Developing Reactive Microservices

Chapter 2. Reactive Microservices and Basic Principles

Traditional application architectures and platforms are obsolete.

Anne Thomas, Gartner’s Modernizing Application Architecture and Infrastructure Primer for 2016

With classical application platforms no longer an option for today’s business requirements, Java developers have little to no choice but to switch to new technologies and paradigms. However, very few of these technologies are built to make an easy transition from traditional Java and Java EE development paradigms. The need to write applications that must be uncompromisingly robust, reliable, available, scalable, secure, and self-healing resulted in the creation of techniques and tools to address these new requirements, such as Akka, Vert.x, and Netty.

The key to implementing reactive microservices in Java-based systems is to find a very opinionated way to build, run, and scale applications on the JVM. Microservices need to be asynchronous by default. Relying on synchronous REST creates coupling that affects productivity, scalability, and availability. These are requirements only a new microservices framework can solve based on the principles of asynchronous message passing, event-based persistence through event sourcing, and CQRS out-of-the-box. All of these requirements are hard to compare with classic middleware platforms as they embrace a new way of programming based on the Reactive Manifesto.

Reactive principles are not new. They have been proven and hardened ...