close onvif sessions on shutdown

`OnvifController.close()` only stopped its event loop, so the aiohttp sessions each `ONVIFCamera` holds and the `_poll_config_updates` task were left to be garbage collected during interpreter shutdown, when their warnings can no longer be logged. Every restart ended with a run of `Unclosed client session` and `Task was destroyed but it is pending!` logging errors, which only became visible once restart started exiting the process itself under non-root. `close()` now closes each camera's client and cancels the tasks on the loop before stopping it.

frigate/ptz/onvif.py

@@ -1120,6 +1120,18 @@ class OnvifController:
                     f"Camera {camera_name} is still in ONVIF 'MOVING' status."
                 )
 
+    async def _shutdown(self) -> None:
+        """Close the camera sessions and cancel the tasks running on the loop."""
+        for cam_name in list(self.cams):
+            await self._close_camera(cam_name)
+
+        tasks = [t for t in asyncio.all_tasks() if t is not asyncio.current_task()]
+
+        for task in tasks:
+            task.cancel()
+
+        await asyncio.gather(*tasks, return_exceptions=True)
+
     def close(self) -> None:
         """Gracefully shut down the ONVIF controller."""
         if not hasattr(self, "loop") or self.loop.is_closed():
@@ -1127,6 +1139,16 @@ class OnvifController:
             return
 
         logger.info("Exiting ONVIF controller...")
+
+        # anything left open here is garbage collected during interpreter
+        # shutdown, where its warnings can no longer be logged cleanly
+        try:
+            asyncio.run_coroutine_threadsafe(self._shutdown(), self.loop).result(
+                timeout=5
+            )
+        except TimeoutError:
+            logger.debug("Timed out closing ONVIF sessions")
+
         self.config_subscriber.stop()
 
         def stop_and_cleanup():

frigate/test/test_ptz_onvif.py

@@ -15,6 +15,8 @@ Also covers the inverse direction: the ptz movement timestamps must not be writt
 for a camera that has autotracking off, because nothing clears them back out.
 """
 
+import asyncio
+import threading
 import unittest
 from unittest.mock import AsyncMock, MagicMock
 
@@ -234,5 +236,40 @@ class TestManualRelativeMoveMetrics(unittest.IsolatedAsyncioTestCase):
         )
 
 
+class TestOnvifClose(unittest.TestCase):
+    """close() must release everything on the loop, since whatever it leaves is
+    garbage collected during interpreter shutdown, where the resulting warnings
+    fail to log and fill the shutdown output with logging errors."""
+
+    def setUp(self) -> None:
+        self.controller = _make_controller(autotracking_enabled=False)
+        self.onvif = self.controller.cams[CAMERA]["onvif"]
+        self.onvif.close = AsyncMock()
+        self.controller.config_subscriber = MagicMock()
+        self.controller.loop = asyncio.new_event_loop()
+        self.controller.loop_thread = threading.Thread(
+            target=self.controller._run_event_loop, daemon=True
+        )
+        self.controller.loop_thread.start()
+        self.addCleanup(self.controller.loop.close)
+
+    def test_close_closes_camera_sessions(self) -> None:
+        self.controller.close()
+
+        self.onvif.close.assert_awaited_once()
+
+    def test_close_cancels_tasks_left_on_the_loop(self) -> None:
+        async def forever() -> None:
+            while True:
+                await asyncio.sleep(1)
+
+        poll = asyncio.run_coroutine_threadsafe(forever(), self.controller.loop)
+
+        self.controller.close()
+
+        self.assertTrue(poll.cancelled())
+        self.assertFalse(self.controller.loop_thread.is_alive())
+
+
 if __name__ == "__main__":
     unittest.main()