在Python中运行后台进程，不要等待 [英] Run background process in Python and do NOT wait

问题描述

我的目标很简单:启动rsync并不要等待.

My goal is simple: kick off rsync and DO NOT WAIT.

Debian上的Python 2.7.9

Python 2.7.9 on Debian

示例代码:

rsync_cmd = "/usr/bin/rsync -a -e 'ssh -i /home/myuser/.ssh/id_rsa' {0}@{1}:'{2}' {3}".format(remote_user, remote_server, file1, file1)
rsync_cmd2 = "/usr/bin/rsync -a -e 'ssh -i /home/myuser/.ssh/id_rsa' {0}@{1}:'{2}' {3} &".format(remote_user, remote_server, file1, file1)
rsync_path = "/usr/bin/rsync"
rsync_args = shlex.split("-a -e 'ssh -i /home/mysuser/.ssh/id_rsa' {0}@{1}:'{2}' {3}".format(remote_user, remote_server, file1, file1))
#subprocess.call(rsync_cmd, shell=True)     # This isn't supposed to work but I tried it
#subprocess.Popen(rsync_cmd, shell=True)    # This is supposed to be the solution but not for me
#subprocess.Popen(rsync_cmd2, shell=True)   # Adding my own shell "&" to background it, still fails
#subprocess.Popen(rsync_cmd, shell=True, stdin=None, stdout=None, stderr=None, close_fds=True)  # This doesn't work
#subprocess.Popen(shlex.split(rsync_cmd))   # This doesn't work
#os.execv(rsync_path, rsync_args)           # This doesn't work
#os.spawnv(os.P_NOWAIT, rsync_path, rsync_args) # This doesn't work
#os.system(rsync_cmd2)                      # This doesn't work
print "DONE"

(我之所以注释掉执行命令，只是因为我实际上将所有试验都保留在了我的代码中，以便我知道自己已经做过什么以及尚未完成什么.显然，我会运行该脚本右行未注释.)

(I've commented out the execution commands only because I'm actually keeping all of my trials in my code so that I know what I've done and what I haven't done. Obviously, I would run the script with the right line uncommented.)

这是怎么回事...我可以在服务器上观看传输，完成传输后，我会在屏幕上看到完成"字样.

What happens is this...I can watch the transfer on the server and when it's finished, then I get a "DONE" printed to the screen.

我想发生的是在发出rsync命令并立即开始传输之后立即打印完成".

What I'd like to have happen is a "DONE" printed immediately after issuing the rsync command and for the transfer to start.

看起来很简单.我关注了其他帖子中概述的详细信息，例如此一个和这一个，但是有一些阻止它正常工作对我来说.

Seems very straight-forward. I've followed details outlined in other posts, like this one and this one, but something is preventing it from working for me.

提前谢谢.

(我已经尝试了我在StackExchange中可以找到的所有内容，但由于我仍然无法使其正常工作，我不觉得这是重复的.我的设置不正确，需要帮助.)

(I have tried everything I can find in StackExchange and don't feel like this is a duplicate because I still can't get it to work. Something isn't right in my setup and need help.)

推荐答案

以下是经过验证的Python REPL示例:

Here is verified example for Python REPL:

>>> import subprocess
>>> import sys
>>> p = subprocess.Popen([sys.executable, '-c', 'import time; time.sleep(100)'], stdout=subprocess.PIPE, stderr=subprocess.STDOUT); print('finished')
finished

如何通过另一个终端窗口进行验证:

How to verify that via another terminal window:

$ ps aux | grep python

输出:

user           32820   0.0  0.0  2447684   3972 s003  S+   10:11PM   0:00.01 /Users/user/venv/bin/python -c import time; time.sleep(100)

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