스프링 게이트웨이 설정

package com.poscoict.onm.apigw.filter;

import com.poscoict.onm.apigw.model.dto.UserDto;
import io.micrometer.core.instrument.util.JsonUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.cloud.gateway.filter.factory.AbstractNameValueGatewayFilterFactory;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.ServerWebExchangeDecorator;
import org.springframework.web.server.WebSession;
import reactor.core.publisher.Mono;

import java.security.Principal;

@Component
public class MyAddRequestHeaderGatewayFilterFactory extends AbstractGatewayFilterFactory<MyAddRequestHeaderGatewayFilterFactory.Config> {

    public MyAddRequestHeaderGatewayFilterFactory() {
        super(MyAddRequestHeaderGatewayFilterFactory.Config.class);
    }

    @Override
    public GatewayFilter apply(Config config) {
//      1. 헤더에 정보를 세팅하는 경우 case1
//        return (exchange, chain) -> {
//            ServerHttpRequest request =
//                  exchange.getRequest().mutate()
//                    .header("authuser", "사용자이름")
//                    .build();
//            return chain.filter(exchange.mutate().request(request).build());
//        };

//      2. 헤더에 사용자 정보만 넘기는 경우 case2
        return (exchange, chain) -> exchange.getPrincipal()
                .map(Principal::getName)
                .defaultIfEmpty("unauthorized")
                .map(userName -> {
                    //adds header to proxied request
                    exchange
                            .getRequest()
                            .mutate()
                            .header("authuser", userName)
                            .build();
                    return exchange;
                })
                .flatMap(chain::filter);
    }

    public static class Config {
        //Put the configuration properties for your filter here
    }
}

spring:
  profiles: local
  cloud:
    gateway:
      routes:
        - id: dummy_a
          uri: http://localhost:8881
          predicates:
            - Path=/a/**
          filters:
            - MyAddRequestHeader
            - PreserveHostHeader
            - SaveSession
            - RewritePath=/a(?<segment>/?.*), /${segment}
        - id: dummy_b
          uri: http://localhost:8882
          predicates:
            - Path=/b/**
          filters:
            - MyAddRequestHeader
            - PreserveHostHeader
            - SaveSession
            - RewritePath=/b(?<segment>/?.*), /${segment}