Python写的服务监控程序实例

#!/usr/bin/python
#-*- coding: UTF-8 -*-
# cheungmine
# stdin、stdout和stderr分别表示子程序的标准输入、标准输出和标准错误。
#
# 可选的值有:
# subprocess.PIPE - 表示需要创建一个新的管道.
# 一个有效的文件描述符（其实是个正整数）
# 一个文件对象
# None - 不会做任何重定向工作，子进程的文件描述符会继承父进程的.
#
# stderr的值还可以是STDOUT, 表示子进程的标准错误也输出到标准输出.
#
# subprocess.PIPE
# 一个可以被用于Popen的stdin、stdout和stderr 3个参数的特输值，表示需要创建一个新的管道.
#
# subprocess.STDOUT
# 一个可以被用于Popen的stderr参数的特输值，表示子程序的标准错误汇合到标准输出.
################################################################################
import os
import sys
import getopt

import time
import datetime

import codecs

import optparse
import ConfigParser

import signal
import subprocess
import select

# logging
# require python2.6.6 and later
import logging
from logging.handlers import RotatingFileHandler

## log settings: SHOULD BE CONFIGURED BY config
LOG_PATH_FILE = "./my_service_mgr.log"
LOG_MODE = 'a'
LOG_MAX_SIZE = 4*1024*1024 # 4M per file
LOG_MAX_FILES = 4 # 4 Files: my_service_mgr.log.1, printmy_service_mgrlog.2, ...
LOG_LEVEL = logging.DEBUG

LOG_FORMAT = "%(asctime)s %(levelname)-10s[%(filename)s:%(lineno)d(%(funcName)s)] %(message)s"

handler = RotatingFileHandler(LOG_PATH_FILE, LOG_MODE, LOG_MAX_SIZE, LOG_MAX_FILES)
formatter = logging.Formatter(LOG_FORMAT)
handler.setFormatter(formatter)

Logger = logging.getLogger()
Logger.setLevel(LOG_LEVEL)
Logger.addHandler(handler)

# color output
#
pid = os.getpid()

def print_error(s):
print '\033[31m[%d: ERROR] %s\033[31;m' % (pid, s)

def print_info(s):
print '\033[32m[%d: INFO] %s\033[32;m' % (pid, s)

def print_warning(s):
print '\033[33m[%d: WARNING] %s\033[33;m' % (pid, s)


def start_child_proc(command, merged):
try:
if command is None:
raise OSError, "Invalid command"

child = None

if merged is True:
# merge stdout and stderr
child = subprocess.Popen(command,
stderr=subprocess.STDOUT, # 表示子进程的标准错误也输出到标准输出
stdout=subprocess.PIPE # 表示需要创建一个新的管道
)
else:
# DO NOT merge stdout and stderr
child = subprocess.Popen(command,
stderr=subprocess.PIPE,
stdout=subprocess.PIPE)

return child

except subprocess.CalledProcessError:
pass # handle errors in the called executable
except OSError:
pass # executable not found

raise OSError, "Failed to run command!"


def run_forever(command):
print_info("start child process with command: " + ' '.join(command))
Logger.info("start child process with command: " + ' '.join(command))

merged = False
child = start_child_proc(command, merged)

line = ''
errln = ''

failover = 0

while True:
while child.poll() != None:
failover = failover + 1
print_warning("child process shutdown with return code: " + str(child.returncode))
Logger.critical("child process shutdown with return code: " + str(child.returncode))

print_warning("restart child process again, times=%d" % failover)
Logger.info("restart child process again, times=%d" % failover)
child = start_child_proc(command, merged)

# read child process stdout and log it
ch = child.stdout.read(1)
if ch != '' and ch != '\n':
line += ch
if ch == '\n':
print_info(line)
line = ''

if merged is not True:
# read child process stderr and log it
ch = child.stderr.read(1)
if ch != '' and ch != '\n':
errln += ch
if ch == '\n':
Logger.info(errln)
print_error(errln)
errln = ''

Logger.exception("!!!should never run to this!!!")


if __name__ == "__main__":
run_forever(["python", "./testpipe.py"])

然后是子进程代码：testpipe.py