app.js

const appRoot = require('app-root-path');
require('dotenv').config({path: `${appRoot}/.env`});

const spawn = require('child_process').spawn;
const path = require('path');
const fs = require('fs');
const rp = require('request-promise');
const os = require('os');
const util = require('util');
const moment = require('moment');
const Promise = require('bluebird');
const zlib = require('zlib')

const ignore = require(`${appRoot}/config/ignore`);
const db = require(`${appRoot}/config/db`);
const s3Client = require(`${appRoot}/config/s3`);

const monitor = process.argv[2] === '-nomonitor' ? false : true;  // determine if using CronAlarm
const allDatabases = []; // will hold the name of each databases to be backed up

//For sending results to CronAlarm
const formData = {
  success: 1,
  server: os.hostname(),
  path: __filename,
  message: ''
};

// If using CronAlarm, call the start API
// Otherwise, start the promise chain with Promise.resolve()
(monitor ? rp(`http://api.cronalarm.com/v2/${process.env.CRONALARM_KEY}/start`) : Promise.resolve())
  .then(() => db.queryAsync('show databases'))
  .then((dbs) => {
    /*
      Create an array of promises that will create a compressed
      backup file for each database
    */
    let promises = dbs.map((db) => {
      if (ignore.indexOf(db.Database) === -1) { // make sure database is not in the ignore list
        allDatabases.push(db.Database); // to be used later
        const gzip = zlib.createGzip();
        const wstream = fs.createWriteStream(process.env.BACKUP_PATH + db.Database + '.sql.gz');
        const mysqldump = spawn('mysqldump', [
          '-h',
          process.env.DB_HOST,
          '-u',
          process.env.DB_USER,
          '-p' + process.env.DB_PASS,
          db.Database
        ]);

        return new Promise(function(resolve, reject) {
          mysqldump.stdout.on('error', reject).pipe(gzip).pipe(wstream);

          wstream.on('finish', resolve);
          wstream.on('error', reject);
        });
      }
    });

    return Promise.all(promises);
  })
  .then(() => {
    const backupDate = moment().format('M-D-YY');

    // create an array of promises to upload each backup file to S3.
    let promises = allDatabases.map((db) => {
      return new Promise(function(resolve, reject) {
        const params = {
          localFile: `${process.env.BACKUP_PATH}${db}.sql.gz`,
          s3Params: {
            Bucket: process.env.S3_BUCKET,
            Key: `${backupDate}/${db}.sql.gz`,
            ServerSideEncryption: 'AES256',
            StorageClass: 'STANDARD_IA' //STANDARD_IA = infrequent access = cheaper storage costs.
          }
        };
        const uploader = s3Client.uploadFile(params);

        uploader.on('end', resolve);
        uploader.on('error', reject);
      });
    });

     return Promise.all(promises);
  })
  .catch((err) => {
    formData.success = 0;
    formData.message = util.inspect(err);
  })
  .finally(() => {
    if (monitor) {
      return rp({
        method: 'POST',
        uri: `http://api.cronalarm.com/v2/${process.env.CRONALARM_KEY}/end`,
        form: formData
      })
    }

    return Promise.resolve();
  })
  .then(() => process.exit());