add logging via MQTT

[CWempe]

When developing my projects I do not use a serial or USB cable, but push the firmware via MQTT to my device.

For that reason it is not possible to see the log messages created by Homie.getLogger(). I think it would be a great improvement if this was possible.

I would propose to add an option where Homie sends all getLogger messaged via mqtt, too.

Like: homie/devicename/$logger "This is an important debug message"

Ideally this could be turned on/off via mqtt. This way you could even debug devices that are installed in hard to reach places.

Instead of using the getLogger we could add a new function, that could support severity level.

Like:

Homie.mqttLogger.info() << "This is an info message!" << endl;
Homie.mqttLogger.debug() << "This is a debug message!" << endl;
Homie.mqttLogger.error() << "This is an error message!" << endl;

Result:

homie/devicename/$logger/info "This is an info message!"
homie/devicename/$logger/debug "This is a debug message!"
homie/devicename/$logger/error "This is an error message!"

Another option would be to support syslog, but I think mqtt would be fine for most users. :)

[luebbe]

Please take a look at https://github.com/euphi/HomieLoggerNode. I think it already does what you need.

[CWempe]

This is great! Thanks 👍

I think it should be listed in the "Community Projects" section.

[luebbe]

@euphi has got some great stuff in his repositories. I came across his LoggerNode when I started using homie and thought "this may be helpful for me some day" and have never used it yet. Now it is at least helpful for you, because I remember it.

A PR is always welcome ;)