Pythonのクラスのメソッド全てに自動でデコレーターを適用する

関数単体へのデコレーターの適用すぐ出るけど、今回の使い方は中々無いので忘れないように残しておく。

https://stackoverflow.com/a/23726462

def for_all_methods(decorator):
    def decorate(cls):
        for attr in cls.__dict__: # there's propably a better way to do this
            if callable(getattr(cls, attr)):
                setattr(cls, attr, decorator(getattr(cls, attr)))
        return cls
    return decorate

@for_all_methods(mydecorator)
class C(object):
    def m1(self): pass
    def m2(self, x): pass

上の機能を使い自動で全てのメソッドでログを出したいのでこんな感じにする

def apply_logger():
    def logger(fn):
        # https://stackoverflow.com/a/6307868
        from functools import wraps

        @wraps(fn)
        def wrapper(*args, **kwargs):
            print(f"START: {fn.__name__}")

            out = fn(*args, **kwargs)

            print(f"END: {fn.__name__}")
            # Return the return value
            return out

        return wrapper

    def decorate(cls):
        for attr in cls.__dict__: # there's propably a better way to do this
            if callable(getattr(cls, attr)):
                setattr(cls, attr, logger(getattr(cls, attr)))
        return cls
    return decorate


@apply_logger()
class A:
    def a(self):
        print("a")

    def b(self):
        print("b")

    def c(self):
        print("c")


if __name__ == "__main__":
    a = A()
    a.a()
    a.b()
    a.c()