uWSGI crashing with KeyError: 'socketio'

[stevegaron]

Hey,

I'm having issues making uWSGI working with Flask-SocketIO, it throws a KeyError for socketio in socketio_manage.

These are snippets from my app.py:

from flask import Flask
#other imports here
...
from flask_socketio import SocketIO, emit

app = Flask(__name__)
#blueprints here
...

socketio = SocketIO(app)

@socketio.on('msg')
def msg_on(data):
    emit('response', "bob")

if __name__ == "__main__":
    socketio.run(app, host="0.0.0.0")

I'm running uWSGI like this:

uwsgi --gevent 100 --wsgi-file app.py --callable app 

What am I doing wrong?
I'm running uWSGI 2.0.2, Flask-SocketIO 0.2.2, gevent-socketio 0.3.6

[miguelgrinberg]

I'll have to spend some time looking at this myself. My impression based on reading the gevent-socketio is that there isn't official support for uWSGI. The problem that you have is that uWSGI is instantiating a regular gevent server, but gevent-socketio overloads that server and adds its own stuff. For this to work we need to tell uWSGI to create a different server, and I don't really know how to do that, I'll have to play with it and try to figure it out.

[stevegaron]

Glad to see that I'm not crazy. Let me know if you figure out how to fix this. If you need anything from me, let me know as well. In the meantime I'll have to resort to pulling o_O.

[miguelgrinberg]

It does not seem to be possible to run gevent-socketio apps on uWSGI. What's missing is that uWSGI uses its own gevent loop, and there is no easy way to provide an alternative one. A gevent-socketio application requires a specialized server that is based on gevent but does some additional work.

I have added a Deployment section to the documentation that lists the known deployment strategies. I have also added a more friendly error when a incompatible server is used.

Sorry I can't give you better news.