a.rb

/**
 * AWS Module: Action: Modularized Code with Promise for Asynchronous functions
 */
 
var Promise = require('bluebird');

// Export For Lambda Handler
module.exports.run = function(event, context, cb) {
    return action(event).then(function(result) {
        cb(null, result);
    }).error(function(error) {
        cb(error, null);
    });
};
// Your Code
var action = function(event) {
  return new Promise(function(resolve, reject) {

    var getUsers() = function() {
    var connection = mysql.createConnection({
      host     : '###',
      user     : '###',
      password : '###',
      database : '###'
    });
    connection.connect();

    var results;
    connection.query('myQuery', function (err, rows, fields) {
      if (err) {
          reject(err);
      }
      resolve(rows);
    });
  
  }});
}