Book Image

Mastering Spring Boot 2.0

By : Dinesh Rajput
Book Image

Mastering Spring Boot 2.0

By: Dinesh Rajput

Overview of this book

Spring is one of the best frameworks on the market for developing web, enterprise, and cloud ready software. Spring Boot simplifies the building of complex software dramatically by reducing the amount of boilerplate code, and by providing production-ready features and a simple deployment model. This book will address the challenges related to power that come with Spring Boot's great configurability and flexibility. You will understand how Spring Boot configuration works under the hood, how to overwrite default configurations, and how to use advanced techniques to prepare Spring Boot applications to work in production. This book will also introduce readers to a relatively new topic in the Spring ecosystem – cloud native patterns, reactive programming, and applications. Get up to speed with microservices with Spring Boot and Spring Cloud. Each chapter aims to solve a specific problem or teach you a useful skillset. By the end of this book, you will be proficient in building and deploying your Spring Boot application.
Table of Contents (23 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Feign and Hystrix


To create a resilient system, we have to implement reactive patterns, such as circuit-breaker patterns. The Feign client supports the circuit-breaker pattern by using Hystrix. We will discuss Hystrix and how we can write fallback methods in Chapter 10, Building Resilient Systems Using Hystrix and Turbine. Feign clients have direct support for fallbacks. If Hystrix is on the classpath and feign.hystrix.enabled=true, Feign will wrap all methods with a circuit-breaker. Returning com.netflix.hystrix.HystrixCommand is also available.

To implement the Feign client with Hystrix, just implement the interface with the fallback code, which will then be used when the actual call to the endpoint delivers an error.

Let's see the following example:

@FeignClient(name = "account-service", fallback = HystrixClientFallback.class) 
interface HystrixClient { 
    @GetMapping("/account/{accountId}") 
    Account get(@PathVariable Integer accountId); 
} 
 
class HystrixClientFallback implements...