Feature: Add MQTT Topic monitor

[aikitori]

Hi!

A MQTT monitor would be awesome ;)

Maybe use some kinde of regex like the http monitor for evaluating?

Paho seems the one to go:
https://pypi.org/project/paho-mqtt/
https://eclipse.dev/paho/
Github repo: https://github.com/eclipse-paho/paho.mqtt.python

Here a a list of other python clients:
https://www.emqx.com/en/blog/comparision-of-python-mqtt-client

[jamesoff]

Can you describe how you'd like it to work? Like subscribe to a topic and alert based on the messages posted? I'm not super-familiar with MQTT. There's a logger which posts to it which I think uses Paho already, which was contributed by someone else.

[aikitori]

i have e.g. an shellyplus1, which report via it's last will on the topic shellys/shellyplus1-cde/online ether true or false.
So a success is "true" , everything else is a fail.

Questions:
Config for the monitor.conf?

• host / ip
• port
• username
• password
• tls
• [server ca]
• [client cert]
• [client key]

Config for the monitors.conf?

• topic
• success match (string/regex)

On startup, you start listening to all topics in the monitors.conf. On every intervall, you check the saved responses.

i don't know how to handle the listing part to the different topics. you need something like the Listener class in the network logger.

edit:
Another posibilty could be to save all the mqtt client infos in the monitors.ini

[aikitori]

I created a little example:
https://github.com/aikitori/simplemonitor/blob/mqtt-monitor/simplemonitor/Monitors/mqtt.py

You need a running mqtt server on localhost:

$ /etc/mosquitto/conf.d/local.conf
listener 1883
allow_anonymous true

and mqtt client like mosquitto_client or http://mqtt-explorer.com/ for testing

Whats your opinion?
Dont know how to handle the credentials ...

[aikitori]

I added a Manager for the mqtt connections to limit them to 1/broker.
I testet the tls option with my mosquitto broker with a lets's encryp cert. The ca option is untested ...
Added some doku, but im propably not finished.
https://github.com/aikitori/simplemonitor/tree/mqtt-monitor

Happy Holidays!

[jamesoff]

Thanks, this is looking good (and better than I'd have known to do!)

Let me know when you think it's about done, or feel free to open a PR for it :)