[Question] Remove/invalidate a single item from cache

[Feijo]

Is there a way to remove a particular item from the cache, rather than clearing the whole cache?

Something like this

cache = LRUCache(maxsize=32)
lock = RLock()

@cached(cache, lock=lock)
def get_data_for_user(user_id):
    return [ 'Item 1', 'Item 2', 'Item 3' ]

user_1_data = get_data_for_user(1)
user_2_data = get_data_for_user(2)
user_3_data = get_data_for_user(3)

with lock:
   cache.remove(1) # This would invalidate user_id = 1 cached data

[tkem]

Did you try

del cache[1]

[Feijo]

Hey, sure did. This is the result:

File "C:\Python38\lib\site-packages\cachetools\lru.py", line 23, in __delitem__
   cache_delitem(self, key)
File "C:\Python38\lib\site-packages\cachetools\cache.py", line 61, in __delitem__
   del self.__data[key]
KeyError: 1

[tkem]

My bad. Since the decorator uses hashkey as the default key function, the proper way to delete a cache item is

del cache[hashkey(1)]

Not really intuitive, so this should probably be mentioned in the docs.