Book Image

Cloud-Native Applications in Java

By : Andreas Olsson, Ajay Mahajan, Munish Kumar Gupta, Shyam Sundar S
Book Image

Cloud-Native Applications in Java

By: Andreas Olsson, Ajay Mahajan, Munish Kumar Gupta, Shyam Sundar S

Overview of this book

Businesses today are evolving so rapidly that they are resorting to the elasticity of the cloud to provide a platform to build and deploy their highly scalable applications. This means developers now are faced with the challenge of building build applications that are native to the cloud. For this, they need to be aware of the environment, tools, and resources they’re coding against. If you’re a Java developer who wants to build secure, resilient, robust, and scalable applications that are targeted for cloud-based deployment, this is the book for you. It will be your one stop guide to building cloud-native applications in Java Spring that are hosted in On-prem or cloud providers - AWS and Azure The book begins by explaining the driving factors for cloud adoption and shows you how cloud deployment is different from regular application deployment on a standard data centre. You will learn about design patterns specific to applications running in the cloud and find out how you can build a microservice in Java Spring using REST APIs You will then take a deep dive into the lifecycle of building, testing, and deploying applications with maximum automation to reduce the deployment cycle time. Gradually, you will move on to configuring the AWS and Azure platforms and working with their APIs to deploy your application. Finally, you’ll take a look at API design concerns and their best practices. You’ll also learn how to migrate an existing monolithic application into distributed cloud native applications. By the end, you will understand how to build and monitor a scalable, resilient, and robust cloud native application that is always available and fault tolerant.
Table of Contents (20 chapters)
Title Page
Dedication
Packt Upsell
Foreword
Contributors
Preface
Index

Enabling cloud-native behaviors


We have just developed a basic service with two APIs that respond to requests. Let's add a few capabilities that will enable to it to be a good cloud citizen. We will discuss the following:

  • Externalizing configuration
  • Instrumentation—health and metrics
  • Service registration and discovery

Externalizing configuration

Configuration can be any property that is likely to differ between environments or production deployments. Typical examples are queue and topic names, ports, URLs, connection and pool properties, and so on.

A deployable should not have configuration in it. A configuration should be injected from outside. This makes the deployable unit immutable as it goes through the various stages of the life cycle, such as Dev, QA, and UAT.

Let's assume we have to run our product service in different environments, where the URL differentiates the environment. Therefore, the small change we make in the request mapping is as follows:

@RequestMapping("/${env}product/{id}...