Handle results from promises from seprate processors

[shamonshan]

Description

I am trying to implement a queue as a separate processor

imageProcessQueue.process(__dirname+'/process-queue.js');

In process-queue.js i m handling

module.exports = async function (job) {

  //some jobs 
  return Promise.resolve({status:"completed"});
}

But on the queue completed event I can't read the results from the promise which I return from the processor

imageProcessQueue.on('completed', function (job, result) {
  // can see this output
  console.log('completed')
  //never logs anything always empty 
 //should log  {status:"completed"}
  console.log(result)
})

Bull version :4.1.1

[manast]

Strange, we have a test case that cover this: https://github.com/OptimalBits/bull/blob/develop/test/test_sandboxed_process.js#L38

[shamonshan]

But if i return a normal statement ie return {status:"completed"} that i can see in the completed event

[manast]

Since you are using "async" already, then what you are returning is a promise not the value of the promise.

[shamonshan]

Ahh shit, I forgot about the async keyword, now it getting the expected result.
Thanks for the point, One more question is it necessary to do a resolve or reject to mark the job as complete??

[manast]

Not needed.

[manast]

I mean, you need to return a promise, either using async or a promise from a promise chain or whatever.

[shamonshan]

module.exports = function (job) {
    ProcessImage(job.data,(err,result)=>{
                 if(result){
                    return Promise.resolve({ status:"success" });
                 }
            });
    }
}

But the above implementation the completed event is not giving any data

[manast]

Because you are not returning any promise. The promise that you are returning is for the callback in ProcessImage...

[manast]

The code should be like this:

module.exports = function (job) {
  return new Promise((resolve, reject) => {
    ProcessImage(job.data, (err, result) => {
      if (err) {
        reject(err);
      } else {
        resolve({ status: "success" });
      }
    });
  });
};

[shamonshan]

Thanks now its working