spring-cloud-starter-gateway
#
Dependency #
- spring-cloud-starter
- spring-boot-starter-webflux
- netty
- …
- spring-cloud-starter-loadbalancer
- (optional)
- spring-cloud-gateway-server
- 실질적으로 이 모듈에 Gateway와 관련된 클래스(코드)가 있다고 보면 될 것 같다.
spring-cloud-gateway-server
#
Dependency #
기본적인 Dependency 가 모두 들어있다. (다만, optional 활성 여부를 꼭 확인할 것)
- spring-boot-starter
- spring-boot-starter-validation
- io.projectreactor.addons:reactor-extra
- spring-boot-starter-oauth2-client (optional)
- spring-boot-starter-actuator (optional)
- …
Flow #
https://dlsrb6342.github.io/2019/05/14/spring-cloud-gateway-%EA%B5%AC%EC%A1%B0/ 여기의 글도 보기 좋다.
HttpServerOperations (reactor-netty-http)
--->
HttpWebHandlerAdapter(spring-web)
---> (WebHandler.handle(), DispatcherHandler.handle())
RoutePredicateHandlerMapping(spring-cloud-gateway-server)
--->
FilteringWebHandler.handle()
DispatcherHandler #
public class DispatcherHandler implements WebHandler, PreFlightRequestHandler, ApplicationContextAware {
@Nullable
private List<HandlerMapping> handlerMappings;
@Nullable
private List<HandlerAdapter> handlerAdapters;
@Nullable
private List<HandlerResultHandler> resultHandlers;
...
HandlerMapping 은 기본적으로 아래 7가지를 가지고 있다.
이것들은 순서(Order)를 갖고 있다. 낮은 값(INT) 앞에 배치하고, 높은 값일수록 뒤에 배치한다.
- AdditionalHealthEndpointPathsWebFluxHandlerMapping
- WebFluxEndpointHandlerMapping
- ControllerEndpointHandlerMapping
- RouterFunctionMapping
- RequestMappingHandlerMapping
- RoutePredicateHandlerMapping
- SimpleUrlHandlerMapping
HandlerAdapter 는 기본적으로 아래 4가지를 가지고 있다.
- WebSocketHandlerAdapter
- RequestMappingHandlerAdapter
- HandlerFunctionAdapter
- SimpleHandlerAdapter
HandlerResultHandler 는 기본적으로 아래 4가지를 가지고 있다.
- ResponseEntityResultHandler
- ServerResponseResultHandler
- ResponseBodyResultHandler
- ViewResolutionResultHandler
RoutePredicateHandlerMapping (AbstractHandlerMapping, HandlerMapping) #
DispatcherHandler (WebHandler)
public class DispatcherHandler implements WebHandler, PreFlightRequestHandler, ApplicationContextAware {
...
@Override
public Mono<Void> handle(ServerWebExchange exchange) {
if (this.handlerMappings == null) {
return createNotFoundError();
}
if (CorsUtils.isPreFlightRequest(exchange.getRequest())) {
return handlePreFlight(exchange);
}
return Flux.fromIterable(this.handlerMappings)
.concatMap(mapping -> mapping.getHandler(exchange)) // 여기 : AbstractHandlerMapping.getHandler() 로 이어진다.
.next()
.switchIfEmpty(createNotFoundError())
.flatMap(handler -> invokeHandler(exchange, handler))
.flatMap(result -> handleResult(exchange, result));
}
...
