x1208-exporter

One-shot Prometheus textfile exporter for the Geekworm X1208 UPS HAT on Raspberry Pi 5.

Reads:

• GPIO 6 (PLD) — 1 = AC plugged in, 0 = on battery.
• I2C 0x36 (MAX17040 fuel gauge) — battery voltage and state of charge.

Writes /var/lib/node-exporter/textfiles/x1208.prom atomically. node-exporter's textfile collector serves it at scrape time.

Metrics

Name	Type	Description
rpi_ups_ac_power	gauge	1 = AC present, 0 = on battery
rpi_ups_voltage_volts	gauge	Battery cell voltage
rpi_ups_battery_percent	gauge	State of charge (0–100)
rpi_ups_last_update_seconds	gauge	Unix timestamp of last exporter run

Deploy

just deploy

Builds the arm64 binary, scps to rpi, installs systemd units, starts the timer.

Verify

just run-once   # forces one read, prints the prom file
just logs       # journalctl tail

How node-exporter picks it up

The monitoring compose stack on the Pi must mount the textfile dir and pass the flag to node-exporter:

node-exporter:
  volumes:
    - /var/lib/node-exporter/textfiles:/textfiles:ro
  command:
    - '--collector.textfile.directory=/textfiles'
    # ...existing flags