MicroServices Spring Boot Eureka Server Example

By | 2018-10-13T13:37:10+00:00 October 13th, 2018|Spring Boot|0 Comments

In this tutorials, we are going to see Spring Boot Eureka/ Spring Cloud Eureka.

Spring Boot Eureka:

Spring Cloud Eureka is a wrapper of Eureka which build from Netflix.

Doc: Spring Cloud Eureka is a Client-side service discovery allows each service to find and communicate with each other without hard coding hostname and port. The only ‘fixed point’ in such an architecture consists of a service registry with which each service has to register.

Spring Boot Eureka Server Example:

Here I am going to create two different micro-services, both are individual applications one will act as a server and another one is a client. Intermediately I am going to create a Eureka server as service registry it allows both client and servers to communicate with each other without knowing the hostname and port number.

Technologies Used:

  • Spring Boot Starter 2.0.5
  • Spring-cloud-starter-netflix-eureka-server
  • Spring-cloud-dependencies
  • Java 8
  • IntelliJ Idea

Application Structure:

Spring Boot Eureka Server Example

Dependencies for Eureka Server:

To implement eureka server as service registry we have to add the below dependencies in pom.xml

pom.xml
<dependencies>
  <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>

Complete pom.xml

pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.onlinetutorialspoint</groupId>
  <artifactId>SpringBoot_Eureka_Server</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>SpringBoot_Eureka_Server</name>
  <description>Spring Boot Eureka Server Example</description>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.5.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
    <spring-cloud.version>Finchley.SR1</spring-cloud.version>
  </properties>
  <dependencies>
    <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 configuration in application.yml file.

application.yml
spring:
  application:
    name: eureka_server
server:
  port: 8090

eureka:
  client:
    registerWithEureka: false
    fetchRegistry: false
    server:
      waitTimeInMsWhenSyncEmpty: 0

Here, I am mentioning application name as eureka_server and port as 8090. As this application act as a eureka server, it should not be registered with default eureka client so that we should make use of reisterWithEureka:false and fetchRegisty:false.

Enabling eureka server in spring boot application.

SpringBootEurekaServerApplication.java
package com.onlinetutorialspoint;

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

@EnableEurekaServer
@SpringBootApplication
public class SpringBootEurekaServerApplication {

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

Enabling Eureka Server with Spring Boot as simple as annotating @EnableEurekaServer annotation on top of @SprinBootApplication.

Run the application:

Console
mvn spring-boot:run

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.0.5.RELEASE)

2018-10-07 20:41:23.423  INFO 2036 --- [           main] c.o.SpringBootEurekaServerApplication    : No active profile set, falling back to default profiles: default
2018-10-07 20:41:23.457  INFO 2036 --- [           main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@53bc1328: startup date [Sun Oct 07 20:41:23 IST 2018]; parent: org.springframework.context.annotation.AnnotationConfigApplicationContext@39d9314d
2018-10-07 20:41:26.040  INFO 2036 --- [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=e1e941da-179e-3162-9b2c-a5223c94cb1f
.........
.........

After running the application, we can see the eureka dashboard like below by accessing our application’s url.

http://localhost:8090/

Spring Boot Eureka Server Dash Board

On the above eureka dashboard, we can see the basic information about system status and current instances. Currently, we do not have any registered instances with eureka service.

References:

Spring Cloud Netflix Eureka

Happy Learning 🙂

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