Prometheus Exporter for metrics received via MQTT

This exporter provides a push gateway for MQTT: You let it listen to some interesting MQTT topics, it collects data into metrics and waits to be scraped by Prometheus.

Caveat: Only float values are supported. Anything else will be ignored.

Features

• Topics can be matched against a set of regular expressions to convert parts of their names into Prometheus keywords. Thus, a topic name such as

  sensor/garage/temperature
  

  when matched using regex

  sensor/(?P<sensor_name>\w+)/(?P<__metric__>\w+)
  

  would be exported to Prometheus as metric

  temperature{mqtt_topic="sensor/garage/temperature",sensor_name="garage"} 29.3
  

• Each metric is accompanied by an mqtt_data_age metric, that tells us when the last update occurred:

  mqtt_data_age{mqtt_topic="sensor/garage/temperature",sensor_name="garage",metric="temperature"} 7
  

  By setting a threshold on this value, you can detect and alert on sensors being broken somehow and not sending updates anymore.

• Allows metrics to expire if we don't get updates for a while. When a metric expires, its value won't be exported anymore, but data_age will continue to be exported. Thus, you can expire a metric after 2 minutes, but only after 5 minutes send an alert.

  Each Topic can have an individual expiry configuration.

• Topics that were matched in a subscription pattern can be hidden from the result through a topic configuration.

Installation

• apt-get install python3-pytoml python3-paho-mqtt python3-flask.
• Copy config.example.toml to config.toml and adapt it to your needs.
• Run mqtt-pushgateway.py. (See mqtt-pushgateway.service)