cache.py

import time

__CACHE = {}

def cache(ns, key, val_func=None , ttl=None):
    
    if ttl is None or ttl <= 0 :
        return val_func()

    now = int(time.time())
    key = ns + ":" + key
    
    val, exp = __CACHE.get(key, (None,-1) )
    
    if (exp < 0 or exp < now) and val_func:
        
        val = val_func()
        __CACHE[key] = val, ttl+now
        
    return val

if __name__ == "__main__":
    
    a = 3
    v = cache("A", "K", val_func=lambda : a+3 , 300)
    print v