mqtt_topic_exporter

Subscribe MQTT topic and export them to prometheus.

usage: mqtt_topic_exporter --mqtt.server=MQTT.SERVER --mqtt.topic=MQTT.TOPIC [<flags>]

Flags: 
  -h, --help                     Show context-sensitive help (also try --help-long and --help-man).
      --web.listen-address=":9981"  
                                 Address on which to expose metrics and web interface.
      --web.telemetry-path="/metrics"  
                                 Path under which to expose metrics.
      --mqtt.retain-time="1m"    Retain duration for a topic
      --mqtt.server=MQTT.SERVER  MQTT Server address URI mqtts://user:pass@host:port
      --mqtt.topic=MQTT.TOPIC    Watch MQTT topic
      --log.level="info"         Only log messages with the given severity or above. Valid levels: [debug, info, warn, error, fatal]
      --log.format="logger:stderr"  
                                 Set the log target and format. Example: "logger:syslog?appname=bob&local=7" or "logger:stdout?json=true"
      --version                  Show application version.

Sample output:

curl -s http://127.0.0.1:9981/metrics | grep mqtt
# HELP mqtt_exporter_build_info A metric with a constant '1' value labeled by version, revision, branch, and goversion from which mqtt_exporter was built.
# TYPE mqtt_exporter_build_info gauge
mqtt_exporter_build_info{branch="",goversion="go1.10.3",revision="",version=""} 1
# HELP mqtt_topic mqtt topic gauge
# TYPE mqtt_topic gauge
mqtt_topic{topic="/home/sensor/co2"} 462
mqtt_topic{topic="/home/sensor/temp"} 31.171875

Development with Dev Container

This repository supports VS Code Dev Containers.

How to start the Dev Container

1. Open this repository in VS Code.
2. Open the command palette (F1 or Ctrl+Shift+P) and select Dev Containers: Reopen in Container.

This will automatically build and start the development container environment.

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Build Instructions

make build

Or

go build -o mqtt_topic_exporter main.go

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Debugging and Testing

1. Start the MQTT broker

docker-compose up -d mosquitto

2. Run the application

make run

Or

./mqtt_topic_exporter --mqtt.server=mqtt://mosquitto:1883 --mqtt.topic=/test/topic

3. Check Prometheus metrics

In another terminal, run:

curl -s http://localhost:9981/metrics | grep mqtt

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Testing MQTT Publish (pubtest)

A sample Go program is included at cmd/pubtest/main.go for publishing test messages to the MQTT broker.

Usage

Run the publisher directly with go run:

 go run cmd/pubtest/main.go /test/topic 42.5

This will publish a test message to the MQTT broker at mqtt://mosquitto:1883.

You can modify the command line arguments to change topics, payloads, or broker address as needed.

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Notes

• The MQTT broker configuration file is located at .devcontainer/mosquitto.conf.
• From inside the Dev Container, you can connect to the broker using mqtt://mosquitto:1883.