}
AbstractHandlerMapping
public abstract class AbstractHandlerMapping extends ApplicationObjectSupport implements HandlerMapping, Ordered, BeanNameAware {
@Override
public Mono<Object> getHandler(ServerWebExchange exchange) {
return getHandlerInternal(exchange).map(handler -> { // 여기 : RoutePredicateHandlerMapping.getHandlerInternal() 로 이어진다.
if (logger.isDebugEnabled()) {
logger.debug(exchange.getLogPrefix() + "Mapped to " + handler);
}
ServerHttpRequest request = exchange.getRequest();
if (hasCorsConfigurationSource(handler) || CorsUtils.isPreFlightRequest(request)) {
CorsConfiguration config = (this.corsConfigurationSource != null ?
this.corsConfigurationSource.getCorsConfiguration(exchange) : null);
CorsConfiguration handlerConfig = getCorsConfiguration(handler, exchange);
config = (config != null ? config.combine(handlerConfig) : handlerConfig);
if (config != null) {
config.validateAllowCredentials();
}
if (!this.corsProcessor.process(config, exchange) || CorsUtils.isPreFlightRequest(request)) {
return NO_OP_HANDLER;
}
}
return handler;
});
}
}
RoutePredicateHandlerMapping #
public class RoutePredicateHandlerMapping extends AbstractHandlerMapping {
private final FilteringWebHandler webHandler;
private final RouteLocator routeLocator;
...
@Override
protected Mono<?> getHandlerInternal(ServerWebExchange exchange) {
// don't handle requests on management port if set and different than server port
if (this.managementPortType == DIFFERENT && this.managementPort != null
&& exchange.getRequest().getURI().getPort() == this.managementPort) {
return Mono.empty();
}
exchange.getAttributes().put(GATEWAY_HANDLER_MAPPER_ATTR, getSimpleName());
return lookupRoute(exchange)
// .log("route-predicate-handler-mapping", Level.FINER) //name this
.flatMap((Function<Route, Mono<?>>) r -> {
exchange.getAttributes().remove(GATEWAY_PREDICATE_ROUTE_ATTR);
if (logger.isDebugEnabled()) {
logger.debug("Mapping [" + getExchangeDesc(exchange) + "] to " + r);
}
exchange.getAttributes().put(GATEWAY_ROUTE_ATTR, r);
return Mono.just(webHandler); // ← 여기 : FilteringWebHandler 를 반환한다.
}).switchIfEmpty(Mono.empty().then(Mono.fromRunnable(() -> {
exchange.getAttributes().remove(GATEWAY_PREDICATE_ROUTE_ATTR);
if (logger.isTraceEnabled()) {
logger.trace("No RouteDefinition found for [" + getExchangeDesc(exchange) + "]");
}
})));
}
...
protected Mono<Route> lookupRoute(ServerWebExchange exchange) {
return this.routeLocator.getRoutes()
// individually filter routes so that filterWhen error delaying is not a
// problem
.concatMap(route -> Mono.just(route).filterWhen(r -> {
// add the current route we are testing
exchange.getAttributes().put(GATEWAY_PREDICATE_ROUTE_ATTR, r.getId());
return r.getPredicate().apply(exchange);
})
// instead of immediately stopping main flux due to error, log and
// swallow it
.doOnError(e -> logger.error("Error applying predicate for route: " + route.getId(), e))
.onErrorResume(e -> Mono.empty()))
// .defaultIfEmpty() put a static Route not found
// or .switchIfEmpty()
// .switchIfEmpty(Mono.<Route>empty().log("noroute"))
.next()
// TODO: error handling
.map(route -> {
if (logger.isDebugEnabled()) {
logger.debug("Route matched: " + route.getId());
}
validateRoute(route, exchange);
return route;
});
/*
* TODO: trace logging if (logger.isTraceEnabled()) {
* logger.trace("RouteDefinition did not match: " + routeDefinition.getId()); }
*/
}
2022-07-17 20:01:37.968 DEBUG 91322 --- [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : Route matched: 4162e05b-be86-4b3b-a2c7-bfcc4d2c89b4
2022-07-17 20:01:37.968 DEBUG 91322 --- [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : Mapping [Exchange: GET http://localhost:8080/api/samples] to Route{id='4162e05b-be86-4b3b-a2c7-bfcc4d2c89b4', uri=http://localhost:8081, order=0, predicate=PredicateSpec$$Lambda$529/0x0000000800510c40, gatewayFilters=[[ModifyResponseBody New content type = [null], In class = Object, Out class = ResponseFormatFilter.Response]], metadata={}}
2022-07-17 20:01:37.968 DEBUG 91322 --- [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : [d9c36f28-2] Mapped to org.springframework.cloud.gateway.handler.FilteringWebHandler@2937f9e0
FilteringWebHandler #
public class FilteringWebHandler implements WebHandler {
protected static final Log logger = LogFactory.getLog(FilteringWebHandler.class);
private final List<GatewayFilter> globalFilters;
...
