Spring Cloud Gateway - Custom Filter

1. lombok에서 제공하는 로그 사용 @Slf4j 을 위한 lombok dependency 등록

<dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
  <optional>true</optional>
</dependency>

2. CustomFilter.java 생성

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 lombok.extern.slf4j.Slf4j;
import reactor.core.publisher.Mono;

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

    public static class Config {
        //Put the configuration properties
    }

    @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());
            }));
        };
    }
}

3. 설정파일 변경 - CustomFilter 추가

spring:
    application:
        name: apigateway-service
    cloud:
        gateway:
            routes:
                -   id: tax-invoice
                    uri: http://tax.blueport.co.kr:8443/
                    predicates:
                        - Path=/v1/**
                    filters:
                        # - AddRequestHeader=headerName, headerValue
                        # - AddResponseHeader=headerName2, headerValue2
                        - CustomFilter