Apache日誌中的時間是GMT格式，如下：

[Fri Oct 20 06:26:24 2017] [error] Server certificate is expired: 'Server-Cert'

用Python轉換時間戳，和系統時間比較時間差的程式碼如下：

import time
time.ctime(time.time())
#'Tue Oct 31 15:38:18 2017'


time.mktime(time.strptime(time.ctime(time.time()),"%a %b %d %H:%M:%S %Y"))


time.mktime(time.strptime("Tue Oct 31 15:38:18 2017","%a %b %d %H:%M:%S %Y"))

#計算時間差
int(time.mktime(time.strptime(time.ctime(time.time()),"%a %b %d %H:%M:%S %Y"))-time.mktime(time.strptime("Tue Oct 31 15:38:18 2017","%a %b %d %H:%M:%S %Y")))