MQTT Publishing

[capi]

Based on the initial example script by @jburdy in #66, improved a bit on the stability of the MQTT publishing and added a possibility to have the script "loop" forever, so that it can be used as part of a systemd service or a Docker deployment without the repeated overhead of starting up the Python runtime.

Note that the script will currently still "crash" while in --loop if anything goes wrong with reading the data. So it is sensible to have the calling service or wrapper re-start it in a loop. I personally use it in a Docker file like this:

version: "3.4"
services:
  solaredge-modbus-mqtt-publisher:
    image: cr.my.domain/solaredge_modbus:latest
    restart: unless-stopped
    entrypoint: [ "/bin/bash", "-c", "while true; do ./modbus-to-mqtt.py --loop --loop_delay 3 --mqttHost 192.168.38.1 --mqttBaseTopic solaredge/ 192.168.38.90 502; sleep 3; done" ]