仅当 cron 作业尚未运行时才运行它 [英] Run cron job only if it isn't already running

问题描述

我正在尝试将 cron 作业设置为我创建的守护程序的一种看门狗.如果守护程序出错并失败，我希望 cron 作业定期重新启动它......我不确定这有多大可能，但我阅读了几个 cron 教程，但找不到任何可以做我想做的事情我在找……

I'm trying to set up a cron job as a sort of watchdog for a daemon that I've created. If the daemon errors out and fails, I want the cron job to periodically restart it... I'm not sure how possible this is, but I read through a couple of cron tutorials and couldn't find anything that would do what I'm looking for...

我的守护进程从一个 shell 脚本启动，所以我真的只是在寻找一种方法来运行一个 cron 作业，前提是该作业的前一次运行没有仍在运行.

My daemon gets started from a shell script, so I'm really just looking for a way to run a cron job ONLY if the previous run of that job isn't still running.

我发现了这篇文章，它确实为我尝试使用锁定文件所做的事情提供了解决方案，而不是我不确定是否有更好的方法来做到这一点...

I found this post, which did provide a solution for what I'm trying to do using lock files, not I'm not sure if there is a better way to do it...

推荐答案

我为我编写的打印后台处理程序执行此操作，它只是一个 shell 脚本:

I do this for a print spooler program that I wrote, it's just a shell script:

#!/bin/sh
if ps -ef | grep -v grep | grep doctype.php ; then
        exit 0
else
        /home/user/bin/doctype.php >> /home/user/bin/spooler.log &
        #mailing program
        /home/user/bin/simplemail.php "Print spooler was not running...  Restarted." 
        exit 0
fi

它每两分钟运行一次，非常有效.如果由于某种原因进程没有运行，我会通过电子邮件向我发送特殊信息.

It runs every two minutes and is quite effective. I have it email me with special information if for some reason the process is not running.

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