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1#!/usr/bin/python
2
3# Copyright (c) 2013 The Chromium Authors. All rights reserved.
4# Use of this source code is governed by a BSD-style license that can be
5# found in the LICENSE file.
6
7"""
8Provides read access to buildbot's global_variables.json .
9"""
10
11
12import HTMLParser
13import json
14import re
15import retrieve_from_googlesource
16import svn
17import sys
18
19
20_global_vars = None
21
22
23SKIABOT_REPO = 'https://skia.googlesource.com/buildbot'
24_GLOBAL_VARS_PATH = 'site_config/global_variables.json'
25
26
27class GlobalVarsRetrievalError(Exception):
28  """Exception which is raised when the global_variables.json file cannot be
29  retrieved from the Skia buildbot repository."""
30  pass
31
32
33class JsonDecodeError(Exception):
34  """Exception which is raised when the global_variables.json file cannot be
35  interpreted as JSON. This may be due to the file itself being incorrectly
36  formatted or due to an incomplete or corrupted downloaded version of the file.
37  """
38  pass
39
40
41class NoSuchGlobalVariable(KeyError):
42  """Exception which is raised when a given variable is not found in the
43  global_variables.json file."""
44  pass
45
46
47def Get(var_name):
48  """Return the value associated with this name in global_variables.json.
49
50  Args:
51      var_name: string; the variable to look up.
52  Returns:
53      The value of the variable.
54  Raises:
55      NoSuchGlobalVariable if there is no variable with that name.
56  """
57  global _global_vars
58  if not _global_vars:
59    try:
60      global_vars_text = retrieve_from_googlesource.get(SKIABOT_REPO,
61                                                        _GLOBAL_VARS_PATH)
62    except Exception as e:
63      raise GlobalVarsRetrievalError('Failed to retrieve %s from %s:\n%s' %
64                                     (_GLOBAL_VARS_PATH, SKIABOT_REPO, str(e)))
65    try:
66      _global_vars = json.loads(global_vars_text)
67    except ValueError as e:
68      raise JsonDecodeError(e.message + '\n' + global_vars_text)
69  try:
70    return _global_vars[var_name]['value']
71  except KeyError:
72    raise NoSuchGlobalVariable(var_name)
73
74
75if __name__ == '__main__':
76  print Get(sys.argv[1])
77