Microservice - Spring Cloud Zuul Reverse Proxy as Service Gateway

Continuing on, Zuul is a router and a server-side load balancer developed and popularized by Netflix. Zuul uses ribbon to call the remote se...

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Microservice Architecture of a Catalog and Sales Order Management System

Continuing on, Zuul is a router and a server-side load balancer developed and popularized by Netflix. Zuul uses ribbon to call the remote services registered in a discovery server such as Eureka. By annotating a SpringBoot class with @EnableZuulProxy, a route is created for each service from the discovery client. As we add new services, routes are refreshed.

@EnableZuulProxy also enables 2 additional endpoints:

• Routes - a get to this endpoint returns a list of map routes, to get more details, add the query param format=details
• Filters - a get to this endpoint returns a map of Zuul filters

Creating a Zuul Enabled project

1. Create a new SpringBoot and add the following dependencies
1. spring-cloud-starter-netflix-zuul
2. spring-cloud-starter-netflix-eureka-client - register this server to the service discovery
3. spring-boot-starter-web and spring-boot-starter-actuator to expose server information
2. Annotate the SpringBoot class with @EnableZuulProxy and @EnableDiscoveryClient.
3. Configuration the application name, port, eureka instance and Zuul in the property file.

No change is needed in our catalog service.

Run the projects in the following order

• Terawarehouse-config-server
• Terawarehouse-service-discovery
• Terawarehouse-load-balancer
• Terawarehouse-catalog 

The following url should be accessible:

• <network_ip>:8000/catalog/default</network_ip>
• <network_ip>:8761</network_ip>
• <network_ip>:8001/api/v1/categories</network_ip>
• <network_ip>:8762/routes</network_ip>
• <network_ip>:8762/filters</network_ip>
• <network_ip>:8762/catalog/api/v1/categories</network_ip>

The last entry routes our request in the /catalog/** path to the catalog service without knowing it’s actual url and port. And that’s the beauty of Eureka with Zuul, it simplifies the adding of a new service. Take note that we can run more than 1 instance of each service without changing the configuration. And that is what we will try to do next.

And that concludes this video. I hope this information will be of use to you when you decided to develop your own project using the microservice architecture.

I would appreciate if you could subscribe to my channel to get notified when I upload the next video and that will validate that what I’m doing is helpful for others, which will definitely inspire me to share more technical videos.

References

• https://cloud.spring.io/spring-cloud-netflix/multi/multi__router_and_filter_zuul.html

Repositories

• https://github.com/terawarehouse
• https://github.com/broodcamp

	spring:
	application:
	name: load-balancer
	server:
	port: 8762
	eureka:
	instance:
	prefer-ip-address: true
	client:
	register-with-eureka: true
	fetch-registry: true
	service-url:
	defaultZone: http://192.168.1.100:8761/eureka
	management:
	endpoints:
	web:
	exposure:
	include:
	- '*'
	base-path: /
	zuul:
	sensitive-headers: # default value is Cookie, Set-Cookie, Authorization
	add-proxy-headers: false
	retryable: true
	#prefix: /api
	routes:
	catalog:
	path: /catalog/**
	service-id: catalog

view raw load_balancer_configuration hosted with ❤ by GitHub

	@SpringBootApplication
	@EnableZuulProxy
	@EnableDiscoveryClient
	public class TerawarehouseLoadBalancerApplication {
	public static void main(String[] args) {
	SpringApplication.run(TerawarehouseLoadBalancerApplication.class, args);
	}
	}

view raw spring_boot_class hosted with ❤ by GitHub

	<dependencies>
	<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-web</artifactId>
	</dependency>
	<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-actuator</artifactId>
	</dependency>
	<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
	</dependency>
	<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-starter-netflix-zuul</artifactId>
	</dependency>
	<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-devtools</artifactId>
	<scope>runtime</scope>
	<optional>true</optional>
	</dependency>
	<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-test</artifactId>
	<scope>test</scope>
	<exclusions>
	<exclusion>
	<groupId>org.junit.vintage</groupId>
	<artifactId>junit-vintage-engine</artifactId>
	</exclusion>
	</exclusions>
	</dependency>
	</dependencies>

view raw tw_load_balancer_pom hosted with ❤ by GitHub