1#!/usr/bin/python
2# Copyright 2013 The Chromium Authors. All rights reserved.
3# Use of this source code is governed by a BSD-style license that can be
4# found in the LICENSE file.
5
6# This script can either source a file and dump the enironment changes done by
7# it, or just simply dump the current environment as JSON into a file.
8
9import json
10import optparse
11import os
12import pipes
13import subprocess
14import sys
15
16
17def main():
18  parser = optparse.OptionParser()
19  parser.add_option('-f', '--output-json',
20                    help='File to dump the environment as JSON into.')
21  parser.add_option(
22      '-d', '--dump-mode', action='store_true',
23      help='Dump the environment to sys.stdout and exit immediately.')
24
25  parser.disable_interspersed_args()
26  options, args = parser.parse_args()
27  if options.dump_mode:
28    if args or options.output_json:
29      parser.error('Cannot specify args or --output-json with --dump-mode.')
30    json.dump(dict(os.environ), sys.stdout)
31  else:
32    if not options.output_json:
33      parser.error('Requires --output-json option.')
34
35    envsetup_cmd = ' '.join(map(pipes.quote, args))
36    full_cmd = [
37        'bash', '-c',
38        '. %s > /dev/null; %s -d' % (envsetup_cmd, os.path.abspath(__file__))
39    ]
40    try:
41      output = subprocess.check_output(full_cmd)
42    except Exception as e:
43      sys.exit('Error running %s and dumping environment.' % envsetup_cmd)
44
45    env_diff = {}
46    new_env = json.loads(output)
47    for k, val in new_env.items():
48      if k == '_' or (k in os.environ and os.environ[k] == val):
49        continue
50      env_diff[k] = val
51    with open(options.output_json, 'w') as f:
52      json.dump(env_diff, f)
53
54
55if __name__ == '__main__':
56  sys.exit(main())
57