build/env_dump.py

   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
   9 import json
  10 import optparse
  11 import os
  12 import pipes
  13 import subprocess
  14 import sys
  15
  16
  17 def 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
  55 if __name__ == '__main__':
  56   sys.exit(main())