@Override
public Mono<Void> handle(ServerWebExchange exchange) {
Route route = exchange.getRequiredAttribute(GATEWAY_ROUTE_ATTR);
List<GatewayFilter> gatewayFilters = route.getFilters();
List<GatewayFilter> combined = new ArrayList<>(this.globalFilters);
combined.addAll(gatewayFilters);
// TODO: needed or cached?
AnnotationAwareOrderComparator.sort(combined);
if (logger.isDebugEnabled()) {
logger.debug("Sorted gatewayFilterFactories: " + combined);
}
return new DefaultGatewayFilterChain(combined).filter(exchange); // 여기 : Filter Chain 에 넘긴다.
}
...
}
DefaultGatewayFilterChain
public class FilteringWebHandler implements WebHandler {
...
private static class DefaultGatewayFilterChain implements GatewayFilterChain {
private final int index;
private final List<GatewayFilter> filters;
...
@Override
public Mono<Void> filter(ServerWebExchange exchange) {
return Mono.defer(() -> {
if (this.index < filters.size()) {
GatewayFilter filter = filters.get(this.index);
DefaultGatewayFilterChain chain = new DefaultGatewayFilterChain(this, this.index + 1);
return filter.filter(exchange, chain); // 여기 : 우리가 등록한 filter(혹은 기본적으로 등록된 filter) 들이 동작한다.
}
else {
return Mono.empty(); // complete
}
});
}
}
아래 로그는 FilteringWebHandler 로그이다.
등록된 Filter 들을 확인할 수 있다.
2022-07-17 20:01:37.968 DEBUG 91322 --- [ctor-http-nio-2] o.s.c.g.handler.FilteringWebHandler : Sorted gatewayFilterFactories: [[GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.RemoveCachedBodyFilter@5707f613}, order = -2147483648], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.AdaptCachedBodyGlobalFilter@526e8108}, order = -2147482648], [ModifyResponseBody New content type = [null], In class = Object, Out class = ResponseFormatFilter.Response], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyWriteResponseFilter@11787b64}, order = -1], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.ForwardPathFilter@319642db}, order = 0], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.GatewayMetricsFilter@35bfa1bb}, order = 0], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.RouteToRequestUrlFilter@77b3752b}, order = 10000], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.config.GatewayNoLoadBalancerClientAutoConfiguration$NoLoadBalancerClientFilter@6b321262}, order = 10150], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.WebsocketRoutingFilter@59498d94}, order = 2147483646], GatewayFilterAdapter{delegate=com.baemin.openapi.filter.global.SampleCustomGlobalGatewayFilter@713a35c5}, [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyRoutingFilter@62aeddc8}, order = 2147483647], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.ForwardRoutingFilter@6367a688}, order = 2147483647]]
아래는 하나의 Request에 대한 전체 로그이다.
