Aiohttp: GunicornWebWorker resetting all connections in python 3.8

[iomintz]

Long story short

When running aiohttp.web with gunicorn in python 3.8, every request results in a reset connection.
This behavior does not occur using Flask, therefore I believe it is aiohttp's fault, not gunicorn's.

Steps to reproduce

from aiohttp import web

app = web.Application()
routes = web.RouteTableDef()

@routes.get('/')
async def index(request):
    return 'Hello, world!'

app.add_routes(routes)

gunicorn --worker-class aiohttp.GunicornWebWorker app:app &
curl http://localhost:8000/

Expected behaviour

Hello, world!

Actual behaviour

curl: (52) Empty reply from server

In a browser, I get "the connection was reset".

Your environment

aiohttp v3.6.2
gunicorn v19.9.0
CPython v3.8.0
Arch Linux, kernel version 5.3.7-arch1-2-ARCH

aiohttp.web

[prostomarkeloff]

You should return a web.Response in handler, not plain text.

from aiohttp import web

app = web.Application()
routes = web.RouteTableDef()

@routes.get('/')
async def index(request):
    return web.Response(text="Hello, world!")

app.add_routes(routes)

gunicorn --worker-class aiohttp.GunicornWebWorker app:app
curl http://localhost:8000/

[iomintz]

You're right, in my example code, I missed that part. However, I have it in my production code and I am getting the same error. I'm not sure how to reproduce this minimally.

[iomintz]

https://github.com/EmoteCollector/EmoteCollector-website/blob/master/app.py
Running this with gunicorn in 3.8 gives me the issues in question.

[prostomarkeloff]

https://github.com/EmoteCollector/EmoteCollector-website/blob/master/app.py
Running this with gunicorn in 3.8 gives me the issues in question.

Can you describe it in more details? Have you this issue in all handlers in your application?

[iomintz]

All handlers, yes. I added a handler that just returns web.Response(text='hi') and I still get the error. I added a handler that just returns 'hi' (incorrectly) and I get the same error.

[prostomarkeloff]

Works for me in Python 3.8.0, Ubuntu 18.04

from aiohttp import web
import gunicorn
import aiohttp
import sys

app = web.Application()
routes = web.RouteTableDef()


@routes.get('/')
async def index(request):
    v = sys.version
    aiohttp_v = aiohttp.__version__
    gunicorn_v = gunicorn.__version__
    return web.Response(text=f"Hello, world!\nPython Version: {v}\nAIOHTTP Version: {aiohttp_v}\nGunicorn Version: {gunicorn_v}\n")


app.add_routes(routes)

# $ gunicorn --worker-class aiohttp.GunicornWebWorker app:app

$ curl 127.0.0.1:8000

Hello, world!
Python Version: 3.8.0 (default, Oct 14 2019, 21:29:03) 
[GCC 7.4.0]
AIOHTTP Version: 3.6.2
Gunicorn Version: 19.9.0

[iomintz]

OK, I've made the test case as minimal as I could, but it's still pretty heavy.
You'll need postgres.

git clone --single-branch --branch add-test-route https://owo.codes/lambda/cm-api.git
cd cm-api
python3.8 -m venv .venv
source .venv/bin/activate
pip install -Ur requirements.txt
cp config.example.json5 config.json5
sed -i "s|discord: ''|discord: 'NjE4NTU0NzEwNTk2NjQ4OTgw.XW7X_A.oBMlTi_8WGGTYpjLgCJ-tbKMuZ4'|" config.json5
createdb cm
./start.sh &
curl http://localhost:8081/api/v0/test

I get curl: (56) Recv failure: Connection reset by peer following these steps.

[prostomarkeloff]

Okay, i have same issue. I think it's a gunicorn (or your application) problem, because plain app works pretty.

[iomintz]

How should I fix it?

[prostomarkeloff]

Give me a few time, i'll try to deal with it.

[prostomarkeloff]

LOL, i found a really comical bug (or no?). In your environment even aiohttp web server doesn't work.

from aiohttp import web
import gunicorn
import aiohttp
import sys

app = web.Application()
routes = web.RouteTableDef()


@routes.get('/')
async def index(request):
    v = sys.version
    aiohttp_v = aiohttp.__version__
    gunicorn_v = gunicorn.__version__
    return web.Response(text=f"Hello, world!\nPython Version: {v}\nAIOHTTP Version: {aiohttp_v}\nGunicorn Version: {gunicorn_v}\n")


app.add_routes(routes)
web.run_app(app)

curl http://127.0.0.1:8080
curl: (56) Recv failure: Connection reset by peer

I really don't know why it's. May do you know @iomintz ?

[iomintz]

Yes, I get the same in that environment. I'm not sure why it is either.

[iomintz]

Ah, discord.py depends on an old version of aiohttp, one which appears to be incompatible with 3.8 when used in this way.

[prostomarkeloff]

¯_(ツ)_/¯