指定したドメイン名の証明書期限(notAfter)までの残日数を返すだけのやつ

mackerel_check_ssl.sh

#!/bin/bash
set -ue

targets=("example.com")
targets_metric_name=("ex")
now=$(date "+%s")

function remaining() {
	local expiresAt=$(echo | openssl s_client -connect $1:443 2>&1 | openssl x509 -dates -noout|grep notAfter|sed -e 's/notAfter=//g'| xargs -i date -d "{}" "+%s")

	if [ $2 -gt $expiresAt ]; then
		echo -1
	else
		local diff=$(($expiresAt - $2))
		local day=$((24 * 60 * 60))
		echo $(($diff / $day))
	fi
}

for ((i=0; i < ${#targets[@]}; ++i)); do
	metric=$(remaining ${targets[$i]} $now)
	echo -e "ssl_expires_in.${targets_metric_name[$i]}\t$metric\t$now"
done