We have have a NodeJS application running with SocketIO and clustering on heroku. To get SocketIO working we use the redis-adapter like discussed here: https://socket.io/docs/using-multiple-nodes/.
Then we've implemented sticky sessions like shown in the sticky session documentation here: https://github.com/elad/node-cluster-socket.io.
Turns out that when we deploy to Heroku, the connection.remoteAddress in:
// Create the outside facing server listening on our port.
var server = net.createServer({ pauseOnConnect: true }, function(connection) {
// We received a connection and need to pass it to the appropriate
// worker. Get the worker for this connection's source IP and pass
// it the connection.
var index = worker_index(connection.remoteAddress, num_processes);
var worker = workers[index];
worker.send('sticky-session:connection', connection);
}).listen(port);
is actually the IP address of some heroku routing server and NOT the client IP. I've seen that the request header "x-forwarded-for" could be used to get the client IP, but when we pause the connection in this way, we don't even have the headers yet?
