Add EmbeddedServerPortFileWriter

Add a EmbeddedServerPortFileWriter which can be used to write server
port information to a file.

Fixes gh-1275
Closes gh-1491

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/system/ApplicationPidFileWriter.java

@@ -74,7 +74,7 @@ public class ApplicationPidFileWriter implements
 	 */
 	public ApplicationPidFileWriter(File file) {
 		Assert.notNull(file, "File must not be null");
-		String override = getOverride();
+		String override = SystemProperties.get(PROPERTY_VARIABLES);
 		if (override != null) {
 			this.file = new File(override);
 		}
@@ -83,23 +83,6 @@ public class ApplicationPidFileWriter implements
 		}
 	}
 
-	private String getOverride() {
-		for (String property : PROPERTY_VARIABLES) {
-			try {
-				String override = System.getProperty(property);
-				override = (override != null ? override : System.getenv(property));
-				if (override != null) {
-					return override;
-				}
-			}
-			catch (Throwable ex) {
-				System.err.println("Could not resolve '" + property
-						+ "' as system property: " + ex);
-			}
-		}
-		return null;
-	}
-
 	@Override
 	public void onApplicationEvent(ApplicationStartedEvent event) {
 		if (created.compareAndSet(false, true)) {

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/system/EmbeddedServerPortFileWriter.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2010-2014 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.actuate.system;
+
+import java.io.File;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.boot.context.embedded.EmbeddedServletContainerInitializedEvent;
+import org.springframework.boot.context.embedded.EmbeddedWebApplicationContext;
+import org.springframework.context.ApplicationListener;
+import org.springframework.util.Assert;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.util.StringUtils;
+
+/**
+ * An {@link ApplicationListener} that saves embedded server port and management port into
+ * file. This application listener will be triggered whenever the servlet container
+ * starts, and the file name can be overridden at runtime with a System property or
+ * environment variable named "PORTFILE" or "portfile".
+ *
+ * @author David Liu
+ * @author Phillip Webb
+ * @since 1.2.0
+ */
+public class EmbeddedServerPortFileWriter implements
+		ApplicationListener<EmbeddedServletContainerInitializedEvent> {
+
+	private static final String DEFAULT_FILE_NAME = "application.port";
+
+	private static final String[] PROPERTY_VARIABLES = { "PORTFILE", "portfile" };
+
+	private static final Log logger = LogFactory.getLog(ApplicationPidFileWriter.class);
+
+	private final File file;
+
+	/**
+	 * Create a new {@link ApplicationPidFileWriter} instance using the filename
+	 * 'application.pid'.
+	 */
+	public EmbeddedServerPortFileWriter() {
+		this.file = new File(DEFAULT_FILE_NAME);
+	}
+
+	/**
+	 * Create a new {@link ApplicationPidFileWriter} instance with a specified filename.
+	 * @param filename the name of file containing pid
+	 */
+	public EmbeddedServerPortFileWriter(String filename) {
+		this(new File(filename));
+	}
+
+	/**
+	 * Create a new {@link ApplicationPidFileWriter} instance with a specified file.
+	 * @param file the file containing pid
+	 */
+	public EmbeddedServerPortFileWriter(File file) {
+		Assert.notNull(file, "File must not be null");
+		String override = SystemProperties.get(PROPERTY_VARIABLES);
+		if (override != null) {
+			this.file = new File(override);
+		}
+		else {
+			this.file = file;
+		}
+	}
+
+	@Override
+	public void onApplicationEvent(EmbeddedServletContainerInitializedEvent event) {
+		File portFile = getPortFile(event.getApplicationContext());
+		try {
+			String port = String.valueOf(event.getEmbeddedServletContainer().getPort());
+			createParentFolder(portFile);
+			FileCopyUtils.copy(port.getBytes(), portFile);
+			portFile.deleteOnExit();
+		}
+		catch (Exception ex) {
+			logger.warn(String.format("Cannot create pid file %s", this.file));
+		}
+	}
+
+	/**
+	 * Return the actual port file that should be written for the given application
+	 * context. The default implementation builds a file from the source file and the
+	 * application context namespace.
+	 * @param applicationContext the source application context
+	 * @return the file that should be written
+	 */
+	protected File getPortFile(EmbeddedWebApplicationContext applicationContext) {
+		String contextName = applicationContext.getNamespace();
+		if (StringUtils.isEmpty(contextName)) {
+			return this.file;
+		}
+		String name = this.file.getName();
+		String extension = StringUtils.getFilenameExtension(this.file.getName());
+		name = name.substring(0, name.length() - extension.length() - 1);
+		if (isUpperCase(name)) {
+			name = name + "-" + contextName.toUpperCase();
+		}
+		else {
+			name = name + "-" + contextName.toLowerCase();
+		}
+		if (StringUtils.hasLength(extension)) {
+			name = name + "." + extension;
+		}
+		return new File(this.file.getParentFile(), name);
+	}
+
+	private boolean isUpperCase(String name) {
+		for (int i = 0; i < name.length(); i++) {
+			if (!Character.isUpperCase(name.charAt(i))) {
+				return false;
+			}
+		}
+		return true;
+	}
+
+	private void createParentFolder(File file) {
+		File parent = file.getParentFile();
+		if (parent != null) {
+			parent.mkdirs();
+		}
+	}
+
+}

