我写了一个Python脚本,检查一个特定的电子邮件地址,并将新的电子邮件传递给一个外部程序。如何让这个脚本全天候执行,比如在Linux中将其转换为守护进程或服务。我是否还需要一个在程序中永不结束的循环,或者可以通过多次重新执行代码来完成?


当前回答

要创建一些像service一样运行的东西,你可以使用这个东西:

你必须做的第一件事是安装水泥框架: 水泥框架是一个CLI框架,您可以在其上部署应用程序。

app命令行界面:

interface.py

 from cement.core.foundation import CementApp
 from cement.core.controller import CementBaseController, expose
 from YourApp import yourApp

 class Meta:
    label = 'base'
    description = "your application description"
    arguments = [
        (['-r' , '--run'],
          dict(action='store_true', help='Run your application')),
        (['-v', '--version'],
          dict(action='version', version="Your app version")),
        ]
        (['-s', '--stop'],
          dict(action='store_true', help="Stop your application")),
        ]

    @expose(hide=True)
    def default(self):
        if self.app.pargs.run:
            #Start to running the your app from there !
            YourApp.yourApp()
        if self.app.pargs.stop:
            #Stop your application
            YourApp.yourApp.stop()

 class App(CementApp):
       class Meta:
       label = 'Uptime'
       base_controller = 'base'
       handlers = [MyBaseController]

 with App() as app:
       app.run()

YourApp.py类:

 import threading

 class yourApp:
     def __init__:
        self.loger = log_exception.exception_loger()
        thread = threading.Thread(target=self.start, args=())
        thread.daemon = True
        thread.start()

     def start(self):
        #Do every thing you want
        pass
     def stop(self):
        #Do some things to stop your application

请记住,你的应用程序必须运行在一个线程作为守护进程

要运行应用程序,只需在命令行中这样做

Python interface.py——help

其他回答

一个简单且受支持的版本是Daemonize。

从Python包索引(PyPI)安装它:

$ pip install daemonize

然后用like:

...
import os, sys
from daemonize import Daemonize
...
def main()
      # your code here

if __name__ == '__main__':
        myname=os.path.basename(sys.argv[0])
        pidfile='/tmp/%s' % myname       # any name
        daemon = Daemonize(app=myname,pid=pidfile, action=main)
        daemon.start()

你应该使用python-daemon库,它会处理所有的事情。

从PyPI:库实现一个行为良好的Unix守护进程。

首先,仔细研究邮件别名。邮件别名将在邮件系统内完成此任务,而无需您在守护进程或服务或任何类似的东西上瞎忙活。

您可以编写一个简单的脚本,每次将邮件消息发送到特定邮箱时,sendmail都会执行该脚本。

参见http://www.feep.net/sendmail/tutorial/intro/aliases.html

如果您真的想编写一个不必要的复杂服务器,您可以这样做。

nohup python myscript.py &

这就够了。您的脚本只是循环和休眠。

import time
def do_the_work():
    # one round of polling -- checking email, whatever.
while True:
    time.sleep( 600 ) # 10 min.
    try:
        do_the_work()
    except:
        pass

我推荐这个解决方案。您需要继承和重写方法运行。

import sys
import os
from signal import SIGTERM
from abc import ABCMeta, abstractmethod



class Daemon(object):
    __metaclass__ = ABCMeta


    def __init__(self, pidfile):
        self._pidfile = pidfile


    @abstractmethod
    def run(self):
        pass


    def _daemonize(self):
        # decouple threads
        pid = os.fork()

        # stop first thread
        if pid > 0:
            sys.exit(0)

        # write pid into a pidfile
        with open(self._pidfile, 'w') as f:
            print >> f, os.getpid()


    def start(self):
        # if daemon is started throw an error
        if os.path.exists(self._pidfile):
            raise Exception("Daemon is already started")

        # create and switch to daemon thread
        self._daemonize()

        # run the body of the daemon
        self.run()


    def stop(self):
        # check the pidfile existing
        if os.path.exists(self._pidfile):
            # read pid from the file
            with open(self._pidfile, 'r') as f:
                pid = int(f.read().strip())

            # remove the pidfile
            os.remove(self._pidfile)

            # kill daemon
            os.kill(pid, SIGTERM)

        else:
            raise Exception("Daemon is not started")


    def restart(self):
        self.stop()
        self.start()

假设您真的希望您的循环作为后台服务全天候运行

对于一个不需要向代码中注入库的解决方案,你可以简单地创建一个服务模板,因为你使用的是linux:

[Unit]
Description = <Your service description here>
After = network.target # Assuming you want to start after network interfaces are made available
 
[Service]
Type = simple
ExecStart = python <Path of the script you want to run>
User = # User to run the script as
Group = # Group to run the script as
Restart = on-failure # Restart when there are errors
SyslogIdentifier = <Name of logs for the service>
RestartSec = 5
TimeoutStartSec = infinity
 
[Install]
WantedBy = multi-user.target # Make it accessible to other users

将该文件放在您的守护进程服务文件夹(通常是/etc/systemd/system/)中,*. .使用以下systemctl命令安装它(可能需要sudo权限):

systemctl enable <service file name without .service extension>

systemctl daemon-reload

systemctl start <service file name without .service extension>

然后你可以使用命令检查你的服务是否在运行:

systemctl | grep running