early exit: Backup restore check failed")
             return
@@ -1127,7 +1147,7 @@ def _on_leader_elected(self, event: LeaderElectedEvent) -> None:
 
         # Don't update connection endpoints in the first time this event run for
         # this application because there are no primary and replicas yet.
-        if "cluster_initialised" not in self._peers.data[self.app]:
+        if not self.is_cluster_initialised:
             logger.debug("Early exit on_leader_elected: Cluster not initialized")
             return
 
@@ -1403,7 +1423,7 @@ def _start_primary(self, event: StartEvent) -> None:
 
     def _start_replica(self, event) -> None:
         """Configure the replica if the cluster was already initialised."""
-        if "cluster_initialised" not in self._peers.data[self.app]:
+        if not self.is_cluster_initialised:
             logger.debug("Deferring on_start: awaiting for cluster to start")
             self.unit.status = WaitingStatus("awaiting for cluster to start")
             event.defer()
@@ -1541,7 +1561,7 @@ def _on_update_status(self, _) -> None:
             return
 
         if (
-            "restoring-backup" in self.app_peer_data or "restore-to-time" in self.app_peer_data
+            self.is_cluster_restoring_backup or self.is_cluster_restoring_to_time
         ) and not self._was_restore_successful():
             return
 
@@ -1566,7 +1586,7 @@ def _on_update_status(self, _) -> None:
         self._observer.start_observer()
 
     def _was_restore_successful(self) -> bool:
-        if "restore-to-time" in self.app_peer_data and all(self.is_pitr_failed()):
+        if self.is_cluster_restoring_to_time and all(self.is_pitr_failed()):
             logger.error(
                 "Restore failed: database service failed to reach point-in-time-recovery target. "
                 "You can launch another restore with different parameters"
@@ -1623,7 +1643,7 @@ def _was_restore_successful(self) -> bool:
         return True
 
     def _can_run_on_update_status(self) -> bool:
-        if "cluster_initialised" not in self._peers.data[self.app]:
+        if not self.is_cluster_initialised:
             return False
 
         if self.has_raft_keys():

src/relations/async_replication.py

@@ -479,7 +479,7 @@ def is_primary_cluster(self) -> bool:
         return self.charm.app == self._get_primary_cluster()
 
     def _on_async_relation_broken(self, _) -> None:
-        if not self.charm._peers or "departing" in self.charm._peers.data[self.charm.unit]:
+        if not self.charm._peers or self.charm.is_unit_departing:
             logger.debug("Early exit on_async_relation_broken: Skipping departing unit.")
             return
 
@@ -521,11 +521,11 @@ def _on_async_relation_changed(self, event: RelationChangedEvent) -> None:
         if not self._stop_database(event):
             return
 
-        if not all(
+        if not (self.charm.is_unit_stopped or self._is_following_promoted_cluster()) or not all(
             "stopped" in self.charm._peers.data[unit]
             or self.charm._peers.data[unit].get("unit-promoted-cluster-counter")
             == self._get_highest_promoted_cluster_counter_value()
-            for unit in {*self.charm._peers.units, self.charm.unit}
+            for unit in self.charm._peers.units
         ):
             self.charm.unit.status = WaitingStatus(
                 "Waiting for the database to be stopped in all units"
@@ -691,10 +691,7 @@ def _set_app_status(self) -> None:
 
     def _stop_database(self, event: RelationChangedEvent) -> bool:
         """Stop the database."""
-        if (
-            "stopped" not in self.charm._peers.data[self.charm.unit]
-            and not self._is_following_promoted_cluster()
-        ):
+        if not self.charm.is_unit_stopped and not self._is_following_promoted_cluster():
             if not self.charm.unit.is_leader() and not os.path.exists(POSTGRESQL_DATA_PATH):
                 logger.debug("Early exit on_async_relation_changed: following promoted cluster.")
                 return False

src/relations/db.py

@@ -117,7 +117,7 @@ def _on_relation_changed(self, event: RelationChangedEvent) -> None:
             return
 
         if (
-            "cluster_initialised" not in self.charm._peers.data[self.charm.app]
+            not self.charm.is_cluster_initialised
             or not self.charm._patroni.member_started
             or not self.charm.primary_endpoint
         ):
@@ -240,7 +240,7 @@ def _on_relation_departed(self, event: RelationDepartedEvent) -> None:
             return
 
         if (
-            "cluster_initialised" not in self.charm._peers.data[self.charm.app]
+            not self.charm.is_cluster_initialised
             or not self.charm._patroni.member_started
             or not self.charm.primary_endpoint
         ):
@@ -266,7 +266,7 @@ def _on_relation_broken(self, event: RelationBrokenEvent) -> None:
         # Check for some conditions before trying to access the PostgreSQL instance.
         if (
             not self.charm.unit.is_leader()
-            or "cluster_initialised" not in self.charm._peers.data[self.charm.app]
+            or not self.charm.is_cluster_initialised
             or not self.charm._patroni.member_started
             or not self.charm.primary_endpoint
         ):
@@ -281,7 +281,7 @@ def _on_relation_broken(self, event: RelationBrokenEvent) -> None:
         # https://bugs.launchpad.net/juju/+bug/1979811.
         # Neither peer relation data nor stored state
         # are good solutions, just a temporary solution.
-        if "departing" in self.charm._peers.data[self.charm.unit]:
+        if self.charm.is_unit_departing:
             logger.debug("Early exit on_relation_broken: Skipping departing unit")
             return
 

src/relations/postgresql_provider.py

@@ -72,7 +72,7 @@ def _on_database_requested(self, event: DatabaseRequestedEvent) -> None:
             return
 
         if (
-            "cluster_initialised" not in self.charm._peers.data[self.charm.app]
+            not self.charm.is_cluster_initialised
             or not self.charm._patroni.member_started
             or not self.charm.primary_endpoint
         ):