def init_counters(cls):
super(VfsCacheConnection, cls).init_counters()
cls.CACHE_NO_METADATA = PerfCounter(
'gcb-models-VfsCacheConnection-cache-no-metadata',
'A number of times an object was requested, but was not found and '
'had no metadata.')
cls.CACHE_INHERITED = PerfCounter(
'gcb-models-VfsCacheConnection-cache-inherited',
'A number of times an object was obtained from the inherited vfs.')
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. """Common classes and methods for managing persistent entities.""" __author__ = 'Pavel Simakov ([email protected])' from counters import PerfCounter import transforms from google.appengine.ext import db # datastore performance counters DB_QUERY = PerfCounter( 'gcb-models-db-query', 'A number of times a query()/all() was executed on a datastore.') DB_GET = PerfCounter( 'gcb-models-db-get', 'A number of times an object was fetched from datastore.') DB_PUT = PerfCounter( 'gcb-models-db-put', 'A number of times an object was put into datastore.') DB_DELETE = PerfCounter( 'gcb-models-db-delete', 'A number of times an object was deleted from datastore.') # String. Name of the safe key property used for data export. SAFE_KEY_NAME = 'safe_key'
# we cache this object below.
NO_OBJECT = {}
# The default amount of time to cache the items for in memcache.
DEFAULT_CACHE_TTL_SECS = 60 * 5
# Global memcache controls.
CAN_USE_MEMCACHE = ConfigProperty(
'gcb_can_use_memcache', bool,
('Whether or not to cache various objects in memcache. For production '
'this value should be on to enable maximum performance. For '
'development this value should be off so you can see your changes to '
'course content instantaneously.'), appengine_config.PRODUCTION_MODE)
# performance counters
CACHE_PUT = PerfCounter('gcb-models-cache-put',
'A number of times an object was put into memcache.')
CACHE_HIT = PerfCounter('gcb-models-cache-hit',
'A number of times an object was found in memcache.')
CACHE_MISS = PerfCounter(
'gcb-models-cache-miss',
'A number of times an object was not found in memcache.')
CACHE_DELETE = PerfCounter(
'gcb-models-cache-delete',
'A number of times an object was deleted from memcache.')
class MemcacheManager(object):
"""Class that consolidates all memcache operations."""
@classmethod
def get_namespace(cls):
"""Look up namespace from namespace_manager or use default."""
def __init__(self):
self._cache = caching.LRUCache(
max_size_bytes=MAX_GLOBAL_CACHE_SIZE_BYTES,
max_item_size_bytes=MAX_GLOBAL_CACHE_ITEM_SIZE_BYTES)
self._cache.get_entry_size = self._get_entry_size
def _get_entry_size(self, key, value):
return sys.getsizeof(key) + value.getsizeof() if value else 0
@property
def cache(self):
return self._cache
VFS_CACHE_LEN = PerfCounter('gcb-models-VfsCacheConnection-cache-len',
'A total number of items in vfs cache.')
VFS_CACHE_SIZE_BYTES = PerfCounter(
'gcb-models-VfsCacheConnection-cache-bytes',
'A total size of items in vfs cache in bytes.')
VFS_CACHE_LEN.poll_value = ProcessScopedVfsCache.get_vfs_cache_len
VFS_CACHE_SIZE_BYTES.poll_value = ProcessScopedVfsCache.get_vfs_cache_size
class CacheFileEntry(caching.AbstractCacheEntry):
"""Cache entry representing a file."""
def __init__(self, filename, metadata, body):
self.filename = filename
self.metadata = metadata
self.body = body
self.created_on = datetime.datetime.utcnow()