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

Persistence query for LevelDB

Akka persistence query provides the functionality to read the journal and also receive live events that are getting persisted thanks to an Akka Stream. Implementations of Akka persistence query differ depending on which underlying technology we select. In this recipe, we will be using the LevelDB plugin to query all current events in a journal, and we will also create a stream to subscribe to real-time events. To learn more about Akka Streams, refer to Chapter 8Akka Streams.

Getting ready

To step through this recipe, we need to import the hell0-Akka project in the IDE; other prerequisites are the same as earlier as we have downloaded the akka-persistence dependency. We will also need the persistence query dependency. We will also make use of the classes created in the Recovering state of the actor recipe for this recipe.

How to do it…

For this recipe, we need to perform the following steps:

  1. First, we need to get the required dependencies. Open build.sbt and make...