Add `spring.pid.fail-on-write-error` support

Update `ApplicationPidFileWriter` to support a 'fail on write error'
properties which allows the user to exit the application if the PID
file cannot be written.

This commit also deprecates `spring.pidfile` in favor of
`spring.pid.file` so that the new property can be added without overlap.

Fixes gh-2764

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

@@ -18,6 +18,9 @@ package org.springframework.boot.actuate.system;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.apache.commons.logging.Log;
@@ -36,11 +39,21 @@ import org.springframework.util.Assert;
  * An {@link ApplicationListener} that saves application PID into file. This application
  * listener will be triggered exactly once per JVM, and the file name can be overridden at
  * runtime with a System property or environment variable named "PIDFILE" (or "pidfile")
- * or using a {@code spring.pidfile} property in the Spring {@link Environment}.
+ * or using a {@code spring.pid.file} property in the Spring {@link Environment}.
+ * <p>
+ * If PID file can not be created no exception is reported. This behavior can be changed
+ * by assigning {@code true} to System property or environment variable named
+ * {@code PID_FAIL_ON_WRITE_ERROR} (or "pid_fail_on_write_error") or to
+ * {@code spring.pid.fail-on-write-error} property in the Spring {@link Environment}.
+ * <p>
+ * Note: access to the Spring {@link Environment} is only possible when the
+ * {@link #setTriggerEventType(Class) triggerEventType} is set to
+ * {@link ApplicationEnvironmentPreparedEvent} or {@link ApplicationPreparedEvent}.
  *
  * @author Jakub Kubrynski
  * @author Dave Syer
  * @author Phillip Webb
+ * @author Tomasz Przybyla
  * @since 1.2.0
  */
 public class ApplicationPidFileWriter implements
@@ -50,9 +63,22 @@ public class ApplicationPidFileWriter implements
 
 	private static final String DEFAULT_FILE_NAME = "application.pid";
 
-	private static final String[] SYSTEM_PROPERTY_VARIABLES = { "PIDFILE", "pidfile" };
+	private static final List<Property> FILE_PROPERTIES;
+	static {
+		List<Property> properties = new ArrayList<Property>();
+		properties.add(new SpringProperty("spring.pid.", "file"));
+		properties.add(new SpringProperty("spring.", "pidfile"));
+		properties.add(new SystemProperty("PIDFILE"));
+		FILE_PROPERTIES = Collections.unmodifiableList(properties);
+	}
 
-	private static final String SPRING_PROPERTY = "spring.pidfile";
+	private static final List<Property> FAIL_ON_WRITE_ERROR_PROPERTIES;
+	static {
+		List<Property> properties = new ArrayList<Property>();
+		properties.add(new SpringProperty("spring.pid.", "fail-on-write-error"));
+		properties.add(new SystemProperty("PID_FAIL_ON_WRITE_ERROR"));
+		FAIL_ON_WRITE_ERROR_PROPERTIES = Collections.unmodifiableList(properties);
+	}
 
 	private static final AtomicBoolean created = new AtomicBoolean(false);
 
@@ -108,7 +134,12 @@ public class ApplicationPidFileWriter implements
 					writePidFile(event);
 				}
 				catch (Exception ex) {
-					logger.warn(String.format("Cannot create pid file %s", this.file), ex);
+					String message = String
+							.format("Cannot create pid file %s", this.file);
+					if (failOnWriteError(event)) {
+						throw new IllegalStateException(message, ex);
+					}
+					logger.warn(message, ex);
 				}
 			}
 		}
@@ -116,31 +147,25 @@ public class ApplicationPidFileWriter implements
 
 	private void writePidFile(SpringApplicationEvent event) throws IOException {
 		File pidFile = this.file;
-		String override = SystemProperties.get(SYSTEM_PROPERTY_VARIABLES);
+		String override = getProperty(event, FILE_PROPERTIES);
 		if (override != null) {
 			pidFile = new File(override);
 		}
-		else {
-			Environment environment = getEnvironment(event);
-			if (environment != null) {
-				override = new RelaxedPropertyResolver(environment)
-						.getProperty(SPRING_PROPERTY);
-				if (override != null) {
-					pidFile = new File(override);
-				}
-			}
-		}
 		new ApplicationPid().write(pidFile);
 		pidFile.deleteOnExit();
 	}
 
