metaclass prototype for collecting https://github.com/tomster/ezjail steps & stages

metafoo.py

from operator import attrgetter


def counter():
    count = 0
    while True:
        yield count
        count += 1


class Step(object):

    def __init__(self):
        self.name = None
        self.id = counter()

    def __call__(self):
        return 'call "%s"!' % self.name


class CustomStep(Step):

    def __init__(self, name, func):
        super(CustomStep, self).__init__()
        self.name = name
        self.func = func

    def __call__(self):
        return self.func(self)


def step(func):
    return CustomStep(func.func_name, func)


class MetaStage(type):

    def __init__(cls, name, bases, attrs):
        steps = []
        for n, step in attrs.items():
            if isinstance(step, Step):
                step.name = n
                steps.append(step)
        cls.steps = sorted(steps, key=attrgetter('id'))
        super(MetaStage, cls).__init__(name, bases, attrs)


class Stage(object):

    __metaclass__ = MetaStage


# now that the package is done, the user can define her stage...

class MyStage(Stage):

    @step
    def foo(self):
        return "don't foo me!"

    hurz = Step()
    blah = Step()

    @step
    def bar(self):
        return "let's go to the bar"


assert [s.name for s in MyStage().steps] == ['foo', 'hurz', 'blah', 'bar']
assert [s() for s in MyStage().steps] == [
    "don't foo me!", 'call "hurz"!', 'call "blah"!', "let's go to the bar"]