Description
Hey Guys
Application Description
We discover on our uvicorn server sometimes that the listening socket is closing.
The Uvicorn get image uploads from cameras and sometimes or often releated to mobile network conditions the connection is lost.
And when a connection is lost on remote site, this error occurs sometimes.
I am not very deep into such low level python code so I tried it hard to find the root couse and this are my results.
I hope this results show's that there is sometings and we can talk about that or you can give me hints or help do resolve this issue.
thank you in advance
Bug/Error that occurs
The Error occurs on ov.getresult() (asyncio.windows_events.py:560)
OSError: [WinError 64] The specified network name is no longer available.
After that the server is unresponsive and the listening socket is closed. In that case we need to restart the service.
To me it looks like this happens when ov.getresult() is called and the remote host is disconnected.
When I just wrap this function in a try\except block the listening socket is not closing and uvicorn detects a connection lost.
Please let me know why just wrapping this into a try block resolve this issue,
because I don't know ;-)
Original
def finish_accept(trans, key, ov):
ov.getresult() # Here happen the OSError
# Use SO_UPDATE_ACCEPT_CONTEXT so getsockname() etc work.
buf = struct.pack('@P', listener.fileno())
conn.setsockopt(socket.SOL_SOCKET,
_overlapped.SO_UPDATE_ACCEPT_CONTEXT, buf)
conn.settimeout(listener.gettimeout())
return conn, conn.getpeername()Mod (No socket closings)
def finish_accept(trans, key, ov):
try:
ov.getresult()
except OSError as Error:
print("This helps", Error)
# Use SO_UPDATE_ACCEPT_CONTEXT so getsockname() etc work.
buf = struct.pack('@P', listener.fileno())
conn.setsockopt(socket.SOL_SOCKET,
_overlapped.SO_UPDATE_ACCEPT_CONTEXT, buf)
conn.settimeout(listener.gettimeout())
return conn, conn.getpeername()Error without the try\catch block
Task exception was never retrieved
future: <Task finished name='Task-248' coro=<IocpProactor.accept.<locals>.accept_coro() done, defined at C:\Program Files\Python310\lib\asyncio\windows_events.py:570> exception=OSError(22, 'The specified network name is no longer available', None, 64, None) created at C:\Program Files\Python310\lib\asyncio\tasks.py:636>
source_traceback: Object created at (most recent call last):
File "Y:\code_projects\pol\pol\server\test\brotle.py", line 31, in <module>
asyncio.run(serve(Starlette(debug=True, routes=routes), config), debug=True)
File "C:\Program Files\Python310\lib\asyncio\runners.py", line 44, in run
return loop.run_until_complete(main)
File "C:\Program Files\Python310\lib\asyncio\base_events.py", line 633, in run_until_complete
self.run_forever()
File "C:\Program Files\Python310\lib\asyncio\windows_events.py", line 321, in run_forever
super().run_forever()
File "C:\Program Files\Python310\lib\asyncio\base_events.py", line 600, in run_forever
self._run_once()
File "C:\Program Files\Python310\lib\asyncio\base_events.py", line 1888, in _run_once
handle._run()
File "C:\Program Files\Python310\lib\asyncio\events.py", line 80, in _run
self._context.run(self._callback, *self._args)
File "C:\Program Files\Python310\lib\asyncio\proactor_events.py", line 838, in loop
f = self._proactor.accept(sock)
File "C:\Program Files\Python310\lib\asyncio\windows_events.py", line 580, in accept
tasks.ensure_future(coro, loop=self._loop)
File "C:\Program Files\Python310\lib\asyncio\tasks.py", line 615, in ensure_future
return _ensure_future(coro_or_future, loop=loop)
File "C:\Program Files\Python310\lib\asyncio\tasks.py", line 636, in _ensure_future
return loop.create_task(coro_or_future)
Traceback (most recent call last):
File "C:\Program Files\Python310\lib\asyncio\windows_events.py", line 573, in accept_coro
await future
File "C:\Program Files\Python310\lib\asyncio\windows_events.py", line 819, in _poll
value = callback(transferred, key, ov)
File "C:\Program Files\Python310\lib\asyncio\windows_events.py", line 561, in finish_accept
ov.getresult()
OSError: [WinError 64] The specified network name is no longer availableMinimal Example to reproduce
- Start Server
- Start Client
Server (Minimal Reproducible Example)
from starlette.applications import Starlette
from starlette.responses import JSONResponse
from starlette.routing import Route
async def test_case(request):
return JSONResponse({'hello': 'world'})
routes = [
Route("/", endpoint=test_case, methods=['POST'])
]
##### Uvicorn Test
import uvicorn
uvicorn.run(
Starlette(debug=True, routes=routes),
reload=False,
log_level="trace",
host="0.0.0.0",
port=8088,
)
##### Hypercorn Test
#import asyncio
#from hypercorn.config import Config
#from hypercorn.asyncio import serve
#config = Config()
#config.bind = ["localhost:8088"]
#asyncio.run(serve(Starlette(debug=True, routes=routes), config), debug=True)Client (Minimal Reproducible Example)
import threading
import requests
import time
import sys
def test():
for i in range(100):
requests.post("http://127.0.0.1:8088/")
if __name__ == "__main__":
for i in range(100):
thread = threading.Thread(target=test, args=(), daemon=True)
thread.start()
time.sleep(1)
sys.exit()Tested with:
Uvicorn [x]
Hypercorn [x]
Environment
Python 3.10.5 (tags/v3.10.5:f377153, Jun 6 2022, 16:14:13) [MSC v.1929 64 bit (AMD64)] on win32
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