Mosquitto

Mosquitto is an open source message broker that implements the MQTT protocol, a lightweight and popular communication method for the Internet of Things (IoT). Mosquitto supports MQTT versions 5.0, 3.1.1 and 3.1, and can run on various devices, from low power single board computers to full servers.

Setup

The following setup enables a local Mosquitto server listening on port 1883, allowing anonymous access for demonstration purpose.

mosquitto = {
  enable = true;
  listeners = [
    {
      acl = [ "pattern readwrite #" ];
      omitPasswordAuth = true;
      settings.allow_anonymous = true;
    }
  ];
};

networking.firewall = {
  enable = true;
  allowedTCPPorts = [ 1883 ];
};

Usage

Testing the server is possible by running a listening comand

nix shell nixpkgs#mosquitto --command mosquitto_sub -h localhost -t test

and sending on a different shell a message which should be received by the command above

nix shell nixpkgs#mosquitto --command mosquitto_pub -h localhost -t test -m "Hello"