Spring Cloud Netfilx를 이용한 MSA 구축
by jsh
Spring Cloud Netfilx를 이용한 MSA 구축
1. Eureka(Service Discovery) 서버 구축
1) gradle 추가
plugins {
id 'org.springframework.boot' version '2.3.10.RELEASE'
id 'io.spring.dependency-management' version '1.0.11.RELEASE'
id 'java'
}
group = 'com.jsh'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'
repositories {
mavenCentral()
}
ext {
set('springCloudVersion', "Hoxton.SR10")
}
dependencies {
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-server'
testImplementation('org.springframework.boot:spring-boot-starter-test') {
exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
}
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
}
}
test {
useJUnitPlatform()
}
2) application.yml 설정
server:
port: 8761 # server의 port 지정
spring:
application:
name: ecureka-server # application name 설정
eureka:
instance:
hostname: localhost
prefer-ip-address: true
client:
register-with-eureka: true # false 자기 자신을 서비스에 등록하지 않는다. true 자기 자신에게 계속 Health check를 하게 됨
fetch-registry: true # 로컬 캐싱여부
serviceUrl:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
3) Eureka 서버 지정
Application java 파일에 @EnableEurekaServer 지정하면 끝.
package com.jsh.eurekaserver;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class, args);
}
}
2. Eureka Client 구축하기
여기서는 display, product 2개의 프로젝트를 클라이언트 지정 하였습니다.
해당 프로젝트는 hystrix 와 open feign 을 이용한 프로젝트로 생성 되었습니다.
2.1 Display Project 생성
1) gradle 추가(display)
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-hystrix'
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-ribbon'
implementation 'org.springframework.retry:spring-retry:1.2.2.RELEASE'
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'
}
2) application.yml 설정
server:
port: 8081
spring:
application:
name: display
# feign 별 hystrix 설정
hystrix:
command:
productInfo: # commnad Key. use 'default' for global setting.
execution:
isolation:
thread:
timeoutInMilliseconds: 3000 # default 1000ms
circuitBreaker:
requestVolumeThreshold: 1 # default 20
errorThresholdPercentage: 50 # default 50
FeignProductRemoteService#getProductInfo(String):
execution:
isolation:
thread:
timeoutInMilliseconds: 3000 # default 1000ms
circuitBreaker:
requestVolumeThreshold: 1 # default 20
errorThresholdPercentage: 50 # default 50
# hystrix 설정
# hystrix:
# command:
# default:
# execution:
# isolation:
# thread:
# timeoutInMilliseconds: 3000 # default 1000ms
# circuitBreaker:
# requestVolumeThreshold: 10 # default 20
# errorThresholdPercentage: 50 # default 50
# ribbon설정(default round robin방식)
product:
ribbon:
# listOfServers가 없는 경우 자동으로 Eureka Server에서 Server List 가져옴
# listOfServers: localhost:8082, localhost:7777
MaxAutoRetries: 0
MaxAutoRetriesNextServer: 1
eureka:
instance:
prefer-ip-address: true # ip address base 등록
client:
service-url:
defaultZone: http://127.0.0.1:8761/eureka, http://localhost:8762/eureka # default address
feign:
hystrix:
enabled: true
3) Eureka 클라이언트 지정
Application java 파일에 @EnableEurekaClient 지정하면 끝.
해당 프로젝트는 CircuitBreaker와 FeignClient를 구현하기 위해서 추가 Annotation 을 지정 하였습니다.
