var google = require('googleapis');

var key = require('./key.json');
var jwt = new google.auth.JWT(
    key.client_email,
    null, // path to key file
    key.private_key,
    ['https://www.googleapis.com/auth/admin.directory.user'],
    'administrator@vmwdev.com' // on behalf
);

// Authorize
jwt.authorize(function (err, data) {
  if (err) {
    throw err;
  }
  console.log('You have been successfully authenticated: ', data);
});