I'm using this at a raspberry pi gaming station (retropie) to enforce usage limits. Other use cases are very plausible, like any other gaming platform or even enforcing a pomodoro timer for your coding time. Be creative and let me know.
# run only on the final loop before apps are blocked
final-warn-command: "notify-send 'App Timer' 'Last minute before shutdown'"
```
`warn-threshold` is measured in minutes and triggers the `warn-command` every loop while there is still time remaining. `final-warn-command` fires once on the last loop before the timer exceeds its limit (based on `check-interval`). All commands are executed through the shell, so they can show desktop notifications, play sounds, etc. You can interpolate values in the command string using `{timer_name}`, `{time_left}`, `{time_left_int}`, `{time_left_floor}`, and `{time_left_seconds}` (any Python format specifiers are supported, e.g. `{time_left:.1f}`).
If the systemd service runs as `root`, wrap desktop commands so they execute inside your session:
The status server shows timer usage at `http://host:port/` (defaults `127.0.0.1:8090`). Override the bind address or port via the `status-server` block, or keep using the `APP_TIMER_STATUS_HOST` / `APP_TIMER_STATUS_PORT` environment variables if you prefer exporting them in your service unit.