Async Rust

Chapter 6. Reactive Programming

Reactive programming is a programming paradigm where code reacts to changes in data values or events. Reactive programming enables us to build systems that respond dynamically to changes in real time. It is essential to underline that this chapter is written in the context of asynchronous programming. We cannot cover every aspect of reactive programming, as entire books have been written on the topic. Instead, we are going to focus on async approaches to polling and reacting to changes in data by building a basic heater system, where futures react to changes in temperature. We will then build an event bus by using atomics, mutexes, and queues to enable us to publish events to multiple subscribers.

By the end of this chapter, you will be familiar with enough async data-sharing concepts to construct thread-safe, mutable data structures. These data structures can be manipulated safely by multiple concurrent async tasks. You will also be able to implement the observer pattern. By the end of this chapter, you’ll be equipped with the skills to build async Rust solutions to reactive design patterns that you’ll find in further reading.

We start our reactive programming journey with building a basic reactive system.

Building a Basic Reactive System

In building our basic reactive system, we are going to implement the observer pattern. With this pattern, we have subjects and then observers that subscribe to updates of that subject. When the subject releases ...