What could be the reasons for not receiving messages in RabbitMQ? - node.js

Question

This is my first time testing RabbitMQ with node.js, and I utilized amqplib.
First, I run the
node ./messages/consumer.js
and out put as follow -:
Connected to RabbitMQ
Channel created
Waiting for messages...
Second, I run the
node ./messages/producer.js
and out put as follow -:
Connected to RabbitMQ
Channel created
Message sent: Hello, world!
Connection to RabbitMQ closed
From the RabbitMQ management console, I observed the presence of test_exchange, test_queue, and test_key, but there was no information regarding any messages. And the consumer terminal did not log any indication of receiving a message. It still displays the message "Waiting for message.". Could you kindly inform me of where I may have overlooked this information?
//config.js
module.exports = {
rabbitmq: {
host: 'localhost',
port: 5672,
username: 'guest',
password: 'guest',
vhost: '/',
exchange: 'test_exchange',
queue: 'test_queue',
routingKey: 'test_key'
}
}
//rabbitmq.js
const amqp = require("amqplib");
const config = require("../config/config");
class RabbitMQ {
constructor() {
this.connection = null;
this.channel = null;
}
async connect() {
try {
const { host, port, username, password, vhost } = config.rabbitmq;
this.connection = await amqp.connect(
`amqp://${username}:${password}#${host}:${port}/${vhost}`
);
console.log("Connected to RabbitMQ");
return this.connection;
} catch (error) {
console.error("Error connecting to RabbitMQ", error);
}
}
async createChannel() {
try {
if (!this.connection) {
await this.connect();
}
this.channel = await this.connection.createChannel();
console.log("Channel created");
return this.channel;
} catch (error) {
console.error("Error creating channel", error);
}
}
async close() {
try {
await this.connection.close();
console.log("Connection to RabbitMQ closed");
} catch (error) {
console.error("Error closing connection to RabbitMQ", error);
}
}
}
module.exports = new RabbitMQ();
//producer.js
const rabbitmq = require('../lib/rabbitmq');
const config = require('../config/config');
async function produceMessage(message) {
try {
const channel = await rabbitmq.createChannel();
const exchange = config.rabbitmq.exchange;
const queue = config.rabbitmq.queue;
const key = config.rabbitmq.routingKey;
await channel.assertExchange(exchange, 'direct', { durable: true });
await channel.assertQueue(queue, { durable: true });
await channel.bindQueue(queue, exchange, key);
const messageBuffer = Buffer.from(message);
await channel.publish(exchange, key, messageBuffer);
console.log(`Message sent: ${message}`);
await rabbitmq.close();
} catch (error) {
console.error('Error producing message', error);
}
}
produceMessage('Hello, world!');
//consumer.js
const rabbitmq = require('../lib/rabbitmq');
const config = require('../config/config');
async function consumeMessage() {
try {
const channel = await rabbitmq.createChannel();
const exchange = config.rabbitmq.exchange;
const queue = config.rabbitmq.queue;
const key = config.rabbitmq.routingKey;
await channel.assertExchange(exchange, 'direct', { durable: true });
await channel.assertQueue(queue, { durable: true });
await channel.bindQueue(queue, exchange, key);
channel.consume(queue, (msg) => {
console.log(`Message received: ${msg.content.toString()}`);
channel.ack(msg);
}, { noAck: false });
console.log('Waiting for messages...');
} catch (error) {
console.error('Error consuming message', error);
}
}
consumeMessage();

Answer 1

Problem:
Your message is failing to send because you are closing the connection immediately after executing the publish command. You can try this by commenting the line await rabbitmq.close(); in producer.js.
Solution:
If you want to close the connection after sending the message. You can create confirm channel instead of a normal channel, which will allow you to receive send acknowledgment.
1. Channel Creation
Change the channel creation line in rabbitmq.js file:
this.channel = await this.connection.createConfirmChannel();
2. Producer:
In the producer.js, call waitForConfirms function before closing the connection:
await channel.waitForConfirms();
await rabbitmq.close();