... [ctor-http-nio-2] reactor.netty.http.server.HttpServer : [d9c36f28-2, L:/0:0:0:0:0:0:0:1:8080 - R:/0:0:0:0:0:0:0:1:53838] Handler is being applied: org.springframework.http.server.reactive.ReactorHttpHandlerAdapter@687105a6
... [ctor-http-nio-2] o.s.w.s.adapter.HttpWebHandlerAdapter : [d9c36f28-2] HTTP GET "/api/samples"
... [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : Route matched: 4162e05b-be86-4b3b-a2c7-bfcc4d2c89b4
... [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : Mapping [Exchange: GET http://localhost:8080/api/samples] to Route{id='4162e05b-be86-4b3b-a2c7-bfcc4d2c89b4', uri=http://localhost:8081, order=0, predicate=PredicateSpec$$Lambda$529/0x0000000800510c40, gatewayFilters=[[ModifyResponseBody New content type = [null], In class = Object, Out class = ResponseFormatFilter.Response]], metadata={}}
... [ctor-http-nio-2] o.s.c.g.h.RoutePredicateHandlerMapping : [d9c36f28-2] Mapped to org.springframework.cloud.gateway.handler.FilteringWebHandler@2937f9e0
... [ctor-http-nio-2] o.s.c.g.handler.FilteringWebHandler : Sorted gatewayFilterFactories: [[GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.RemoveCachedBodyFilter@5707f613}, order = -2147483648], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.AdaptCachedBodyGlobalFilter@526e8108}, order = -2147482648], [ModifyResponseBody New content type = [null], In class = Object, Out class = ResponseFormatFilter.Response], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyWriteResponseFilter@11787b64}, order = -1], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.ForwardPathFilter@319642db}, order = 0], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.GatewayMetricsFilter@35bfa1bb}, order = 0], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.RouteToRequestUrlFilter@77b3752b}, order = 10000], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.config.GatewayNoLoadBalancerClientAutoConfiguration$NoLoadBalancerClientFilter@6b321262}, order = 10150], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.WebsocketRoutingFilter@59498d94}, order = 2147483646], GatewayFilterAdapter{delegate=com.baemin.openapi.filter.global.SampleCustomGlobalGatewayFilter@713a35c5}, [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.NettyRoutingFilter@62aeddc8}, order = 2147483647], [GatewayFilterAdapter{delegate=org.springframework.cloud.gateway.filter.ForwardRoutingFilter@6367a688}, order = 2147483647]]
... [ctor-http-nio-2] r.n.resources.PooledConnectionProvider : [d27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] Channel acquired, now: 1 active connections, 0 inactive connections and 0 pending acquire requests.
... [ctor-http-nio-2] r.netty.http.client.HttpClientConnect : [d27fde7a-2, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] Handler is being applied: {uri=http://localhost:8081/api/samples, method=GET}
... [ctor-http-nio-2] r.n.r.DefaultPooledConnectionProvider : [d27fde7a-2, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] onStateChange(GET{uri=/api/samples, connection=PooledConnection{channel=[id: 0xd27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081]}}, [request_prepared])
... [ctor-http-nio-2] reactor.netty.channel.FluxReceive : [d9c36f28-2, L:/0:0:0:0:0:0:0:1:8080 - R:/0:0:0:0:0:0:0:1:53838] FluxReceive{pending=0, cancelled=false, inboundDone=false, inboundError=null}: subscribing inbound receiver
... [ctor-http-nio-2] r.n.r.DefaultPooledConnectionProvider : [d27fde7a-2, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] onStateChange(GET{uri=/api/samples, connection=PooledConnection{channel=[id: 0xd27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081]}}, [request_sent])
... [ctor-http-nio-2] r.n.http.client.HttpClientOperations : [d27fde7a-2, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] Received response (auto-read:false) : [Content-Type=application/json, Transfer-Encoding=chunked, Date=Sun, 17 Jul 2022 11:01:37 GMT]
... [ctor-http-nio-2] r.n.r.DefaultPooledConnectionProvider : [d27fde7a-2, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] onStateChange(GET{uri=/api/samples, connection=PooledConnection{channel=[id: 0xd27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081]}}, [response_received])
... [ctor-http-nio-2] reactor.netty.channel.FluxReceive : [d27fde7a-2, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] FluxReceive{pending=0, cancelled=false, inboundDone=false, inboundError=null}: subscribing inbound receiver
... [ctor-http-nio-2] r.n.http.client.HttpClientOperations : [d27fde7a-2, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] Received last HTTP packet
... [ctor-http-nio-2] o.s.http.codec.json.Jackson2JsonDecoder : Decoded [{timestamp=0, errorCode=, statusCode=200, statusMessage=OK, data=[{name=, age=12}, {name=길동 (truncated)...]
