pinger-callbacks-async.js

import request from 'request';
import asyncLib from 'async';

export function pingServers(servers, onComplete) {
  let failedServers = {};
  asyncLib.eachSeries(servers, (url, onNextUrl) => {
    let failures = 0;
    asyncLib.timesSeries(3, (n, onNextAttempt) => {
      request(url, (error, response) => {
        if (error || response.statusCode !== 200) failures++;
        setTimeout(onNextAttempt, 10000);
      });
    }, () => {
      if (failures > 0) failedServers[url] = failures;
      onNextUrl();
    });
  }, () => {
    onComplete(failedServers);
  });
}