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Spring Cloud Tutorial - Spring Cloud Gateway + Netflix Eureka Example | JavaInUse

Spring Cloud Tutorial - Spring Cloud Gateway + Netflix Eureka Example

In a previous tutorial we had implemented Spring Cloud Gateway Hello World Example. In this tutorial we will be implementing Spring Cloud Gateway and get the microservices deployment url using Netflix Eureka Discovery Service. In a previous tutorial we had implemented Netflix Eureka Discovery Service. When we start a project, we usually have all the configurations in the properties file. As more and more services are developed and deployed, adding and modifying these properties become more complex. Some services might go down, while some the location might change. This manual changing of properties may create issues. Eureka Service Registration and Discovery helps in such scenarios. As all services are registered to the Eureka server and lookup done by calling the Eureka Server, any change in service locations need not be handled and is taken care of

Spring Cloud - Table Of Contents

Microservice Registration and Discovery with Spring cloud using Netflix Eureka- Part 1. Microservice Registration and Discovery with Spring cloud using Netflix Eureka - Part 2. Microservice Registration and Discovery with Spring cloud using Netflix Eureka - Part 3. Microservice Registration and Discovery with Spring cloud using Netflix Eureka - Part 4. Spring Cloud- Netflix Eureka + Ribbon Simple Example Spring Cloud- Netflix Eureka + Ribbon + Hystrix Fallback Simple Example Spring Cloud- Netflix Hystrix Circuit Breaker Simple Example Spring Cloud- Netflix Feign REST Client Simple Example Spring Cloud- Netflix Zuul +Eureka Simple Example Spring Cloud Config Server using Native Mode Simple Example Spring Cloud Config Server Using Git Simple Example Spring Boot Admin Simple Example Spring Cloud Stream Tutorial - Publish Message to RabbitMQ Simple Example Spring Cloud Stream Tutorial - Consume Message from RabbitMQ Simple Example Spring Cloud Tutorial - Publish Events Using Spring Cloud Bus Spring Cloud Tutorial - Stream Processing Using Spring Cloud Data Flow Spring Cloud Tutorial - Distributed Log Tracing using Sleuth and Zipkin Example Spring Cloud Tutorial - Spring Cloud Gateway Hello World Example Spring Cloud Tutorial - Spring Cloud Gateway + Netflix Eureka Example

Spring Cloud Gateway + Neflix Eureka Discovery Service

We will be modifying the code we had implemented in the previous Spring Cloud Tutorial - Spring Cloud Gateway Hello World Example.
spring cloud gateway + Netflix Eureka

Netflix Eureka Discovery Service Implementation

The maven project will be as follows-
spring cloud netflix
The pom.xml will be as follows-
<?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>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.7.RELEASE</version>
		<relativePath />
	</parent>
	<groupId>com.javainuse</groupId>
	<artifactId>cloud-eureka-discovery-service</artifactId>
	<version>1.0.0-SNAPSHOT</version>
	<name>cloud-eureka-discovery-service</name>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.SR2</spring-cloud.version>
	</properties>

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

	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>0</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>

	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>
	</repositories>

</project>

Define the application.properties as follows-
spring:
  application:
    name: eureka-discovery-service

server:
  port: 8083
eureka:
  client:
    registerWithEureka: false
    fetchRegistry: false
    service-url:
      defaultZone: http://localhost:8083/eureka
Define the bootstrap class with the SpringBootApplication Annotation. Also here we will also be using the EnableEurekaServer annotation.
package com.javainuse;

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

@SpringBootApplication
@EnableEurekaServer
public class EurekaDiscoveryApplication {

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

}

Modify First Microservice

We will be modifying the first-service module we had developed in the previous tutorial.
The Maven project will be as follows-
spring cloud second microservice
In the pom.xml add the netflix eureka client dependency as follows -
<?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>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.7.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.javainuse</groupId>
	<artifactId>first-service</artifactId>
	<version>0.0.1-SNAPSHOT</version>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.SR2</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-client</artifactId>
        </dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>0</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>
	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>
	</repositories>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>
Define the application.yml as follows-
spring:
  application:
    name: first-service
server:
  port: 8081
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8083/eureka
Modify the FirstApplication to add the EnableEurekaClient annotation
package com.javainuse;

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

@SpringBootApplication
@EnableEurekaClient
public class FirstApplication {

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

}

Modify Second Microservice

We will be modifying the second-service module we had developed in the previous tutorial.
In the pom.xml add the netflix eureka client dependency as follows -
spring cloud second microservice
The pom.xml will be as follows-
<?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>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.7.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.javainuse</groupId>
	<artifactId>second-service</artifactId>
	<version>0.0.1-SNAPSHOT</version>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.SR2</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-client</artifactId>
        </dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>0</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>
	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>
	</repositories>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>
Define the application.properties as follows-
spring:
  application:
    name: second-service
server:
  port: 8082
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8083/eureka
Modify the SecondApplication to add the EnableEurekaClient annotation
package com.javainuse;

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

@SpringBootApplication
@EnableEurekaClient
public class SecondApplication {

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

}

Modify Spring Cloud Gateway Microservice

We will be modifying the spring-cloud-gateway-service module we had developed in the previous tutorial.
In the pom.xml add the netflix eureka client dependency as follows -
spring cloud gateway microservice
The pom.xml will be as follows-
<?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>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.7.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.javainuse</groupId>
	<artifactId>cloud-gateway-service</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>gateway-service</name>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.SR2</spring-cloud.version>
	</properties>

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

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>0</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>
	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>
	</repositories>
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

</project>
Define the application.yml as follows-
server:
  port: 8080
 
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8083/eureka 

spring:
  application:
    name: gateway-service
  cloud:
    gateway:
      routes:
      - id: employeeModule
        uri: lb://FIRST-SERVICE
        predicates:
        - Path=/employee/**
      - id: consumerModule
        uri: lb://SECOND-SERVICE
        predicates:
        - Path=/consumer/**
Modify the APIGatewayApplication to add the EnableEurekaClient annotation
package com.javainuse;

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

@SpringBootApplication
@EnableEurekaClient
public class APIGatewayApplication {

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

}
Start the three microservices we have developed-
  • Go to url - localhost:8083/
    spring cloud gateway API tutorial
  • Go to url - localhost:8080/employee/message
    spring cloud gateway API tutorial
  • Go to url - localhost:8080/consumer/message
    spring cloud gateway example

Download Source Code

Download it -
Spring Cloud Eureka Discovery service
Spring Boot First Microservice
Spring Boot Second Microservice
Spring Cloud Gateway Microservice

See Also

Spring Boot Hello World Application- Create simple controller and jsp view using Maven Spring Boot Tutorial-Spring Data JPA Spring Boot + Simple Security Configuration Pagination using Spring Boot Simple Example Spring Boot + ActiveMQ Hello world Example Spring Boot + Swagger Example Hello World Example Spring Boot + Swagger- Understanding the various Swagger Annotations Spring Boot Main Menu Spring Boot Interview Questions