消息队列

Bull can also be used for persistent message queues. This is a quite useful feature in some use cases. For example, you can have two servers that need to communicate with each other. By using a queue the servers do not need to be online at the same time, so this creates a very robust communication channel. You can treat add as send and process as receive:

Server A:

TypeScript

const Queue = require("bull");

const sendQueue = new Queue("Server B");
const receiveQueue = new Queue("Server A");

receiveQueue.process(function (job, done) {
  console.log("Received message", job.data.msg);
  done();
});

sendQueue.add({ msg: "Hello" });

Server B:

TypeScript

const Queue = require("bull");

const sendQueue = new Queue("Server A");
const receiveQueue = new Queue("Server B");

receiveQueue.process(function (job, done) {
  console.log("Received message", job.data.msg);
  done();
});

sendQueue.add({ msg: "World" });