GAE websockets support flask-socketio

[Altiire]

In which file did you encounter the issue?

app.yaml

Did you change the file? If so, how?

Nope

Describe the issue

My project is using Flask-Socketio for websocket support.
My entrypoint is: entrypoint: gunicorn supervisor.wsgi:app -k eventlet
I also set network: session_affinity: true

Everything is running except the websocket, I get the following error on Firefox:
Firefox can’t establish a connection to the server at wss://myproject.appspot.com/socket.io/?EIO=3&transport=websocket&sid=500afafea543442dad546cc325ce5def.

There is no such error when running my project with the same command on my computer.

[andrewsg]

The samples are built around flask-sockets so that we can leverage the gunicorn flask_sockets.worker, which allows gunicorn to simultaneously serve http and websocket traffic. I don't think socketio on Python is compatible with gunicorn out of the box; you may have to explore alternative webservers to make this work.

I don't know why it's working on your local machine, though. What command are you running locally to start the server?

[Altiire]

To support web sockets :

python supervisor/app.py

sample of supervisor/app.py

def create_app(testing=False, cli=False):
    """Application factory, used to create application
    """
    app = Flask('supervisor')
    CORS(app)
    app.config.from_object('supervisor.config')

    if testing is True:
        app.config['TESTING'] = True

    force_auto_coercion()
    configure_extensions(app, cli)
    register_blueprints(app)

    socketio.init_app(app)

    return app

if __name__ == '__main__':
    app = create_app()
    socketio.run(app)

If I remember well, the socket was working on GAE in July, and not now as I just checked

I don't think socketio on Python is compatible with gunicorn out of the box; you may have to explore alternative webservers to make this work.

The eventlet worker is supposed to support socketio