chrome/common/extensions/docs/server2/branch_utility.py

   1 # Copyright (c) 2012 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 logging
   7 import operator
   8
   9 from environment_wrappers import CreateUrlFetcher
  10 import url_constants
  11
  12
  13 class ChannelInfo(object):
  14   '''Represents a Chrome channel with three pieces of information. |channel| is
  15   one of 'stable', 'beta', 'dev', or 'master'. |branch| and |version| correspond
  16   with each other, and represent different releases of Chrome. Note that
  17   |branch| and |version| can occasionally be the same for separate channels
  18   (i.e. 'beta' and 'dev'), so all three fields are required to uniquely
  19   identify a channel.
  20   '''
  21
  22   def __init__(self, channel, branch, version):
  23     assert isinstance(channel, basestring), channel
  24     assert isinstance(branch, basestring), branch
  25     # TODO(kalman): Assert that this is a string. One day Chromium will probably
  26     # be served out of a git repository and the versions will no longer be ints.
  27     assert isinstance(version, int) or version == 'master', version
  28     self.channel = channel
  29     self.branch = branch
  30     self.version = version
  31
  32   def __eq__(self, other):
  33     return self.__dict__ == other.__dict__
  34
  35   def __ne__(self, other):
  36     return not (self == other)
  37
  38   def __repr__(self):
  39     return '%s%s' % (type(self).__name__, repr(self.__dict__))
  40
  41   def __str__(self):
  42     return repr(self)
  43
  44
  45 class BranchUtility(object):
  46   '''Provides methods for working with Chrome channel, branch, and version
  47   data served from OmahaProxy.
  48   '''
  49
  50   def __init__(self, fetch_url, history_url, fetcher, object_store_creator):
  51     self._fetcher = fetcher
  52     def create_object_store(category):
  53       return object_store_creator.Create(BranchUtility, category=category)
  54     self._branch_object_store = create_object_store('branch')
  55     self._version_object_store = create_object_store('version')
  56     self._fetch_result = self._fetcher.FetchAsync(fetch_url)
  57     self._history_result = self._fetcher.FetchAsync(history_url)
  58
  59   @staticmethod
  60   def Create(object_store_creator):
  61     return BranchUtility(url_constants.OMAHA_PROXY_URL,
  62                          url_constants.OMAHA_DEV_HISTORY,
  63                          CreateUrlFetcher(),
  64                          object_store_creator)
  65
  66   @staticmethod
  67   def GetAllChannelNames():
  68     return ('stable', 'beta', 'dev', 'master')
  69
  70   @staticmethod
  71   def NewestChannel(channels):
  72     channels = set(channels)
  73     for channel in reversed(BranchUtility.GetAllChannelNames()):
  74       if channel in channels:
  75         return channel
  76
  77   def Newer(self, channel_info):
  78     '''Given a ChannelInfo object, returns a new ChannelInfo object
  79     representing the next most recent Chrome version/branch combination.
  80     '''
  81     if channel_info.channel == 'master':
  82       return None
  83     if channel_info.channel == 'stable':
  84       stable_info = self.GetChannelInfo('stable')
  85       if channel_info.version < stable_info.version:
  86         return self.GetStableChannelInfo(channel_info.version + 1)
  87     names = self.GetAllChannelNames()
  88     return self.GetAllChannelInfo()[names.index(channel_info.channel) + 1]
  89
  90   def Older(self, channel_info):
  91     '''Given a ChannelInfo object, returns a new ChannelInfo object
  92     representing the previous Chrome version/branch combination.
  93     '''
  94     if channel_info.channel == 'stable':
  95       if channel_info.version <= 5:
  96         # BranchUtility can't access branch data from before Chrome version 5.
  97         return None
  98       return self.GetStableChannelInfo(channel_info.version - 1)
  99     names = self.GetAllChannelNames()
 100     return self.GetAllChannelInfo()[names.index(channel_info.channel) - 1]
 101
 102   @staticmethod
 103   def SplitChannelNameFromPath(path):
 104     '''Splits the channel name out of |path|, returning the tuple
 105     (channel_name, real_path). If the channel cannot be determined then returns
 106     (None, path).