package com.jsh.hystrix;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@EnableCircuitBreaker
@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
public class DisplayApplication {
@Bean
@LoadBalanced
public RestTemplate restTemplate(){
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(DisplayApplication.class, args);
}
}
4) 테스트를 위한 파일 생성
4.1) RestConroller 생성
package com.jsh.hystrix.api;
import com.jsh.hystrix.service.FeignProductRemoteService;
import com.jsh.hystrix.service.ProductRemoteService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping(path = "/displays")
public class DisplayController {
@Autowired
private ProductRemoteService productRemoteService;
@Autowired
private FeignProductRemoteService feignProductRemoteService;
@GetMapping(path = "/{displayId}")
public String getDisplayDetail(@PathVariable String displayId){
String productInfo = getProductInfo();
return String.format("[display id = %s at %s %s]", displayId, System.currentTimeMillis(), productInfo);
}
private String getProductInfo(){
// return productRemoteService.getProductInfo("12345");
return feignProductRemoteService.getProductInfo("12345");
}
}
4.2) Feign 처리를 위한 Feign Client 생성
package com.jsh.hystrix.service;
import com.jsh.hystrix.factory.FeignProductRemoteServiceFallbackFactory;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
/**
* FeignClient설정 시 application명으로 접근이 가능하고 FallbackFactory설정으로 circuitBreaker 기능을 사용할 수 있다.
* application config 파일에 feign.hystrix.enabled=true 설정 필요
*
* @FeignClient(name = "[spring.application.name]으로 등록 된 Application명 지정")
* default 로드밸런싱(Eureka의 Ribbon)
* 직접 url지정을 원할 경우는 @FeignClient(name = "product", url= "지정 url")형태로 사용
* 다른 Application과 통신을 할 때 유용
*
* Zuul Api Gateway Server 송신하는 방식
* @FeignClient(name = "[zuul server의 application name]", fallbackFactory = FeignProductRemoteServiceFallbackFactory.class)
*
* eureka server를 통해 송신하는 방식
* @FeignClient(name = "[eureka server에 등록 된 application name]", fallbackFactory = FeignProductRemoteServiceFallbackFactory.class)
*/
//@FeignClient(name = "product", fallbackFactory = FeignProductRemoteServiceFallbackFactory.class)
@FeignClient(name = "zuul", fallbackFactory = FeignProductRemoteServiceFallbackFactory.class)
public interface FeignProductRemoteService {
@RequestMapping("/products/{productId}")
String getProductInfo(@PathVariable("productId") String productId);
}
4.3) Feign Fallback 처리를 위한 Fallback Factory 생성
package com.jsh.hystrix.factory;
import com.jsh.hystrix.service.FeignProductRemoteService;
import feign.hystrix.FallbackFactory;
import org.springframework.stereotype.Component;
@Component
public class FeignProductRemoteServiceFallbackFactory implements FallbackFactory<FeignProductRemoteService> {
@Override
public FeignProductRemoteService create(Throwable cause) {
System.out.println("t = " + cause);
return productId -> "[This Product is sold out]";
}
}
2.2 Product Project 생성
1) gradle 추가(product)
dependencies {
implementation 'org.springframework.boot:spring-boot-starter-web'
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
}
2) application.yml 설정
server:
port: 8082
spring:
application:
name: product
eureka:
instance:
prefer-ip-address: true
client:
service-url:
defaultZone: http://127.0.0.1:8761/eureka, http://localhost:8762/eureka # default address
3) Eureka 클라이언트 지정
Application java 파일에 @EnableEurekaClient 지정하면 끝.
