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We're working on a Ruby on Rails app that needs to take advantage of html5 websockets. At the moment, we have two separate "servers" so to speak: our main app running on nginx+passenger, and a separate server using Pratik Naik's Cramp framework (which is running on Thin) to handle the websocket connections.
Ideally, when it comes time for deployment, we'd have the rails app running on nginx+passenger, and the websocket server would be proxied behind nginx, so we wouldn't need to have the websocket server running on a different port.
Problem is, in this setup it seems that nginx is closing the connections to Thin too early. The connection is successfully established to the Thin server, then immediately closed with a 200 response code. Our guess is that nginx doesn't realize that the client is trying to establish a long-running connection for websocket traffic.
Admittedly, I'm not all that savvy with nginx config, so, is it even possible to configure nginx to act as a reverse proxy for a websocket server? Or do I have to wait for nginx to offer support for the new websocket handshake stuff? Assuming that having both the app server and the websocket server listening on port 80 is a requirement, might that mean I have to have Thin running on a separate server without nginx in front for now?
Thanks in advance for any advice or suggestions. :)
-John
243
NGINX supports WebSocket by allowing a tunnel to be set up between both client and back-end servers. NGINX will send the Upgrade request from the client to the back-end server, the Upgrade and Connection headers must be set explicitly. Once this is done, NGINX deals with this as a WebSocket connection.
Nginx is an open source web server that can also serve as a reverse proxy. Apart from being used to host websites, it's also one of the most widely used reverse proxy and load balancing solutions.
A reverse HTTP proxy over WebSocket is a type of proxies, which retrieves resources on behalf on a client from servers and uses the WebSocket protocol as a "tunnel" to pass TCP communication from server to client.
NGINX Plus and NGINX are the best-in-class reverse proxy and load balancing solutions used by high-traffic websites such as Dropbox, Netflix, and Zynga. More than 350 million websites worldwide rely on NGINX Plus and NGINX Open Source to deliver their content quickly, reliably, and securely.
You can't use nginx for this currently[it's not true anymore], but I would suggest looking at HAProxy. I have used it for exactly this purpose.
The trick is to set long timeouts so that the socket connections are not closed. Something like:
timeout client 86400000 # In the frontend timeout server 86400000 # In the backend If you want to serve say a rails and cramp application on the same port you can use ACL rules to detect a websocket connection and use a different backend. So your haproxy frontend config would look something like
frontend all 0.0.0.0:80 timeout client 86400000 default_backend rails_backend acl websocket hdr(Upgrade) -i WebSocket use_backend cramp_backend if websocket For completeness the backend would look like
backend cramp_backend timeout server 86400000 server cramp1 localhost:8090 maxconn 200 check If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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