“What is a Coroutine Anyway?“ - John Reese (North Bay Python 2019)

John Reese This talk will start with basic concepts of functions, including how they are represented in memory, how state is tracked, and how function calls interact with the stack. We’ll then cover the common methods of running multiple functions concurrently, as well as the benefits and difficulties of concurrency in Python. We’ll then introduce the concept of coroutines, a variant of functions, and discuss how coroutines manage state and execution differently from functions. We’ll show some high level examples of coroutines that communicate with each other, and look at how they can be of use for I/O bound workloads. Then we’ll finish by showing how coroutines are implemented in Python, what the async/await keywords are actually doing when you use them in your code, and how all of these concepts are leveraged by the AsyncIO framework to build high performance applications in modern, clean Python. AsyncIO uses coroutines to deliver high p