cache_instance_method_result.py

import time
import wrapt
import random
import weakref


def cache_it(keyfn):
    cache = weakref.WeakKeyDictionary()

    @wrapt.decorator
    def pass_through(wrapped, instance, args, kwargs):
        if instance not in cache:
            print("put", instance.name)
            cache[instance] = {}

        key = (wrapped.__name__, keyfn(*args, **kwargs))
        if key in cache[instance]:
            print('cache', list(cache.items()))
            return cache[instance][key]

        ret = wrapped(*args, **kwargs)
        cache[instance][key] = ret
        return ret

    pass_through.__cache = cache
    return pass_through



class Calculator:
    def __init__(self):
        self.name = f'name_{random.randint(0, 100)}'
    @cache_it(keyfn=lambda a, b: f"add:{a}:{b}")
    def add(self, a, b):
        return a + b + random.random()

def main():
    cal = Calculator()
    # print(cal)
    # print(cal.add(3, 5))
    # print(cal.add(3, 5))
    # print(cal.add(3, 5))
    # print(cal.add(3, 6))
    # print(cal.add(3, 7))
    cal.add(1, 3)
    cal.add(1, 3)
    cal.add(2, 4)
    cal.add(2, 4)

    cal_b = Calculator()
    cal_b.add(2, 3)
    cal_b.add(3, 4)
    cal_b.add(2, 3)
    cal_b.add(3, 4)
    # print(cal_b)
    # print(cal_b.add(3, 5))
    # print(cal_b.add(3, 5))

main()
main()