socketio_watch.js

#!/usr/bin/env node

var io = require('socket.io-client')
  , argv = require('optimist').argv
  , w, c, h, u;

w = argv.w, c = argv.c, h = argv.h, u = argv.u;

w = w || 500;          // value for "WARNING" notification
c = c || 4000;         // value for "CRITICAL" notification
h = h || "localhost";  // hostname
u = u || "/";          // resource path of socket.io

var socket = io.connect("http://" + h + u, {
  resource: u.replace(/^\//, '')
});

var reqt;

socket.on('connect', function (data) {
  reqt = new Date;
  // send some data to server if needs
  socket.emit("foobar");
});

socket.on('hogefuga', function (data) {
  var rest = new Date
    , exit_code  = 0
    , exit_state = "OK"
    , exit_msg   = "no problem: "
    , diff_t     = rest - reqt;
  try {
    // type check here

    // if (invalid) throw "error";

    if (w <= diff_t && diff_t < c) {
      exit_code = 1;
      exit_state = "WARNING";
      exit_msg  = "slow response: ";
    }
    else if (c <= diff_t) {
      exit_code = 2;
      exit_state = "CRITICAL";
      exit_msg  = "very slow response: ";
    }
    exit_msg += String(diff_t) + "ms";
    console.log(exit_state + " - " + exit_msg + "|node=valid;" + w + ";" + c);
    socket.disconnect();
    process.exit(exit_code);
  } catch(e) {
    console.log("CRITICAL - " + e + "|node=invalid;" + w + ";" + c);
    socket.disconnect();
    process.exit(2);
  }
});