sonar

A lightweight Docker container metrics exporter for Prometheus, written in Rust, uses Serde and Axum

Features

• Exports CPU and memory usage metrics per container
• Prometheus-compatible output format
• Low resource footprint

Requirements

• Docker API v1.41+

Usage

sonar --port 3000 --socket-path /var/run/docker.sock

Docker

docker run -v /var/run/docker.sock:/var/run/docker.sock -p 3000:3000 ababarytskyi/sonar:latest

Or build from source:

docker build -t sonar .
docker run -v /var/run/docker.sock:/var/run/docker.sock -p 3000:3000 sonar

Metrics

Metric	Description
container_cpu_usage_percent	CPU usage percentage
container_memory_usage_percent	Memory usage percentage
container_memory_usage_bytes	Memory usage in bytes

Endpoints

• GET /metrics

  • Description: Returns Prometheus-formatted metrics for all running containers.
  • Response Example:

    # HELP container_cpu_usage_percent CPU usage percentage
    # TYPE container_cpu_usage_percent gauge
    container_cpu_usage_percent{container="sonar"} 0.12
    container_memory_usage_bytes{container="sonar"} 123456
    ...
    

• GET /json

  • Description: Returns raw container stats in JSON format.
  • Response Schema:

    [
    	{
    		"id": "<container_id>",
    		"name": "<container_name>",
    		"cpu_usage_percent": 0.12,
    		"memory_usage_percent": 0.5,
    		"memory_usage_bytes": 123456
    	},
    	...
    ]

Docker Image & Resource Usage

• Image Size: ~4.5 MB (compressed)
• Runtime Memory Usage: 700–900 KB RAM, RSS ~1.5 MB, VIRT ~2 MB

This makes the container lightweight and suitable for resource-constrained environments.

License

MIT