... [ctor-http-nio-2] o.s.http.codec.json.Jackson2JsonEncoder : Encoding [Response(data={timestamp=0, errorCode=, statusCode=200, statusMessage=OK, data=[{name=현재, age= (truncated)...]
... [ctor-http-nio-2] r.n.http.server.HttpServerOperations : [d9c36f28-2, L:/0:0:0:0:0:0:0:1:8080 - R:/0:0:0:0:0:0:0:1:53838] Decreasing pending responses, now 0
... [ctor-http-nio-2] r.n.http.server.HttpServerOperations : [d9c36f28-2, L:/0:0:0:0:0:0:0:1:8080 - R:/0:0:0:0:0:0:0:1:53838] Last HTTP packet was sent, terminating the channel
... [ctor-http-nio-2] o.s.w.s.adapter.HttpWebHandlerAdapter : [d9c36f28-2] Completed 200 OK
... [ctor-http-nio-2] r.n.http.server.HttpServerOperations : [d9c36f28-2, L:/0:0:0:0:0:0:0:1:8080 - R:/0:0:0:0:0:0:0:1:53838] Last HTTP response frame
... [ctor-http-nio-2] r.n.r.DefaultPooledConnectionProvider : [d27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] onStateChange(GET{uri=/api/samples, connection=PooledConnection{channel=[id: 0xd27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081]}}, [response_completed])
... [ctor-http-nio-2] r.n.r.DefaultPooledConnectionProvider : [d27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] onStateChange(GET{uri=/api/samples, connection=PooledConnection{channel=[id: 0xd27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081]}}, [disconnecting])
... [ctor-http-nio-2] r.n.r.DefaultPooledConnectionProvider : [d27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] Releasing channel
... [ctor-http-nio-2] r.n.resources.PooledConnectionProvider : [d27fde7a, L:/127.0.0.1:53841 - R:localhost/127.0.0.1:8081] Channel cleaned, now: 0 active connections, 1 inactive connections and 0 pending acquire requests.
... [ctor-http-nio-2] r.n.r.DefaultPooledConnectionProvider : [d27fde7a, L:/127.0.0.1:53841 ! R:localhost/127.0.0.1:8081] onStateChange(PooledConnection{channel=[id: 0xd27fde7a, L:/127.0.0.1:53841 ! R:localhost/127.0.0.1:8081]}, [disconnecting])
참고 (L, R, -, !) #
L : Local Address
R : Remote Address
- : active (active and so connected)
! : not active
AbstractChannel 에서 확인할 수 있다.
public abstract class AbstractChannel extends DefaultAttributeMap implements Channel {
...
@Override
public String toString() {
boolean active = isActive();
if (strValActive == active && strVal != null) {
return strVal;
}
SocketAddress remoteAddr = remoteAddress();
SocketAddress localAddr = localAddress();
if (remoteAddr != null) {
StringBuilder buf = new StringBuilder(96)
.append("[id: 0x")
.append(id.asShortText())
.append(", L:")
.append(localAddr)
.append(active? " - " : " ! ")
.append("R:")
.append(remoteAddr)
.append(']');
strVal = buf.toString();
} else if (localAddr != null) {
StringBuilder buf = new StringBuilder(64)
.append("[id: 0x")
.append(id.asShortText())
.append(", L:")
.append(localAddr)
.append(']');
strVal = buf.toString();
} else {
StringBuilder buf = new StringBuilder(16)
.append("[id: 0x")
.append(id.asShortText())
.append(']');
strVal = buf.toString();
}
strValActive = active;
return strVal;
}
...
}