Graceful shutdown in node

shutdown.js

var shutDown = function() {
  logger.info('Gracefully shutting down.');

  process.nextTick(function() {
    logger.info('Shutting down Express.');
    server.close();
  });

  process.nextTick(function() {
    logger.info('Shutting down database connection.');
    db.close();
  });

  setTimeout(function() {
    logger.error("Couldn\'t shut down gracefully. Forcefully shutting down!");
    process.exit();
  }, 15*1000);
};

process.on("SIGTERM", shutDown);
process.on("SIGINT", shutDown);