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

Enveloping actor

It is easy to find scenarios where our messages need additional information or metadata to do some extra tasks, for example, when you need a correlation ID or a timestamp to track when things were created or tagged. Other frameworks, such as Apache Camel, use an envelope that contains the actual message, some headers, and some attachments. This envelope is called Exchange in the Apache Camel world. Unlike Apache Camel, Akka does not provide an out-of-the-box envelope implementation of this kind. Since actors exchange messages of the type Any (different from null), we can indeed create our own implementation of an envelope, where we can add additional knowledge about the message we are sending around. 

In this recipe, we will define our own envelope, which will have capabilities to hold the additional knowledge in a headers map. Also, we will create an actor that will turn any message into an envelope.

Getting ready

To step through this recipe, we need to import the Hello-Akka...