Mosquitto Node.js Development Test Support Library

Usage no npm install needed!

<script type="module">
  import northscalerMosquittoTestSupport from 'https://cdn.skypack.dev/@northscaler/mosquitto-test-support';



Handy-dandy Mosquitto integration testing utility that starts a local Docker container running mosquitto if you're not running in a CI/CD pipeline. This allows you to run integration tests locally in a manner similar to how they'd be run in the CI/CD pipeline. This module does nothing when running in a CI build pipeline, because Mosquitto should be configured as part of the build via something like .gitlab-ci.yml's services element.

This package is intended to be installed in your project in devDependencies.

Your application must install its desired versions of mqtt.

NOTE: requires a Unix-y shell (/usr/bin/env sh) to be available. This is not designed to run on Windows; PRs/MRs welcome.


const { mosquittoConnect } = require('@northscaler/mosquitto-test-support')

const client = await mosquittoConnect()

Usage to work in both local environment & CI pipeline:

const { mosquittoConnect } =  require('@northscaler/mosquitto-test-support')
const client = await mosquittoConnect(process.env.CI_COMMIT_SHA ? { host: 'mosquitto', port: 1883 } : undefined)


The default configuration is pretty conventional, with the sole exception of the default port that mosquitto will listen on for clients. Instead of 1883, which might already be in use on developers' machines when they run integration tests, the default configuration uses 2883. It is a TODO to search for an available port.

NOTE: This module detects when it's running in a CI/CD pipeline by seeing if the environment variable CI_COMMIT_SHA or GITHUB_SHA is of nonzero length.

Environment variables

The following environment variables can be set to configure the docker container:

  • MOSQUITTO_TEST_SUPPORT_TAG: The tag of the eclipse-mosquitto Docker image or custom image to use, default latest
  • MOSQUITTO_TEST_SUPPORT_PORT: visible client port on localhost to map to container port, default is content of mosquitto/default-mosquitto-test-port
  • MOSQUITTO_TEST_SUPPORT_CONTAINER: name of container, default is content of file mosquitto/default-mosquitto-test-container
  • MOSQUITTO_TEST_SUPPORT_CONTAINER_PORT: mosquitto client port in container, default 9042
  • MOSQUITTO_TEST_SUPPORT_IMAGE: docker image name, default mosquitto