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/system/SystemProperties.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012-2014 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.actuate.system;
+
+/**
+ * @author Phillip Webb
+ */
+class SystemProperties {
+
+	public static String get(String... properties) {
+		for (String property : properties) {
+			try {
+				String override = System.getProperty(property);
+				override = (override != null ? override : System.getenv(property));
+				if (override != null) {
+					return override;
+				}
+			}
+			catch (Throwable ex) {
+				System.err.println("Could not resolve '" + property
+						+ "' as system property: " + ex);
+			}
+		}
+		return null;
+	}
+
+}

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/system/EmbeddedServerPortFileWriterTests.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright 2010-2014 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.actuate.system;
+
+import java.io.File;
+import java.io.FileReader;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.springframework.boot.context.embedded.EmbeddedServletContainer;
+import org.springframework.boot.context.embedded.EmbeddedServletContainerInitializedEvent;
+import org.springframework.boot.context.embedded.EmbeddedWebApplicationContext;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.util.StringUtils;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests {@link EmbeddedServerPortFileWriter}.
+ *
+ * @author David Liu
+ * @author Phillip Webb
+ */
+public class EmbeddedServerPortFileWriterTests {
+
+	@Rule
+	public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+	@Before
+	@After
+	public void reset() {
+		System.clearProperty("PORTFILE");
+	}
+
+	@Test
+	public void createPortFile() throws Exception {
+		File file = this.temporaryFolder.newFile();
+		EmbeddedServerPortFileWriter listener = new EmbeddedServerPortFileWriter(file);
+		listener.onApplicationEvent(mockEvent("", 8080));
+		assertThat(FileCopyUtils.copyToString(new FileReader(file)), equalTo("8080"));
+	}
+
+	@Test
+	public void overridePortFile() throws Exception {
+		File file = this.temporaryFolder.newFile();
+		System.setProperty("PORTFILE", this.temporaryFolder.newFile().getAbsolutePath());
+		EmbeddedServerPortFileWriter listener = new EmbeddedServerPortFileWriter(file);
+		listener.onApplicationEvent(mockEvent("", 8080));
+		assertThat(FileCopyUtils.copyToString(new FileReader(System
+				.getProperty("PORTFILE"))), equalTo("8080"));
+	}
+
+	@Test
+	public void createManagementPortFile() throws Exception {
+		File file = this.temporaryFolder.newFile();
+		EmbeddedServerPortFileWriter listener = new EmbeddedServerPortFileWriter(file);
+		listener.onApplicationEvent(mockEvent("", 8080));
+		listener.onApplicationEvent(mockEvent("management", 9090));
+		assertThat(FileCopyUtils.copyToString(new FileReader(file)), equalTo("8080"));
+		String managementFile = file.getName();
+		managementFile = managementFile.substring(0, managementFile.length()
+				- StringUtils.getFilenameExtension(managementFile).length() - 1);
+		managementFile = managementFile + "-management."
+				+ StringUtils.getFilenameExtension(file.getName());
+		assertThat(FileCopyUtils.copyToString(new FileReader(new File(file
+				.getParentFile(), managementFile))), equalTo("9090"));
+	}
+
+	@Test
