5.11 Lab — health check script with dry-run

Lab

Build health_restart.sh for your badge API hello API (local Docker/Node/Python or a small service on your VM).

1. Shebang + set -euo pipefail.
2. Default APP_URL to your health endpoint (environment can override).
3. curl -fsS the URL; on success print OK and exit 0.
4. On failure: if --dry-run was passed, print what you would restart and exit 1; else restart the service you actually use in the lab, wait two seconds, curl again.
5. Log a one-line timestamp result under ~/badge-api-logs/ (mkdir -p first).
6. Run once healthy, once with the app stopped (dry-run), once with a real restart if safe.
7. Optional: add a cron line that runs every five minutes with log redirect — remove the cron entry when the lab ends.

Practice task

List three reasons a script that works in your SSH session can fail under cron. Fix each with one concrete habit (absolute path, env, logging).