uvicorn: Shutdown process is broken in 0.15

Checklist

The bug is reproducible against the latest release and/or master.
There are no similar issues or pull requests to fix it yet.

Describe the bug

My FastAPI ASGI server cannot shutdown properly with uvicorn==0.15 while it can with 0.14

To reproduce

Setup minimal FastAPI app and add some functions with logs(prints) to shutdown event

Expected behavior

You see all logs(prints) from functions on shutdown

Actual behavior

Get ASGI 'lifespan' protocol appears unsupported. without --lifespan on Get error trace with --lifespan on

Debugging material

uvicorn scheduler.main:app --host=0.0.0.0 --port ${WEB_PORT:-8000} --reload --lifespan on INFO: Will watch for changes in these directories: [‘/home/dmytro/storage/chimplie/projects/raok-main/raok-scheduler’] INFO: Uvicorn running on http://0.0.0.0:8004 (Press CTRL+C to quit) INFO: Started reloader process [177653] using statreload INFO: Started server process [177655] INFO: Waiting for application startup. INFO: Tortoise-ORM started, {‘default’: <tortoise.backends.asyncpg.client.AsyncpgDBClient object at 0x7f63d4a10e50>}, {‘models’: {‘Task’: <class ‘scheduler.models.task.Task’>, ‘Aerich’: <class ‘aerich.models.Aerich’>}} INFO: Application startup complete. ^CINFO: Shutting down INFO: Finished server process [177655] ERROR: Exception in ‘lifespan’ protocol Traceback (most recent call last): File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/uvicorn/lifespan/on.py”, line 84, in main await app(scope, self.receive, self.send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/uvicorn/middleware/proxy_headers.py”, line 75, in call return await self.app(scope, receive, send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/fastapi/applications.py”, line 199, in call await super().call(scope, receive, send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/starlette/applications.py”, line 112, in call await self.middleware_stack(scope, receive, send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/starlette/middleware/errors.py”, line 146, in call await self.app(scope, receive, send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/starlette/middleware/cors.py”, line 70, in call await self.app(scope, receive, send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/starlette/exceptions.py”, line 58, in call await self.app(scope, receive, send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/starlette/routing.py”, line 569, in call await self.lifespan(scope, receive, send) File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/starlette/routing.py”, line 544, in lifespan await receive() File “/home/dmytro/.local/share/virtualenvs/raok-scheduler-hpGGYNLi/lib/python3.8/site-packages/uvicorn/lifespan/on.py”, line 135, in receive return await self.receive_queue.get() File “/usr/lib64/python3.8/asyncio/queues.py”, line 163, in get await getter asyncio.exceptions.CancelledError INFO: Stopping reloader process [177653]

Environment

Fedora 34 / Python 3.8 / Uvicorn version: 0.15 - bug, 0.14 - ok
command to run: uvicorn main:app --host=0.0.0.0 --port 8000 --reload

About this issue

Original URL
State: closed
Created 3 years ago
Reactions: 8
Comments: 24 (9 by maintainers)

Commits related to this issue

Update: [Server] pipenv run serve を通常起動、pipenv run develop を開発用のリロードモードでの起動に変更 Uvicorn の --reload オプションはファイルに変更があった時に自動でリロードしてくれる優れものなんだけど、Linux 環境では Uvicorn 0.15 のバグで Ctrl+C が効かないそもそも通常利用でリロードモードにする... — committed to tsukumijima/KonomiTV by tsukumijima 3 years ago

Most upvoted comments

I’m having the exactly same issue!! Here’s the code https://github.com/igormcsouza/kitty-api/blob/master/api/__init__.py

I downgrade to 0.14 just to avoid error

igormcsouza on Oct 12, 2021

Even though the problem persist! I tried once more yesterday! That error at the end causes issues on my routine! I will keep on 0.14 until it is fixed!

igormcsouza on Nov 10, 2021

I get the same error with Starlette 0.16.0 when I send a SIGINT:

[2021-08-19 11:01:19,614][25024] INFO:     Uvicorn running on http://0.0.0.0:5000 (Press CTRL+C to quit)
[2021-08-19 11:01:23,189][25024] ERROR:    Traceback (most recent call last):
  File "c:\Users\...\.venv\lib\site-packages\starlette\routing.py", line 624, in lifespan
    await receive()
  File "c:\Users\...\.venv\lib\site-packages\uvicorn\lifespan\on.py", line 135, in receive
    return await self.receive_queue.get()
  File "C:\Users\...\python\current\lib\asyncio\queues.py", line 166, in get
    await getter
asyncio.exceptions.CancelledError

I never had to create a lifespan function in previous versions, but I found that the error disappears if I bootstrap Starlette like so:

async def _lifespan(app):
  import asyncio
  try:
    yield
  except asyncio.exceptions.CancelledError:
    pass
server_app = Starlette(routes=routes, lifespan=_lifespan)

v1b1 on Aug 19, 2021

Ok… It was quite fast to find it 😅

The problem is that on reload mode, we terminate the process on the shutdown(): https://github.com/encode/uvicorn/commit/de53c2366f1df9f55ac88d8bde67cfd314d2d98e

Kludex on Aug 19, 2021