+	public void createUpperCaseManagementPortFile() throws Exception {
+		File file = this.temporaryFolder.newFile();
+		file = new File(file.getParentFile(), file.getName().toUpperCase());
+		EmbeddedServerPortFileWriter listener = new EmbeddedServerPortFileWriter(file);
+		listener.onApplicationEvent(mockEvent("management", 9090));
+		String managementFile = file.getName();
+		managementFile = managementFile.substring(0, managementFile.length()
+				- StringUtils.getFilenameExtension(managementFile).length() - 1);
+		managementFile = managementFile + "-MANAGEMENT."
+				+ StringUtils.getFilenameExtension(file.getName());
+		assertThat(FileCopyUtils.copyToString(new FileReader(new File(file
+				.getParentFile(), managementFile))), equalTo("9090"));
+
+	}
+
+	private EmbeddedServletContainerInitializedEvent mockEvent(String name, int port) {
+		EmbeddedWebApplicationContext applicationContext = mock(EmbeddedWebApplicationContext.class);
+		EmbeddedServletContainer source = mock(EmbeddedServletContainer.class);
+		given(applicationContext.getNamespace()).willReturn(name);
+		given(source.getPort()).willReturn(port);
+		EmbeddedServletContainerInitializedEvent event = new EmbeddedServletContainerInitializedEvent(
+				applicationContext, source);
+		return event;
+	}
+
+}

spring-boot-docs/src/main/asciidoc/production-ready-features.adoc

@@ -856,30 +856,38 @@ if needed.
 
 [[production-ready-process-monitoring]]
 == Process monitoring
-In Spring Boot Actuator you can find `ApplicationPidFileWriter` which creates file
-containing application PID (by default in application directory and file name is
-`application.pid`). It's not activated by default, but you can do it in two simple
-ways described below.
+In Spring Boot Actuator you can find a couple of classes to create files that are useful
+for process monitoring:
+
+* `ApplicationPidFileWriter` creates a file containing the application PID (by default in
+  the application directory with the file name `application.pid`).
+* `EmbeddedServerPortFileWriter` creates a file (or files) containing the ports of the
+  embedded server (by default in the application directory with the file name
+  `application.port`).
+
+These writers are not activated by default, but you can enable them in one of the ways
+described below.
 
 
 
 [[production-ready-process-monitoring-configuration]]
 === Extend configuration
-In `META-INF/spring.factories` file you have to activate the listener:
+In `META-INF/spring.factories` file you have to activate the listener(s):
 
 [indent=0]
 ----
 	org.springframework.context.ApplicationListener=\
-	org.springframework.boot.actuate.system.ApplicationPidFileWriter
+	org.springframework.boot.actuate.system.ApplicationPidFileWriter,
+	org.springframework.boot.actuate.system.EmbeddedServerPortFileWriter
 ----
 
 
 
 [[production-ready-process-monitoring-programmatically]]
 === Programmatically
-You can also activate this listener by invoking `SpringApplication.addListeners(...)`
-method and passing `ApplicationPidFileWriter` object. You can also customize file name
-and path through constructor.
+You can also activate a listener by invoking the `SpringApplication.addListeners(...)`
+method and passing the appropriate `Writer` object. This method also allows you to
+customize file name and path via the `Writer` constructor.