[Spring Cloud] LoadBancer-02

API Gateway 생성

• 3개 dependencies 추가해서 생선한다
  

| application.yml

server:
  port: 8000

eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://localhost:8761/eureka

spring:
  application:
    name: apigateway-service
  cloud:
    gateway:eureka:
  client:
    fetch-registry: true
    register-with-eureka: true
    service-url:
      defaultZone: http://localhost:8761/eureka
      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:
            - CustomFilter
        - id: second-service
          uri: lb://MY-SECOND-SERVICE
          predicates:
            - Path=/second-service/**
          filters:
            - name: CustomFilter
            - name: LoggingFilter
              args:
                baseMessage: Hi, there.
                preLogger: true
                postLogger: true

| CustomFilter.java

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 resposne = exchange.getResponse();

            log.info("Custom PRE fiter: request id -> {}", request.getId());

            //Custom Post Filter
            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
                log.info("Custom POST filter: response  code -> {}", resposne.getStatusCode());
            }));
        });

    }

    public static class Config {
        // Put the configuration properties

    }
}

| GlobalFilter.java

@Slf4j
@Component
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 resposne = exchange.getResponse();

            log.info("Global PRE fiter: request id -> {}", request.getId());

            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 -> {}", resposne.getStatusCode());
                }

            }));
        });
    }

    @Data
    public static class Config {
        private String baseMessage;
        private boolean preLogger;
        private boolean postLogger;
    }
}

| LoggingFilter.java

@Slf4j
@Component
public class LoggingFilter extends AbstractGatewayFilterFactory<LoggingFilter.Config> {
    public LoggingFilter() { super(Config.class); }

    @Override
    public GatewayFilter apply(Config config) {

        GatewayFilter filter = new OrderedGatewayFilter( (exchange, chain) -> {
            ServerHttpRequest request = exchange.getRequest();
            ServerHttpResponse resposne = exchange.getResponse();

            log.info("Logging Filter baseMessage : request id -> {}", config.getBaseMessage());

            if (config.isPreLogger()) {
                log.info("Logging PRE Filter : request id -> {}", request.getId());
            }

            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
                if (config.isPostLogger()) {
                    log.info("Logging POST Filter: response code -> {}", resposne.getStatusCode());
                }
            }));

        }, Ordered.LOWEST_PRECEDENCE); // 우선순위 조절가능 HIGHEST_PRECEDENCE

        return filter;
    }


    @Data
    public static class Config {
        private String baseMessage;
        private boolean preLogger;
        private boolean postLogger;
    }
}