Adonis MQTT Event Bus

A cross-process event bus for AdonisJS based on MQTT

Features

• Provides centralized, event-driven architecture across containerized applications.
• Clean integration with AdonisJS IoC, leveraging dependency injection.
• Efficient, lightweight inter-container/event-driven communication.

Getting Started

Installation

Install the package using your preferred package manager:

npm install @nhtio/adonis-mqtt-event-bus

Run the Adonis configuration command to set up the package:

node ace configure @nhtio/adonis-mqtt-event-bus

Configuration

The configuration file for the MQTT Event Bus will be located at config/meb.ts. You can customize the following options:

export default {
  host: 'mqtt://127.0.0.1:1883', // The MQTT broker URL
  baseTopic: 'adonis',           // The base topic for all events
  // you can add more options here
};

Make sure your MQTT broker is running and accessible at the specified host.

Accessing the Event Bus

You can access the event bus through one of the following methods:

1. As an Importable Service

import meb from '@nhtio/adonis-mqtt-event-bus/services/main';

// Example usage
meb.emit('my:event', { key: 'value' });
meb.on('my:event', (payload) => {
  console.log(payload);
});

2. As an Attribute of the Application

import { default as app } from "@adonisjs/core/services/app";

// Access the event bus
app.meb.emit('my:event', { key: 'value' });

3. Using Container Services

import { default as app } from "@adonisjs/core/services/app";

// Resolve the event bus from the IoC container
const meb = await app.container.make('meb');
meb.emit('my:event', { key: 'value' });

Adding Typescript Definitions for Events

You can add support for more events by augmenting the EventCallbackSignatures interface:

declare module "@nhtio/adonis-mqtt-event-bus" {
  interface EventCallbackSignatures {
    // your additional definitions here
  }
}

Instance Methods

| Method | Description | Documentation | | -------------------------------------------------- | -------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------ | | addListener(eventName, listener) | Adds the listener function to the end of the listeners array for the event. | Documentation | | emit(eventName[, ...args]) | Syncronously emits the event to the MQTT broker | Documentation | | eventNames() | Returns an array listing the events for which the emitter has registered listeners. | Documentation | | getMaxListeners() | Returns the current max listener value for the EventEmitter | Documentation | | listenerCount(eventName[, listener]) | Returns the number of listeners listening for the event. | Documentation | | listeners(eventName) | Returns a copy of the array of listeners for the event. | Documentation | | off(eventName, listener) | Removes the specified listener from the listener array for the event | Documentation | | on(eventName, listener) | Adds the listener function to the end of the listeners array for the event. | Documentation | | once(eventName, listener) | Adds a one-time listener function for the event. | Documentation | | prependListener(eventName, listener) | Adds the listener function to the beginning of the listeners array for the event. | Documentation | | prependOnceListener(eventName, listener) | Adds a one-time listener function for the event | Documentation | | removeAllListeners([eventName]) | Removes all listeners, or those of the specified eventName. | Documentation | | removeListener(eventName, listener) | Removes the specified listener from the listener array for the event | Documentation | | setMaxListeners(n) | Set the maximum number of listeners for a specific event before a warning is triggered | Documentation | | rawListeners(eventName) | Returns a copy of the array of listeners for the event, including any wrappers | Documentation | | boot | Runs tasks for when the Adonis bindings have booted | | | start | Run tasks for when the Adonis application has started | | | ready | Run tasks for when the Adonis application is in a ready state | | | shutdown | Run tasks for when the Adonis application is shutting down | | | clearDeadLetterQueue | Clears the dead-letter queue | | | publish(eventName, options, [, ...args]) | Asyncronously emits the event to the MQTT Broker. Uses options from mqttjs#publish | mqttjs#publish | | addWildcardListener(eventName, listener) | Adds the listener function to the end of the listeners array for the event. | Documentation | | offWildcard(eventName, listener) | Removes the specified listener from the listener array for the event | Documentation | | onWildcard(eventName, listener) | Adds the listener function to the end of the listeners array for the event. | Documentation | | onceWildcard(eventName, listener) | Adds a one-time listener function for the event. | Documentation | | prependWildcardListener(eventName, listener) | Adds the listener function to the beginning of the listeners array for the event. | Documentation | | prependOnceWildcardListener(eventName, listener) | Adds a one-time listener function for the event | Documentation | | removeAllWildcardListeners([eventName]) | Removes all listeners, or those of the specified eventName. | Documentation | | removeWildcardListener(eventName, listener) | Removes the specified listener from the listener array for the event | Documentation |

Instance Properties

| Property | Description | | ----------------- | ------------------------------------------------------------------------------------ | | connected | Boolean for if connected to the MQTT Broker | | state | An object which indicates the Adonis Application Lifecycle progress | | deadLetterQueue | A list of events for which there has not been a listener active since the last check |

Adonis MQTT Event Bus is a commercial work product released under the MIT License and is provided as-is with no warranty or guarantee of support.

Copyright © 2025-present New Horizon Technology LTD