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(base_config_path, platform_config_path=None):
  26   try:
  27     with open(base_config_path, 'r') as base_file:
  28       variations = json.load(base_file)
  29       if platform_config_path:
  30         try:
  31           with open(platform_config_path, 'r') as platform_file:
  32             platform_specifics = json.load(platform_file)
  33             variations.update(platform_specifics)
  34         except (IOError, ValueError):
  35           pass
  36   except (IOError, ValueError):
  37     return []
  38
  39   field_trials = []
  40   params = []
  41   for trial, groups in variations.iteritems():
  42     if not len(groups):
  43       continue
  44     # For now, only take the first group.
  45     group = groups[0]
  46     trial_group = [trial, group['group_name']]
  47     field_trials.extend(trial_group)
  48     param_list = []
  49     if 'params' in group:
  50       for key, value in group['params'].iteritems():
  51         param_list.append(key)
  52         param_list.append(value)
  53     if len(param_list):
  54        # Escape the variables for the command-line.
  55        trial_group = [_escape(x) for x in trial_group]
  56        param_list = [_escape(x) for x in param_list]
  57        param = '%s:%s' % ('.'.join(trial_group), '/'.join(param_list))
  58        params.append(param)
  59   if not len(field_trials):
  60     return []
  61   args = ['--force-fieldtrials=%s' % '/'.join(field_trials)]
  62   if len(params):
  63     args.append('--force-fieldtrial-params=%s' % ','.join(params))
  64   return args
  65
  66 def main():
  67   if len(sys.argv) < 3:
  68     print 'Usage: fieldtrial_util.py [base_config_path] [platform_config_path]'
  69     exit(-1)
  70   print GenerateArgs(sys.argv[1], sys.argv[2])
  71
  72 if __name__ == '__main__':
  73   main()