def __init__(self, config, usethreads=False, writeback=False):
"Initialize the datastore."
encoding = config.get(C.DATASTORE, C.DATASTORE_ENCODING)
if encoding == C.JSON:
self.decode = decode_json
self.encode = encode_json
elif encoding == C.PROTOBUF:
self.decode = decode_protobuf
self.encode = encode_protobuf
bound = config.getint(C.DATASTORE, C.SLAB_LRU_SIZE)
if bound <= 0:
raise ValueError, "Illegal SLAB LRU size %d" % bound
if writeback:
if usethreads:
nthreads = config.getint(C.DATASTORE, C.SLAB_LRU_THREADS)
else:
nthreads = 0
self.nthreads = nthreads
if nthreads:
self.threads = []
self.workqueue = Queue(nthreads)
for n in xrange(nthreads):
t = threading.Thread(target=self._worker)
self.threads.append(t)
t.daemon = True
t.name = "DS-%d" % n
t.start()
callback = self._cbthreaded
else:
callback = self._cbwrite
else:
callback = None
self.cache = LRUIOCache(bound=bound, callback=callback)
