promise decorator to resolve future arguments

gistfile1.py

from concurrent.futures import Future, ThreadPoolExecutor


class promise(object):

    executor = ThreadPoolExecutor(max_workers=100)

    def __init__(self, func):
        self.func = func

    def resolve(self, *args, **kwargs):
        resolved_args = []
        resolved_kwargs = {}

        for i, arg in enumerate(args):
            if isinstance(arg, Future):
                resolved_args.append(arg.result())
            else:
                resolved_args.append(arg)

        for kw, arg in kwargs.items():
            if isinstance(arg, Future):
                resolved_kwargs[kw] = arg.result()
            else:
                resolved_kwargs[kw] = arg

        return self.func(*resolved_args, **resolved_kwargs)

    def __call__(self, *args, **kwargs):
        return self.executor.submit(self.resolve, *args, **kwargs)