Python监控主机是否存活并以邮件报警

#!/usr/bin/env python 
# coding:UTF-8 
import time 
import pexpect 
import smtplib 
from email.mime.text import MIMEText 
mail_host = "smtp.163.com" #定义smtp服务器 
mail_to = "baojingtongzhi@163.com" #邮件收件人 
mail_from = "monitor@163.com" #邮件发件人 
mail_pass = "123456" #邮件发件人邮箱密码 
while True: 
 def Mail(error_ip): 
 date = time.strftime('%Y-%m-%d %H:%M:%S') 
 msg = MIMEText("%s Ping %s failed from 255.252." % (date, error_ip)) 
 msg['Subject'] = "Ping %s failed." % error_ip #定义邮件主题 
 msg['From'] = mail_from 
 msg['To'] = mail_to 
 try: 
 s = smtplib.SMTP() #创建一个SMTP()对象 
 s.connect(mail_host, "25") #通过connect方法连接smtp主机 
 s.starttls() #启动安全传输模式 
 s.login(mail_from,mail_pass) #邮箱账户登录认证 
 s.sendmail(mail_from, mail_to, msg.as_string()) #邮件发送 
 s.quit() #断开smtp连接 
 except Exception, e: 
 print str(e) 
 ip_list = ['192.168.18.10', 
 '192.168.18.11', 
 '192.168.18.12'] 
 for ip in ip_list: 
 ping = pexpect.spawn('ping -c 1 %s' % ip) 
 check = ping.expect([pexpect.TIMEOUT,"1 packets transmitted, 1 received, 0% packet loss"],2) #2代表超时时间 
 if check == 0: 
 Mail(ip) 
 print "Ping %s failed,Have email." % ip 
 if check == 1: 
 print "Ping %s successful." % ip 
 print "Sleep 10s..."
 time.sleep(10)
#直接运行
# python ping.py 
Ping 192.168.18.10 successful.
Ping 192.168.18.11 successful.
Ping 192.168.18.12 successful.
Sleep 10s...