Python守护进程没有pidfile [英] Python daemon no pidfile

问题描述

你好，我正在使用python-daemon模块在python中编写一个守护程序，我的应用程序正确启动，创建了一个pidfile.lock，但没有包含进程ID的pidfile的迹象。

Hello I'm writing a daemon in python which uses the python-daemon module, my application starts correctly, there is a pidfile.lock created but no sign of the pidfile containing the process id.

import daemon
import lockfile

import perfagentmain

context = daemon.DaemonContext(
    working_directory='/opt/lib/perf-agent',
    umask=0o002,
    pidfile=lockfile.FileLock('/var/run/perf-agent.pid')
    )


with context:
    perfagentmain.start()

推荐答案

我同意@npoektop对解决方案的评论。我只是说 daemon.pidlockfile 在撰写本文时不存在。 daemon.pidfile 代替。

I agree with @npoektop 's comment about the solution. I would just say that daemon.pidlockfile does not exist at the time I am writing this. daemon.pidfile instead. Maybe that's a recent name change?

因此，这里是使用 daemon.pidfile 模块而不是的常规解决方案。 lockfile 模块。

So instead, here's the general solution using the daemon.pidfile module instead of the lockfile module.

import daemon
import daemon.pidfile
import perfagentmain

context = daemon.DaemonContext(
    working_directory='/opt/lib/perf-agent',
    umask=0o002,
    pidfile=daemon.pidfile.PIDLockFile('/var/run/perf-agent.pid')
    )

with context:
    perfagentmain.start()

@Martino Dino，您说的很对，看来 lockfile 模块具有完全不同的写入锁定文件的实现。 （即使 python-daemon 实际上需要 lockfile ）

And @Martino Dino, you're absolutely right, it seems the lockfile module has a totally different implementation of writing lock files. (even though python-daemon actually requires lockfile)

当我尝试 pidfile = lockfile.FileLock（'/ var / run / mydaemon.pid'）来满足自己的需要时，却看到了一个名为<$ c $的文件c>< MY_MACHINE_NAME>-< 8CHAR_HEX_ID>。< PID_OFF_BY_2> ，以及文件 /var/run/mydaemon.pid.lock 。 此答案提到了这种将随机命名的文件硬链接到pidlock文件的方法是一种文件锁定方法，然后使用 O_EXCL 标志打开文件时使用。

When I tried out pidfile = lockfile.FileLock('/var/run/mydaemon.pid') for my own needs, I instead saw a file called <MY_MACHINE_NAME>-<8CHAR_HEX_ID>.<PID_OFF_BY_2>, along with a file /var/run/mydaemon.pid.lock . This answer mentions how this method of hard linking a randomly named file to your pidlock file was a file-locking method prior to the use of the O_EXCL flag used when opening files.

但是令人讨厌的部分是该文件不包含您所说的PID，并且文件名的PID与某些正确的PID 偏离，因此极具误导性。

But the annoying part was that the file did not contain the PID as you said, and the file name had a PID which was off by a few numbers of the correct PID, so it was terribly misleading.

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