如何使用python书写守护进程？daemon、python-daemon

可以参考的supervisor实现：https://github.com/Supervisor/supervisor；http://supervisord.org/configuration.html

pip包python-daemon：https://www.jianshu.com/p/76ecdea99ac7；https://www.python.org/dev/peps/pep-3143/；https://github.com/serverdensity/python-daemon

https://pypi.org/project/python-daemon/

来个摘抄的示例：https://codeday.me/bug/20180115/119802.html

#!/usr/bin/env python3.5

import sys

import os

import time

import argparse

import logging

import daemon

from daemon import pidfile

debug_p = False

def do_something(logf):

    ### This does the "work" of the daemon

    logger = logging.getLogger('eg_daemon')

    logger.setLevel(logging.INFO)

    fh = logging.FileHandler(logf)

    fh.setLevel(logging.INFO)

    formatstr = '%(asctime)s - %(name)s - %(levelname)s - %(message)s'

    formatter = logging.Formatter(formatstr)

    fh.setFormatter(formatter)

    logger.addHandler(fh)

    while True:

        logger.debug("this is a DEBUG message")

        logger.info("this is an INFO message")

        logger.error("this is an ERROR message")

        time.sleep(5)

def start_daemon(pidf, logf):

    ### This launches the daemon in its context

    ### XXX pidfile is a context

    with daemon.DaemonContext(

        working_directory='/var/lib/eg_daemon',

        umask=0o002,

        pidfile=pidfile.TimeoutPIDLockFile(pidf),

        ) as context:

        do_something(logf)

if __name__ == "__main__":

    parser = argparse.ArgumentParser(description="Example daemon in Python")

    parser.add_argument('-p', '--pid-file', default='/var/run/eg_daemon.pid')

    parser.add_argument('-l', '--log-file', default='/var/log/eg_daemon.log')

    args = parser.parse_args()

    start_daemon(pidf=args.pid_file, logf=args.log_file)

#!/bin/bash

#

# eg_daemon      Startup script for eg_daemon

#

# chkconfig: -

# description: eg_daemon is a dummy Python-based daemon

# config: /etc/eg_daemon/eg_daemon.conf

# config: /etc/sysconfig/eg_daemon

# pidfile: /var/run/eg_daemon.pid

#

### BEGIN INIT INFO

# Provides: eg_daemon

# Required-Start: $local_fs

# Required-Stop: $local_fs

# Short-Description: start and stop eg_daemon server

# Description: eg_daemon is a dummy Python-based daemon

### END INIT INFO

# Source function library.

. /etc/rc.d/init.d/functions

if [ -f /etc/sysconfig/eg_daemon ]; then

        . /etc/sysconfig/eg_daemon

fi

eg_daemon=/var/lib/eg_daemon/eg_daemon.py

prog=eg_daemon

pidfile=${PIDFILE-/var/run/eg_daemon.pid}

logfile=${LOGFILE-/var/log/eg_daemon.log}

RETVAL=

OPTIONS=""

start() {

        echo -n $"Starting $prog: "

        if [[ -f ${pidfile} ]] ; then

            pid=$( cat $pidfile  )

            isrunning=$( ps -elf | grep  $pid | grep $prog | grep -v grep )

            if [[ -n ${isrunning} ]] ; then

                echo $"$prog already running"

                return

            fi

        fi

        $eg_daemon -p $pidfile -l $logfile $OPTIONS

        RETVAL=$?

        [ $RETVAL =  ] && success || failure

        echo

        return $RETVAL

}

stop() {

    if [[ -f ${pidfile} ]] ; then

        pid=$( cat $pidfile )

        isrunning=$( ps -elf | grep $pid | grep $prog | grep -v grep | awk '{print $4}' )

        if [[ ${isrunning} -eq ${pid} ]] ; then

            echo -n $"Stopping $prog: "

            kill $pid

        else

            echo -n $"Stopping $prog: "

            success

        fi

        RETVAL=$?

    fi

    echo

    return $RETVAL

}

reload() {

    echo -n $"Reloading $prog: "

    echo

}

# See how we were called.

case "$1" in

  start)

    start

    ;;

  stop)

    stop

    ;;

  status)

    status -p $pidfile $eg_daemon

    RETVAL=$?

    ;;

  restart)

    stop

    start

    ;;

  force-reload|reload)

    reload

    ;;

  *)

    echo $"Usage: $prog {start|stop|restart|force-reload|reload|status}"

    RETVAL=

esac

exit $RETVAL