latency_test.js

var latency_test  = module.exports;
var request       = require('request');
var _             = require('lodash');
var async         = require('async');
var nconf         = require('nconf');
var url           = require('url');
var test_url      = 'https://' + url.parse(nconf.get('PROVISIONING_TICKET')).host + '/test';
var exit          = require('./lib/exit');

/**
 * test the url and return the ns
 * @param  {[type]}   message [description]
 * @param  {Function} done    [description]
 * @return {[type]}           [description]
 */
latency_test.run = function (done) {
  var start = process.hrtime();
  request.get(test_url, function(err){
    if (err) return done(err);
    var took = process.hrtime(start);
    done(null, took[0] * 1e9 + took[1]);
  });
};

latency_test.run_many = function (n, done) {
  async.mapSeries(_.range(n), function (n, callback) {
    latency_test.run(callback);
  }, function (err, times){
    if (err) {
      console.log('Error when doing the latency test, exiting.');
      exit(1);
    }

    var sum = times.reduce(function (prev, curr) {
      return prev + curr;
    }, 0);

    var max = times.reduce(function (prev, curr) {
      return Math.max(prev, curr);
    }, 0);

    var min = times.reduce(function (prev, curr) {
      return Math.min(prev, curr);
    }, Infinity);

    var result = [sum / n, max, min].map(function (nanos) {
      return (nanos / 1e6).toFixed(2);
    });

    console.log('latency test took avg: %d ms, max: %d ms, min: %d ms',
                result[0], result[1], result[2]);

    if (done) {
      done(null, result);
    }
  });
};

if (require.main === module) {
  latency_test.run_many(10);
}