Add local watchdog (HTTP-200 probe + per-minute cron auto-restart)

README.md

@@ -23,12 +23,38 @@ This project solves all three with a tiny **wrapper script** + an **adaptive cro
 
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+## Optional: local watchdog (auto-restart if it dies)
+
+`@reboot` starts the service at boot but does **not** restart it if the parent
+`-t` process later dies. Add a local watchdog that probes the API every minute
+and restarts 9router if it isn't healthy.
+
+`9router-watchdog.sh` checks `http://127.0.0.1:20128/v1/models` — if it does **not**
+return HTTP 200, it calls `start-9router.sh` again. Run it from root's crontab:
+
+```bash
+# root crontab — every minute
+* * * * * /usr/local/bin/9router-watchdog.sh
+```
+
+Or just run `sudo ./install.sh` (it registers both the `@reboot` job and the
+per-minute watchdog for you).
+
+Notes:
+- The check is a real HTTP 200 probe (not just "is the port open"), so a hung
+  Next.js process that still holds the port will also be detected and restarted.
+- Max recovery delay is ~1 minute (the cron interval).
+- The watchdog runs **locally** on the same machine — no external monitoring infra needed.
+
+---
+
 ## Files
 
 | File | Purpose |
 |------|---------|
 | `start-9router.sh` | Detached launcher. Drops to `ardhi` if run as root, runs directly if already `ardhi`. Uses absolute paths (cron `@reboot` has a minimal `PATH`). |
-| `install.sh` | One-shot setup: installs the wrapper, fixes log ownership, and registers the `@reboot` cron as **root**. |
+| `9router-watchdog.sh` | Local health monitor. Probes `/v1/models`; restarts via the wrapper if not HTTP 200. |
+| `install.sh` | One-shot setup: installs both scripts, fixes log ownership, and registers the `@reboot` cron + per-minute watchdog as **root**. |
 | `README.md` | This file. |
 
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