gometrum

GoMetrum

A lightweight system metrics agent written in Go.

GoMetrum collects host-level metrics and publishes them to Home Assistant using MQTT Discovery.

The project focuses on explicit configuration, deterministic behavior, and low runtime overhead, while avoiding implicit defaults and hidden logic.

Documentation

Project documentation:

• Installation
• Configuration
• Running GoMetrum
• Command-line interface

Overview

GoMetrum is a background agent designed to run on Linux hosts and report system-level metrics to Home Assistant.

Key characteristics:

• single explicit YAML configuration file,
• sensors enabled only by presence,
• predictable Home Assistant entity set,
• clean startup and shutdown behavior.
• publishes states via MQTT,

Explicit configuration model

Each sensor exists only if it is explicitly defined in the configuration file.

There are:

• no global enable/disable switches,
• no implicit or auto-generated sensors,
• no “magic defaults”.

As a result:

• the number of Home Assistant entities is always predictable,
• the configuration file fully describes the resulting system state,
• behavior is deterministic and easy to reason about.

Features

• System metrics collection (CPU, memory, disk, network, GPU)
• Explicit per-sensor configuration
• Per-sensor refresh intervals
• MQTT retained state publishing
• Home Assistant MQTT Discovery integration
• Availability reporting (online / offline)
• Discovery cleanup (--purge mode)
• Low runtime overhead

Technologies

Project is created with:

• Go 1.25.1
• MQTT (Eclipse Paho client)
• Home Assistant MQTT Discovery
• gopsutil
• systemd (optional)

Status

The project is in active development.