package com.jsh.hystrix;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@SpringBootApplication
@EnableEurekaClient
public class ProductApplication {
public static void main(String[] args) {
SpringApplication.run(ProductApplication.class, args);
}
}
4) 테스트를 위한 파일 생성
package com.jsh.hystrix.api;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@Slf4j
@RestController
@RequestMapping(path = "/products")
public class ProductController {
@GetMapping(path = "{productId}")
public String getProductInfo(@PathVariable String productId){
// throw new RuntimeException("I/O Exception");
log.info("productId = " + productId);
return "[product id = " + productId + " at " + System.currentTimeMillis() + "]";
}
}
3. API Gateway 서버(Zuul) 구축
1) gradle 추가
dependencies {
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-eureka-client'
implementation 'org.springframework.cloud:spring-cloud-starter-netflix-zuul'
implementation 'org.springframework.retry:spring-retry:1.2.2.RELEASE'
implementation 'org.springframework.boot:spring-boot-actuator'
}
2) application.yml 설정
spring:
application:
name: zuul
# profiles:
# active: default # 서비스가 실행할 기본 프로파일
# cloud:
# config:
# uri: http://localhost:8889 # Config Server 위치
# cloud config git주소에 [서비스 ID]폴더 생성 후 profile생성
server:
port: 8765
management:
endpoints:
web:
exposure:
include: "*"
endpoint:
shutdown:
enabled: true
zuul:
# ignored-services: 'product' # 자동 경로 매핑 무시, 쉼표로 한 번에 여러 서비스 제외 가능
ignored-services: '*' # 유레카 기반 모든 경로 제외
# prefix: /api # 정의한 모든 서비스에 /api 접두어
routes:
product:
path: /products/**
serviceId: product
stripPrefix: false
display:
path: /displays/**
serviceId: display
stripPrefix: false
ribbon-isolation-strategy: thread
thread-pool:
use-separate-thread-pools: true
thread-pool-key-prefix: zuul-
eureka:
instance:
non-secure-port: ${server.port}
prefer-ip-address: true
client:
register-with-eureka: true # Eureka Server에 서비스 등록
fetch-registry: true # 레지스트리 정보를 로컬에 캐싱
service-url:
defaultZone: http://localhost:8761/eureka, http://localhost:8762/eureka
# apllication 별 hystrix설정
hystrix:
command:
# default hystrix 설정
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 1000
# application 별 hytrix 설정
product:
execution:
isolation:
thread:
timeoutInMilliseconds: 12000 # hystrix timeout 12sec로 설정 (default 1sec, ribbon 의 timeout 보다 커야 기대하는 대로 동작함)
# application 별 threadpool 설정
# 위에 정의 한 thread-pool-key-prefix 명 뒤에 zuul routes명이 붙는다.
threadpool:
zuul-product:
coreSize: 1
maximumSize: 2
allowMaximumSizeToDivergeFromCoreSize: true
zuul-display:
coreSize: 1
maximumSize: 2
allowMaximumSizeToDivergeFromCoreSize: true
# application 별 ribbon timeout 설정
product:
ribbon:
MaxAutoRetriesNextServer: 1
ReadTimeout: 3000
ConnectTimeout: 3000
MaxTotalConnections: 30
MaxConnectionsPerHost: 10
display:
ribbon:
MaxAutoRetriesNextServer: 1
ReadTimeout: 3000
ConnectTimeout: 3000
MaxTotalConnections: 30
MaxConnectionsPerHost: 10
3) Zuul Proxy 지정
@EnableZuulProxy 지정하면 끝.
@EnableDiscoveryClient 를 지정하여 Eureka 서버에 등록
package com.jsh.zuul;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
@EnableZuulProxy
@EnableDiscoveryClient
@SpringBootApplication
public class ZuulApplication {
public static void main(String[] args) {
SpringApplication.run(ZuulApplication.class, args);
}
}
4. 결과 확인
테스트는 Eureka 서버 2대(port: 8761, 8762), Zuul 서버 1대(port: 8765), Product 서버 2대(port: 8082, 8083), Display 서버 1대(port: 8081)로 테스트 진행 하였습니다.
4.1 Eureka 서버 확인
- Eureka 서버1
- Eureka 서버2
위 그림을 보면 Eureka 서버1(8761)에 Eureka Client들이 붙은 걸 확인 할 수 있다.
Eureka 서버2(8762)는 Eureka Client들이 붙지 않은 걸 볼 수 있는데 Eureka 서버1이 장애(Down) 시 아래 Log처럼
Eureka 서버2(8762)로 retry하는 걸 볼 수 있다.
