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

Sharing data between nodes in an Akka cluster

Another interesting task you can accomplish through an Akka cluster is to have distributed data across all the nodes. The distributed data module allows you to use Conflict-Free Replicated Data Types (CRDTs) to have eventually consistent data structures. CRDTs permit you to execute updates from any node without coordination. In the case of update collision, the algorithm uses a monotonic merge function to resolve the issue.

This data is spread across cluster nodes via replication, and all the updates to these data structures are advertised by a Gossip protocol. The idea behind using Gossip is that all members should converge and decide the current state of a given data structure. By default, the Akka distributed data module provides the following data structures; however, it is possible to create your own custom ReplicatedData types:

  • Counters: GCounter and PNCounter
  • Sets: GSet and  ORSet
  • Maps: ORMap, ORMultiMap, LWWMap, and PNCounterMap
  • Registers...