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

Using persistence query

Akka persistence query is a helper module in the Akka persistence ecosystem that gives visibility into the journal events. Akka persistence query provides means to run asynchronous queries against the journal by using Akka Streams. Akka persistence query defines a set of predefined queries to analyze the log of events. Akka persistence query has a very loose API on purpose, so it is common to find different journal plugins with slightly different implementations. In this recipe, we will review the different predefined queries and see what each query is used for.

Getting ready

This recipe does not have any prerequisites. However before going through this recipe, it is required to understand what event adapters are in the Akka persistence context. Event adapters help to detach the data model from the domain model completely. This might be helpful in scenario where your data model evolves over time or you want to use a different format when storing the events in the journal...