Preface

The Akka library is well known in the Scala world for providing a means to build reactive applications. Akka’s core building block is the Actor, which is a simple concurrency unit that allows you to build asynchronous, event driven, fault tolerant, and potentially distributed components on top of. Actors are an excellent starting point to build your reactive applications and services on top of, but there’s a lot more within the entire Akka platform that you should be considering as well.

This book will provide the reader with a purpose-built tour through some of the additional modules within the Akka platform. The tour will be conducted by progressively refactoring an initial Akka application from an inflexible monolith all the way to a set of loosely coupled microservices. Along the way, you will learn how to apply new features, such as event sourcing via Akka Persistence, to the application in an effort to help it scale better. When the journey is complete, you will have a much better understanding of these additional offerings within the Akka platform and how they can help you build your applications and services.

Throughout the refactoring process, new concepts and libraries within Akka will be introduced to the reader on a chapter by chapter basis.  Within those chapters, I will detail what each new feature is, and how that feature fits into breaking down a monolith into a set of loosely coupled services. Each chapter will also involve coding homework for the reader, giving them an active role in the progressive refactoring process. This hands-on experience will give the reader an immersive understanding of how to use these newer Akka features in the real-world code, which is the main goal of this book.