tools/telemetry/json_format

#!/usr/bin/env python
# Copyright 2015 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import argparse
import json
import os
import sys


def GetFormattedJSONString(file_path):
 with open(file_path, 'r') as f:
    json_obj = json.load(f)
    file_content = f.read()
 return json.dumps(
     json_obj, indent=2, sort_keys=True, separators=(',', ': '))


def ValidateJSONFormat(file_path):
 with open(file_path, 'r') as f:
    file_content = f.read()
 if file_content != GetFormattedJSONString(file_path):
   raise Exception(
       'Reformat your JSON file by running: %s --format %s' %
       (__file__, file_path))
 print >> sys.stdout, ('%s passes the JSON format validation' % file_path)


def Format(file_path):
  formatted_JSON_string = GetFormattedJSONString(file_path)
  with open(file_path, 'w') as f:
    f.write(formatted_JSON_string)


def Main(args):
  description = """A JSON formatting tool.

  This is a tool that validate and reformats JSON file so that it complies with
  a certain style. The JSON style imposed by this tool is:
    * JSON array elements and object members are indented with 2 spaces.
    * Dictionaries objects are sorted by key.
    * Items are sperated by ', ' and ': '.
  """
  parser = argparse.ArgumentParser(
      description=description, formatter_class=argparse.RawTextHelpFormatter)
  parser.add_argument('file_path', type=str, help='The path to JSON file.')
  parser.add_argument('--format', action='store_true', default=False,
                      help='Format the JSON file.')
  options = parser.parse_args(args)
  if options.format:
    Format(options.file_path)
    return 0
  ValidateJSONFormat(options.file_path)
  return 0


if __name__ == '__main__':
  sys.exit(Main(sys.argv[1:]))