如何编写自己的 python awaitable function 即不仅调用其他异步函数？

Question

I have one blocking function:

def blocking_function():
    doing.start_preparing()
    while not doing.is_ready():
        pass
    return doing.do()

I want to change it into an async function.

I've read some source code of asyncio, and I've found this two options:

@types.coroutine
def yield_option() -> typing.Generator:
    doing.start_preparing()
    while not doing.is_ready():
        yield
    return doing.do()

def future_and_call_soon_option() -> asyncio.Future:
    doing.start_preparing()
    loop = asyncio.get_running_loop()
    future = loop.create_future()
    def inner():
        if not doing.is_ready():
            loop.call_soon(inner)
        else:
            future.set_result(doing.do())
    inner()
    return future

async def main():
    await asyncio.gather(yield_option(), future_and_call_soon_option()) #runs concurently

asyncio.run(main())

Both of these options do work but which of them is better? Or is there any third option that is better to use?

Answer 1

How about:

async def blocking_function():
    doing.start_preparing()
    while not doing.is_ready():
        await asyncio.sleep(0)
    return doing.do()

This will cooperate with other tasks. It is simple and would probably be acceptable in practice if the blocking functions are fast enough. But if the blocking functions take a significant amount of time it would be better to move them to another thread.