use the gevent-websocket server. See the Deployment section of the documentation for more information.

[shivarajalagond]

Hi, I am running the app with gunicorn and I get this error whenever I restart the container and there are stale tabs open.
It gives error for all users that had tabs open. Can you guide on this?

RuntimeError: You need to use the gevent-websocket server. See the Deployment section of the documentation for more information.
[2022-03-03 17:42:38 -0500] [9] [ERROR] Error handling request /socket.io/?username=USER&EIO=3&transport=websocket&sid=5879be715cf14b33acb95d4db9a50f46
Traceback (most recent call last):
File "/usr/local/lib/python3.6/site-packages/gunicorn/workers/base_async.py", line 56, in handle
self.handle_request(listener_name, req, client, addr)
File "/usr/local/lib/python3.6/site-packages/gunicorn/workers/ggevent.py", line 160, in handle_request
addr)
File "/usr/local/lib/python3.6/site-packages/gunicorn/workers/base_async.py", line 107, in handle_request
respiter = self.wsgi(environ, resp.start_response)
File "/usr/local/lib/python3.6/site-packages/flask/app.py", line 2309, in call
return self.wsgi_app(environ, start_response)
File "/usr/local/lib/python3.6/site-packages/flask_socketio/init.py", line 46, in call
start_response)
File "/usr/local/lib/python3.6/site-packages/engineio/middleware.py", line 60, in call
return self.engineio_app.handle_request(environ, start_response)
File "/usr/local/lib/python3.6/site-packages/socketio/server.py", line 560, in handle_request
return self.eio.handle_request(environ, start_response)
File "/usr/local/lib/python3.6/site-packages/engineio/server.py", line 377, in handle_request
environ, start_response)
File "/usr/local/lib/python3.6/site-packages/engineio/socket.py", line 108, in handle_get_request
start_response)
File "/usr/local/lib/python3.6/site-packages/engineio/socket.py", line 152, in _upgrade_websocket
return ws(environ, start_response)
File "/usr/local/lib/python3.6/site-packages/engineio/async_drivers/gevent.py", line 35, in call
raise RuntimeError('You need to use the gevent-websocket server. '

[miguelgrinberg]

The error message tells you exactly what you need to do.

• First, install gevent-websocket.
• Then see the docs for instructions on how to run your server: https://flask-socketio.readthedocs.io/en/latest/deployment.html#gunicorn-web-server

[Judimax]

the docs dont, even the code does not indicate, how to get this socket server leveraging gevent to use ssl,

[miguelgrinberg]

This package does not include a web server, so it does not configure TLS. If you use gevent through Gunicorn, then you have to pass your TLS options to Gunicorn. If you use the standard gevent web server, then the run() command takes kwargs that are passed through to the web server, so look for the TLS options in the gevent WSGI server (see ssl_args in their documentation).

[Judimax]

Yep gevent has some issue, there was way more documentation on evenlet at least for windows, much appreciation and great work!