def get_many(cls, keys, attributes_to_get=None):
"""
Returns a list of :class:`PersistentObject` identical in length to the
list of keys provided. If a key could not be found, it's slot will be
`None`
This operation performs `BatchGetItem` on the DynamoDB store. This
method is typically limited to 100 items. Depending on your configured
capacity, this can easily outstrip it. This method will retry in a loop
until all the keys you asked for are satisfied. `keys` is not limited
to 100 items.
:type keys: list
:param keys: A list of keys
"""
cls._load_meta()
keys = map(cls.prepare_key, keys)
t1 = time.time()
# get the items
items, unprocessed, consumed_capacity = cls._fetch_batch_queue(
cls._get_batch_queue(keys))
# if there are unprocessed items, create a batch from them
if len(unprocessed):
unprocessed_queue = cls._get_batch_queue(unprocessed)
else:
unprocessed_queue = []
# and continue fetching unprocessed items until there are no more
while len(unprocessed_queue):
new_items, new_unprocessed, new_consumed = cls._fetch_batch_queue(
unprocessed_queue)
consumed_capacity += new_consumed
items.extend(new_items)
if len(new_unprocessed):
unprocessed_queue = cls._get_batch_queue(new_unprocessed)
else:
unprocessed_queue = []
# create a hash out of the values' keys for quick reordering
h = dict(
(item[cls._hash_key_name], idx) for idx, item in enumerate(items))
ret = []
for key in keys:
if key in h:
ret.append(cls(Item(cls._table, key, None, items[h[key]])))
else:
ret.append(None)
logger.info(
'Got %i of %s in %s ConsumedCapacityUnits=%f' %
(len(items), cls.__name__, time.time() - t1, consumed_capacity))
return ret
def new_item(self, hash_key, range_key=None, attrs=None):
"""
Return an new, unsaved Item which can later be PUT to
Amazon DynamoDB.
"""
return Item(self, hash_key, range_key, attrs)
