Python caching with decorator

caching-decorator.py

import random
from functools import wraps


disk = dict()


def read_cache(path):
    return disk.get(path, None)


def write_cache(path, data):
    disk[path] = data


def caching(cache_path_builder):
    def cache_path_wrapper(func):
        @wraps(func)
        def cache_wrapper(*arg, **kwargs):
            cache_path = cache_path_builder(*arg)
            force_update = kwargs.pop('force_update', False)
            no_cache = kwargs.pop('no_cache', False)

            cached_result = read_cache(cache_path) if not force_update else None

            if cached_result:
                return cached_result, True
            else:
                result = func(*arg, **kwargs)
                if not no_cache:
                    write_cache(cache_path, result)
                return result, False

        return cache_wrapper
    return cache_path_wrapper


@caching(lambda range: str(range))
def get_random_number(range):
    """I return a random number.

    After decorating with @caching(...), I return a tuple `ret`,
    which `ret[0]` is the random number and `ret[1]` indicates whether cache is used.
    """
    return random.randint(0, range)


if __name__ == "__main__":
    print("__doc__", get_random_number.__doc__)

    print("\n#1")
    print(get_random_number(100)) #1
    print(get_random_number(100, force_update=True, no_cache=True)) #2
    print(get_random_number(100)) #3, same with #1
    print(get_random_number(100)) #4, same with #1
    print(get_random_number(100, force_update=True)) #4
    print(get_random_number(100)) #5, same with #4

    print("\n#2")
    print(get_random_number(200)) #6
    print(get_random_number(200)) #7, same with #6

example-output.txt

__doc__ I return a random number.

    After decorating with @caching(...), I return a tuple `ret`,
    which `ret[0]` is the random number and `ret[1]` indicates whether cache is used.


#1
(38, False)
(12, False)
(38, True)
(38, True)
(43, False)
(43, True)

#2
(130, False)
(130, True)