KUE - experiment w/ various ways to shutdown after processing only one payload

worker.js

var kue = require('kue')

var queue = kue.createQueue({
  redis: process.env.REDIS_URL
});

queue.process('crawl', function(job, ctx, done){
  console.log((new Date()).toLocaleString(), 'inside queue.process("crawl") for job id:', job.id);
  doSomething(job.data, ctx, done);
  //exit(); // Scenario C: don't like it because shutdown can happen before the job finishes,
            // the TIMEOUT is total guess work
            // what i really want is for kue to run one job
            // and one job only
            // and then shutdown
});

// WARN: if we forget a variable in the signature and NODE crashes, the container does not shutdown in 1 out of a 1000 times
function doSomething(payload, ctx, done) {
  console.log((new Date()).toLocaleString(), 'inside doSomething()');
  // pretend to work and finish after 30 seconds
  setTimeout(function() {
    console.log('successfully ran the job');
    console.log('payload', payload);
    done();

    // scenario A - try shut down after only one job
    /*console.log((new Date()).toLocaleString(), 'WILL TRY TO PAUSE NOW...');
    ctx.pause( 1000, function(err){
      console.log((new Date()).toLocaleString(), 'Worker is paused...');
      setTimeout( function(){
        console.log( (new Date()).toLocaleString(), 'shutdown will now commence');
        exit();
      }, 1000 );
    });*/

  }, 5000);
}

function exit(){
  var TIMEOUT = 1;
  queue.shutdown( TIMEOUT, function(err) {
    console.log( (new Date()).toLocaleString(), 'Kue shutdown', err||'' );
    process.exit( 0 );
  });
}

// scenario B - try shut down after only one job
setTimeout( function () {
  console.log( '[ Shutting down when all jobs finish... ]' );
  queue.shutdown( function ( err ) {
    console.log( '[ All jobs finished. Kue is shut down. ]' );
    process.exit( 0 );
  } )
}, 1000 );