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

Cluster Sharding

Akka Cluster Sharding is a helper module that automatically distributes actors across multiple cluster nodes. These actors have an identifier and they are commonly known as entities. Each actor entity runs only at one location, and you can interact with them through the ClusterSharding extension. A shard is a group of entities that is managed together through an EntityId.

Cluster Sharding takes care of routing the message to the expected destination, so you don't need to know where the actors are running. It needs a persistent store to store actor information. We will configure our app to use the distributed data store, which will be the default as of Akka 2.5.0. We will learn more about distributed data in the next recipe.

Cluster Sharding is used when you have stateful actors where the size of the state does not fit the memory of a single machine. We can easily scale an application beyond a single machine, thanks to Cluster Sharding.

In this recipe, we are going to test this...