Add remote debug tunnel auto-configuration

Provide auto-configuration for remote debugging over a HTTP tunnel.
The RemoteClientConfiguration provides a server that the local IDE can
connect to. When a client connects the remote connection is established
using the HTTP tunnel.

See gh-3087

spring-boot-developer-tools/src/main/java/org/springframework/boot/developertools/autoconfigure/RemoteDeveloperToolsAutoConfiguration.java

@@ -23,6 +23,7 @@ import javax.servlet.Filter;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -39,6 +40,10 @@ import org.springframework.boot.developertools.restart.server.DefaultSourceFolde
 import org.springframework.boot.developertools.restart.server.HttpRestartServer;
 import org.springframework.boot.developertools.restart.server.HttpRestartServerHandler;
 import org.springframework.boot.developertools.restart.server.SourceFolderUrlFilter;
+import org.springframework.boot.developertools.tunnel.server.HttpTunnelServer;
+import org.springframework.boot.developertools.tunnel.server.HttpTunnelServerHandler;
+import org.springframework.boot.developertools.tunnel.server.RemoteDebugPortProvider;
+import org.springframework.boot.developertools.tunnel.server.SocketTargetServerConnection;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.server.ServerHttpRequest;
@@ -109,4 +114,32 @@ public class RemoteDeveloperToolsAutoConfiguration {
 
 	}
 
+	/**
+	 * Configuration for remote debug HTTP tunneling.
+	 */
+	@ConditionalOnProperty(prefix = "spring.developertools.remote.debug", name = "enabled", matchIfMissing = true)
+	static class RemoteDebugTunnelConfiguration {
+
+		@Autowired
+		private DeveloperToolsProperties properties;
+
+		@Bean
+		@ConditionalOnMissingBean(name = "remoteDebugHanderMapper")
+		public UrlHandlerMapper remoteDebugHanderMapper(
+				@Qualifier("remoteDebugHttpTunnelServer") HttpTunnelServer server) {
+			String url = this.properties.getRemote().getContextPath() + "/debug";
+			logger.warn("Listening for remote debug traffic on " + url);
+			Handler handler = new HttpTunnelServerHandler(server);
+			return new UrlHandlerMapper(url, handler);
+		}
+
+		@Bean
+		@ConditionalOnMissingBean(name = "remoteDebugHttpTunnelServer")
+		public HttpTunnelServer remoteDebugHttpTunnelServer() {
+			return new HttpTunnelServer(new SocketTargetServerConnection(
+					new RemoteDebugPortProvider()));
+		}
+
+	}
+
 }

spring-boot-developer-tools/src/main/java/org/springframework/boot/developertools/autoconfigure/RemoteDeveloperToolsProperties.java

@@ -35,6 +35,8 @@ public class RemoteDeveloperToolsProperties {
 
 	private Restart restart = new Restart();
 
+	private Debug debug = new Debug();
+
 	public String getContextPath() {
 		return this.contextPath;
 	}
@@ -47,6 +49,10 @@ public class RemoteDeveloperToolsProperties {
 		return this.restart;
 	}
 
+	public Debug getDebug() {
+		return this.debug;
+	}
+
 	public static class Restart {
 
 		/**
@@ -64,4 +70,36 @@ public class RemoteDeveloperToolsProperties {
 
 	}
 
+	public static class Debug {
+
+		public static final Integer DEFAULT_LOCAL_PORT = 8000;
+
+		/**
+		 * Enable remote debug support.
+		 */
+		private boolean enabled = true;
+
+		/**
+		 * Local remote debug server port.
+		 */
+		private int localPort = DEFAULT_LOCAL_PORT;
+
+		public boolean isEnabled() {
+			return this.enabled;
+		}
+
+		public void setEnabled(boolean enabled) {
+			this.enabled = enabled;
+		}
+
+		public int getLocalPort() {
+			return this.localPort;
+		}
+
+		public void setLocalPort(int localPort) {
+			this.localPort = localPort;
+		}
+
+	}
+
 }

