Spring Cloud로 개발하는 마이크로서비스 애플리케이션(MSA)-2.API Gateway Service
Spring Cloud Netflix Zuul 은 Spring Boot 2.4에서 Maintenance 상태이다. 오늘은 Spring Cloud Gateway에 대한 정리만 할 예정이다.
Spring Cloud Gateway
pom.xml
프로젝트 생성 시 Spring Cloud Routing > gateway(spring-cloud-starter-gateway)를 선택한다.
spring-cloud-starter-netflix-eureka-client, lombok 은 나중 작업을 위해 미리 추가한 라이브러리이다.
<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>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
Spring Cloud Gateway-Filter 적용
아래 두개의 예시의 결과는 동일하다.
- @Configuration Bean을 등록해서 적용 - Java 레벨에서 RequestHeader, ResponseHeader에 값을 설정한 예시이다.
import org.springframework.cloud.gateway.route.RouteLocator;
import org.springframework.cloud.gateway.route.builder.RouteLocatorBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class FilterConfig {
@Bean
public RouteLocator gatewayRoutes(RouteLocatorBuilder builder){
return builder.routes()
.route(r -> r.path("/first-service/**")
.filters(f -> f.addRequestHeader("first-request", "first-request-header")
.addResponseHeader("first-response", "first-response-header"))
.uri("http://localhost:8081"))
.route(r -> r.path("/second-service/**")
.filters(f -> f.addRequestHeader("second-request", "second-request-header")
.addResponseHeader("second-response", "second-response-header"))
.uri("http://localhost:8082"))
.build();
}
}
- yaml 파일로 적용 - Yaml 설정파일로 RequestHeader, ResponseHeader에 값을 설정한 예시이다.
server: port: 8000 eureka: client: register-with-eureka: false fetch-registry: false spring: application: name: apigateway-service cloud: gateway: routes: - id: first-service uri: http://localhost:8081 predicates: - Path=/first-service/** filters: - AddRequestHeader=first-request, first-request-header - AddResponseHeader=first-response, first-response-header - id: second-service uri: http://localhost:8082 predicates: - Path=/second-service/** filters: - AddRequestHeader=second-request, second-request-header - AddResponseHeader=second-response, second-response-header
Spring Cloud Gateway-Custom Filter 적용
Custom Filter 클래스 생성
AbstractGatewayFilterFactory 상속받고 apply 메소드를 재정의 한다.
Config inner class 를 만든다.
기본생성자를 만든다.
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;
@Component
@Slf4j
public class CustomFilter extends AbstractGatewayFilterFactory<CustomFilter.Config> {
public CustomFilter() {
super(Config.class);
}
@Override
public GatewayFilter apply(Config config) {
// Custom Pre Filter
return (exchange, chain) -> {
ServerHttpRequest request = exchange.getRequest();
ServerHttpResponse response = exchange.getResponse();
log.info("Custom PRE filter : request id -> {}", request.getId());
// Custom Post Filter
return chain.filter(exchange).then(Mono.fromRunnable(() -> {
log.info("Custom POST filter : response code -> {}", response.getStatusCode());
}));
};
}
public static class Config {
// Put the configuration properties
}
}
application.yml 파일에 CustomFilter 등록
AddRequestHeader, AddResponseHeader를 주석하고 CustomFilter를 등록한다.
server:
port: 8000
eureka:
client:
register-with-eureka: false
fetch-registry: false
spring:
application:
name: apigateway-service
cloud:
gateway:
routes:
- id: first-service
uri: http://localhost:8081
predicates:
- Path=/first-service/**
filters:
# - AddRequestHeader=first-request, first-request-header2
# - AddResponseHeader=first-response, first-response-header2
- CustomFilter
- id: second-service
uri: http://localhost:8082
predicates:
- Path=/second-service/**
filters:
# - AddRequestHeader=second-request, second-request-header2
# - AddResponseHeader=second-response, second-response-header2
- CustomFilter
Spring Cloud Gateway-Global Filter 적용
Global Filter 클래스 생성
Global Filter를 만드는 방법은 Custom Filter와 동일하다.
AbstractGatewayFilterFactory 상속받고 apply 메소드를 재정의 한다.
Config inner class 를 만든다.
기본생성자를 만든다.
