"""Background thread that periodically prunes old logs / errors / forensics."""
import logging
import threading
import time

import db
from settings import RETENTION_RUN_INTERVAL_SECONDS

logger = logging.getLogger("web.retention")


def _loop():
    while True:
        try:
            db.cleanup_retention()
        except Exception:
            logger.exception("retention cleanup failed")
        time.sleep(RETENTION_RUN_INTERVAL_SECONDS)


def start() -> None:
    t = threading.Thread(target=_loop, name="retention", daemon=True)
    t.start()
    logger.info("retention thread started (interval=%ss)", RETENTION_RUN_INTERVAL_SECONDS)