python 后台运行

def createDaemon():
    try:
        if os.fork() >0:
            os._exit(0)
    except OSError as error:
        err_msg = "fork #1 failed: %d (%s)" %(error.errno, error.strerror)
        logging.error(err_msg)
        os._exit(1)
    os.chdir('/')
    os.setsid()
    os.umask(0)
    try:
        pid = os.fork()
        if pid > 0:
            msg = "Daemon PID %d" %pid
            logging.error(msg)
            os._exit(0)
    except OSError as error:
        err_msg = "fork #2 failed %d (%s)" %(error.errno, error.strerror)
        logging.error(err_msg)
        os._exit(1)
    while 1:
        处理逻辑