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;
@Component
@Slf4j
public class GlobalFilter extends AbstractGatewayFilterFactory<GlobalFilter.Config> {
public GlobalFilter() {
super(Config.class);
}
@Override
public GatewayFilter apply(Config config) {
return (exchange, chain) -> {
ServerHttpRequest request = exchange.getRequest();
ServerHttpResponse response = exchange.getResponse();
log.info("Global filter baseMessage : {}", config.getBaseMessage());
if(config.isPreLogger()){
log.info("Global filter Start : request id -> {}", request.getId());
}
// Custom Post Filter
return chain.filter(exchange).then(Mono.fromRunnable(() -> {
if(config.isPostLogger()){
log.info("Global filter End : response code -> {}", response.getStatusCode());
}
}));
};
}
@Data
public static class Config {
// Put the configuration properties
private String baseMessage;
private boolean preLogger;
private boolean postLogger;
}
}
application.yml 파일에 GlobalFilter 등록
spring.cloud.gateway.default-filters에 Global Filter를 등록한다.
server:
port: 8000
eureka:
client:
register-with-eureka: false
fetch-registry: false
spring:
application:
name: apigateway-service
cloud:
gateway:
default-filters:
- name: GlobalFilter
args:
baseMessage: Spring Cloud Gateway Global Filter
PreLogger: true
PostLogger: true
routes:
- id: first-service
uri: http://localhost:8081
predicates:
- Path=/first-service/**
filters:
# - AddRequestHeader=first-request, first-request-header2
# - AddResponseHeader=first-response, first-response-header2
- CustomFilter
- id: second-service
uri: http://localhost:8082
predicates:
- Path=/second-service/**
filters:
# - AddRequestHeader=second-request, second-request-header2
# - AddResponseHeader=second-response, second-response-header2
- CustomFilter
Spring Cloud Gateway-Logging Filter 적용
Logging Filter 클래스 생성
기존 작업한 Global Filter와 거의 동일하기 때문에 GlobalFilter.java 파일을 복사해서 작업한다.
OrderedGatewayFilter 를 구현한다.
import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.OrderedGatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.core.Ordered;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;
@Component
@Slf4j
public class LoggingFilter extends AbstractGatewayFilterFactory<LoggingFilter.Config> {
public LoggingFilter() {
super(Config.class);
}
// Ordered.HIGHEST_PRECEDENCE
// Ordered.LOWEST_PRECEDENCE
@Override
public GatewayFilter apply(Config config) {
GatewayFilter filter = new OrderedGatewayFilter((exchange, chain) -> {
ServerHttpRequest request = exchange.getRequest();
ServerHttpResponse response = exchange.getResponse();
log.info("Logging filter baseMessage : {}", config.getBaseMessage());
if(config.isPreLogger()){
log.info("Logging PRE filter : request id -> {}", request.getId());
}
// Custom Post Filter
return chain.filter(exchange).then(Mono.fromRunnable(() -> {
if(config.isPostLogger()){
log.info("Logging POST filter : response code -> {}", response.getStatusCode());
}
}));
}, Ordered.LOWEST_PRECEDENCE);
return filter;
}
@Data
public static class Config {
// Put the configuration properties
private String baseMessage;
private boolean preLogger;
private boolean postLogger;
}
}
application.yml 파일에 LoggingFilter 등록
second 서비스에만 Logging Filter 를 적용.
