Make sure to keep a reference to asyncio tasks

as suggested in the docs

app/__init__.py

@@ -21,11 +21,16 @@ if not os.environ.get("NO_MIDDLEWARE"):
     app.middleware("http")(check_is_ready)
 
 
+_background_tasks = set()
+
+
 # https://github.com/tiangolo/fastapi/issues/1480
 @app.on_event("startup")
 async def startup_event() -> None:
     if not os.environ.get("NO_UPDATE_THREAD"):
-        asyncio.create_task(update_loop())
+        task = asyncio.create_task(update_loop())
+        _background_tasks.add(task)
+        task.add_done_callback(_background_tasks.discard)
 
 
 @webapp.exception_handler(Exception)

app/fetch.py

@@ -435,9 +435,13 @@ async def trigger_loop() -> None:
         await asyncio.sleep(UPDATE_INTERVAL)
         queue_update()
 
+_background_tasks = set()
+
 
 async def update_loop() -> None:
-    asyncio.create_task(trigger_loop())
+    task = asyncio.create_task(trigger_loop())
+    _background_tasks.add(task)
+    task.add_done_callback(_background_tasks.discard)
     while True:
         async with _rate_limit:
             print("check for updates")