spring-boot-developer-tools/src/main/java/org/springframework/boot/developertools/remote/client/LocalDebugPortAvailableCondition.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2012-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.developertools.remote.client;
+
+import javax.net.ServerSocketFactory;
+
+import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
+import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
+import org.springframework.boot.bind.RelaxedPropertyResolver;
+import org.springframework.boot.developertools.autoconfigure.RemoteDeveloperToolsProperties;
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.core.type.AnnotatedTypeMetadata;
+
+/**
+ * Condition used to check that the actual local port is available.
+ */
+class LocalDebugPortAvailableCondition extends SpringBootCondition {
+
+	@Override
+	public ConditionOutcome getMatchOutcome(ConditionContext context,
+			AnnotatedTypeMetadata metadata) {
+		RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(
+				context.getEnvironment(), "spring.developertools.remote.debug.");
+		Integer port = resolver.getProperty("local-port", Integer.class);
+		if (port == null) {
+			port = RemoteDeveloperToolsProperties.Debug.DEFAULT_LOCAL_PORT;
+		}
+		if (isPortAvailable(port)) {
+			return ConditionOutcome.match("Local debug port availble");
+		}
+		return ConditionOutcome.noMatch("Local debug port unavailble");
+	}
+
+	private boolean isPortAvailable(int port) {
+		try {
+			ServerSocketFactory.getDefault().createServerSocket(port).close();
+			return true;
+		}
+		catch (Exception ex) {
+			return false;
+		}
+	}
+
+}

spring-boot-developer-tools/src/main/java/org/springframework/boot/developertools/remote/client/LoggingTunnelClientListener.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.developertools.remote.client;
+
+import java.nio.channels.SocketChannel;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.boot.developertools.tunnel.client.TunnelClientListener;
+
+/**
+ * {@link TunnelClientListener} to log open/close events.
+ *
+ * @author Phillip Webb
+ */
+class LoggingTunnelClientListener implements TunnelClientListener {
+
+	private static final Log logger = LogFactory
+			.getLog(LoggingTunnelClientListener.class);
+
+	@Override
+	public void onOpen(SocketChannel socket) {
+		logger.info("Remote debug connection opened");
+	}
+
+	@Override
+	public void onClose(SocketChannel socket) {
+		logger.info("Remote debug connection closed");
+	}
+
+}

spring-boot-developer-tools/src/main/java/org/springframework/boot/developertools/remote/client/RemoteClientConfiguration.java

@@ -21,11 +21,13 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
 import javax.annotation.PostConstruct;
+import javax.servlet.Filter;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
+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.context.properties.EnableConfigurationProperties;
@@ -40,7 +42,11 @@ import org.springframework.boot.developertools.livereload.LiveReloadServer;
 import org.springframework.boot.developertools.restart.DefaultRestartInitializer;
 import org.springframework.boot.developertools.restart.RestartScope;
 import org.springframework.boot.developertools.restart.Restarter;
+import org.springframework.boot.developertools.tunnel.client.HttpTunnelConnection;
+import org.springframework.boot.developertools.tunnel.client.TunnelClient;
+import org.springframework.boot.developertools.tunnel.client.TunnelConnection;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.event.EventListener;
 import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
@@ -79,8 +85,9 @@ public class RemoteClientConfiguration {
 	@PostConstruct
 	private void logWarnings() {
 		RemoteDeveloperToolsProperties remoteProperties = this.properties.getRemote();
-		if (!remoteProperties.getRestart().isEnabled()) {
-			logger.warn("Remote restart is not enabled.");
+		if (!remoteProperties.getDebug().isEnabled()
+				&& !remoteProperties.getRestart().isEnabled()) {
+			logger.warn("Remote restart and debug are both disabled.");
 		}
 	}
 
@@ -168,4 +175,32 @@ public class RemoteClientConfiguration {
 
 	}
 
+	/**
+	 * Client configuration for remote debug HTTP tunneling.
+	 */
+	@ConditionalOnProperty(prefix = "spring.developertools.remote.debug", name = "enabled", matchIfMissing = true)
+	@ConditionalOnClass(Filter.class)
+	@Conditional(LocalDebugPortAvailableCondition.class)
+	static class RemoteDebugTunnelClientConfiguration {
+
+		@Autowired
+		private DeveloperToolsProperties properties;
+
+		@Value("${remoteUrl}")
+		private String remoteUrl;
+
+		@Bean
+		public TunnelClient remoteDebugTunnelClient(
+				ClientHttpRequestFactory requestFactory) {
+			RemoteDeveloperToolsProperties remoteProperties = this.properties.getRemote();
+			String url = this.remoteUrl + remoteProperties.getContextPath() + "/debug";
+			TunnelConnection connection = new HttpTunnelConnection(url, requestFactory);
+			int localPort = remoteProperties.getDebug().getLocalPort();
+			TunnelClient client = new TunnelClient(localPort, connection);
+			client.addListener(new LoggingTunnelClientListener());
+			return client;
+		}
+
+	}
+
 }