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

Reducing recovery time using snapshots

As we have mentioned in the introduction, Akka persistence uses event sourcing to persist the state of an actor. Event sourcing is a technique to store the changes to the state instead of the state itself. This way, we can have a sequence of what happened. This mechanism is great and has some advantages over the traditional approach, but it might be overkill when you have millions of events to persist and replay when recovering. That is why Akka persistence allows you to take snapshots of our current state to speed up the recovery time. Persistent actors can save snapshots of the internal state by calling the saveSnapShot method. If saving a snapshot succeeds, the persistent actor receives a SaveSnapshotSuccess message; otherwise, they receive a SaveSnapshotFailure message. 

Getting ready

To step through this recipe, we need to import the hello-Akka project in the IDE; other prerequisites are the same as earlier as we have downloaded the akka-persistence...