python监控tomcat日志，内存溢出错误（单台tomcat）

#!/usr/bin/python 
#-*- coding:utf-8 -*-
#
from os.path import getsize
from sys import exit
from re import compile, IGNORECASE
import sys, getpass
import smtplib
from email.mime.text import MIMEText

tomcat_log = '/data/python/catalina.out'
# 该文件是用于记录上次读取日志文件的位置
last_position_logfile = '/data/python/last_position.txt'
# 匹配的错误信息关键字的正则表达式
pattern = compile('outofmemory', IGNORECASE)

#定义发送邮件函数
def mail(content):
  email_host = 'test1.com'
  maillist ='tanxin@wisers.com'
  me = email_host

  msg = MIMEText(content)
  msg['Subject'] = 'tomcat 内存溢出'
  msg['From'] = me
  msg['To'] = maillist

  try:
    smtp = smtplib.SMTP('localhost')
    smtp.sendmail(me, maillist, msg.as_string())
    smtp.quit()
    print ('email send success.')
  except smtplib.SMTPException:
    print "Error: 无法发送邮件"
#读取上一次日志文件的读取位置
def get_last_position(file):
  try:
    data = open(file, 'r')
    last_position = data.readline()
    if last_position:
      last_position = int(last_position)
    else:
      last_position = 0
  except:
      last_position = 0
  return last_position

#写入本次日志文件的读取到的本次位置
def write_this_position(file, last_position):
  try:
    data = open(file, 'w')
    data.write(str(last_position))
    data.write('\n' + "Don't Delete This File,It is Very important for Looking Tomcat Error Log !! \n")
    data.close()
  except:
    print "Can't Create File !" + file
    exit()

#分析文件找出Outofmemory
def analysis_log(file):
  error_list = []
  try:
    data = open(file, 'r')
  except:
    exit()
  last_position = get_last_position(last_position_logfile)
  this_position = getsize(tomcat_log)
  if this_position < last_position:
    data.seek(0)
  elif this_position == last_position:
    exit()
  elif this_position > last_position:
    data.seek(last_position)
  for line in data:
    if pattern.search(line):
      error_list.append(line)
  write_this_position(last_position_logfile, data.tell())
  data.close()
  return ''.join(error_list)

if __name__ == '__main__':
  error_info = analysis_log(tomcat_log)
  if  error_info != "":
    mail(error_info)