Make RetriableHttp to be composable

infra_libs/httplib2_utils.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.
 
 import collections
 import copy
 import json
 import logging
 import os
 import re
@@ skipping 144 matching lines @@
     credentials_filename,
     scope=scope,
     service_accounts_creds_root=service_accounts_creds_root)
 
   if http_identifier:
     http = InstrumentedHttp(http_identifier, timeout=timeout)
   else:
     http = httplib2.Http(timeout=timeout)
   return creds.authorize(http)
 
-class RetriableHttp(httplib2.Http):
+class RetriableHttp(object):
   """A httplib2.Http object that retries on failure."""
 
-  def __init__(self, max_tries=5, retrying_statuses_fn=None, **kwargs):
+  def __init__(self, http, max_tries=5, retrying_statuses_fn=None):
     """
     Args:
-      http_obj: an httplib2.Http instance
+      http: an httplib2.Http instance
       max_tries: a number of maximum tries
       retrying_statuses_fn: a function that returns True if a given status
                             should be retried
     """
-    super(RetriableHttp, self).__init__(**kwargs)
+    self._http = http
     self._max_tries = max_tries
     self._retrying_statuses_fn = retrying_statuses_fn or \
                                  set(range(500,599)).__contains__
 
   def request(self, uri, method='GET', body=None, *args, **kwargs):
     for i in range(1, self._max_tries + 1):
       try:
-        response, content = super(RetriableHttp, self).request(
-            uri, method, body, *args, **kwargs)
+        response, content = self._http.request(uri, method, body, *args,
+                                               **kwargs)
 
         if self._retrying_statuses_fn(response.status):
           logging.info('RetriableHttp: attempt %d receiving status %d, %s',
                        i, response.status,
                        'final attempt' if i == self._max_tries else \
                        'will retry')
         else:
           break
       except (ValueError, errors.Error,
               socket.timeout, socket.error, socket.herror, socket.gaierror,
               httplib2.HttpLib2Error) as error:
         logging.info('RetriableHttp: attempt %d received exception: %s, %s',
                      i, error, 'final attempt' if i == self._max_tries else \
                      'will retry')
         if i == self._max_tries:
           raise
 
     return response, content
 
+  def __getattr__(self, name):
+    return getattr(self._http, name)
+
+  def __setattr__(self, name, value):
+    if name in ('_http', '_max_tries', '_retrying_statuses_fn'):
+      self.__dict__[name] = value
+    else:
+      setattr(self._http, name, value)
 
 class InstrumentedHttp(httplib2.Http):
   """A httplib2.Http object that reports ts_mon metrics about its requests."""
 
   def __init__(self, name, time_fn=time.time, timeout=DEFAULT_TIMEOUT,
                **kwargs):
     """
     Args:
       name: An identifier for the HTTP requests made by this object.
       time_fn: Function returning the current time in seconds. Use for testing
@@ skipping 83 matching lines @@
     self.requests_made.append(self.HttpCall(uri, method, body, headers))
     headers = None
     body = None
     for candidate in self._uris:
       if candidate[0].match(uri):
         _, headers, body = candidate
         break
     if not headers:
       raise AssertionError("Unexpected request to %s" % uri)
     return httplib2.Response(headers), body