sandbox / environ-getter.py

from __future__ import print_function
import sys
import subprocess
import itertools

def validate_pair(ob):
	try:
		if not (len(ob) == 2):
			print("Unexpected result:", ob, file=sys.stderr)
			raise ValueError
	except:
		return False
	return True

def consume(iter):
	try:
		while True: next(iter)
	except StopIteration:
		pass

def get_environment_from_batch_command(env_cmd, initial=None):
	"""
	Take a command (either a single command or list of arguments)
	and return the environment created after running that command.
	Note that if the command must be a batch file or .cmd file, or the
	changes to the environment will not be captured.
	
	If initial is supplied, it is used as the initial environment passed
	to the child process.
	"""
	if not isinstance(env_cmd, (list, tuple)):
		env_cmd = [env_cmd]
	# construct the command that will alter the environment
	env_cmd = subprocess.list2cmdline(env_cmd)
	# create a tag so we can tell in the output when the proc is done
	tag = 'Done running command'
	# construct a cmd.exe command to do accomplish this
	cmd = 'cmd.exe /s /c "{env_cmd} && echo "{tag}" && set"'.format(**vars())
	# launch the process
	proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, env=initial)
	# parse the output sent to stdout
	lines = proc.stdout
	# consume whatever output occurs until the tag is reached
	consume(itertools.takewhile(lambda l: tag not in l, lines))
	# define a way to handle each KEY=VALUE line
	handle_line = lambda l: l.rstrip().split('=',1)
	# parse key/values into pairs
	pairs = map(handle_line, lines)
	# make sure the pairs are valid
	valid_pairs = filter(validate_pair, pairs)
	# construct a dictionary of the pairs
	result = dict(valid_pairs)
	# let the process finish
	proc.communicate()
	return result

def __test__():
	# test it
	cmd = [
		r'c:\program files (x86)\Microsoft Visual Studio 9.0\VC\vcvarsall.bat',
		'x86',
		]
	env = get_environment_from_batch_command(cmd)
Tip: Filter by directory path e.g. /media app.js to search for public/media/app.js.
Tip: Use camelCasing e.g. ProjME to search for ProjectModifiedEvent.java.
Tip: Filter by extension type e.g. /repo .js to search for all .js files in the /repo directory.
Tip: Separate your search with spaces e.g. /ssh pom.xml to search for src/ssh/pom.xml.
Tip: Use ↑ and ↓ arrow keys to navigate and return to view the file.
Tip: You can also navigate files with Ctrl+j (next) and Ctrl+k (previous) and view the file with Ctrl+o.
Tip: You can also navigate files with Alt+j (next) and Alt+k (previous) and view the file with Alt+o.