Python heroku configure procfile gunicorn + gevent for socket.io chat app | RuntimeError: You need to use the gevent-websocket server

问题

I have a working chat app on localhost, but it does not work on heroku (Question from yesterday). After some research I think the problem is how I start the app.

Procfile currently:

web: gunicorn adult_main:app

I need to use gevent in combination with gunicorn. This way I should be able to have max. 1000 socket.io connections, which is enough for me for the moment.

I already installed and added gevent to the requirements.txt. Here an extract of the file:

Flask-SocketIO==2.9.6
gunicorn==19.7.1
gevent==1.2.2
gevent-socketio==0.3.6
gevent-websocket==0.10.1

But I do not understand how to start the app correctly. On a sidenote, I am using heroku's free tier to test everything.

I tried a few solutions, which I found online, but I do not fully understand them and I have not found a documentation on that yet. Here are some of my attempts:

web: gunicorn -k gevent-socketio adult_main:app
web: gunicorn -k gevent adult_main:app

I also tried to start without gunicorn, but I think that was completely wrong. Am I on the correct path here?

EDIT

I managed to make some progress with:

web: gunicorn -k gevent -w 1 adult_main:app

The app does not crash on start now, but in the web console I see an error:

socket.io.js:7 WebSocket connection to 'wss://my-    
project.herokuapp.com/socket.io/? 
EIO=3&transport=websocket&sid=0022c1937df648bbab836bfcb4c35' failed: Error   
during WebSocket handshake: Unexpected response code: 500

In the heroku logs:

RuntimeError: You need to use the gevent-websocket server.

EDIT

Eventhough I see these errors, the chat works now on heroku. That is really weird. Probably I can establish now only 1 connection, how to continue now?

回答1:

The error is correct, you need to use the gevent-websocket webserver and not the native gevent web server that comes with gunicorn.

It seems you are searching for answers all over the place. I would suggest that you use the Flask-SocketIO documentation as the ultimate source of truth, as I keep that updated.

For this specific case, the Gunicorn section of the documentation shows you how you need to start your server:

gunicorn -k geventwebsocket.gunicorn.workers.GeventWebSocketWorker -w 1 module:app

来源：https://stackoverflow.com/questions/50059102/python-heroku-configure-procfile-gunicorn-gevent-for-socket-io-chat-app-runt