I can't connect to an MQTT broker running on Docker with a Node application

[nicola907]

I have an MQTT broker running on a docker container:

mqtt-broker:
    image: rabbitmq
    container_name: mqtt-broker
    ports:
        - "1883:1883"
        - "9001:9001"

I want to create a Node client running on the host machine, but I can't make it connect to the broker. Here is my code:

const mqtt = require('mqtt');
const brokerUrl = 'mqtt://localhost:1883';
const topic = 'myTopic';

const client = mqtt.connect(brokerUrl, {
    protocol: 'tcp'
});

client.on('error', (err) => {
    console.error('Error:', err);
});

client.on('connect', () => {
    console.log('Connected to MQTT broker');
    client.subscribe(topic, (err) => {
        if (err) {
            console.error('Error subscribing to topic:', err);
        } else {
            console.log('Subscribed to topic:', topic);
        }
    });
});

Here is what I get:

Error: Error: read ECONNRESET
    at TCP.onStreamRead (node:internal/stream_base_commons:217:20) {
  errno: -104,
  code: 'ECONNRESET',
  syscall: 'read'
}

I tried to set the brokerUrl variables to other values such as 'mqtt://localhost:9001', 'mqtt://mqtt-broker:9001', 'mqtt://mqtt-broker:1883' but it has never worked. The "mqtt-broker" container is running without errors.

[robertsLando]

I think you should double check your rabbitmq.conf and ensure to have mqtt.listeners.tcp.default = 1883. Another try you can do is to use network_mode: host in your docker compose like this:

mqtt-broker:
    image: rabbitmq
    container_name: mqtt-broker
    network_mode: host

If it works it means the problem is the container ports are not accessible from localhost for some reasons. For sure this is not an MQTTjs related issue BTW

[nicola907]

Apparently the RabbitMQ Docker image doesn't include a default "rabbitmq.conf" file, therefore I tried to set mqtt.listeners.tcp.default = 1883 through the docker-compose.yml file. Since it didn't work I also tried to add network_mode: host, but it didn't work either.

mqtt-broker:
  image: rabbitmq
  container_name: mqtt-broker
  ports:
    - "1883:1883"
    - "9001:9001"
  environment:
    RABBITMQ_SERVER_ADDITIONAL_ERL_ARGS: "-rabbit mqtt.listeners.tcp.default 1883"
  network_mode: host

[robertsLando]

Does it work by using another mqtt client? like mqtt explorer? As said I'm quite sure this is nothing related to MQTTjs itself.