decorator for context management outside functions

with_context.py

from functools import partial
from contextlib import ExitStack
from types import SimpleNamespace
from collections import namedtuple


def with_context(**contexts):
    def decorator(func):
        def wrapper(*args, **kwargs):
            with ExitStack() as stack:
                contextns = SimpleNamespace(
                    **{
                        key: stack.enter_context(
                            value if not callable(value) else value()
                        )
                        for key, value in contexts.items()
                    }
                )
                return func(contextns, *args, **kwargs)

        return wrapper

    return decorator


@with_context(output=partial(open, "/tmp/output.txt", "w"))
def helloworld(context):
    print(context)
    print("hello, world", file=context.output)


helloworld()