"""Crashing demo service: works for ~30 s, then dies with a traceback and exit code 1.

With `restart: on-failure` Docker brings it back, so it also turns into 🔁 «цикл рестартов».
Expected alerts: 💥 краш (exit 1), then 🔁 after 3 restarts within 10 minutes.
"""

import sys
import time

print("crash demo: starting, will fail in 30 s", flush=True)
time.sleep(30)
try:
    {}["db_url"]
except KeyError:
    import traceback

    traceback.print_exc()
    print("ERROR fatal: config key db_url is missing", file=sys.stderr, flush=True)
    sys.exit(1)