Issue 2432 - Ignore temporary issues when retrieving browser versions

globals/get_browser_versions.py

 import re
 import os
 import sys
 import json
 import urllib2
 import errno
 import logging
+import time
 from xml.dom import minidom
 
 from jinja2 import contextfunction
 
 BROWSERS = {}
 
 CHROME_UPDATE_XML = '''\
 <?xml version="1.0" encoding="UTF-8"?>
 <request protocol="3.0" ismachine="0">
   <os platform="win" version="99" arch="x64"/>
@@ skipping 155 matching lines @@
   filename = os.path.join(context['source'].get_cache_dir(), 'browsers.json')
   with open_cache_file(filename) as file:
     try:
       persistent_cache = json.load(file)
     except ValueError:
       if file.tell() > 0:
         raise
       persistent_cache = {}
 
     cached_versions = persistent_cache.get(browser)
+    now = time.mktime(time.gmtime())
     if exc_info:
       if not cached_versions:
         raise exc_info[0], exc_info[1], exc_info[2]
 
       versions = cached_versions
-      logging.warning('Failed to get %s versions, falling back to '
-                      'cached versions', browser, exc_info=exc_info)
+      if now - versions['timestamp'] > 60*60*2:
+        logging.warning('Failed to get %s versions, falling back to '
+                        'cached versions', browser, exc_info=exc_info)
     else:
       # Determine previous version: If we recorded the version before and it
       # changed since then, the old current version becomes the new previous
       # version. If the version didn't change, use the cached previous version.
       current = versions['current']
       previous = None
       if cached_versions:
         cached_current = cached_versions['current']
         if cached_current != current:
           previous = cached_current
         else:
           previous = cached_versions['previous']
       versions['previous'] = previous
 
       # Remove duplicates from unreleased versions. Occasionally,
       # different channels are on the same version, but we want
       # to list each version only once.
       versions['unreleased'] = sorted(
         set(versions['unreleased']) - {current, previous},
         key=lambda ver: map(int, ver.split('.'))
       )
 
+      versions['timestamp'] = now
       persistent_cache[browser] = versions
       file.seek(0)
       json.dump(persistent_cache, file)
       file.truncate()
 
   if not versions['previous']:
     logging.warning("Couldn't determine previous browser version, "
                     'please set %s.previous in %s', browser, filename)
 
   cache[browser] = versions
   return versions