Async Rust

Already popular among programmers for its memory safety and speed, the Rust programming language is also valuable for asynchrony. This practical book shows you how asynchronous Rust can help you solve problems that require multitasking. You’ll learn how to apply async programming to solve problems with an async approach. You will also dive deeper into async runtimes, implementing your own ways in which async runtimes handle incoming tasks.

Authors Maxwell Flitton and Caroline Morton also show you how to implement the Tokio software library to help you with incoming traffic, communicate between threads with shared memory and channels, and design a range of complex solutions using actors. You’ll also learn to perform unit and end-to-end tests on a Rust async system.

With this book, you’ll learn:

• How Rust approaches async programming
• How coroutines relate to async Rust
• Reactive programming and how to implement pub sub in async rust
• How to solve problems using actors
• How to customize Tokio to gain control over how tasks are processed
• Async Rust design patterns
• How to build an async TCP server just using the standard library
• How to unit test async Rust

By the end of the book, you’ll be able to implement your own async TCP server completely from the standard library with zero external dependencies, and unit test your async code.

What Is Async Rust?

Asynchronous programming in Rust, often referred to as Async Rust, is a powerful paradigm that allows developers to write concurrent code that is more efficient and scalable. In contrast to traditional synchronous programming, where tasks are executed one after another, async programming enables tasks to run concurrently, which is particularly useful when dealing with I/O-bound operations like network requests or file handling. This approach allows for the efficient use of system resources and can lead to significant performance improvements in applications that need to handle multiple tasks at once without the need for additional cores.

Rust’s type system and ownership model provide the safety guarantees that we all love. However, mastering async Rust requires an understanding of specific concepts, such as futures, pinning, and executors. This book will guide you through these concepts, equipping you with the knowledge needed to apply async to your own projects and programs.

Table of Contents

Chapter 1. Introduction to Async

Chapter 2. Basic Async Rust

Chapter 3. Building Our Own Async Queues

Chapter 4. Integrating Networking into Our Own Async Runtime

Chapter 5. Coroutines

Chapter 6. Reactive Programming

Chapter 7. Customizing Tokio

Chapter 8. The Actor Model

Chapter 9. Design Patterns

Chapter 10. Building an Async Server with No Dependencies

Chapter 11. Testing

About the Author

Maxwell Flitton is a software engineer who works for the open source financial loss modeling foundation OasisLMF. In 2011, Maxwell achieved his Bachelor of Science degree in nursing from the University of Lincoln, UK and a degree in physics from the Open University with a postgraduate diploma in physics and engineering in medicine from UCL in London whilst working as a nurse at Charing Cross A&E. He’s worked on numerous projects such as medical simulation software for the German government and supervising computational medicine students at Imperial College London. He also has experience in financial tech and Monolith AI. While building the medical simulation software Maxwell and Caroline had to build Rust async systems in the Kubernetes cluster to solve real time event solutions and caching mechanisms. Maxwell has written the Packt textbooks “Rust Web Programming” and “Speed Up Your Python with Rust”.

Caroline Morton studied Medicine and International Health at the University of Birmingham before moving to London to work as a doctor. She completed an Epidemiology MSc at the London School of Hygiene and Tropical Medicine. She later set up the first course in the UK training doctors and medical students to learn programming (“Coding for Medicine”) which later developed into a 10 week module and wrote a textbook covering the same topic called “Computational Medicine”, Elsevier 2018. In 2019, she moved to University of Oxford to work as an Epidemiologist and Software Developer and was key in developing OpenSAFELY – a trusted research environment that processed COVID-19 data during the Pandemic. This resulted in over 40 peer reviewed papers including Nature, the Lancet and the BMJ. Together with Maxwell, she has had to develop cutting edge techniques in Rust to solve problems in developing a Virtual Emergency Room app for training new doctors. She therefore has real-world experience of writing and deploying async rust in production.