def set_list(self, key, value, ttl=None, key_extractor=None):
# locking it to prevent concurrency violation
lock = self.lock(key)
# check if item loaded
v = self.get_list(key)
if v[1]:
self.unlock(lock)
return v # packed: (value_metadata, value)
if key_extractor is None:
def key_extractor(x):
return x["id"]
try:
value_metadata, value = value() if callable(value) else value
item_keys = []
assert isinstance(value, collections.Iterable), "Value must be iterable"
for item_value in value:
item_key = create_cache_key(key.split(":")[0], key_extractor(item_value))
item_keys.append(item_key)
self.set_item(item_key, item_value, ttl=ttl)
self.redis.set(key, serialize((value_metadata, item_keys)), ex=ttl)
return value_metadata, value
finally:
if lock:
self.unlock(lock)
def hset_item(self, key, dict_key, value, ttl=None):
old_item_key = self.redis.get(key)
if old_item_key is None:
# this is a new item
# locking it to prevent concurrency violation
lock = self.lock(key, nowait=True)
if not lock:
# it seems this item is loading in another thread
# so, waiting for that:
# wait & make sure the object is reloaded, the release the lock
self.unlock(self.lock(key))
return self.hget_item(key, dict_key)
# check if item loaded
v = self.hget_item(key, dict_key, None)
if v:
self.unlock(lock)
return v
else:
lock = None
try:
guid = uuid.uuid1()
item_key = "%s:%s" % (key, guid)
value = value() if callable(value) else value
self.redis.hset(item_key, dict_key, serialize(value))
self.redis.expire(item_key, time=ttl)
self.redis.set(key, item_key, ex=ttl)
if old_item_key:
self.redis.delete(old_item_key)
return value
finally:
if lock:
self.unlock(lock)