python-socketio: Error while running the server example from the docs

I’m trying to run this example which is in the docs here

import eventlet
import socketio

sio = socketio.Server()
app = socketio.WSGIApp(sio, static_files={
    '/': {'content_type': 'text/html', 'filename': 'index.html'}
})

@sio.event
def connect(sid, environ):
    print('connect ', sid)

@sio.event
def my_message(sid, data):
    print('message ', data)

@sio.event
def disconnect(sid):
    print('disconnect ', sid)

if __name__ == '__main__':
    eventlet.wsgi.server(eventlet.listen(('', 5000)), app)

But as soon as I execute it I get this error

(15262) wsgi starting up on http://0.0.0.0:5000
(15262) wsgi exited, is_accepting=True
Traceback (most recent call last):
  File "the_path_in_my_pc/__init__.py", line 70, in <module>
    eventlet.wsgi.server(eventlet.listen(('', 5000)), app)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/eventlet/wsgi.py", line 990, in server
    client_socket, client_addr = sock.accept()
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/eventlet/greenio/base.py", line 230, in accept
    self._trampoline(fd, read=True, timeout=self.gettimeout(), timeout_exc=_timeout_exc)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/eventlet/greenio/base.py", line 208, in _trampoline
    return trampoline(fd, read=read, write=write, timeout=timeout,
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/eventlet/hubs/__init__.py", line 155, in trampoline
    listener = hub.add(hub.READ, fileno, current.switch, current.throw, mark_as_closed)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/eventlet/hubs/kqueue.py", line 53, in add
    self._control([event], 0, 0)
  File "/Library/Frameworks/Python.framework/Versions/3.9/lib/python3.9/site-packages/eventlet/hubs/kqueue.py", line 39, in _control
    return self.kqueue.control(events, max_events, timeout)
TypeError: changelist must be an iterable of select.kevent objects

What may be the cause?

About this issue

Original URL
State: closed
Created 4 years ago
Reactions: 3
Comments: 17 (5 by maintainers)

Most upvoted comments

I realize this issue is stale, however since this is an edge issue - and this is the first result on Google while researching, here’s how I was able to work around the issue.

Only applicable for 3.9.x from what I’ve seen

Install uvloop (pip install uvloop)
import uvloop at the beginning of your code.
Before invoking the event loop - run uvloop.install()

This should stop it from giving this issue.

Hope this helps!

Pizzaface on Mar 4, 2022

@miguelgrinberg only at macos with python3.9

leadscloud on Mar 9, 2021

Also hijacking this for other Googlers: if you’re encountering this issue outside of, or without even using asyncio/the event loop, the weird error can be sidestepped by using a different selector strategy.

Just throw this somewhere it will be run early on:

import sys

if sys.platform == "darwin":
    import selectors
    selectors.DefaultSelector = selectors.PollSelector

selector.KqueueSelector is the default on OSX, as it’s the most performant set of syscalls to implement file descriptor selection on OSX. But since it ain’t working at all on Python 3.9, dropping down to a less performant but working selector seems like a good trade-off.

theY4Kman on Dec 30, 2022

I don’t know yet. I also noticed it in my unit tests. It happens only on Python 3.9 on Mac, and I do not believe it is related to this package, but I need to investigate and see if others are seeing this error as well.

miguelgrinberg on Nov 19, 2020

Ok, for the moment I’ll use python 3.7 then.

albertoxamin on Nov 19, 2020