Book Image

Akka Cookbook

By : Vivek Mishra, Héctor Veiga Ortiz
Book Image

Akka Cookbook

By: Vivek Mishra, Héctor Veiga Ortiz

Overview of this book

Akka is an open source toolkit that simplifies the construction of distributed and concurrent applications on the JVM. This book will teach you how to develop reactive applications in Scala using the Akka framework. This book will show you how to build concurrent, scalable, and reactive applications in Akka. You will see how to create high performance applications, extend applications, build microservices with Lagom, and more. We will explore Akka's actor model and show you how to incorporate concurrency into your applications. The book puts a special emphasis on performance improvement and how to make an application available for users. We also make a special mention of message routing and construction. By the end of this book, you will be able to create a high-performing Scala application using the Akka framework.
Table of Contents (18 chapters)
Title Page
About the Authors
About the Reviewer
Customer Feedback

Understanding event sourcing

As we have been discussing through this whole chapter, event sourcing is the technique used by Akka persistence. Event sourcing is a pattern to store the state of entities where instead of persisting the actual state at a given time, you persist the changes happening to that particular entity. These changes are known as events. In this recipe, we will review the advantages of event sourcing and how this mechanism can be a better fit for distributed application.

Getting ready

There are no prerequisites for this recipe.

How to do it…

For this recipe, we will list the steps on how event sourcing works with Akka:

  1. Once we create a persistent actor, recovery triggers. Akka persistence checks whether there are either events in the journal or snapshots in the snapshot store for the given persistence ID.
  2. If it finds events in the journal, it proceeds to replay those events to update the state accordingly. If  your actor receives other messages while doing this, they get stashed...