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
您还可以使用shell脚本使python脚本作为服务运行。首先创建一个shell脚本,像这样运行python脚本(scriptname任意名称)
#!/bin/sh
script='/home/.. full path to script'
/usr/bin/python $script &
现在在/etc/init.d/scriptname中创建一个文件
#! /bin/sh
PATH=/bin:/usr/bin:/sbin:/usr/sbin
DAEMON=/home/.. path to shell script scriptname created to run python script
PIDFILE=/var/run/scriptname.pid
test -x $DAEMON || exit 0
. /lib/lsb/init-functions
case "$1" in
start)
log_daemon_msg "Starting feedparser"
start_daemon -p $PIDFILE $DAEMON
log_end_msg $?
;;
stop)
log_daemon_msg "Stopping feedparser"
killproc -p $PIDFILE $DAEMON
PID=`ps x |grep feed | head -1 | awk '{print $1}'`
kill -9 $PID
log_end_msg $?
;;
force-reload|restart)
$0 stop
$0 start
;;
status)
status_of_proc -p $PIDFILE $DAEMON atd && exit 0 || exit $?
;;
*)
echo "Usage: /etc/init.d/atd {start|stop|restart|force-reload|status}"
exit 1
;;
esac
exit 0
现在可以使用/etc/init.命令启动和停止python脚本D /scriptname start or stop。
其他回答
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()
您还可以使用shell脚本使python脚本作为服务运行。首先创建一个shell脚本,像这样运行python脚本(scriptname任意名称)
#!/bin/sh
script='/home/.. full path to script'
/usr/bin/python $script &
现在在/etc/init.d/scriptname中创建一个文件
#! /bin/sh
PATH=/bin:/usr/bin:/sbin:/usr/sbin
DAEMON=/home/.. path to shell script scriptname created to run python script
PIDFILE=/var/run/scriptname.pid
test -x $DAEMON || exit 0
. /lib/lsb/init-functions
case "$1" in
start)
log_daemon_msg "Starting feedparser"
start_daemon -p $PIDFILE $DAEMON
log_end_msg $?
;;
stop)
log_daemon_msg "Stopping feedparser"
killproc -p $PIDFILE $DAEMON
PID=`ps x |grep feed | head -1 | awk '{print $1}'`
kill -9 $PID
log_end_msg $?
;;
force-reload|restart)
$0 stop
$0 start
;;
status)
status_of_proc -p $PIDFILE $DAEMON atd && exit 0 || exit $?
;;
*)
echo "Usage: /etc/init.d/atd {start|stop|restart|force-reload|status}"
exit 1
;;
esac
exit 0
现在可以使用/etc/init.命令启动和停止python脚本D /scriptname start or stop。
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。
你有两个选择。
Make a proper cron job that calls your script. Cron is a common name for a GNU/Linux daemon that periodically launches scripts according to a schedule you set. You add your script into a crontab or place a symlink to it into a special directory and the daemon handles the job of launching it in the background. You can read more at Wikipedia. There is a variety of different cron daemons, but your GNU/Linux system should have it already installed. Use some kind of python approach (a library, for example) for your script to be able to daemonize itself. Yes, it will require a simple event loop (where your events are timer triggering, possibly, provided by sleep function).
我不建议你选择2。,因为您实际上是在重复cron功能。Linux系统范例是让多个简单工具交互并解决您的问题。除非有其他原因需要创建守护进程(除了定期触发之外),否则选择其他方法。
此外,如果你使用daemonize进行循环并且发生了崩溃,那么没有人会在那之后检查邮件(正如Ivan Nevostruev在回答的评论中指出的那样)。而如果脚本作为cron作业添加,它将再次触发。
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
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