def __init__(self,
store,
cache_expiration_time=60,
cache_size_in_mb=2000,
cache_id=None,
cache_dir='/tmp/cloudfusion/'):
"""
:param store: the store whose access should be cached
:param cache_expiration_time: the time in seconds until any cache entry is expired
:param cache_size_in_mb: Approximate limit of the cache in MB.
:param cache_id: Serves as identifier for a persistent cache instance.
:param cache_dir: Cache directory on local hard drive disk, default value is */tmp/cloudfusion*. """
#prevent simultaneous access to store (synchronous use of __deepcopy__ by _store SyncThread and a different method):
self.store = SynchronizeProxy(
store, private_methods_to_synchronize=['__deepcopy__'])
if cache_id == None:
cache_id = str(random.random())
self.logger = logging.getLogger(self.get_logging_handler())
self.logger.debug("creating CachingStore object")
if cache_expiration_time < 240:
self.logger.warning(
"Be aware of the synchronization issue https://github.com/joe42/CloudFusion/issues/16 \
or to avoid the issue set cache_expiration_time to more than 240 seconds."
)
# self.temp_file = tempfile.SpooledTemporaryFile()
self.cache_expiration_time = cache_expiration_time
self.time_of_last_flush = time.time()
self.cache_dir = cache_dir[:-1] if cache_dir[
-1:] == '/' else cache_dir # remove slash at the end
cache = PersistentLRUCache(
self.cache_dir + "/cachingstore_" + cache_id,
cache_expiration_time, cache_size_in_mb)
cache.set_resize_intervall(10)
self.entries = SynchronizeProxy(
cache) #[shares_resource: write self.entries]
self.sync_thread = StoreSyncThread(self.entries, self.store,
self.logger)
self.sync_thread.start()
