如何使用Popen运行后台进程并避免僵尸? [英] How to use Popen to run backgroud process and avoid zombie?

问题描述

我有一个为每个客户端处理程序运行新线程的侦听器服务器.每个处理程序都可以使用:

I've a listener server running new thread to for each client handler. Each handler can use:

proc = subprocess.Popen(argv, executable = "./Main.py", stdout = _stdout, stderr = subprocess.STDOUT, close_fds=False)

在处理程序线程结束之后，在后台运行新进程.

to run new process in background, after what the handler thread is ended.

后台进程结束后，保持在Z状态.是否有可能要求subprocess.Popen()处理SIG_CHILD以避免这种僵尸?

After the background process is ended, it is kept in Z state. Is it possible to ask subprocess.Popen() to handle SIG_CHILD to avoid this zombie?

我不想使用proc.wait()来读取进程状态，因为为此，我必须保存所有正在运行的后台进程的列表...

I don't want to read process state using proc.wait(), since for this I've to save the list of all running background processes...

UPD

我需要在后台运行某些进程以避免僵尸，并使用.communicate()运行某些进程以从这些进程读取数据.在那种情况下，使用 koblas 的信号技巧，我会收到一个错误:

I need to run some processes in background avoiding zombies and to run some processes with .communicate() to read data from these processes. In that case using signal trick from koblas I get an error:

File "./PyZWServer.py", line 115, in IsRunning
  return (subprocess.Popen(["pgrep", "-c", "-x", name], stdout=subprocess.PIPE).communicate()[0] == "0")
File "/usr/lib/python2.6/subprocess.py", line 698, in communicate
  self.wait()
File "/usr/lib/python2.6/subprocess.py", line 1170, in wait
  pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
File "/usr/lib/python2.6/subprocess.py", line 465, in _eintr_retry_call
   return func(*args)
OSError: [Errno 10] No child processes
Error happened during handling of client

推荐答案

如果为SIGCHLD添加信号处理程序，则将由内核来处理等待/收获部分.

If you add a signal handler for SIGCHLD you will have the kernel handle the wait/reap piece.

特别是这行:

signal.signal(signal.SIGCHLD, signal.SIG_IGN)

会照顾好你的僵尸.

这篇关于如何使用Popen运行后台进程并避免僵尸?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！