fix: async task leak in SlackAlerting

add_deployment (from scheduler) -> _update_general_settings calls this
function every 30s.

Each call starts a new while True: loop.

/debug/asyncio-tasks tells me there's thousands of active tasks with no names,
which impacts my ability to work out why the application is hung.

I don't think it's a big problem, but it's not helping with debuggability.

litellm/integrations/SlackAlerting/slack_alerting.py

@@ -115,8 +115,9 @@ class SlackAlerting(CustomBatchLogger):
     ):
         if alerting is not None:
             self.alerting = alerting
-            asyncio.create_task(self.periodic_flush())
-            self.periodic_started = True
+            if not self.periodic_started:
+                asyncio.create_task(self.periodic_flush())
+                self.periodic_started = True
         if alerting_threshold is not None:
             self.alerting_threshold = alerting_threshold
         if alert_types is not None:

tests/test_litellm/integrations/SlackAlerting/test_slack_alerting.py

@@ -173,6 +173,21 @@ class TestSlackAlerting(unittest.TestCase):
         self.slack_alerting.update_values(alerting_args={"slack_alerting": "True"})
         assert self.slack_alerting.periodic_started == True
         
+    # Repeated calls to update_values should not spawn additional periodic_flush tasks
+    @patch("asyncio.create_task")
+    def test_update_values_does_not_leak_periodic_tasks(self, mock_create_task):
+        mock_create_task.return_value = AsyncMock()
+
+        self.slack_alerting.update_values(alerting=["slack"])
+        assert self.slack_alerting.periodic_started == True
+        assert mock_create_task.call_count == 1
+
+        # Simulate repeated calls from add_deployment scheduler (runs every 30s)
+        self.slack_alerting.update_values(alerting=["slack"])
+        self.slack_alerting.update_values(alerting=["slack"])
+        self.slack_alerting.update_values(alerting_args={"slack_alerting": "True"})
+        assert mock_create_task.call_count == 1
+
     @patch("litellm.integrations.SlackAlerting.slack_alerting.datetime")
     def test_alert_type_in_formatted_message(self, mock_datetime):
         # Setup mocks