 107     '''
 108     if '/' in path:
 109       first, second = path.split('/', 1)
 110     else:
 111       first, second = (path, '')
 112     if first in BranchUtility.GetAllChannelNames():
 113       return (first, second)
 114     return (None, path)
 115
 116   def GetAllBranches(self):
 117     return tuple((channel, self.GetChannelInfo(channel).branch)
 118             for channel in BranchUtility.GetAllChannelNames())
 119
 120   def GetAllVersions(self):
 121     return tuple(self.GetChannelInfo(channel).version
 122             for channel in BranchUtility.GetAllChannelNames())
 123
 124   def GetAllChannelInfo(self):
 125     return tuple(self.GetChannelInfo(channel)
 126             for channel in BranchUtility.GetAllChannelNames())
 127
 128
 129   def GetChannelInfo(self, channel):
 130     version = self._ExtractFromVersionJson(channel, 'version')
 131     if version != 'master':
 132       version = int(version)
 133     return ChannelInfo(channel,
 134                        self._ExtractFromVersionJson(channel, 'branch'),
 135                        version)
 136
 137   def GetStableChannelInfo(self, version):
 138     '''Given a |version| corresponding to a 'stable' version of Chrome, returns
 139     a ChannelInfo object representing that version.
 140     '''
 141     return ChannelInfo('stable', self.GetBranchForVersion(version), version)
 142
 143   def _ExtractFromVersionJson(self, channel_name, data_type):
 144     '''Returns the branch or version number for a channel name.
 145     '''
 146     if channel_name == 'master':
 147       return 'master'
 148
 149     if data_type == 'branch':
 150       object_store = self._branch_object_store
 151     elif data_type == 'version':
 152       object_store = self._version_object_store
 153
 154     data = object_store.Get(channel_name).Get()
 155     if data is not None:
 156       return data
 157
 158     try:
 159       version_json = json.loads(self._fetch_result.Get().content)
 160     except Exception as e:
 161       # This can happen if omahaproxy is misbehaving, which we've seen before.
 162       # Quick hack fix: just serve from master until it's fixed.
 163       logging.error('Failed to fetch or parse branch from omahaproxy: %s! '
 164                     'Falling back to "master".' % e)
 165       return 'master'
 166
 167     numbers = {}
 168     for entry in version_json:
 169       if entry['os'] not in ('win', 'linux', 'mac', 'cros'):
 170         continue
 171       for version in entry['versions']:
 172         if version['channel'] != channel_name:
 173           continue
 174         if data_type == 'branch':
 175           number = version['version'].split('.')[2]
 176         elif data_type == 'version':
 177           number = version['version'].split('.')[0]
 178         if number not in numbers:
 179           numbers[number] = 0
 180         else:
 181           numbers[number] += 1
 182
 183     sorted_numbers = sorted(numbers.iteritems(),
 184                             key=operator.itemgetter(1),
 185                             reverse=True)
 186     object_store.Set(channel_name, sorted_numbers[0][0])
 187     return sorted_numbers[0][0]
 188
 189   def GetBranchForVersion(self, version):
 190     '''Returns the most recent branch for a given chrome version number using
 191     data stored on omahaproxy (see url_constants).
 192     '''
 193     if version == 'master':
 194       return 'master'
 195
 196     branch = self._branch_object_store.Get(str(version)).Get()
 197     if branch is not None:
 198       return branch
 199
 200     version_json = json.loads(self._history_result.Get().content)
 201     for entry in version_json:
 202       version_title = entry['version'].split('.')
 203       if version_title[0] == str(version):
 204         self._branch_object_store.Set(str(version), version_title[2])
 205         return version_title[2]
 206
 207     raise ValueError('The branch for %s could not be found.' % version)
 208
 209   def GetChannelForVersion(self, version):
 210     '''Returns the name of the development channel corresponding to a given
 211     version number.
 212     '''
 213     for channel_info in self.GetAllChannelInfo():
 214       if channel_info.channel == 'stable' and version <= channel_info.version:
 215         return channel_info.channel
 216       if version == channel_info.version:
 217         return channel_info.channel
 218
 219   def GetLatestVersionNumber(self):
 220     '''Returns the most recent version number found using data stored on
 221     omahaproxy.
 222     '''
 223     latest_version = self._version_object_store.Get('latest').Get()
 224     if latest_version is not None:
 225       return latest_version
 226
 227     version_json = json.loads(self._history_result.Get().content)
 228     latest_version = 0
 229     for entry in version_json:
 230       version_title = entry['version'].split('.')
 231       version = int(version_title[0])
 232       if version > latest_version:
 233         latest_version = version
 234
 235     self._version_object_store.Set('latest', latest_version)
 236     return latest_version