Unable to use module attributes when specifying a MFA cache within the decorator

[suzdalnitski]

Hi,

The following works:

@decorate cacheable(
            cache: {MyApp.Cache, :get_cache, []},
            key: @some_key,
            opts: [ttl: @cache_ttl]
          )
def some_func do

While the following fails:

@my_cache {MyApp.Cache, :get_cache, []}

@decorate cacheable(
            cache: @my_cache,
            key: @some_key,
            opts: [ttl: @cache_ttl]
          )
def some_func do

The error I'm getting is:

** (ArgumentError) you attempted to apply a function on {MyApp.Cache, :get_cache, []}. Modules (the first argument of apply) must always be an atom
(nebulex 2.4.2) lib/nebulex/caching.ex:827: Nebulex.Caching.run_cmd/5

Is this expected behaviour?

Thanks!

[cabol]

Hey 👋 !! Yeah, that is expected because the :cache option is resolved in compilation time, so when you do something like cache: @my_cache in the decorator, since it is a constant, what is received in the decorator is the constant itself, means the cache will be that constant, not expanded value. However, this is something we can handle maybe in runtime, making this possible, Let me think about that option (handling the :cache option in runtime) and maybe create a separate ticket. In the meantime, yeah, it is an expected behaviour.

[suzdalnitski]

That makes sense, thank you!