Dump request URLs in case of CancelledError or SystemExit?

[lambdaq]

Hello,

I am running a FastAPI (which is based on starlette) with Gunicorn+uvicorn stack, the worker process sometimes quits over SystemExit and the traceback is like:

SystemExit: 1
  File "asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "uvloop/loop.pyx", line 1511, in uvloop.loop.Loop.run_until_complete
  File "uvloop/loop.pyx", line 1504, in uvloop.loop.Loop.run_until_complete
  File "uvloop/loop.pyx", line 1377, in uvloop.loop.Loop.run_forever
  File "uvloop/loop.pyx", line 555, in uvloop.loop.Loop._run
  File "uvloop/handles/poll.pyx", line 216, in uvloop.loop.__on_uvpoll_event
  File "uvloop/cbhandles.pyx", line 83, in uvloop.loop.Handle._run
  File "uvloop/cbhandles.pyx", line 66, in uvloop.loop.Handle._run
  File "uvloop/loop.pyx", line 397, in uvloop.loop.Loop._read_from_self
  File "uvloop/loop.pyx", line 402, in uvloop.loop.Loop._invoke_signals
  File "uvloop/loop.pyx", line 377, in uvloop.loop.Loop._ceval_process_signals
  File "gunicorn/workers/base.py", line 199, in handle_abort
    sys.exit(1)
CancelledError: null
  File "uvicorn/protocols/http/httptools_impl.py", line 426, in run_asgi
    result = await app(  # type: ignore[func-returns-value]
  File "uvicorn/middleware/proxy_headers.py", line 84, in __call__
    return await self.app(scope, receive, send)
  File "fastapi/applications.py", line 1106, in __call__
    await super().__call__(scope, receive, send)
  File "starlette/applications.py", line 122, in __call__
    await self.middleware_stack(scope, receive, send)
  File "starlette/middleware/errors.py", line 162, in __call__
    await self.app(scope, receive, _send)
  File "starlette/middleware/exceptions.py", line 68, in __call__
    await self.app(scope, receive, sender)
  File "fastapi/middleware/asyncexitstack.py", line 17, in __call__
    await self.app(scope, receive, send)
  File "starlette/routing.py", line 718, in __call__
    await route.handle(scope, receive, send)
  File "starlette/routing.py", line 276, in handle
    await self.app(scope, receive, send)
  File "starlette/routing.py", line 69, in app
    await response(scope, receive, send)
  File "starlette/responses.py", line 277, in __call__
    await wrap(partial(self.listen_for_disconnect, receive))
  File "starlette/responses.py", line 273, in wrap
    await func()
  File "starlette/responses.py", line 250, in listen_for_disconnect
    message = await receive()
  File "uvicorn/protocols/http/httptools_impl.py", line 587, in receive
    await self.message_event.wait()
  File "asyncio/locks.py", line 309, in wait
    await fut

The errors aren't that helpful. I suspect there's some blocking code hidden somewhere caused this. Is there a way to show what requests are been handled when worker timeout happens? Can we dump the URL before SystemExit? Thanks!