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

Creating a circuit breaker to avoid cascading failure

In an Akka distributed system, we are expected to write a lot of services in the form of actors who do their work asynchronously. In such an application, there are chances that some services would be under a huge load and might fail anytime. So there would be chances that if a service depends on a particular service and if that particular service fails, then there would be propagation of failure in the services that are calling that particular service. Thus, we need a mechanism to avoid calling those services if they are failing or unresponsive and stop serving further requests.

To deal with such a scenario, Akka provides a circuit breaker.

Getting ready 

To step through this recipe, import the Hello-Akka project in the IDE; other prerequisites are the same as earlier. In this recipe, we will create a dummy database and fetch records from it. We will use the circuit breaker to see how it blocks further requests if there is a delay in serving...