-	private Environment getEnvironment(SpringApplicationEvent event) {
-		if (event instanceof ApplicationEnvironmentPreparedEvent) {
-			return ((ApplicationEnvironmentPreparedEvent) event).getEnvironment();
-		}
-		if (event instanceof ApplicationPreparedEvent) {
-			return ((ApplicationPreparedEvent) event).getApplicationContext()
-					.getEnvironment();
+	private boolean failOnWriteError(SpringApplicationEvent event) {
+		String value = getProperty(event, FAIL_ON_WRITE_ERROR_PROPERTIES);
+		return (value == null ? false : Boolean.parseBoolean(value));
+	}
+
+	private String getProperty(SpringApplicationEvent event, List<Property> candidates) {
+		for (Property candidate : candidates) {
+			String value = candidate.getValue(event);
+			if (value != null) {
+				return value;
+			}
 		}
 		return null;
 	}
@@ -160,4 +185,69 @@ public class ApplicationPidFileWriter implements
 	static void reset() {
 		created.set(false);
 	}
+
+	/**
+	 * Provides access to a property value.
+	 */
+	private static interface Property {
+
+		String getValue(SpringApplicationEvent event);
+
+	}
+
+	/**
+	 * {@link Property} obtained from Spring's {@link Environment}.
+	 */
+	private static class SpringProperty implements Property {
+
+		private final String prexfix;
+
+		private final String key;
+
+		public SpringProperty(String prefix, String key) {
+			this.prexfix = prefix;
+			this.key = key;
+		}
+
+		@Override
+		public String getValue(SpringApplicationEvent event) {
+			Environment environment = getEnvironment(event);
+			if (environment == null) {
+				return null;
+			}
+			return new RelaxedPropertyResolver(environment, this.prexfix)
+					.getProperty(this.key);
+		}
+
+		private Environment getEnvironment(SpringApplicationEvent event) {
+			if (event instanceof ApplicationEnvironmentPreparedEvent) {
+				return ((ApplicationEnvironmentPreparedEvent) event).getEnvironment();
+			}
+			if (event instanceof ApplicationPreparedEvent) {
+				return ((ApplicationPreparedEvent) event).getApplicationContext()
+						.getEnvironment();
+			}
+			return null;
+		}
+
+	}
+
+	/**
+	 * {@link Property} obtained from {@link SystemProperties}.
+	 */
+	private static class SystemProperty implements Property {
+
+		private final String[] properties;
+
+		public SystemProperty(String name) {
+			this.properties = new String[] { name.toUpperCase(), name.toLowerCase() };
+		}
+
+		@Override
+		public String getValue(SpringApplicationEvent event) {
+			return SystemProperties.get(this.properties);
+		}
+
+	}
+
 }

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

@@ -17,6 +17,8 @@
 package org.springframework.boot.actuate.system;
 
 /**
+ * Access to system properties.
+ *
  * @author Phillip Webb
  */
 class SystemProperties {

spring-boot-actuator/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -87,9 +87,22 @@
     "type": "java.lang.String",
     "description": "Resource reference to a generated git info properties file."
   },
+  {
+    "name": "spring.pid.file",
+    "type": "java.lang.String",
+    "description": "Location of the PID file to write (if ApplicationPidFileWriter is used).",
+    "sourceType": "org.springframework.boot.actuate.system.ApplicationPidFileWriter"
+  }
+  {
+    "name": "spring.pid.fail-on-write-error",
+    "type": "java.lang.Boolean",
+    "description": "Fail if ApplicationPidFileWriter is used but it cannot write the PID file.",
+    "sourceType": "org.springframework.boot.actuate.system.ApplicationPidFileWriter"
+  }
   {
     "name": "spring.pidfile",
     "type": "java.lang.String",
+    "deprecated:" true,
     "description": "Location of the PID file to write (if ApplicationPidFileWriter is used).",
     "sourceType": "org.springframework.boot.actuate.system.ApplicationPidFileWriter"
   }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2014 the original author or authors.
+ * Copyright 2010-2015 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.
@@ -23,11 +23,13 @@ import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 import org.junit.rules.TemporaryFolder;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;
 import org.springframework.boot.context.event.ApplicationStartedEvent;
+import org.springframework.boot.context.event.SpringApplicationEvent;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.StandardEnvironment;
@@ -46,6 +48,7 @@ import static org.mockito.Mockito.mock;
  * @author Jakub Kubrynski
  * @author Dave Syer
  * @author Phillip Webb
+ * @author Tomasz Przybyla
  */
 public class ApplicationPidFileWriterTests {
 
@@ -56,10 +59,14 @@ public class ApplicationPidFileWriterTests {
 	@Rule
 	public TemporaryFolder temporaryFolder = new TemporaryFolder();
 
+	@Rule
+	public ExpectedException exception = ExpectedException.none();
+
 	@Before
 	@After
 	public void resetListener() {
 		System.clearProperty("PIDFILE");
+		System.clearProperty("PID_FAIL_ON_WRITE_ERROR");
 		ApplicationPidFileWriter.reset();
 	}
 
