Spring Cloud (MSA) - 로드밸런싱 Eureka, Feign

 

이전 포스팅

 

네이밍서버 (유레카 서버)

 

여러 포트 번호를 쓰고 있기 때문에

네이밍 서버를 통해 포트 번호에 상관없이 가져옴.

 

 

 

Eureka 유레카를 통해 관리

 

네이밍 서버

 

naming server 생성

의존성 등록(maven)

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

	<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>

 

Gradle

plugins {
	id 'java'
	id 'org.springframework.boot' version '2.7.6'
	id 'io.spring.dependency-management' version '1.0.15.RELEASE'
}

group = 'com.javapp'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

configurations {
	compileOnly {
		extendsFrom annotationProcessor
	}
}

repositories {
	mavenCentral()
}

ext {
	set('springCloudVersion', "2021.0.5")
}

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter'
	implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-server'
	compileOnly 'org.projectlombok:lombok'
	developmentOnly 'org.springframework.boot:spring-boot-devtools'
	annotationProcessor 'org.projectlombok:lombok'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'
}

dependencyManagement {
	imports {
		mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
	}
}

tasks.named('test') {
	useJUnitPlatform()
}

 

 

앱 설정

spring.application.name=naming-server
server.port=8761

eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false

 

메인

@EnableEurekaServer
@SpringBootApplication
public class NamingServerApplication {

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

}

 

---

 

currency-conversion , currency-exchange 마이크로 서비스

 

의존성 등록(maven)

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

	<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>

 

(Gradle)

plugins {
	id 'java'
	id 'org.springframework.boot' version '2.7.6'
	id 'io.spring.dependency-management' version '1.0.15.RELEASE'
}

group = 'com.javapp'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

configurations {
	compileOnly {
		extendsFrom annotationProcessor
	}
}

repositories {
	mavenCentral()
}

ext {
	set('springCloudVersion', "2021.0.5")
}

dependencies {
	implementation 'org.springframework.boot:spring-boot-starter-web'
	implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
	implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'

	implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
	implementation 'mysql:mysql-connector-java'

	implementation 'org.springframework.boot:spring-boot-starter-security'
	implementation 'org.springframework.security:spring-security-test'

	runtimeOnly group: 'io.jsonwebtoken', name: 'jjwt-jackson', version: '0.11.5'
	implementation group: 'io.jsonwebtoken', name: 'jjwt-impl' , version: '0.11.5'
	implementation group: 'io.jsonwebtoken', name: 'jjwt-api', version: '0.11.5'

	implementation 'org.springframework.boot:spring-boot-starter-validation'

	compileOnly 'org.projectlombok:lombok'
	developmentOnly 'org.springframework.boot:spring-boot-devtools'
	annotationProcessor 'org.projectlombok:lombok'
	testImplementation 'org.springframework.boot:spring-boot-starter-test'

}

dependencyManagement {
	imports {
		mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
	}
}

tasks.named('test') {
	useJUnitPlatform()
}

 

# 유레카 네이밍 서버 등록
eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka

 

---

 

 

 

Feign 과 Eureka를 사용한 로드밸런싱

네이밍 서버를 로드밸런싱을 해서 부하를 낮출 수 있음

 

 

Currency Exchange 인스턴스 2개 생성

 

 

Currency Conversion Microservice

CurrencyConversionController.java

@GetMapping("/currency-converter-feign/from/{from}/to/{to}/quantity/{quantity}")
public CurrencyConversion calculateCurrencyConversionFeign(
        @PathVariable String from, @PathVariable String to, @PathVariable BigDecimal quantity
){
    CurrencyConversion currencyConversion = currencyExchangeProxy.retrieveExchangeValue(from,to);

    return new CurrencyConversion(currencyConversion.getId(),from,to,quantity,
            currencyConversion.getConversionMultiple(), quantity.multiply(currencyConversion.getConversionMultiple()) ,currencyConversion.getEnvironment());
}

 

 

CurrencyExchangeProxy.java

//@FeignClient(name = "currency-exchange", url="localhost:8000") // properties의 name
@FeignClient(name = "currency-exchange") // properties의 name
public interface CurrencyExchangeProxy
{
    @GetMapping("/currency-exchange/from/{from}/to/{to}")
    public CurrencyConversion retrieveExchangeValue(
            @PathVariable String from, @PathVariable String to
    );
}

Currency Exchange Microservice 사용하는 프록시

 

 

유레카 로드밸런서 사용

 

localhost:8100/currency-conversion/from/USD/to/INR/quantity/10

It's automatically load balancing