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

Preparing an actor for persistence

Before we take a look at Akka persistence, let's review the terminology and architectures used in it:

  • PersistentActor: A stateful actor that persists events to the journal. When a persistent actor is started or restarted, journaled messages are replayed to that actor so that it can recover the internal state from these messages.
  • AsyncWriteJournal: A journal keeps an ordered collection of events that can be sent to a persistent actor. An application can control which messages are journaled and which are received by the persistent actor without being journaled. The data store behind the journal is configurable and needs to be decided depending on the needs. By default, Akka persistence comes with a LevelDB journal plugin (which uses the local filesystem and is not replicated). 
  • AtLeastOnceDelivery: A messaging delivery mechanism that ensures at-least-once delivery semantics to destinations.
  • Snapshot store: A snapshot store persists snapshots of a persistent actor...