For a while now I’ve been meaning to investigate the Message Queuing Telemetry Transport protocol or MQTT as it’s more commonly known. While the protocol is nearly 20 years old it has become increasingly popular with the Internet of Things (IoT).

The original MQTT code was donated by IBM and Eurotech to the Eclipse Paho project more than 10 years ago now and since then has been extended and massaged into what is known as Mosquitto today. I also like that Eclipse have done a lot of work writing clients for a great many platforms making the developers job just that much easier. A few of my friends have used it professionally so it comes recommended and seems like a good place to start.

So I wanted to experiment with this on a Raspberry Pi (there is a plan more on this later!), so after a bit of googling I found a nice guide written by Adafruit (click) that was the basis of what I used to setup my MQTT stack.

The following is what I needed to do to install Mosquitto on a stock installation of Raspbian Buster Lite. The Mosquitto package is available pre-compiled for ARM in the Debian repo’s so that makes life much easier;

$ sudo apt-get install mosquitto mosquitto-clients
$ cd /etc/mosquitto/conf.d/
$ pico mosquitto.conf

Once pico has created thew mosquitto.conf file then copy the following configuration into it;

# Config file for mosquitto
#
# See mosquitto.conf(5) for more information.

user mosquitto
max_queued_messages 200
message_size_limit 0
allow_zero_length_clientid true
allow_duplicate_messages false

listener 1883
autosave_interval 900
autosave_on_changes false
persistence true
persistence_file mosquitto.db
allow_anonymous true
password_file /etc/mosquitto/passwd

The configuration above is just a basic one for testing. It is by no means secure or ready for production systems, you have been warned. Once the config has been written the following two commands can be used to start Mosquitto and check it is actually running;

$ sudo systemctl start mosquitto.service
$ sudo systemctl status mosquitto.service 

There are small apps that can be used to throw data into the MQTT broker and create topics to publish and subscribe data to and from. Once I’ve worked this out for myself I’ll throw something here.