server:
port: 8000
eureka:
client:
register-with-eureka: false
fetch-registry: false
spring:
application:
name: apigateway-service
cloud:
gateway:
default-filters:
- name: GlobalFilter
args:
baseMessage: Spring Cloud Gateway Global Filter
PreLogger: true
PostLogger: true
routes:
- id: first-service
uri: http://localhost:8081
predicates:
- Path=/first-service/**
filters:
# - AddRequestHeader=first-request, first-request-header2
# - AddResponseHeader=first-response, first-response-header2
- CustomFilter
- id: second-service
uri: http://localhost:8082
predicates:
- Path=/second-service/**
filters:
- name: CustomFilter
- name: LoggingFilter
args:
baseMessage: Hi, there
PreLogger: true
PostLogger: true
Ordered.HIGHEST_PRECEDENCE 실행결과
OrderedGatewayFilter 생성시 우선순위 Ordered.HIGHEST_PRECEDENCE 로 설정
2022-02-06 14:11:02.101 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.LoggingFilter : Logging filter baseMessage : Hi, there
2022-02-06 14:11:02.101 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.LoggingFilter : Logging PRE filter : request id -> 37903ef2-3
2022-02-06 14:11:02.101 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.GlobalFilter : Global filter baseMessage : Spring Cloud Gateway Global Filter
2022-02-06 14:11:02.101 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.GlobalFilter : Global filter Start : request id -> 37903ef2-3
2022-02-06 14:11:02.101 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.CustomFilter : Custom PRE filter : request id -> 37903ef2-3
2022-02-06 14:11:02.115 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.CustomFilter : Custom POST filter : response code -> 200 OK
2022-02-06 14:11:02.115 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.GlobalFilter : Global filter End : response code -> 200 OK
2022-02-06 14:11:02.116 INFO 21280 --- [ctor-http-nio-2] c.s.a.filter.LoggingFilter : Logging POST filter : response code -> 200 OK
Ordered.LOWEST_PRECEDENCE 실행결과
OrderedGatewayFilter 생성시 우선순위 Ordered.LOWEST_PRECEDENCE 로 설정
2022-02-06 14:15:44.650 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.GlobalFilter : Global filter baseMessage : Spring Cloud Gateway Global Filter
2022-02-06 14:15:44.650 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.GlobalFilter : Global filter Start : request id -> 7abe4ddd-1
2022-02-06 14:15:44.651 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.CustomFilter : Custom PRE filter : request id -> 7abe4ddd-1
2022-02-06 14:15:46.625 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.LoggingFilter : Logging filter baseMessage : Hi, there
2022-02-06 14:15:46.626 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.LoggingFilter : Logging PRE filter : request id -> 7abe4ddd-1
2022-02-06 14:15:46.626 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.LoggingFilter : Logging POST filter : response code -> 200 OK
2022-02-06 14:15:46.626 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.CustomFilter : Custom POST filter : response code -> 200 OK
2022-02-06 14:15:46.626 INFO 18540 --- [ctor-http-nio-2] c.s.a.filter.GlobalFilter : Global filter End : response code -> 200 OK
Spring Cloud Gateway- Eureka 연동
apigateway-service, first-service, second-service pom.xml 확인
Eureka Client 라이브러리 확인
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
apigateway-service, first-service, second-service application.yml 확인
Eureka 서버에 등록을 하기 위한 Eureka Client 설정 확인
eureka:
client:
register-with-eureka: true
fetch-registry: true
service-url:
defaultZone: http://localhost:8761/eureka
apigateway-service application.yml spring.cloud.routes.uri 변경
ip:port로 작성된 uri를 lb://{서비스명}으로 변경한다.
spring:
application:
name: apigateway-service
cloud:
gateway:
default-filters:
- name: GlobalFilter
args:
baseMessage: Spring Cloud Gateway Global Filter
PreLogger: true
PostLogger: true
routes:
- id: first-service
uri: lb://MY-FIRST-SERVICE
predicates:
- Path=/first-service/**
filters:
# - AddRequestHeader=first-request, first-request-header2
# - AddResponseHeader=first-response, first-response-header2
- CustomFilter
- id: second-service
uri: lb://MY-SECOND-SERVICE
predicates:
- Path=/second-service/**
filters:
# - AddRequestHeader=second-request, second-request-header2
# - AddResponseHeader=second-response, second-response-header2
- name: CustomFilter
- name: LoggingFilter
args:
baseMessage: Hi, there
PreLogger: true
PostLogger: true
first-service application.yml 로드밸런싱을 위한 설정
server.port: 0으로 변경
eureka.instance.instance-id 추가
server:
port: 0
spring:
application:
name: my-first-service
eureka:
client:
register-with-eureka: true
fetch-registry: true
service-url:
defaultZone: http://localhost:8761/eureka
instance:
instance-id: ${spring.application.name}:${spring.application.instance_id:${random.value}}
Eureka Dashboard 화면
APIGATEWAY-SERVICE 1개, MY-FIRST-SERVICE 2개, MY-SECOND-SERVICE 2개가 등록된 것을 확인할 수 있다.
MY-FIRST-SERVICE는 두 개의 Random PORT 로 설정된 것을 확인 할 수 있다.
