rpi-metrics

A metrics agent for Raspberry Pi written in Go.

Features

• Collector based architecture
• Interval scheduler/runner
• Console exporter (JSON Lines to stdout)
• CPU temperature collector with sysfs:
  • /sys/class/thermal/thermal_zone0/temp (millidegrees Celsius)
• Storage usage collector (Linux statfs):
  • Total/free/available/used bytes and used percent (per configured path)

Requirements

• Raspberry Pi OS
• Go installed (Go 1.22+ recommended)

Usage

To verify the temperature source exists:

cat /sys/class/thermal/thermal_zone0/temp

You should see an integer like 51250 (meaning 51.250°C). Build

From the rpi-metrics/ directory:

cd ~/Code/raspberry-pi-system-control/rpi-metrics
go mod tidy
mkdir -p bin
go build -o ./bin/rpi-metrics ./cmd/rpi-metrics

Run Basic run (collect every 5 seconds)

./bin/rpi-metrics -interval=5s

Example output (JSON line per interval):

{"collected_at":"2025-12-26T12:45:06.543191272Z","samples":
[{"name":"cpu_temperature","value":51.25,"unit":"celsius",
"ts":"2025-12-26T12:45:06.543188513Z","labels":{"path":"/sys/
class/thermal/thermal_zone0/temp","source":"sysfs"}}]}

To run discord messenger:

./bin/rpi-metrics -interval= {x}s -discord-webhook="https://discord.com/api/webhooks/{webook_id}" -discord-every= {x}s

Running persistently (SSH disconnect safe)

If you start rpi-metrics directly in an SSH session, it will usually stop when the SSH connection closes (e.g. you close your laptop).

TMUX

On the Pi:

sudo apt-get update
sudo apt-get install -y tmux
./scripts/tmux-start.sh -- -interval=5s -discord-webhook="https://discord.com/api/webhooks/REPLACE_ME" -discord-every=1m

Detach without stopping it: press Ctrl-b then d.

Later, reattach:

./scripts/tmux-attach.sh

Stop it: Ctrl-c inside the tmux session.

Or stop the session directly:

./scripts/tmux-stop.sh

Check logs:

sudo journalctl -u rpi-metrics -f

Stop it:

sudo systemctl stop rpi-metrics

Flags

• interval - Collection interval duration (Go duration format). Examples: 500ms, 2s, 30s, 1m.

• temp-path - Path to the sysfs temperature file.

• storage-paths - Comma-separated list of filesystem paths to measure. Examples: / or /,/boot.

Example:

./bin/rpi-metrics -interval=2s -temp-path=/sys/class/thermal/thermal_zone0/temp

./bin/rpi-metrics -interval=5s -storage-paths=/,/boot

./bin/rpi-metrics -interval=5s -discord-webhook=https://discord.com/api/webhooks/{INSERT WEBHOOK} -discord-every=5s 

Web UI Dashboard

A web-based dashboard is available to visualize metrics in real-time. This should be packaged eventually

Build

cd ~/Code/raspberry-pi-system-control/rpi-metrics
go build -o ./bin/rpi-metrics-ui ./cmd/rpi-metrics-ui

Run

./bin/rpi-metrics-ui

Then open http://localhost:8080 in your browser.

Flags

• -port - HTTP server port (default: 8080)

Example with custom port:

./bin/rpi-metrics-ui -port=3000

Features

• CPU Temperature - Color-coded display with progress bar
• CPU Utilization - Total usage plus per-core breakdown
• Cooling State - Visual fan speed indicator (0-4 levels)
• Storage - Multiple mount points with used/free/total display
• Auto-refresh every 2 seconds
• Pause/Resume functionality
• Responsive design for mobile devices

Notes

This tool currently exports to stdout only. It is designed so additional exporters can be added later (HTTP/Prometheus scrape endpoint, MQTT, InfluxDB, etc.). CPU metrics reading uses sysfs for simplicity and performance.