sockets.js

function modulo(a, b) { return (+a % (b = +b) + b) % b; };

var h = require("highland");
var net = require("net");

var HOST = "127.0.0.1";

function createServer(port) {
  net.createServer(function(sock) {
    if (port === 7001) {
      setInterval((function() {
        return sock.write("700" + ((Math.random() * 3 | 0) + 2) + "\r\n");
      }), 0);
      return;
    }
    sock.on("data", function(data) {
      if ((Math.random() * 3 | 0) + 1 === 3) {
        sock.write("wait 10 seconds and retry\n");
      } else {
        sock.write((data * 2) + "\n");
      }
      return sock.close;
    });
  }).listen(port, HOST);
  console.log("server listening on " + port);
};

for (var i = 7001; i <= 7004; ++i) {
  createServer(i);
}

var g = net.createConnection(7001, HOST);
var tots = {
  7002: 0,
  7003: 0,
  7004: 0
};
var portcnt = {
  7002: 0,
  7003: 0,
  7004: 0
};

g.on("data", function(data) {
  var port = parseInt(data);
  if (isNaN(port)) {
    return;
  }
  var w = net.createConnection(port, "127.0.0.1");
  w.theport = port;
  w.write("50\n");
  w.on("data", function(d) {
    var p = w.theport;
    var ans = parseInt(d.toString());
    if (isNaN(ans)) {
      w.end();
      return;
    }
    tots[p] += ans;
    portcnt[p] += 1;
    if (tots[p] % 10000 === 0) {
      console.log("tots " + p + ": " + tots[p]);
    }
    if (portcnt[p] % 1000 === 0) {
      console.log("portcnt " + p + ": " + portcnt[p]);
    }
    w.end();
  });
});