gerrit_util is aware of auth errors

gerrit_util.py

 # Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Utilities for requesting information for a gerrit server via https.
 
 https://gerrit-review.googlesource.com/Documentation/rest-api.html
 """
 
 import base64
 import httplib
 import json
 import logging
 import netrc
 import os
+import re
 import time
 import urllib
 from cStringIO import StringIO
 
 try:
   NETRC = netrc.netrc()
 except (IOError, netrc.NetrcParseError):
   NETRC = netrc.netrc(os.devnull)
 LOGGER = logging.getLogger()
 TRY_LIMIT = 5
 
 # Controls the transport protocol used to communicate with gerrit.
 # This is parameterized primarily to enable GerritTestCase.
 GERRIT_PROTOCOL = 'https'
 
 
 class GerritError(Exception):
   """Exception class for errors commuicating with the gerrit-on-borg service."""
   def __init__(self, http_status, *args, **kwargs):
     super(GerritError, self).__init__(*args, **kwargs)
     self.http_status = http_status
     self.message = '(%d) %s' % (self.http_status, self.message)
 
 
+class GerritAuthenticationError(GerritError):
+  """Exception class for authentication errors during Gerrit communication."""
+
+
 def _QueryString(param_dict, first_param=None):
   """Encodes query parameters in the key:val[+key:val...] format specified here:
 
   https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#list-changes
   """
   q = [urllib.quote(first_param)] if first_param else []
   q.extend(['%s:%s' % (key, val) for key, val in param_dict.iteritems()])
   return '+'.join(q)
 
 
@@ skipping 57 matching lines @@
     expect_status: Success is indicated by this status in the response.
     ignore_404: For many requests, gerrit-on-borg will return 404 if the request
                 doesn't match the database contents.  In most such cases, we
                 want the API to return None rather than raise an Exception.
   Returns: A string buffer containing the connection's reply.
   """
 
   sleep_time = 0.5
   for idx in range(TRY_LIMIT):
     response = conn.getresponse()
+
+    # Check if this is an authentication issue.
+    www_authenticate = response.getheader('www-authenticate')
+    if (response.status in (httplib.UNAUTHORIZED, httplib.FOUND) and
+        www_authenticate):
+      auth_match = re.search('realm="([^"]+)"', www_authenticate, re.I)
+      host = auth_match.group(1) if auth_match else conn.req_host
+      reason = ('Authentication failed. Please make sure your .netrc file '
+                'has credentials for %s' % host)
+      raise GerritAuthenticationError(response.status, reason)
+
     # If response.status < 500 then the result is final; break retry loop.
     if response.status < 500:
       break
     # A status >=500 is assumed to be a possible transient error; retry.
     http_version = 'HTTP/%s' % ('1.1' if response.version == 11 else '1.0')
     msg = (
         'A transient error occured while querying %s:\n'
         '%s %s %s\n'
         '%s %d %s' % (
             conn.host, conn.req_params['method'], conn.req_params['url'],
@@ skipping 302 matching lines @@
         username = review.get('email', jmsg.get('name', ''))
         raise GerritError(200, 'Unable to set %s label for user "%s"'
                        ' on change %s.' % (label, username, change))
   jmsg = GetChangeCurrentRevision(host, change)
   if not jmsg:
     raise GerritError(
         200, 'Could not get review information for change "%s"' % change)
   elif jmsg[0]['current_revision'] != revision:
     raise GerritError(200, 'While resetting labels on change "%s", '
                    'a new patchset was uploaded.' % change)