Adds support for netty wiretap on server and client.

fixes gh-1194

docs/src/main/asciidoc/spring-cloud-gateway.adoc

@@ -21,7 +21,7 @@ for details on setting up your build system with the current Spring Cloud Releas
 
 If you include the starter, but, for some reason, you do not want the gateway to be enabled, set `spring.cloud.gateway.enabled=false`.
 
-IMPORTANT: Spring Cloud Gateway is built upon https://spring.io/projects/spring-boot#learn[Spring Boot 2.0],
+IMPORTANT: Spring Cloud Gateway is built upon https://spring.io/projects/spring-boot#learn[Spring Boot 2.x],
 https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html[Spring WebFlux],
 and https://projectreactor.io/docs[Project Reactor].  As a consequence
 many of the familiar synchronous libraries (Spring Data and Spring Security, for example) and patterns you may
@@ -1704,6 +1704,29 @@ The table below summarises the Spring Cloud Gateway actuator endpoints. Note tha
 
 |===
 
+[[troubleshooting]]
+== Troubleshooting
+
+=== Log Levels
+
+Below are some useful loggers that contain valuable trouble shooting infomration at the `DEBUG` and `TRACE` levels.
+
+- `org.springframework.cloud.gateway`
+- `org.springframework.http.server.reactive`
+- `org.springframework.web.reactive`
+- `org.springframework.boot.autoconfigure.web`
+- `reactor.netty`
+- `redisratelimiter`
+
+=== Wiretap
+
+The Reactor Netty `HttpClient` and `HttpServer` can have wiretap enabled. When combined
+with setting the `reactor.netty` log level to `DEBUG` or `TRACE` will enable logging of
+information such as headers and bodies sent and received across the wire. To enable this,
+set `spring.cloud.gateway.httpserver.wiretap=true` and/or
+`spring.cloud.gateway.httpclient.wiretap=true` for the `HttpServer` and `HttpClient`
+respectively.
+
 == Developer Guide
 
 TODO: overview of writing custom integrations

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/config/GatewayAutoConfiguration.java

@@ -40,10 +40,13 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.autoconfigure.condition.NoneNestedConditions;
+import org.springframework.boot.autoconfigure.web.ServerProperties;
+import org.springframework.boot.autoconfigure.web.embedded.NettyWebServerFactoryCustomizer;
 import org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration;
 import org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.context.properties.PropertyMapper;
+import org.springframework.boot.web.embedded.netty.NettyReactiveWebServerFactory;
 import org.springframework.cloud.gateway.actuate.GatewayControllerEndpoint;
 import org.springframework.cloud.gateway.actuate.GatewayLegacyControllerEndpoint;
 import org.springframework.cloud.gateway.filter.AdaptCachedBodyGlobalFilter;
@@ -517,6 +520,19 @@ public class GatewayAutoConfiguration {
 	@ConditionalOnClass(HttpClient.class)
 	protected static class NettyConfiguration {
 
+		@Bean
+		@ConditionalOnProperty(name = "spring.cloud.gateway.httpserver.wiretap")
+		public NettyWebServerFactoryCustomizer nettyServerWiretapCustomizer(
+				Environment environment, ServerProperties serverProperties) {
+			return new NettyWebServerFactoryCustomizer(environment, serverProperties) {
+				@Override
+				public void customize(NettyReactiveWebServerFactory factory) {
+					factory.addServerCustomizers(httpServer -> httpServer.wiretap(true));
+					super.customize(factory);
+				}
+			};
+		}
+
 		@Bean
 		@ConditionalOnMissingBean
 		public HttpClient gatewayHttpClient(HttpClientProperties properties) {
@@ -594,8 +610,9 @@ public class GatewayAutoConfiguration {
 				});
 			}
 
-			// TODO: add configuration to turn on wiretap
-			// httpClient = httpClient.wiretap(true);
+			if (properties.isWiretap()) {
+				httpClient = httpClient.wiretap(true);
+			}
 
 			return httpClient;
 		}

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/config/HttpClientProperties.java

@@ -57,6 +57,9 @@ public class HttpClientProperties {
 	/** SSL configuration for Netty HttpClient. */
 	private Ssl ssl = new Ssl();
 
+	/** Enables wiretap debugging for Netty HttpClient. */
+	private boolean wiretap;
+
 	public Integer getConnectTimeout() {
 		return connectTimeout;
 	}
@@ -97,11 +100,26 @@ public class HttpClientProperties {
 		this.ssl = ssl;
 	}
 
+	public boolean isWiretap() {
+		return this.wiretap;
+	}
+
+	public void setWiretap(boolean wiretap) {
+		this.wiretap = wiretap;
+	}
+
 	@Override
 	public String toString() {
-		return new ToStringCreator(this).append("connectTimeout", connectTimeout)
-				.append("responseTimeout", responseTimeout).append("pool", pool)
-				.append("proxy", proxy).append("ssl", ssl).toString();
+		// @formatter:off
+		return new ToStringCreator(this)
+				.append("connectTimeout", connectTimeout)
+				.append("responseTimeout", responseTimeout)
+				.append("pool", pool)
+				.append("proxy", proxy)
+				.append("ssl", ssl)
+				.append("wiretap", wiretap)
+				.toString();
+		// @formatter:on
 	}
 
 	public static class Pool {

spring-cloud-gateway-core/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -17,6 +17,12 @@
       "type": "java.lang.Boolean",
       "description": "Enables the collection of metrics data.",
       "defaultValue": "true"
+    },
+    {
+      "name": "spring.cloud.gateway.httpserver.wiretap",
+      "type": "java.lang.Boolean",
+      "description": "Enables wiretap debugging for Netty HttpServer.",
+      "defaultValue": "false"
     }
   ]
 }