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SpringBoot MSA (7) - API Gateway Service Filter (2)

Spring/SpringBoot-MSA

by ChrisMare 2023. 10. 10. 00:29

본문

앞의 기본적으로 라우팅과 필터를 간단하게 등록하여 사용해보았는데

 

이제는 Custom Filter를 등록해보자

 

Spring Cloud - Custom Filter를 사용한다면 요청이 들어오기 전에 작업할 것과 요청 후에 작업할 내용을 설정할 수 있다. 대표적으로는  로그인 인증, 로깅 등의 작업들을 처리할 수 있다.

 

filter 패키지 생성 후 CustomFilter.java 클래스를 만들어서 테스트 해보겠습니다.

CustomFilter.java

package com.example.apigatewayservice.filter;

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
    }

}

first-service, second-service의 프로젝트에 방금 추가한 filter 테스트용의 api 추가

FirstServiceController.java

package com.example.firstservice;

import lombok.extern.log4j.Log4j;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

// http://localhost:8081/welcome
// http://localhost:8081/first-service/welcome
@RestController
@RequestMapping("/first-service")
@Slf4j
public class FirstServiceController {

    @GetMapping("/welcome")
    public String welcome() {
        return "Welcome to the First Service";
    }

    @GetMapping("/message")
    public String message(@RequestHeader("first-request") String header) {
        log.info(header);
        return "Hello World in First Service.";
    }

    @GetMapping("/check")
    public String check() {
        return "Hi, there, This is a message from First Service.";
    }
}

 

SecondServiceController.java

package com.example.secondservice;

import lombok.extern.log4j.Log4j;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

// http://localhost:8082/welcome
// http://localhost:8082/second-service/welcome
@RestController
@RequestMapping("/second-service")
@Slf4j
public class SecondServiceController {

    @GetMapping("/welcome")
    public String welcome() {
        return "Welcome to the Second Service";
    }

    @GetMapping("/message")
    public String message(@RequestHeader("second-request") String header) {
        log.info(header);
        return "Hello World in Second Service.";
    }

    @GetMapping("/check")
    public String check() {
        return "Hi, there, This is a message from Second Service.";
    }

}

 

check API 테스트!

http://localhost:8000/first-service/check

 

로그 맨 아래 부분에 Custom PRE FIlter, Custom POST filter가 출력된 것을 확인할 수 있습니다.

 

 

Spring Cloud - Global Filter 설정

 

Global Filter는 이전 Custom Filter와 다르게 yml 파일에 각 서비스별로 추가 설정하는 것이아니라

공통적으로 처리하는 부분이기 때문에 한번에 설정한다.

 

filter 패키지에 GlobalFilter.java 를 생성하자

package com.example.apigatewayservice.filter;

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) {
        // Custom Pre Filter
        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;
    }

}

 

위의 Config에 들어올 baseMessage, preLogger, postLogger등을 전달할 매개변수를 application.yml에 전달하고 설정해보자

application.yml

spring.cloud.gateway.default-filters를 설정하면된다.

server:
  port: 8000

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

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

check API 테스트!

http://localhost:8000/first-service/check

이전과 달리 Custom Filter 전과 후에 Global Filter가 실행된 것을 확인 할 수 있다.

 

이제 Global Filter 처럼 Custom Filter에 매개변수를 사용하여 LoggingFilter를 생성해보자

LoggingFilter.java

package com.example.apigatewayservice.filter;

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);
    }

    @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());
//                }
//            }));
//        };
        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 End: response code -> {}", response.getStatusCode());
                }
            }));
        }, Ordered.HIGHEST_PRECEDENCE);



        return filter;
    }

    @Data
    public static class Config {
        // Put the configuration properties
        private String baseMessage;
        private boolean preLogger;
        private boolean postLogger;
    }

}

 

application.yml > custom으로 등록

필터를 여러개 등록 시 name을 부여해야된다.

server:
  port: 8000

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

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
            - name: CustomFilter
            - name: LoggingFilter
              args:  
                baseMessage: Hi, there
                preLogger: true
                postLogger: true

 

서버 재실행 및 테스트!

second-service에만 등록했기때문에 second check api로 테스트

http://localhost:8000/second-service/check

이전과 달리 GlobalFilter -> Custom Filter -> Logging Filter -> CustomFilter -> GlobalFilter 가 아니라

LoggingFilter -> GlobalFilter -> CustomFilter -> GlobalFilter -> LoggingFilter 인것을 알 수 있습니다.

이 순서는 Filter에서 설정할 때 우선순위를 아래설정값 처럼 변경하여 사용할 수 있습니다.

Ordered.LOWEST_PRECEDENCE

로 설정한다면

GlobalFilter -> Custom Filter -> Logging Filter -> CustomFilter -> GlobalFilter

이전 처럼 진행될 수 있습니다.

저작자표시 비영리

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