Python 3 Object-Oriented Programming - Third Edition

Executors

Now let's look at the executor code. We import the exact same ProcessPoolExecutor that we used in the previous section. Notice that we don't need a special AsyncIO version of it. The event loop has a handy run_in_executor coroutine that we can use to run futures on. By default, the loop runs code in ThreadPoolExecutor, but we can pass in a different executor if we wish. Or, as we did in this example, we can set a different default when we set up the event loop by calling loop.set_default_executor().

As you probably recall, there is not a lot of boilerplate for using futures with an executor. However, when we use them with AsyncIO, there is none at all! The coroutine automatically wraps the function call in a future and submits it ...