Added `cros_pin` CrOS pin-bump tool.

infra/libs/gitiles/gitiles.py

 # Copyright 2015 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.
 
 
 """Make authenticated calls to gitiles."""
 
 
 import base64
 import logging
+import httplib
 import httplib2
 import json
 import urlparse
 import netrc
 import time
 
 
 LOGGER = logging.getLogger(__name__)
 
 
+# The default number of retries when a Gitiles error is encountered.
+DEFAULT_RETRIES = 10
+
+
 class GitilesError(Exception):
   pass
 
 
-def call_gitiles(url, response_format, netrc_path=None, max_attempts=10):
+def call_gitiles(url, response_format, netrc_path=None, max_attempts=None):
   """Invokes Gitiles API and parses the JSON result.
   
   Given a gitiles URL, makes a ?format=json or ?format=text call and interprets
   the result. The 'json' format is parsed and returned as a python object, while
   'text' calls are automatically base64-decoded.
 
   url is the gitiles URL to call. It must not contain a query parameter.
 
   response_format is either 'json' or 'text'. This controls whether JSON or
                   textual output is desired. This usually depends on the query.
 
   netrc_path is the path to the netrc credentials used for authentication. If
              not specified, no authentication is used.
 
   max_attempts is the number of attempts to call gitiles before giving up on
-              error.
+              error. If None/zero, DEFAULT_RETRIES will be used.
   """
   assert response_format in ('json', 'text'), (
       'response must be either json or text')
   assert '?' not in url, 'url must not have a query parameter (?)'
 
+  max_attempts = max_attempts or DEFAULT_RETRIES
   http = httplib2.Http()
   headers = {}
   if netrc_path:
     token = get_oauth_token_from_netrc(url, netrc_path)
     headers['Authorization'] = 'OAuth %s' % token
   attempt = 0
   while attempt < max_attempts:
     time.sleep(attempt)
     attempt += 1
     LOGGER.debug('GET %s', url)
     response, content = http.request(
         '%s?format=%s' % (url, response_format),
         'GET',
         headers=headers
     )
-    if response['status'] != '200':
-      LOGGER.warning('GET %s failed with HTTP code %s', url, response['status'])
+    if response.status != httplib.OK:
+      LOGGER.warning('GET %s failed with HTTP code %d', url, response.status)
+      if response.status < httplib.INTERNAL_SERVER_ERROR:
+        break
       if attempt != max_attempts:
         LOGGER.warning('Retrying...')
       continue  # pragma: no cover (actually reached, see https://goo.gl/QA8B2U)
     if response_format == 'json':
       if not content.startswith(')]}\'\n'):
         raise GitilesError('Unexpected gitiles response: %s' % content)
       prefix_removed = content.split('\n', 1)[1]
       return json.loads(prefix_removed)
     elif response_format == 'text':
       return base64.b64decode(content)
     else:
       raise AssertionError()
   raise GitilesError('Failed to fetch %s: %s' % (url, content))
 
 
 def get_oauth_token_from_netrc(url, netrc_path):
   """Looks up OAuth token for |url| in .netrc file at |netrc_path|."""
   parsed = urlparse.urlparse(url)
   auth = netrc.netrc(netrc_path).authenticators(parsed.hostname)
   if not auth:
     raise GitilesError(
         'netrc file %s is missing an entry for %s' % (
           netrc_path, parsed.hostname))
   return auth[2]
+
+
+class Repository(object):
+  def __init__(self, base_url, netrc_path=None, max_attempts=None):
+    self._base_url = self._trim_slashes(base_url)
+    self._netrc_path = netrc_path
+    self._max_attempts = max_attempts
+
+  @staticmethod
+  def _trim_slashes(v):
+    return v.strip('/')
+
+  def __call__(self, ref='master', subpath=None):
+    url = [self._base_url, '+', ref]
+    if subpath:
+      url.append(self._trim_slashes(subpath))
+    url = '/'.join(url)
+    return call_gitiles(
+        url,
+        'json',
+        netrc_path=self._netrc_path,
+        max_attempts=self._max_attempts)
+
+  def ref_info(self, ref):
+    return self(ref)