Question: How does BullMQ interact with Redis?


BullMQ is a Node.js library that uses Redis as a message broker to handle job queues. Here's an overview of how it functions:

  1. Creating Jobs: You can create jobs by pushing them into a queue using the add method. These jobs are stored in Redis until they can be processed.
const queue = new Queue('my-queue'); const job = await queue.add({ foo: 'bar' });
  1. Processing Jobs: Workers pull jobs from the queue and process them. The process method specifies what to do with each job.
const worker = new Worker('my-queue', async (job) => { // Do something with job data console.log(; });
  1. Storing Results: After a job is processed, the result can be stored back in Redis for later retrieval.
const worker = new Worker('my-queue', async (job) => { // Do something with job data and return a result return {result: + ' processed'}; }); // Elsewhere... const job = await queue.getJob(jobId); if (job !== null) { const result = await job.finished(); console.log(result); // Logs: "{result: 'bar processed'}" }
  1. Scheduling Jobs: BullMQ supports delayed jobs, meaning you can schedule a job to be added to the queue after a certain delay.
const job = await queue.add( { foo: 'bar' }, { delay: 5000 } // Delay of 5 seconds );
  1. Job Prioritization: You can also specify job priorities.
const job = await queue.add( { foo: 'bar' }, { priority: 1 } // Lower numbers are higher priority );
  1. Repeatable Jobs: BullMQ supports repeatable jobs, which are jobs that are automatically re-added to the queue at specified intervals.
const job = await queue.add( { foo: 'bar' }, { repeat: { every: 5000 } } // Repeats every 5 seconds );
  1. Event-Driven: BullMQ is built around events. For instance, you can listen for when a job has been completed:
queue.on('completed', (job, result) => { // Do something when a job completes console.log(`Job ${} completed with result ${result}`); });

In these ways and more, BullMQ leverages Redis's capabilities to create a robust, flexible job queue system.

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Dragonfly is fully compatible with the Redis ecosystem and requires no code changes to implement.