Devserver: only populate data during cron jobs, meaning all data from instances

chrome/common/extensions/docs/server2/in_memory_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 time
-
-from appengine_wrappers import CACHE_TIMEOUT
-from future import Future
-from object_store import ObjectStore
-
-class _CacheEntry(object):
-  def __init__(self, value, expire_time):
-    self.value = value
-    self._never_expires = (expire_time == 0)
-    self._expiry = time.time() + expire_time
-
-  def HasExpired(self):
-    if self._never_expires:
-      return False
-    return time.time() > self._expiry
-
-class _AsyncGetFuture(object):
-  """A future for memcache gets.
-
-  Properties:
-  - |cache| the in-memory cache used by InMemoryObjectStore
-  - |time| the cache timeout
-  - |future| the |Future| from the backing |ObjectStore|
-  - |initial_mapping| a mapping of cache items already in memory
-  """
-  def __init__(self, cache, time, future, initial_mapping):
-    self._cache = cache
-    self._time = time
-    self._future = future
-    self._mapping = initial_mapping
-
-  def Get(self):
-    if self._future is not None:
-      result = self._future.Get()
-      self._cache.update(
-          dict((k, _CacheEntry(v, self._time)) for k, v in result.iteritems()))
-      self._mapping.update(result)
-    return self._mapping
-
-class InMemoryObjectStore(ObjectStore):
-  def __init__(self, object_store):
-    self._object_store = object_store
-    self._cache = {}
-
-  def SetMulti(self, mapping, time=CACHE_TIMEOUT):
-    for k, v in mapping.iteritems():
-      self._cache[k] = _CacheEntry(v, time)
-      # TODO(cduvall): Use a batch set? App Engine kept throwing:
-      # ValueError: Values may not be more than 1000000 bytes in length
-      # for the batch set.
-      self._object_store.Set(k, v, time=time)
-
-  def GetMulti(self, keys, time=CACHE_TIMEOUT):
-    keys = keys[:]
-    mapping = {}
-    for key in keys:
-      cache_entry = self._cache.get(key, None)
-      if cache_entry is None or cache_entry.HasExpired():
-        mapping[key] = None
-      else:
-        mapping[key] = cache_entry.value
-        keys.remove(key)
-    future = self._object_store.GetMulti(keys, time=time)
-    return Future(delegate=_AsyncGetFuture(self._cache,
-                                           time,
-                                           future,
-                                           mapping))
-
-  def Delete(self, key):
-    if key in self._cache:
-      self._cache.pop(key)
-    self._object_store.Delete(key)