message-queues

name	message-queues
description	Message queue patterns with RabbitMQ, Redis Streams, BullMQ, dead letter queues, exactly-once delivery, and event-driven architectures
layer	domain
category	backend
triggers	["message queue","rabbitmq","redis streams","bullmq","bull","event driven","pub sub","dead letter queue","job queue","task queue","background jobs"]
inputs	["Async processing requirements","Event-driven architecture needs","Job scheduling specifications"]
outputs	["Queue topology designs","Producer/consumer implementations","Retry and dead letter configurations"]
linksTo	["redis","microservices","nodejs","python","golang"]
linkedFrom	["error-handling","logging","monitoring"]
preferredNextSkills	["redis","microservices","nodejs"]
fallbackSkills	["websockets","redis"]
riskLevel	low
memoryReadPolicy	selective
memoryWritePolicy	none
sideEffects	[]

Message Queues Domain Skill

Purpose

Provide expert-level guidance on message queue patterns, including RabbitMQ exchange topologies, Redis Streams consumer groups, BullMQ job processing, dead letter queues, retry strategies, exactly-once semantics, and event-driven architecture design.

When to Use What

Technology	Best For	Ordering	Persistence	Throughput
BullMQ	Job queues in Node.js apps	FIFO per queue	Redis-backed	High
Redis Streams	Event logs, lightweight pub/sub	Per-stream	Configurable	Very high
RabbitMQ	Complex routing, multi-consumer	Per-queue	Durable	High
Kafka	Event sourcing, high-volume streaming	Per-partition	Durable	Extreme
SQS	Serverless, AWS-native	Best-effort	Managed	High

Key Patterns

1. BullMQ (Node.js)

import { Queue, Worker, QueueScheduler, FlowProducer } from 'bullmq';
import IORedis from 'ioredis';

const connection = new IORedis({
  host: process.env.REDIS_HOST,
  port: 6379,
  maxRetriesPerRequest: null, // Required by BullMQ
});

// Define typed job data
  {
  : ;
  : ;
  : ;
  : <, >;
}

  {
  : ;
  : ;
}


 emailQueue =  <, >(, {
  connection,
  : {
    : ,
    : {
      : ,
      : , 
    },
    : { :  *  }, 
    : { :  *  *  },  
  },
});


  () {
   emailQueue.(, data, {
    : opts?.,
    : opts?., 
    : , 
  });
}


 emailWorker =  <, >(
  ,
   (job) => {
    job.();
    job.();

     html =  (job.., job..);
    job.();

     result =  mailer.({
      : job..,
      : job..,
      html,
    });
    job.();

     { : result., :  ().() };
  },
  {
    connection,
    : ,           
    : {
      : ,               
      : ,       
    },
  }
);


emailWorker.(,  {
  logger.({ : job., result }, );
});

emailWorker.(,  {
  logger.({ : job?., : err., : job?. }, );
});


 emailQueue.(, { :  }, {
  : {
    : , 
    : ,
  },
});


 flow =  ({ connection });

 flow.({
  : ,
  : ,
  : { :  },
  : [
    { : , : , : { :  } },
    { : , : , : { :  } },
  ],
});