Extension docs server: assume everything is "trunk" if the branch can't be

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

 # Copyright (c) 2012 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 json
+import logging
 
 import object_store
 import operator
 
 class BranchUtility(object):
   def __init__(self, base_path, default_branches, fetcher, object_store):
     self._base_path = base_path
     self._default_branches = default_branches
     self._fetcher = fetcher
     self._object_store = object_store
@@ skipping 28 matching lines @@
     for development that should be handled differently.
     """
     if channel_name in ['trunk', 'local']:
       return channel_name
 
     branch_number = self._object_store.Get(channel_name + '.' + self._base_path,
                                            object_store.BRANCH_UTILITY).Get()
     if branch_number is not None:
       return branch_number
 
-    fetch_data = self._fetcher.Fetch(self._base_path).content
-    version_json = json.loads(fetch_data)
+    try:
+      version_json = json.loads(self._fetcher.Fetch(self._base_path).content)
+    except Exception as e:
+      # This can happen if omahaproxy is misbehaving, which we've seen before.
+      # Quick hack fix: just serve from trunk until it's fixed.
+      logging.error('Failed to fetch or parse branch from omahaproxy: %s! '
+                    'Falling back to "trunk".' % e)
+      return 'trunk'
+
     branch_numbers = {}
     for entry in version_json:
       if entry['os'] not in ['win', 'linux', 'mac', 'cros']:
         continue
       for version in entry['versions']:
         if version['channel'] != channel_name:
           continue
         branch = version['version'].split('.')[2]
         if branch not in branch_numbers:
           branch_numbers[branch] = 0
         else:
           branch_numbers[branch] += 1
 
     sorted_branches = sorted(branch_numbers.iteritems(),
                              None,
                              operator.itemgetter(1),
                              True)
     self._object_store.Set(channel_name + '.' + self._base_path,
                            sorted_branches[0][0],
                            object_store.BRANCH_UTILITY)
 
     return sorted_branches[0][0]