Microservices Part 01: Creating Service Registry Application

In order to create a Microservices Application we will first require a Service Registry which is nothing but a special kind of microservice that will have a list of microservices registered inside it.

There are total three steps to create a Service Registry.

Step1: We are going to write our Service Registry microservice application using the spring-cloud-starter-netflix-eureka-server dependency.

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.4.1</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.sky</groupId>
    <artifactId>service-registry</artifactId>
    <version>1.0</version>
    <name>service-registry</name>
    <description>Registry for Job Portal Application</description>
    <url/>
    <licenses>
        <license/>
    </licenses>
    <developers>
        <developer/>
    </developers>
    <scm>
        <connection/>
        <developerConnection/>
        <tag/>
        <url/>
    </scm>
    <properties>
        <java.version>21</java.version>
        <spring-cloud.version>2024.0.0</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

service-registry/pom.xml

Step 2: Now, we need to also include the annotation @EnableEurekaServer to notify that this particular application will act as a Registry Server.

package com.sky.service_registry;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class ServiceRegistryApplication {

    public static void main(String[] args) {
        SpringApplication.run(ServiceRegistryApplication.class, args);
    }

}

service_registry/ServiceRegistryApplication.java

Step 3: We need to also specify the below details. To tell Spring to not register this application as a microservice. As all the other microservices will be registered inside this special microservice.

spring.application.name=service-registry
server.port=8761

eureka.instance.hostname=localhost
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false

/service-registry/src/main/resources/application.properties

Step 4: We will create a new microservice and try to register it in the Service Registry that was created in the previous steps.

We need to add the spring-cloud-starter-netflix-eureka-client dependency in our pom.xml of the new microservice in order to make it available/discoverable for registeration in the Service Registry.

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

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

Step 5: Also, we have to add below configuration for newly created microservice to specify the url for eureka server i.e. our Service Registry.

spring.application.name=job-search-service
server.port=8762

eureka.client.service-url.defaultZone=http://localhost:8761/eureka

Step 6: Now, make sure the Service Registry and the newly created microservice is running. To validate if the registration is success we can go to the Eureka Server URL(http://localhost:8761/) and locate the new microservice name there as shown in below snapshot.

Stay tuned for the next part of the Microservices Blog.
Thanks for reading!