#!/usr/bin/python
# SergAT (https://serg.at)
import os, glob, time, random
from datetime import datetime
from OpenSSL import crypto as c

RENEW_AT	= 30
RENEW_NOW	= False
CERT_LOCATION	= '/etc/letsencrypt/live/'

def cert_expiration_days(path):
	certificate	= c.load_certificate(c.FILETYPE_PEM, file(path).read())
	cur_date	= datetime.now().strftime('%Y-%m-%d %H:%M:%S')
	exp_date	= str(datetime.strptime(certificate.get_notAfter(),"%Y%m%d%H%M%SZ"))
	date_format	= "%Y-%m-%d %H:%M:%S"
	a = datetime.strptime(cur_date, date_format)
	b = datetime.strptime(exp_date, date_format)
	delta = b - a
	return delta.days

if os.path.exists(CERT_LOCATION):
	certs = glob.glob(CERT_LOCATION + '*')
	for cert_path in certs:
	 if os.path.isfile(cert_path + '/cert.pem'):
	  if RENEW_AT > cert_expiration_days(cert_path + '/cert.pem'):
		RENEW_NOW = True
		break

if RENEW_NOW:
 time.sleep(random.randint(0,3600))
 os.system('/usr/bin/letsencrypt renew')