Working example of bull and external processor

index.js

// index.js
const path = require('path');
const Queue = require('bull');

let queue = new Queue('test queue', 'redis://192.168.99.100:6379');

queue.process(1, path.join(__dirname, './processor.js'))

queue.on('completed', function(job, result) {
    console.log("Completed: " + job.id + ", result = " + JSON.stringify(result));
    job.remove();
});

queue.add({ text: 'Hello world...' }).then(job => {
    console.log("Job started with id = " + job.id);
});

processor.js

// processor.js

module.exports = function(job) {
    console.log("data = " + JSON.stringify(job.data));

    console.log("Started working on job: " + job.id);

    return Promise.resolve({ 'data': 123 });
}