Chapter 5. Concluding Thoughts

When substantial new features appear in Python, they’re new for everybody: even though I have nearly two decades’ experience with Python, I found Asyncio substantially different to my existing knowledge, even taking into account that I had already worked with Twisted and Tornado on previous projects, so event-based programming was not new to me. I found the asyncio API to be much more complex than I had expected. Part of this was due to a lack of high-level documentation.

Now, having spent the time to learn how to use Asyncio in Python, I feel a lot more comfortable with it, and this progression will likely be similar for you too. There is a coherent structure and a purpose behind the design of the API, and hopefully this book will make it much easier for you to learn than it was for me. With a basic understanding in place, I am finding it quite easy to write new asyncio-based code without having to constantly refer back to the docs: this is a very good sign, and certainly isn’t the case with all the standard library modules.

There are still some rough edges.

The asyncio standard library will continue to have a large, fine-grained API, since it caters to both framework designers, as well as end-user developers. This means that we—as end-user developers—will have to learn which parts of the API are applicable to us, and which are not. In time, as the third-party library ecosystem for asyncio grows and matures, we will likely be working with those library APIs rather than the raw asyncio standard library API. Existing libraries like aiohttp and Sanic are good examples of this.

The asyncio API itself will also continue to improve as more people gain experience with it. As covered earlier in the book, there are many improvements to asyncio coming in Python 3.7, and there is also work currently under way for more substantial improvements like Task-local storage, analogous to thread-local storage for threaded programming, but instead for asyncio Task contexts.

There were also unexpected discoveries I made along the way: by happy coincidence, it turned out that I needed to (finally!) learn ZeroMQ at around the same time this book was being written. I am finding that asyncio in combination with pyzmq makes network programming a joy!

Finally, my recommendation for the best way to learn Asyncio is to experiment, try things out, and have fun!