uvloop blocks app and not executes aiohttp server

[semakmillev]

Hi! I have very strange bug.
On server (only on the one - i cant reproduce error on others) i m tryin to start application using uvloop. Here is the code (i tried using docker, or executing script - result was the same) in console:

Python 3.8.10 (default, Jun 2 2021, 10:49:15)
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

import uvloop
asyncio.set_event_loop_policy(uvloop.EventLoopPolicy()) # here i tried uvloop.install()
from aiohttp import web
app = web.Application()
web.run_app(app, port=17000)

And after that nothing happens! Moreover, i can't stop process using Ctrl+C or Ctrl+D - only kill from other console

*i changed ports and got same results

uvloop version: 0.15.3
OS Version:
NAME="Ubuntu"
VERSION="20.04.1 LTS (Focal Fossa)"

[1st1]

Sounds like the 17000 port is used by something else on that particular server. And most likely aiohttp has some timeout/retry logic in place and waits for it to become available. I don't think this is a uvloop bug. That said, check what happens if you don't activate uvloop -- does vanilla asyncio behave differently?

[semakmillev]

Sounds like the 17000 port is used by something else on that particular server. And most likely aiohttp has some timeout/retry logic in place and waits for it to become available. I don't think this is a uvloop bug. That said, check what happens if you don't activate uvloop -- does vanilla asyncio behave differently?

1. As i mentioned - i used different ports - like 8023, 7091, 17091, 17000, 80 and several another with same result
2. Yes, if i run just
   from aiohttp import web
   app = web.Application()
   web.run_app(app, port=17000)
   everything works fine.

It's really strange. Seems that i have some hardware or system problem, because on other machine with same software i don't get this bug. But how to find out it - i dont know(

[roman27t]

Hello.

I have the same issue after upgrade libs:

works fine:
python 3.6
aiohttp 3.6.2
uvloop 0.14.0

issue:
python 3.7, 3.9
aiohttp 3.7.4.post0
uvloop 0.16.0

If I have only one pod - it was ok, but when I start 2nd pod - pod doesn't listen 8080 port

My system:
sh-4.2# cat /etc/*release : CentOS Linux release 7.8.2003 (Core)

If I run without uvloop.install() - it was ok.

When I set Debug mode: PYTHONASYNCIODEBUG=1
I finally got a log:

WARNING:asyncio:create_server() failed to create socket.socket(10, 1, 6)
Traceback (most recent call last):
File "uvloop/loop.pyx", line 1745, in uvloop.loop.Loop.create_server
File "/usr/local/lib/python3.9/socket.py", line 232, in init
_socket.socket.init(self, family, type, proto, fileno)
OSError: [Errno 97] Address family not supported by protocol

[nehanagendra02]

@bumer-t , @semakmillev were you able to figure out the root cause or solution to this problem? I am facing similar issues.

[kfur]

Try set ipv4 address, because by default it will try to bind to ipv6 first