공식문서 : link
getting started : link
1. 개요
Spring Cloud Gateway는 API Gateway 기능을 구현할 수 있는 라이브러리로 대표적인 기능으로는 routing, filtering 있다.
@SpringBootApplication
public class DemogatewayApplication {
@Bean
public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
return builder.routes()
.route("path_route", r -> r.path("/get")
.uri("http://httpbin.org"))
.route("host_route", r -> r.host("*.myhost.org")
.uri("http://httpbin.org"))
.route("rewrite_route", r -> r.host("*.rewrite.org")
.filters(f -> f.rewritePath("/foo/(?<segment>.*)", "/${segment}"))
.uri("http://httpbin.org"))
.route("hystrix_route", r -> r.host("*.hystrix.org")
.filters(f -> f.hystrix(c -> c.setName("slowcmd")))
.uri("http://httpbin.org"))
.route("hystrix_fallback_route", r -> r.host("*.hystrixfallback.org")
.filters(f -> f.hystrix(c -> c.setName("slowcmd").setFallbackUri("forward:/hystrixfallback")))
.uri("http://httpbin.org"))
.route("limit_route", r -> r
.host("*.limited.org").and().path("/anything/**")
.filters(f -> f.requestRateLimiter(c -> c.setRateLimiter(redisRateLimiter())))
.uri("http://httpbin.org"))
.build();
}
}
2. 설정 클래스
- org.springframework.cloud.gateway.route.RouteDefinition : 라우터 IO
- org.springframework.cloud.gateway.route.Route : RouteDefinitionRouteLocator에서 RouteDefinition을 Route로 변경
- org.springframework.cloud.gateway.route.Route.AsyncBuilder : Route Builder
- org.springframework.cloud.gateway.route.Route.Builder : Route Builder
3. 중요 클래스
org.springframework.cloud.gateway.route.CachingRouteLocator
- Route를 캐싱하는 클래스
- RefreshRoutesEvent 이벤트를 받아 RouteLocator에서 라우터를 다시 읽어 캐시 갱신
- 요청이 들어올 경우 RoutePredicateHandlerMapping.lookupRoute에서 CachingRouteLocator.getRoutes를 호출하여 캐싱된 Route 리스트 Get
org.springframework.cloud.gateway.handler.RoutePredicateHandlerMapping
- 클라이언트 요청에 대해 알맞은 라우팅을 lookup하는 클래스
org.springframework.cloud.gateway.handler.FilteringWebHandler
- 글로벌 필터와 라우터에 등록되어 있는 필터를 합쳐 필터를 수행한다.
org.springframework.cloud.gateway.filter.NettyRoutingFilter
- 실제 라우팅 URI에 요청하는 필터
org.springframework.cloud.gateway.actuate.AbstractGatewayControllerEndpoint, GatewayControllerEndpoint
- 실제 actuate 요청을 받는 컨트롤러
- 5. actuator 설정 참조
4. 요청 흐름도
0. Client Request
1. reactor.netty.http.server.HttpServer.HttpServerHandle.onStateChange
2. org.springframework.http.server.reactive.ReactorHttpHandlerAdapter.apply
3. org.springframework.web.server.adapter.HttpWebHandlerAdapter.handle
4. org.springframework.web.reactive.DispatcherHandler.handle
5. org.springframework.cloud.gateway.handler.RoutePredicateHandlerMapping.getHandlerInternal
6. org.springframework.cloud.gateway.handler.FilteringWebHandler.handle
7. org.springframework.cloud.gateway.handler.FilteringWebHandler.DefaultGatewayFilterChain.filter
5. actuator 설정
- pom.xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
- application.yml
management:
endpoints:
web:
exposure:
include:
- gateway
endpoint:
gateway:
enabled: true
- endpoints
- GET /actuator/gateway/globalfilters: Displays the list of global filters applied to the routes.
- GET /actuator/gateway/routefilters: Displays the list of GatewayFilter factories applied to a particular route.
- POST /actuator/gateway/refresh: Clears the routes cache.
- GET /actuator/gateway/routes: Displays the list of routes defined in the gateway.GET /actuator/gateway/routes/{id}: 특정 route 설정 정보
- GET /actuator/gateway/routes/{id} : Displays information about a particular route.
- POST /actuator/gateway/routes/{id}: Add a new route to the gateway.
- DELETE /actuator/gateway/routes/{id}: Remove an existing route from the gateway.
참고
https://blog.jungbin.kim/spring/2021/02/27/spring-cloud-gateway-route-locator.html
https://dlsrb6342.github.io/2019/05/14/spring-cloud-gateway-%EA%B5%AC%EC%A1%B0/
DB를 이용한 동적반영
https://medium.com/bliblidotcom-techblog/spring-cloud-gateway-dynamic-routes-from-database-dc938c6665de
