set permissions for /var/lib/rabbitmq

For certain storage providers, the mounted directory
/var/lib/rabbitmq is created with root:root as owner
and 755 permissions. This causes issues to start the
rabbitmq server.
Change permissions for directory /var/lib/rabbitmq
to 777.

src/charm.py

@@ -74,6 +74,7 @@
 RABBITMQ_SERVICE = "rabbitmq"
 RABBITMQ_USER = "rabbitmq"
 RABBITMQ_GROUP = "rabbitmq"
+RABBITMQ_DATA_DIR = "/var/lib/rabbitmq"
 RABBITMQ_COOKIE_PATH = "/var/lib/rabbitmq/.erlang.cookie"
 
 SELECTOR_ALL = "all"
@@ -201,6 +202,9 @@ def _on_config_changed(self, event: EventBase) -> None:
             event.defer()
             return
 
+        # Change permission of /var/lib/rabbitmq
+        self._set_permission_on_data_dir()
+
         # Render and push configuration files
         self._render_and_push_config_files()
 
@@ -711,6 +715,16 @@ def _initialize_operator_user(self) -> None:
         logging.warning("Deleting the guest user.")
         api.delete_user("guest")
 
+    def _set_permission_on_data_dir(self) -> None:
+        """Set permission on /var/lib/rabbitmq."""
+        container = self.unit.get_container(RABBITMQ_CONTAINER)
+
+        logger.debug(f"Changing permission for {RABBITMQ_DATA_DIR}")
+        try:
+            container.exec(["chmod", "777", RABBITMQ_DATA_DIR])
+        except ExecError as e:
+            logger.error(f"Exited with code {e.exit_code}. Stderr:\n{e.stderr}")
+
     def _render_and_push_config_files(self) -> None:
         """Render and push configuration files.
 

tests/unit/test_charm.py

@@ -66,6 +66,7 @@ def test_rabbitmq_pebble_ready(self):
         """Test pebble handler."""
         # self.harness.charm._render_and_push_config_files = Mock()
         # self.harness.charm._render_and_push_plugins = Mock()
+        self.harness.charm._set_ownership_on_lib_dir = Mock()
         # Check the initial Pebble plan is empty
         self.harness.set_can_connect("rabbitmq", True)
         initial_plan = self.harness.get_container_pebble_plan("rabbitmq")