chrome/common/extensions/docs/server2/memcache_object_store.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 logging

from appengine_wrappers import memcache
from future import Future
from object_store import ObjectStore

class _AsyncMemcacheIOFuture(object):
  def __init__(self, rpc):
    self._rpc = rpc

  def Get(self):
    return self._rpc.get_result()

class MemcacheObjectStore(ObjectStore):
  def __init__(self, namespace):
    self._namespace = namespace

  def SetMulti(self, mapping):
    # talking_alarm_clock always fails because the zip is too big.
    # TODO(kalman): store example zips in blobstore.
    if any(key.find('talking_alarm_clock') != -1 for key in mapping.iterkeys()):
      return Future(value=None)
    try:
      rpc = memcache.Client().set_multi_async(mapping,
          namespace=self._namespace)
      return _AsyncMemcacheIOFuture(rpc)
    except ValueError as e:
      logging.error('Caught "ValueError: %s" when mapping keys %s' % (
          e, mapping.keys()))

  def GetMulti(self, keys):
    rpc = memcache.Client().get_multi_async(keys, namespace=self._namespace)
    return _AsyncMemcacheIOFuture(rpc)

  def DelMulti(self, keys):
    memcache.delete_multi(keys, namespace=self._namespace)