tools/variations/fieldtrial_util.py

   1 # Copyright 2015 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import json
   6 import sys
   7
   8
   9 def _hex(ch):
  10   hv = hex(ord(ch)).replace('0x', '')
  11   hv.zfill(2)
  12   return hv.upper()
  13
  14 # URL escapes the delimiter characters from the output. urllib.quote is not
  15 # used because it cannot escape '.'.
  16 def _escape(str):
  17   result = str
  18   # Must perform replace on '%' first before the others.
  19   for c in '%:/.,':
  20     result = result.replace(c, '%' + _hex(c))
  21   return result
  22
  23 # Generate a list of command-line switches to enable field trials defined in
  24 # fieldtrial_testing_config_*.json.
  25 def GenerateArgs(config_path):
  26   try:
  27     with open(config_path, 'r') as base_file:
  28       variations = json.load(base_file)
  29   except (IOError, ValueError):
  30     return []
  31
  32   field_trials = []
  33   params = []
  34   for trial, groups in variations.iteritems():
  35     if not len(groups):
  36       continue
  37     # For now, only take the first group.
  38     group = groups[0]
  39     trial_group = [trial, group['group_name']]
  40     field_trials.extend(trial_group)
  41     param_list = []
  42     if 'params' in group:
  43       for key, value in group['params'].iteritems():
  44         param_list.append(key)
  45         param_list.append(value)
  46     if len(param_list):
  47        # Escape the variables for the command-line.
  48        trial_group = [_escape(x) for x in trial_group]
  49        param_list = [_escape(x) for x in param_list]
  50        param = '%s:%s' % ('.'.join(trial_group), '/'.join(param_list))
  51        params.append(param)
  52   if not len(field_trials):
  53     return []
  54   args = ['--force-fieldtrials=%s' % '/'.join(field_trials)]
  55   if len(params):
  56     args.append('--force-fieldtrial-params=%s' % ','.join(params))
  57   return args
  58
  59 def main():
  60   if len(sys.argv) < 3:
  61     print 'Usage: fieldtrial_util.py [base_config_path] [platform_config_path]'
  62     exit(-1)
  63   print GenerateArgs(sys.argv[1], sys.argv[2])
  64
  65 if __name__ == '__main__':
  66   main()