In a world where there are constant triggers and responding quickly can be a significant competitive advantage, reactive programming is becoming ever more common. The idea is that, instead of users needing to take action when an event occurs, software responds automatically. Reactive programming creates an efficient way to handle data updates whenever a user makes an inquiry by using automated data streams.
While reactive programming was initially used to monitor networks, servers and software, the focus is now changing. The rapid growth of the Internet of Things (IoT) and the cloud has driven the need for increased automation. Reactive programming is used in facilities management, home automation and more. Meanwhile, the cloud has enabled reactive applications to improve scalability and reliability, further driving their growth within software development.
What is Reactive Programming?
Reactive programming is a design model that uses asynchronous programming logic to manage real-time updates to static content. Reactions are based on events occurring, such as alerts or keystrokes, calls from workflows or system messages. Ultimately, an event is a signal that something has happened in real-time; the reaction needs to be processed in real time too, so that it happens in unison. In reactive programming, these events are thought of as streams of cohesive data signals that flow through several processing elements and can be stopped, handled or diverted along the way. Processing is time-sensitive, which requires a different programming style, and this is where reactive programming comes into its own.
Reactive programming utilises observer and handler functions. Observer functions recognise changes as they occur and signal that they’ve taken place. Meanwhile, handler functions deal with those messages and evoke the necessary action. Software created with reactive programming needs to be resilient, scalable and able to manage variable loads, as there is no control over the number or timing of events.
How Does Reactive Programming Work?
As we’ve touched on, reactive programming is centred around data streams or sequences of events. A stream starts with an observer function that either waits for an event to occur or triggers an event. The stream then flows from the observer to one or more handlers that manage the necessary processing. When it comes to software development, reactive programming is the process of building the observers and handlers that make up the required stream.
Streams that are generated by observers within software either work alongside application processing or run periodically to look for a database element. When the software recognises a prescribed condition, it creates an event within the stream. The message-handling process will then determine whether a single handler or multiple handlers are required and will also monitor load-balancing amongst simultaneous handlers. Each handler can either pass the message along, end the message, generate an error or fork the message to other streams.
The 8 Principles of Reactive Programming
Many programs treat events as an afterthought, either as operational or infrastructure problems that are managed with increasingly complex technology stacks and workarounds. However, distributed systems that incorporate reactive programming incorporate certain foundational principles that enable them to deal with events effectively in real time:
- Stay Responsive – always responding in a timely manner
- Accept Uncertainty – building reliability despite unreliable foundations
- Embrace Failure – designing for resilience even when things go wrong
- Assert Autonomy – creating components that act independently and collaboratively
- Tailor Consistency – balancing components to ensure availability and performance
- Decouple Time – processing asynchronously to avoid delays
- Decouple Space – creating flexibility by embracing the network
- Handle Dynamics – continuously adapt to changing demands and resources
The Benefits of Reactive Programming
Reactive programming changes how code is designed and written, so it’s not something that should be used without considerable thought. However, for an experienced software development team, it can offer some incredible benefits:
- Improved Control – better control over the time it takes to respond to and process events.
- Faster development – more consistency in the development of real-time systems, reducing development time, cost and effort.
- Better Resilience – more control over load balancing, which in turn improves the quality of the user experience.
- Easier Management – the management of compute elements and processing resources is more visual and easier to manage.
- More Concise Code – instead of focusing on implementation details, developers review the interference between events that define business logic, often resulting in more compact implementations.
- Less Code – by using reactive programming libraries, such as RxJS, developers can spend less time writing behaviours that are already built-in.
- Reduced Costs – developers can leverage reactive libraries to solve complex problems with little effort, meaning there is no need to reinvent the wheel.
- Simple maintenance – with complex problems solved in a very declarative manner, code becomes more concise and straightforward and easier to maintain.
Of course, reactive programming doesn’t come without its challenges. Adding observer processes to existing software can be extremely complicated depending on the availability of source code and if reactive systems have a huge amount of processes linked to a stream, delays can start to accumulate. However, the biggest challenge is the mindset shift for developers.
How Can Your Business Leverage Reactive Programming?
Reactive programming has many use cases that can help improve the speed and quality of applications. This explains why the traditional target of reactive programming has involved to incorporate new technologies that have come to the forefront.
The most common intended use of reactive programming is in applications that gather status information from networks. However, this is now converging with IoT. Today, one of the primary uses are IoT applications, with sensors creating events that control real-world reactions or, indeed, transactions. Meanwhile, any application where each keystroke or action needs to be processed and interpreted can benefit hugely from reactive programming.
Ultimately, with reactive programming, your development team can work towards creating an event-driven architecture that is more reliable, scalable and resilient.