cacher.py

import time
import wrapt
import contextlib
import weakref
import functools


class Cacher:

    def __init__(self):
        self.meta = {}
        self.cache = {}


    def wrapper(self, fn, keyfn):

        @functools.wraps(fn)
        def wrapped(*args, **kw):
            key = keyfn(*args, **kw)
            if key in self.cache[wrapped]:
                print("cached", wrapped.__name__, *args, **kw)
                return self.cache[wrapped][key]
            ret = fn(*args, **kw)
            self.cache[wrapped][key] = ret
            return ret

        self.meta[wrapped] = keyfn
        self.cache[wrapped] = {}
        return wrapped

    def cache_it(self, keyfn):
        return functools.partial(self.wrapper, keyfn=keyfn)

    def pre_cache_it(self, wrapped, result, args, kw):
        keyfn = self.meta.get(wrapped)
        key = keyfn(*args, **kw)
        self.cache[wrapped][key] = result


cacher = Cacher()

@cacher.cache_it(keyfn=lambda a, b: f'{a}:{b}')
def foo(a, b)  -> int:
    time.sleep(1)
    return a + b

@cacher.cache_it(keyfn=lambda a, b: f'{a}:{b}')
def bar(a, b) -> int:
    time.sleep(1)
    return a * b

print(foo(10, 20))
print(foo(10, 20))
print(bar(10, 20))
print(bar(10, 20))
print(foo(10, 20))
print(foo(10, 20))
print(foo(10, 20))
print(bar(10, 20))
print(bar(10, 20))
print(bar(10, 20))

print(foo.__annotations__)
print(foo.__annotations__)


print(bar(10, 20))
cacher.pre_cache_it(bar, 199, (), {'a':10, 'b': 20})
print(bar(10, 20))
print(bar(10, 20))
print(bar(10, 20))