Python装饰器，其参数取决于装饰函数

Question

i have a function decorated like this:

@do_something(cache_key=CACHE_ID ,timeout=CACHE_ID_TIMEOUT)        
def get_something_from_cache():
    ...
    ...
    ...
    return result

my decorator:

def do_something(function=None, cache_key='', timeout=300):

    def decorator(func):
        @wraps(func, assigned=available_attrs(func))
        def inner(*args, **kwargs):
            ...
            ...
            ...
    return decorator if function is None else decorator(function) 

i want to be able to have different 'cache_key' depends the decorated function input. something like:

@do_something(cache_key=CACHE_ID.format(att) ,timeout=CACHE_ID_TIMEOUT)        
def get_something_from_cache(att):
    ...
    ...
    ...
    return result

is it possible??

Answer 1

Nope.

Function decorators are executed just after the decorated function is defined. att does not exist until the function is called, which may be long after definition, or never at all.