A gateway listening on MQTT packets to obtain information from sensors and publish it as a prometheus metric.
Some years ago, my electricity provider installed a new electric meter (Landis+Gyr E350) whose data can be accessed via an infrared interface. I always wanted to know more about my electric consumption, so I was thrilled when a colleague gave me a few surplus pieces to do just that. It was an infrared sensor and a ESP 8266 microcontroller. The microcontroller, equipped with the Tasmota Firmware, is capable to access the sensor over its serial interface, talk the meter language and send the data via MQTT protocol to a broker.
I use a Mosquitto message broker, Prometheus and Grafana to make this data visible. The only missing link is to get the data from the broker to Prometheus, and so I created this little utility.
In the meantime, I've added a gas meter sensor, which also uses a ESP8266, but a reed relay to measure the turns of the meter's wheel. So I expanded the tool to be more configurable which MQTT topics to subscribe and to which Prometheus metrics to publish the data. Also, I've added a HY001 temperature sensor which measures the outside temperature.
MQTT and HTTP configuration is made in an .env file. A template can be found in the root folder. Copy and adapt it to match your own configuration:
cp .env.template .env
The configuration about MQTT topic subscriptions and the mapping of topic data to Prometheus metrics is done in config.yaml. The file provided contains my own settings and can be adapted as you need it.
The file is formatted as YAML, containing only one entry "metrics" which contains a list of mappings. Each mapping has the following fields:
- name: Prometheus metrics name
- description: A description what the metrics value means. This is shown in Prometheus
- type: The Prometheus metrics type
- topic: The MQTT topic path to subscribe to (may be used for multiple metrics)
- path: Path to single value in MQTT topic
- labels: Labels to add to the Prometheus metric. These are also key / path pairs, with the path being the source of the actual value in the MQTT topic
Mosquitto, Prometheus, Grafana and the mqtt-prometheus-gateway tool are run in a docker environment. You can find a docker compose file here. It uses some configuration files I've included here as a starting point.
To run this, you need NodeJS >= version 18. Install dependencies, and run the docker compose file:
npm install
docker compose up
You can find my Grafana dashboard here.
To use only the gateway utility itself locally, you need NodeJS >= version 18.
Clone the repository and install the dependencies:
git clone https://github.com/jschirrmacher/mqtt-prometheus-gateway.git
cd mqtt-prometheus-gateway
npm install
Next, copy the .env.template file to .env.local and edit this new file to match your needs.
Then, start the program:
npm start
Metrics are served under http://localhost:PORT/metrics with the PORT from the .env file.