Book Image

Spring Microservices

By : Rajesh R V
Book Image

Spring Microservices

By: Rajesh R V

Overview of this book

The Spring Framework is an application framework and inversion of the control container for the Java platform. The framework's core features can be used by any Java application, but there are extensions to build web applications on top of the Java EE platform. This book will help you implement the microservice architecture in Spring Framework, Spring Boot, and Spring Cloud. Written to the latest specifications of Spring, you'll be able to build modern, Internet-scale Java applications in no time. We would start off with the guidelines to implement responsive microservices at scale. We will then deep dive into Spring Boot, Spring Cloud, Docker, Mesos, and Marathon. Next you will understand how Spring Boot is used to deploy autonomous services, server-less by removing the need to have a heavy-weight application server. Later you will learn how to go further by deploying your microservices to Docker and manage it with Mesos. By the end of the book, you'll will gain more clarity on how to implement microservices using Spring Framework and use them in Internet-scale deployments through real-world examples.
Table of Contents (18 chapters)
Spring Microservices
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface
Index

Adding a custom health module


Adding a new custom module to the Spring Boot application is not so complex. To demonstrate this feature, assume that if a service gets more than two transactions in a minute, then the server status will be set as Out of Service.

In order to customize this, we have to implement the HealthIndicator interface and override the health method. The following is a quick and dirty implementation to do the job:

class TPSCounter {
  LongAdder count;
  int threshold = 2;
  Calendar expiry = null; 

  TPSCounter(){
    this.count = new LongAdder();
    this.expiry = Calendar.getInstance();
    this.expiry.add(Calendar.MINUTE, 1);
  }
  
  boolean isExpired(){
    return Calendar.getInstance().after(expiry);
  }
  
  boolean isWeak(){
    return (count.intValue() > threshold);
  }
  
  void increment(){
     count.increment();
  }
}

The preceding class is a simple POJO class that maintains the transaction counts in the window. The isWeak method checks whether the transaction...