2021-05-06 17:07:31.586 INFO 24932 --- [trap-executor-0] c.n.d.s.r.aws.ConfigClusterResolver : Resolving eureka endpoints via configuration
2021-05-06 17:08:08.671 INFO 24932 --- [freshExecutor-0] c.n.d.s.t.d.RedirectingEurekaHttpClient : Request execution error. endpoint=DefaultEndpoint{ serviceUrl='http://localhost:8762/eureka/} exception=java.net.ConnectException: Connection refused: connect stacktrace=com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException: Connection refused: connect
at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:187)
at com.sun.jersey.api.client.filter.GZIPContentEncodingFilter.handle(GZIPContentEncodingFilter.java:123)
at com.netflix.discovery.EurekaIdentityHeaderFilter.handle(EurekaIdentityHeaderFilter.java:27)
at com.sun.jersey.api.client.Client.handle(Client.java:652)
at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682)
at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74)
at com.sun.jersey.api.client.WebResource$Builder.get(WebResource.java:509)
at com.netflix.discovery.shared.transport.jersey.AbstractJerseyEurekaHttpClient.getApplicationsInternal(AbstractJerseyEurekaHttpClient.java:196)
at com.netflix.discovery.shared.transport.jersey.AbstractJerseyEurekaHttpClient.getDelta(AbstractJerseyEurekaHttpClient.java:172)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$7.execute(EurekaHttpClientDecorator.java:152)
at com.netflix.discovery.shared.transport.decorator.MetricsCollectingEurekaHttpClient.execute(MetricsCollectingEurekaHttpClient.java:73)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.getDelta(EurekaHttpClientDecorator.java:149)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$7.execute(EurekaHttpClientDecorator.java:152)
at com.netflix.discovery.shared.transport.decorator.RedirectingEurekaHttpClient.execute(RedirectingEurekaHttpClient.java:91)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.getDelta(EurekaHttpClientDecorator.java:149)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$7.execute(EurekaHttpClientDecorator.java:152)
at com.netflix.discovery.shared.transport.decorator.RetryableEurekaHttpClient.execute(RetryableEurekaHttpClient.java:120)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.getDelta(EurekaHttpClientDecorator.java:149)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$7.execute(EurekaHttpClientDecorator.java:152)
at com.netflix.discovery.shared.transport.decorator.SessionedEurekaHttpClient.execute(SessionedEurekaHttpClient.java:77)
at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.getDelta(EurekaHttpClientDecorator.java:149)
at com.netflix.discovery.DiscoveryClient.getAndUpdateDelta(DiscoveryClient.java:1135)
at com.netflix.discovery.DiscoveryClient.fetchRegistry(DiscoveryClient.java:1016)
at com.netflix.discovery.DiscoveryClient.refreshRegistry(DiscoveryClient.java:1531)
at com.netflix.discovery.DiscoveryClient$CacheRefreshThread.run(DiscoveryClient.java:1498)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:121)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:180)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:144)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:134)
at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:605)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:440)
at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:835)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:118)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56)
at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:173)
... 29 more
2021-05-06 17:08:08.671 WARN 24932 --- [freshExecutor-0] c.n.d.s.t.d.RetryableEurekaHttpClient : Request execution failed with message: java.net.ConnectException: Connection refused: connect
2021-05-06 17:08:08.690 INFO 24932 --- [freshExecutor-0] c.n.d.s.t.d.RetryableEurekaHttpClient : Request execution succeeded on retry #1
- Eureka 서버1을 임의로 Down 후 Eureka 서버2의 모습
- API Gateway(Zuul)를 이용한 Rest 통신 테스트(postman 이용)
위 그림과 같이 정상적으로 데이터를 응답 받는 것을 확인 할 수 있다.
결론
몇 가지 간단한 어노테이션을 사용하여 어플리케이션 내부의 공통 패턴을 신속하게 사용하고 설정할 수 있습니다.
그리고 battle-tested를 거친 Netflix component를 통해 대규모 분산 시스템을 구축할 수 있습니다.
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