执行使用Python定义环境变量的bash脚本 [英] Execute bash script that defines environment variables using Python

问题描述

我正在使用下一个代码来执行bash脚本，该脚本定义了许多环境变量:

I'm using the next code to execute a bash script that defines a lot of environment variables:

#!/usr/bin/python
# -*- coding: utf-8 -*-

import subprocess

# Code used to get the value of variable before the call to my script
command = "echo $MYDIR"
ps = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
my_dir = ps.communicate()[0]
print "my_dir", my_dir

subprocess.Popen(["/bin/sh", "/home/user/env_file"])

# Code used to get the value of established variable
command = "echo $MYDIR"
ps = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
my_dir = ps.communicate()[0]
print "my_dir", my_dir

我的/home/user/env_file的内容是下一个:

The content of my /home/user/env_file is the next:

#!/bin/bash

export MYDIR=/home/user
export MYDIR2=/home/user2
export MYDIR3=/home/user3
export MYDIR4=/home/user4
export MYDIR5=/home/user5
export MYDIR6=/home/user6
export MYDIR7=/home/user7
export MYDIR8=/home/user8
export MYDIR9=/home/user9
export MYDIR10=/home/user10
export MYDIR11=/home/user11
export MYDIR12=/home/user12
export MYDIR13=/home/user13
export MYDIR14=/home/user14
export MYDIR15=/home/user15
export MYDIR16=/home/user16

当我执行Python代码时，my_dir变量没有任何值.我该如何执行呢?

When I execute the Python code I do not get any value for my_dir variable. How can I perform this?

最诚挚的问候.

推荐答案

一个进程影响其父级环境(缺少丑陋的黑客滥用开发/调试功能)的唯一方法是该父级进程的直接参与(这就是为什么一个运行eval "$(ssh-agent)"-eval，其输出是在这种情况下，父级需要合作才能让ssh-agent在启动它的进程中设置环境变量).考虑以下外壳包装程序:

The only way for a process to influence its parent's environment (absent ugly hacks abusing development/debugging facilities) is with that parent process's direct involvement (which is why one runs eval "$(ssh-agent)" -- evaling its output is, in this case, the cooperation needed from the parent to let ssh-agent set environment variables in the process that started it). Consider the following shell wrapper:

#!/usr/bin/env bash
# Save this script as "envvar-extraction-wrapper"
exec {orig_stdout}>&1 # create a backup of stdout
exec >&2              # and then use stderr while sourcing the child script

source "$@"           # run arbitrary script with arbitrary arguments *in this shell*
                      # note that this means that if it runs "exit", we abort prematurely

while read -r varname; do
  printf '%s\0%s\0' "$varname" "${!varname}" >&$orig_stdout
done < <(compgen -e)

...从以下Python中调用:

...called from the following Python:

import subprocess, itertools, os

ps = subprocess.Popen(['envvar-extraction-wrapper', '/home/user/env_file'],
                      stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
(stdout, stderr) = ps.communicate()
items_iter = iter(stdout.split('\0'))
for (k,v) in itertools.izip(items_iter, items_iter):
    os.environ[k]=v

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