Caddy — алерт если auto-renewal не сработал

#!/usr/bin/env bash
# Reads the cert directly off the live socket; fails when < N days remain.
DOMAIN="${1:-example.com}"
DAYS_LEFT_THRESHOLD="${DAYS_LEFT_THRESHOLD:-14}"

EXPIRY=$(echo | openssl s_client -servername "$DOMAIN" -connect "$DOMAIN:443" 2>/dev/null \
        | openssl x509 -noout -enddate 2>/dev/null \
        | cut -d= -f2)
[ -z "$EXPIRY" ] && { echo "fetch-failed"; exit 1; }

EXP_TS=$(date -d "$EXPIRY" +%s)
NOW=$(date +%s)
DAYS=$(( (EXP_TS - NOW) / 86400 ))

[ "$DAYS" -lt "$DAYS_LEFT_THRESHOLD" ] && echo "low $DAYS" || echo "ok $DAYS"