检查服务器的pid文件，如果文件不存在或pid对应的进程已死重启服务器

# -*- coding: utf-8 -*-
# @author flynetcn
import sys, os, re, datetime;

LOG_FILE = '/var/log/www/serverMonitor.log';
SERVER_PID_FILE = '/var/log/www/server.pid';
SERVER_NAME = 'myserver';
START_SERVER_CMD = 'sh /bin/www/service/start.sh';

def logger(level, str):
    logFd = open(LOG_FILE, 'a');
    logFd.write(datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S.%f')+": "+("WARNING " if level else "NOTICE ")+str);
    logFd.close();

def startServer():
    import subprocess;
    logger(0, "start server...\n");
    logFd = open(LOG_FILE, 'a');
    ret = subprocess.call([START_SERVER_CMD], shell=True, stdout=logFd, stderr=logFd);
    logFd.close();
    if ret != 0:
        logger(1, "start server failed - %s\n" % (str(ret)));
    else:
        logger(0, "start server ok\n");

def monitorServer():
    try:
        pidFd = open(SERVER_PID_FILE);
        pid = pidFd.readlines();
    except:
        pid = [];
    if not pid:
        logger(1, "pidfile is empty\n");
        startServer();
        return;
    pid = pid[0].strip();
    if not os.access('/proc/'+pid, os.R_OK):
        logger(1, "start server - process(pid:%s) not find\n" % (pid));
        startServer();
        return;
    elif SERVER_NAME not in open('/proc/'+pid+'/cmdline').readline():
        logger(1, "start server - process(pid:%s) is not %s\n" % (pid, SERVER_NAME));
        startServer();
        return;
    else:
        logger(0, "server is running - pid:%s\n" % (pid));
        return;

if __name__ == "__main__":
    monitorServer();