Trigger livereload on remote updates

Add livereload support to RemoteClientConfiguration which is triggered
whenever updates are pushed to the remote application.

Closes gh-3086

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

@@ -0,0 +1,116 @@
+/*
+ * 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.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.boot.developertools.autoconfigure.OptionalLiveReloadServer;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.ClientHttpRequest;
+import org.springframework.http.client.ClientHttpRequestFactory;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.util.Assert;
+
+/**
+ * {@link Runnable} that waits to triggers live reload until the remote server has
+ * restarted.
+ *
+ * @author Phillip Webb
+ */
+class DelayedLiveReloadTrigger implements Runnable {
+
+	private static final long SHUTDOWN_TIME = 1000;
+
+	private static final long SLEEP_TIME = 500;
+
+	private static final long TIMEOUT = 30000;
+
+	private static final Log logger = LogFactory.getLog(DelayedLiveReloadTrigger.class);
+
+	private final OptionalLiveReloadServer liveReloadServer;
+
+	private final ClientHttpRequestFactory requestFactory;
+
+	private final URI uri;
+
+	private long shutdownTime = SHUTDOWN_TIME;
+
+	private long sleepTime = SLEEP_TIME;
+
+	private long timeout = TIMEOUT;
+
+	public DelayedLiveReloadTrigger(OptionalLiveReloadServer liveReloadServer,
+			ClientHttpRequestFactory requestFactory, String url) {
+		Assert.notNull(liveReloadServer, "LiveReloadServer must not be null");
+		Assert.notNull(requestFactory, "RequestFactory must not be null");
+		Assert.hasLength(url, "URL must not be empty");
+		this.liveReloadServer = liveReloadServer;
+		this.requestFactory = requestFactory;
+		try {
+			this.uri = new URI(url);
+		}
+		catch (URISyntaxException ex) {
+			throw new IllegalArgumentException(ex);
+		}
+	}
+
+	protected void setTimings(long shutdown, long sleep, long timeout) {
+		this.shutdownTime = shutdown;
+		this.sleepTime = sleep;
+		this.timeout = timeout;
+	}
+
+	@Override
+	public void run() {
+		try {
+			Thread.sleep(this.shutdownTime);
+			long start = System.currentTimeMillis();
+			while (!isUp()) {
+				long runTime = System.currentTimeMillis() - start;
+				if (runTime > this.timeout) {
+					return;
+				}
+				Thread.sleep(this.sleepTime);
+			}
+			logger.info("Remote server has changed, triggering LiveReload");
+			this.liveReloadServer.triggerReload();
+		}
+		catch (InterruptedException ex) {
+		}
+	}
+
+	private boolean isUp() {
+		try {
+			ClientHttpRequest request = createRequest();
+			ClientHttpResponse response = request.execute();
+			return response.getStatusCode() == HttpStatus.OK;
+		}
+		catch (Exception ex) {
+			return false;
+		}
+	}
+
+	private ClientHttpRequest createRequest() throws IOException {
+		return this.requestFactory.createRequest(this.uri, HttpMethod.GET);
+	}
+
+}

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

@@ -17,6 +17,8 @@
 package org.springframework.boot.developertools.remote.client;
 
 import java.net.URL;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 
 import javax.annotation.PostConstruct;
 
@@ -24,16 +26,23 @@ 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.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.developertools.autoconfigure.DeveloperToolsProperties;
+import org.springframework.boot.developertools.autoconfigure.OptionalLiveReloadServer;
 import org.springframework.boot.developertools.autoconfigure.RemoteDeveloperToolsProperties;
+import org.springframework.boot.developertools.classpath.ClassPathChangedEvent;
 import org.springframework.boot.developertools.classpath.ClassPathFileSystemWatcher;
 import org.springframework.boot.developertools.classpath.ClassPathRestartStrategy;
 import org.springframework.boot.developertools.classpath.PatternClassPathRestartStrategy;
+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.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.event.EventListener;
 import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
 import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.SimpleClientHttpRequestFactory;
@@ -75,6 +84,52 @@ public class RemoteClientConfiguration {
 		}
 	}
 
+	/**
+	 * LiveReload configuration.
+	 */
+	@ConditionalOnProperty(prefix = "spring.developertools.livereload", name = "enabled", matchIfMissing = true)
+	static class LiveReloadConfiguration {
+
+		@Autowired
+		private DeveloperToolsProperties properties;
+
+		@Autowired(required = false)
+		private LiveReloadServer liveReloadServer;
+
+		@Autowired
+		private ClientHttpRequestFactory clientHttpRequestFactory;
+
+		@Value("${remoteUrl}")
+		private String remoteUrl;
+
+		private ExecutorService executor = Executors.newSingleThreadExecutor();
+
+		@Bean
+		@RestartScope
+		@ConditionalOnMissingBean
+		public LiveReloadServer liveReloadServer() {
+			return new LiveReloadServer(this.properties.getLivereload().getPort(),
+					Restarter.getInstance().getThreadFactory());
+		}
+
+		@EventListener
+		public void onClassPathChanged(ClassPathChangedEvent event) {
+			String url = this.remoteUrl + this.properties.getRemote().getContextPath();
+			this.executor.execute(new DelayedLiveReloadTrigger(
+					optionalLiveReloadServer(), this.clientHttpRequestFactory, url));
+		}
+
+		@Bean
+		public OptionalLiveReloadServer optionalLiveReloadServer() {
+			return new OptionalLiveReloadServer(this.liveReloadServer);
+		}
+
+		final ExecutorService getExecutor() {
+			return this.executor;
+		}
+
+	}
+
 	/**
 	 * Client configuration for remote update and restarts.
 	 */