启动一个完全独立的过程 [英] Launch a completely independent process

问题描述

我想从我的python脚本 main.py 启动一个进程。具体来说，我想运行以下命令：

I want to initiate a process from my python script main.py. Specifically, I want to run the below command:

`nohup python ./myfile.py &`

和文件 myfile.py 应该继续运行，即使在 main.py 脚本退出。

and the file myfile.py should continue running, even after the main.py script exits.

我也希望获得 pid

I also wish to get the pid of the new process.

我尝试过：

• os.spawnl *


• os.exec *


• 子进程。Popen

• os.spawnl*
• os.exec*
• subprocess.Popen

都终止了 myfile.py 当 main.py 脚本退出时。

and all are terminating the myfile.py when the main.py script exits.

更新：我可以在 xdg-open中使用 os.startfile 吗？ ？

Update: Can I use os.startfile with xdg-open? Is it the right approach?

示例

a = subprocess.Popen([sys.executable, "nohup /usr/bin/python25 /long_process.py &"],\
     stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
print a.pid

如果我检查 ps aux | grep long_process ，没有进程在运行。

If I check ps aux | grep long_process, there is no process running.

long_process.py ，它会继续打印一些文本：不退出

long_process.py which keeps on printing some text: no exit.

我在这里做错什么了吗？

Am I doing anything wrong here?

推荐答案

您打开您长期运行的过程，并保留一个管道。因此，您希望与其交谈。当启动器脚本退出时，您将无法与其进行对话。 长时间运行的进程收到 SIGPIPE 并退出。

You open your long-running process and keep a pipe to it. So you expect to talk to it. When yor launcher script exits, you can no longer talk to it. The long-running process receives a SIGPIPE and exits.

下面的代码才起作用对我来说（Linux，Python 2.7）。

The following just worked for me (Linux, Python 2.7).

创建一个长时间运行的可执行文件：

Create a long-running executable:

$ echo "sleep 100" > ~/tmp/sleeper.sh

运行Python REPL：

Run Python REPL:

$ python
>>>

import subprocess
import os
p = subprocess.Popen(['/bin/sh', os.path.expanduser('~/tmp/sleeper.sh')])
# look ma, no pipes!
print p.pid
# prints 29893

退出REPL并查看进程仍在运行：

Exit the REPL and see the process still running:

>>> ^D
$ ps ax | grep sleeper
29893 pts/0    S      0:00 /bin/sh .../tmp/sleeper.sh
29917 pts/0    S+     0:00 grep --color=auto sleeper

如果您想先与已启动的进程进行交流，然后再让它继续运行，则有几种选择：

If you want to first communicate to the started process and then leave it alone to run further, you have a few options:

• 在长期运行的过程中处理 SIGPIPE ，不要死于此。启动程序退出后，无需stdin即可继续生活。


• 使用参数，环境或临时文件传递您想要的任何内容。


• 如果您想进行双向通信，请考虑使用命名管道（ man mkfifo ）或套接字，或编写适当的服务器


• 在完成双向双向通信阶段后，使运行时间较长的分叉。

• Handle SIGPIPE in your long-running process, do not die on it. Live without stdin after the launcher process exits.
• Pass whatever you wanted using arguments, environment, or a temporary file.
• If you want bidirectional communication, consider using a named pipe (man mkfifo) or a socket, or writing a proper server.
• Make the long-running process fork after the initial bi-direcional communication phase is done.

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