python - 如何在Python中从 future 检索任务？

Question

假设我有以下代码来并行运行多个任务。

with concurrent.futures.ThreadPoolExecutor(max_workers=connections) as executor:
    loop = asyncio.get_event_loop()
    futures = [
        loop.run_in_executor(
             executor,
             fun,
             arg
        )
        for i in range(connections)
    ]
    for result in await asyncio.gather(*futures):
        # I want to access the futures task here
        pass

Future 任务执行后是否可以读取它？

Answer 1

Is it possible to read the the futures' task once it has been executed?

在 asyncio 中，单词 task 有专门的含义，指的是 class子类 Future专门用于驱动协程。

在您的代码中，asyncio.gather() 返回结果，并且您还有包含 Future 对象的 futures 变量，该对象可以也可用于访问相同的结果。如果您需要访问其他信息(例如原始的 fun 或 arg)，您可以将其附加到适当的 Future 或使用字典来映射它。例如:

futures = []
for conn in connections:
    fut = loop.run_in_executor(executor, fun, arg)
    fut.conn = conn  # or other info you need
await asyncio.wait(futures)
# at this point all the futures are done, and you can use future.result()
# to access the result of an individual future, and future.conn to obtain
# the connection the future was created for