defer before leader election call (#635)

Author: paulomach

src/log_rotation_setup.py

@@ -93,8 +93,12 @@ def _update_logs_rotation(self, _):
         self.charm.unit_peer_data[_LOGS_SYNCED] = "true"
         self.setup()
 
-    def _cos_relation_created(self, _):
+    def _cos_relation_created(self, event):
         """Handle relation created."""
+        if not self.charm._is_peer_data_set:
+            logger.debug("Charm not yet set up. Deferring log rotation setup.")
+            event.defer()
+            return
         logger.info("Reconfigure log rotation on cos relation created")
         self.setup()
 

tests/unit/test_log_rotation_setup.py

@@ -2,7 +2,7 @@
 # See LICENSE file for licensing details.
 
 import unittest
-from unittest.mock import MagicMock, mock_open, patch
+from unittest.mock import MagicMock, PropertyMock, mock_open, patch
 
 from ops.testing import Harness
 
@@ -23,14 +23,25 @@ def setUp(self):
         )
         self.charm = self.harness.charm
 
+    @patch("charm.MySQLOperatorCharm._on_cos_agent_relation_created")
     @patch("mysql_vm_helpers.MySQL.setup_logrotate_and_cron")
-    def test_cos_relation_created(self, mock_setup):
+    @patch(
+        "charm.MySQLOperatorCharm._is_peer_data_set", new_callable=PropertyMock, return_value=True
+    )
+    def test_cos_relation_created(self, mock_is_peer_data_set, mock_setup, mock_charm_on_created):
         self.harness.add_relation(COS_AGENT_RELATION_NAME, "grafana-agent")
         mock_setup.assert_called_once_with(3, self.charm.text_logs, False)
+        mock_is_peer_data_set.assert_called_once()
 
+    @patch("charm.MySQLOperatorCharm._on_cos_agent_relation_created")
+    @patch(
+        "charm.MySQLOperatorCharm._is_peer_data_set", new_callable=PropertyMock, return_value=True
+    )
     @patch("pathlib.Path.exists", return_value=True)
     @patch("mysql_vm_helpers.MySQL.setup_logrotate_and_cron")
-    def test_log_syncing(self, mock_setup, mock_exist):
+    def test_log_syncing(
+        self, mock_setup, mock_exist, mock_is_peer_data_set, mock_charm_on_created
+    ):
         self.harness.update_config({"logs_retention_period": "auto"})
         self.harness.add_relation(COS_AGENT_RELATION_NAME, "grafana-agent")
         positions = (