Heroku nginx websockets - node.js

Question

I've been trying to get websockets to work on heroku over nginx and seem to be stuck. I'm using the nginx-buildpack which has worked great but I haven't had any success thus far getting an upgraded websocket connection.
Here is my nginx.conf.erb, which is just slightly modified from the buildpack example...
daemon off;
#Heroku dynos have 4 cores.
worker_processes 4;
events {
use epoll;
accept_mutex on;
worker_connections 1024;
}
http {
gzip on;
gzip_comp_level 2;
gzip_min_length 512;
log_format l2met 'measure.nginx.service=$request_time request_id=$http_heroku_request_id';
access_log logs/nginx/access.log l2met;
error_log logs/nginx/error.log;
include mime.types;
default_type application/octet-stream;
sendfile on;
#Must read the body in 5 seconds.
client_body_timeout 5;
proxy_read_timeout 950s;
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
server {
listen <%= ENV["PORT"] %>;
server_name _;
keepalive_timeout 5;
location /test {
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_redirect off;
proxy_pass http://127.0.0.1:3000;
}
location / {
proxy_pass http://127.0.0.1:3001;
proxy_redirect off;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $http_host;
proxy_set_header X-NginX-Proxy true;
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-Server $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header Host $host;
}
}
}
To test this configuration< i've just been using the websocket.org Echo Test. Unfortunately it is not able to connect.
On port 3001 I've just got a simple socket.io server, and I'm logging any connections (none so far...)...
var app2 = require('http').createServer().listen(3001);
var io = require('socket.io').listen(app2);
io.on('connection', function(socketconnection){
socketconnection.send("Connected to Server-1");
console.log("connected to websocket server!");
socketconnection.on('message', function(message){
socketconnection.send(message);
});
});
When I try connecting with the websockets tester this is the error that I get in my heroku logs...
*3 upstream prematurely closed connection while reading response
header from upstream, client: 10.140.231.210, server: _, request: "GET /? encoding=text HTTP/1.1", upstream: "http://127.0.0.1:3001/?encoding=t
ext", host: "www.mydomain.com"
Any ideas what I may be doing wrong here?
UPDATE 1 :
Ok, I so I've found that if I alter the section of my config where it is says :
map $http_upgrade $connection_upgrade {
default upgrade;
'' close;
}
to:
map $http_upgrade $connection_upgrade {
default upgrade;
}
this seems to prevent that error from occurring. I suppose this is due to a blank response being returned on connect. However, now that I've done this I get a new error:
*5 connect() failed (111: Connection refused) while connecting to upstream,
client: 10.99.212.2, server: _, request: "GET /?encoding=text HTTP/1.1",
upstream: "http://127.0.0.1:3001/?encoding=text", host: "www.mydomain.com"
I suppose this may be an issue unrelated to the first, but I'm not sure!