How to Build Service Governance with Spring Cloud Eureka and Consul

Spring Cloud Overview

Spring Cloud is a set of tools built on Spring Boot that simplifies development of cloud‑native JVM applications. It provides configuration management, service discovery, circuit breaking, intelligent routing, distributed sessions, and more through sub‑projects such as Spring Cloud Config, Netflix, Zookeeper, and others.

Microservice Architecture

Microservices split a monolithic application into independently deployable services that communicate via RESTful APIs, allowing each service to be developed, scaled, and maintained separately.

Service Governance with Spring Cloud

Spring Cloud abstracts service‑governance implementations, enabling seamless switching between frameworks like Netflix Eureka, Consul, or Zookeeper without changing registration or discovery code.

Using Spring Cloud Eureka

First, create a Spring Boot project and add the following Maven dependencies:

<parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>1.4.3.RELEASE</version>
</parent>

<dependencies>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-eureka-server</artifactId>
  </dependency>
</dependencies>

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-dependencies</artifactId>
      <version>Camden.SR4</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

Enable the Eureka server with @EnableEurekaServer on a Spring Boot application class and run it. In application.properties disable the server’s own client registration:

server.port=1111
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://localhost:${server.port}/eureka/

After starting, visiting http://localhost:1111/ shows the Eureka dashboard with no registered services.

Creating a Service Provider

Create another Spring Boot project with the same Eureka dependency and add a REST controller that exposes an /add endpoint. The controller logs the service instance information obtained via DiscoveryClient and returns the sum of the two request parameters.

@RestController
public class ComputeController {
    private final Logger logger = Logger.getLogger(getClass());

    @Autowired
    private DiscoveryClient client;

    @RequestMapping(value = "/add", method = RequestMethod.GET)
    public Integer add(@RequestParam Integer a, @RequestParam Integer b) {
        ServiceInstance instance = client.getLocalServiceInstance();
        Integer r = a + b;
        logger.info("/add, host:" + instance.getHost()
            + ", service_id:" + instance.getServiceId()
            + ", result:" + r);
        return r;
    }
}

Activate discovery on the provider side with @EnableDiscoveryClient and configure:

spring.application.name=compute-service
server.port=2222
eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka/

Running the provider registers it with Eureka; the dashboard now lists the service.

Spring Cloud Consul

Consul offers service discovery, health checking, a key/value store, and multi‑datacenter support. Switching to Consul only requires changing the Maven dependency to spring-cloud-starter-consul-discovery and adding Consul connection properties:

spring.cloud.consul.host=localhost
spring.cloud.consul.port=8500

Consul runs its own agent; start it in development mode with consul agent -dev. No separate registration server is needed.

Key Takeaway

Spring Cloud’s abstraction layer lets developers move between Eureka and Consul (or other registries) by swapping dependencies and configuration, without modifying business logic.