Client not finding Socket.IO server

[alexanderdushkin]

I'm using Flask with uWSGI and NGINX, having set up the Socket.IO server as sio = socketio.Server(async_mode='gevent_uwsgi', logger=True). The whole thing is running in a Docker container which listens on localhost port 3536.

On the client side, I have JS which sends socket requests to Socket.IO. On all requests Chrome shows 404 NOT FOUND, while server logs don't show nothing at all.

For instance, I have this thing on server side:

@sio.on('process_registration', namespace='/regauth')
def process_registration(sid, message):
    <...>

And this on the client:

<script type="text/javascript">
      /* global io, grecaptcha, $ */
      namespace = "/regauth";
      var socket = io.connect('http://' + document.domain + ':' + location.port + namespace);

      $('#register-send_btn').click(function() {
           var username = $('#register-username').val(),
               pwd = $('#register-pwd').val(),
               pwd_confirm = $('#register-pwd_confirm').val(),
               email = $('#register-email').val(),
               grecaptcha_response = $('#register-grecaptcha_response').val();

           socket.emit("process_registration", {
               uname: username,
               password: pwd,
               password2: pwd_confirm,
               email: email,
               recaptcha_response: grecaptcha_response
           });
    });
</script>

The error I'm getting is:

socket.io.js:4196 GET http://127.0.0.1:3536/socket.io/?EIO=3&transport=polling&t=LX4DrIW 404 (NOT FOUND)

It seems either that the browser ignores the io.connect('http://' + document.domain + ':' + location.port + namespace); line because requests are still sent to /socket.io, or the server is not listening. Help me, please :)

[miguelgrinberg]

How are you running the server inside your docker container?

[alexanderdushkin]

nginx
uwsgi --master \
      --processes 5 \
      --socket /sockets/site.sock \
      --gevent 1000 \
      --http-websockets \
      --chmod-socket=660 \
      --die-on-term \
      --wsgi-file /app/wsgi.py

And inside the app:

sio = socketio.Server(async_mode='gevent_uwsgi', logger=True)
application = Flask(__name__)

[miguelgrinberg]

First of all, you can't use more than one server process unless you also use a message queue. I don't think that's the reason for the 404s, but keep that in mind once you resolve this issue.

I would switch to the configuration that I recommend in the documentation (here). That's something that I tested, so start from there. Main difference is that I did not use a unix socket.

[alexanderdushkin]

Sorry, what do you mean by using more than one server process?

Thanks, I will try using that configuration and a couple of other ones if it don't work.

[miguelgrinberg]

I mean this option will not work: --processes 5. It needs to be 1, or else you need to do the message queue configuration for the 5 processes to be able to talk among themselves.