Python in-memory cache with time to live

Question

I have multiple threads running the same process that need to be able to to notify each other that something should not be worked on for the next n seconds its not the end o

Answer 1

Regarding an expiring in-memory cache, for general purpose use, a common design pattern to typically do this is not via a dictionary, but via a function or method decorator. A cache dictionary is managed behind the scenes. As such, this answer somewhat complements the answer by User which uses a dictionary rather than a decorator.

The ttl_cache decorator in cachetools==3.1.0 works a lot like functools.lru_cache, but with a time to live.

import cachetools.func

@cachetools.func.ttl_cache(maxsize=128, ttl=10 * 60)
def example_function(key):
    return get_expensively_computed_value(key)


class ExampleClass:
    EXP = 2

    @classmethod
    @cachetools.func.ttl_cache()
    def example_classmethod(cls, i):
        return i * cls.EXP

    @staticmethod
    @cachetools.func.ttl_cache()
    def example_staticmethod(i):
        return i * 3