yarddog

A self-hosted watchdog for a home GPON router (Nokia G-240W-A): a short-lived process that checks the internet uplink and reboots the router over its web UI when the link is down. No cloud, no open ports. (The stock firmware has a reboot button but no scheduler.)

Two binaries: yarddog, the collector — check, reboot if needed, record, notify, exit; and yarddogd, an optional read-only query daemon that serves the recorded history as a JSON API and status dashboard over the LAN.

What it does

• checks connectivity against independent IP and domain targets
• soft mode (default) reboots only when the uplink is actually down; hard mode (--hard-reboot) reboots unconditionally
• a down verdict must survive re-probing within the run and be corroborated by the previous run before anything reboots; a failure of the domain targets alone, while raw IP connectivity holds, is reported as degraded and never reboots
• monitor-only mode (YARDDOG_REBOOT_ENABLED=false): watch and record, never reboot
• records every run, check and recovery phase in SQLite, with optional per-run host-telemetry and ping metrics
• Telegram alerts, outbox-queued so they still arrive after an outage
• yarddogd serves all of it read-only over the LAN

Build & run

make build OS=arm64          # -> build/{yarddog,yarddogd}-arm64; drop OS= for the host
cp yarddog.env.example .env  # LABEL, TELEGRAMBOT_DSN, ROUTER_USER, ROUTER_PASS are required
./build/yarddog              # runs one cycle and exits

yarddog is short-lived — schedule it however you like. yarddogd is the long-running daemon (YARDDOG_DAEMON_TOKEN=… yarddogd). Config is an env file with YARDDOG_-prefixed keys; yarddog.env.example documents every setting. For the reference Raspberry Pi deployment, run deploy/pi5-install.sh.

Notes

• The router UI is plain HTTP — the password crosses the LAN in cleartext, so keep .env at mode 600 and the router UI off the internet.
• Tested on Nokia G-240W-A; a different device is a driver in gateway/router/, selected by YARDDOG_ROUTER_KIND.