fmt + lint

lib/charms/mongodb/v0/helpers.py

@@ -10,6 +10,8 @@
 from typing import List
 
 from charms.mongodb.v0.mongodb import MongoDBConfiguration, MongoDBConnection
+from ops.charm import CharmBase, RelationDepartedEvent
+from ops.framework import Object
 from ops.model import (
     ActiveStatus,
     BlockedStatus,
@@ -29,7 +31,7 @@
 
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
-LIBPATCH = 8
+LIBPATCH = 9
 
 # path to store mongodb ketFile
 KEY_FILE = "keyFile"
@@ -49,6 +51,50 @@
 logger = logging.getLogger(__name__)
 
 
+class MongoDBHelper(Object):
+    """In this class, we manage client database relations."""
+
+    def __init__(self, charm: CharmBase) -> None:
+        """Constructor for MongoDBProvider object.
+
+        Args:
+            charm: the charm for which this relation is provided
+        """
+        super().__init__(charm, None)
+        self.charm = charm
+
+    def _is_departed_removed_relation(self, event: RelationDepartedEvent):
+        """Sets app metadata indicating if a relation should be removed.
+
+        Relation-broken executes after relation-departed, and it must know if it should remove the
+        related user. Relation-broken doesn't have access to `event.departing_unit`, so we make
+        use of it here.
+
+        We receive relation departed events when: the relation has been removed, units are scaling
+        down, or the application has been removed. Only proceed to process user removal if the
+        relation has been removed.
+        """
+        if not self.charm.unit.is_leader():
+            return
+
+        # assume relation departed is due to manual removal of relation.
+        relation_departed = True
+
+        # check if relation departed is due to current unit being removed. (i.e. scaling down the
+        # application.)
+        if event.departing_unit == self.charm.unit:
+            logger.debug(
+                "Relation departed is due to scale down, no need to process removed relation in RelationBrokenEvent."
+            )
+            relation_departed = False
+
+        self.charm.app_peer_data[f"relation_{event.relation.id}_departed"] = json.dumps(
+            relation_departed
+        )
+
+        return relation_departed
+
+
 # noinspection GrazieInspection
 def get_create_user_cmd(config: MongoDBConfiguration, mongo_path=MONGO_SHELL) -> List[str]:
     """Creates initial admin user for MongoDB.

lib/charms/mongodb/v0/mongodb_provider.py

@@ -83,28 +83,11 @@ def __init__(self, charm: CharmBase, substrate="k8s", relation_name: str = "data
         )
 
     def _on_relation_departed(self, event):
-        """Checks if users should be removed on the following event (relation-broken).
-
-        Relation-broken executes after relation-departed, and it must know if it should remove the
-        related user. Relation-broken doesn't have access to `event.departing_unit`, so we make
-        use of it here.
-
-        We receive relation departed events when: the relation has been removed, units are scaling
-        down, or the application has been removed. Only proceed to process user removal if the
-        relation has been removed.
-        """
-        if not self.charm.unit.is_leader():
-            return
-
-        # assume relation departed is due to manual removal of relation.
-        relation_departed = True
-
-        # check if relation departed is due to current unit being removed. (i.e. scaling down the
-        # application.)
-        if event.departing_unit == self.charm.unit:
-            relation_departed = False
-
-        self.charm.app_peer_data[f"relation_{event.relation.id}_departed"] = json.dumps(relation_departed)
+        """Checks if users should be removed on the following event (relation-broken)."""
+        if self.charm.mongodb_helpers._is_departed_removed_relation(event):
+            logger.info(
+                "Relation departed event occurred due to relation removal, proceed to clean up users in RelationBroken."
+            )
 
     def _on_relation_event(self, event):
         """Handle relation joined events.

src/charm.py

@@ -19,6 +19,7 @@
     TLS_EXT_PEM_FILE,
     TLS_INT_CA_FILE,
     TLS_INT_PEM_FILE,
+    MongoDBHelper,
     build_unit_status,
     copy_licenses_to_unit,
     generate_keyfile,
@@ -123,6 +124,7 @@ def __init__(self, *args):
         self.framework.observe(self.on.secret_changed, self._on_secret_changed)
 
         # handle provider side of relations
+        self.mongodb_helpers = MongoDBHelper(self)
         self.client_relations = MongoDBProvider(self, substrate=Config.SUBSTRATE)
         self.legacy_client_relations = MongoDBLegacyProvider(self)
         self.tls = MongoDBTLS(self, Config.Relations.PEERS, substrate=Config.SUBSTRATE)