@@ -85,14 +92,8 @@ public class ApplicationPidFileWriterTests {
 	@Test
 	public void overridePidFileWithSpring() throws Exception {
 		File file = this.temporaryFolder.newFile();
-		ConfigurableEnvironment environment = new StandardEnvironment();
-		MockPropertySource propertySource = new MockPropertySource();
-		propertySource.setProperty("spring.pidfile", file.getAbsolutePath());
-		environment.getPropertySources().addLast(propertySource);
-		ConfigurableApplicationContext context = mock(ConfigurableApplicationContext.class);
-		given(context.getEnvironment()).willReturn(environment);
-		ApplicationPreparedEvent event = new ApplicationPreparedEvent(
-				new SpringApplication(), new String[] {}, context);
+		SpringApplicationEvent event = createPreparedEvent("spring.pidfile",
+				file.getAbsolutePath());
 		ApplicationPidFileWriter listener = new ApplicationPidFileWriter();
 		listener.onApplicationEvent(event);
 		assertThat(FileCopyUtils.copyToString(new FileReader(file)), not(isEmptyString()));
@@ -101,12 +102,8 @@ public class ApplicationPidFileWriterTests {
 	@Test
 	public void differentEventTypes() throws Exception {
 		File file = this.temporaryFolder.newFile();
-		ConfigurableEnvironment environment = new StandardEnvironment();
-		MockPropertySource propertySource = new MockPropertySource();
-		propertySource.setProperty("spring.pidfile", file.getAbsolutePath());
-		environment.getPropertySources().addLast(propertySource);
-		ApplicationEnvironmentPreparedEvent event = new ApplicationEnvironmentPreparedEvent(
-				new SpringApplication(), new String[] {}, environment);
+		SpringApplicationEvent event = createEnvironmentPreparedEvent("spring.pidfile",
+				file.getAbsolutePath());
 		ApplicationPidFileWriter listener = new ApplicationPidFileWriter();
 		listener.onApplicationEvent(event);
 		assertThat(FileCopyUtils.copyToString(new FileReader(file)), isEmptyString());
@@ -125,4 +122,64 @@ public class ApplicationPidFileWriterTests {
 		assertThat(FileCopyUtils.copyToString(new FileReader(file)), not(isEmptyString()));
 	}
 
+	@Test
+	public void continueWhenPidFileIsReadOnly() throws Exception {
+		File file = this.temporaryFolder.newFile();
+		file.setReadOnly();
+		ApplicationPidFileWriter listener = new ApplicationPidFileWriter(file);
+		listener.onApplicationEvent(EVENT);
+		assertThat(FileCopyUtils.copyToString(new FileReader(file)), isEmptyString());
+	}
+
+	@Test
+	public void throwWhenPidFileIsReadOnly() throws Exception {
+		File file = this.temporaryFolder.newFile();
+		file.setReadOnly();
+		System.setProperty("PID_FAIL_ON_WRITE_ERROR", "true");
+		ApplicationPidFileWriter listener = new ApplicationPidFileWriter(file);
+		this.exception.expect(IllegalStateException.class);
+		this.exception.expectMessage("Cannot create pid file");
+		listener.onApplicationEvent(EVENT);
+	}
+
+	@Test
+	public void throwWhenPidFileIsReadOnlyWithSpring() throws Exception {
+		File file = this.temporaryFolder.newFile();
+		file.setReadOnly();
+		SpringApplicationEvent event = createPreparedEvent(
+				"spring.pid.fail-on-write-error", "true");
+		ApplicationPidFileWriter listener = new ApplicationPidFileWriter(file);
+		this.exception.expect(IllegalStateException.class);
+		this.exception.expectMessage("Cannot create pid file");
+		listener.onApplicationEvent(event);
+	}
+
+	private SpringApplicationEvent createEnvironmentPreparedEvent(String propName,
+			String propValue) {
+		ConfigurableEnvironment environment = createEnvironment(propName, propValue);
+		return new ApplicationEnvironmentPreparedEvent(new SpringApplication(),
+				new String[] {}, environment);
+	}
+
+	private SpringApplicationEvent createPreparedEvent(String propName, String propValue) {
+		ConfigurableEnvironment environment = createEnvironment(propName, propValue);
+		ConfigurableApplicationContext context = mock(ConfigurableApplicationContext.class);
+		given(context.getEnvironment()).willReturn(environment);
+		return new ApplicationPreparedEvent(new SpringApplication(), new String[] {},
+				context);
+	}
+
+	private ConfigurableEnvironment createEnvironment(String propName, String propValue) {
+		MockPropertySource propertySource = mockPropertySource(propName, propValue);
+		ConfigurableEnvironment environment = new StandardEnvironment();
+		environment.getPropertySources().addLast(propertySource);
+		return environment;
+	}
+
+	private MockPropertySource mockPropertySource(String name, String value) {
+		MockPropertySource propertySource = new MockPropertySource();
+		propertySource.setProperty(name, value);
+		return propertySource;
+	}
+
 }

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -612,7 +612,8 @@ content into your application; rather pick only the properties that you need.
 	management.security.sessions=stateless # session creating policy to use (always, never, if_required, stateless)
 
 	# PID FILE ({sc-spring-boot-actuator}/system/ApplicationPidFileWriter.{sc-ext}[ApplicationPidFileWriter])
-	spring.pidfile= # Location of the PID file to write
+	spring.pid.file= # Location of the PID file to write
+	spring.pid.fail-on-write-error= # Fail if the PID file cannot be written
 
 	# ENDPOINTS ({sc-spring-boot-actuator}/endpoint/AbstractEndpoint.{sc-ext}[AbstractEndpoint] subclasses)
 	endpoints.autoconfig.id=autoconfig