Add `server.session.store-dir` support

Add support for a `server.session.store-dir` property which can be used
to specify where session data source be saved.

Fixes gh-4191

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -162,6 +162,7 @@ public class ServerProperties
 			container.setSessionTimeout(getSession().getTimeout());
 		}
 		container.setPersistSession(getSession().isPersistent());
+		container.setSessionStoreDir(getSession().getStoreDir());
 		if (getSsl() != null) {
 			container.setSsl(getSsl());
 		}
@@ -392,6 +393,11 @@ public class ServerProperties
 		 */
 		private boolean persistent;
 
+		/**
+		 * The directory used to store session data.
+		 */
+		private File storeDir;
+
 		private Cookie cookie = new Cookie();
 
 		public Cookie getCookie() {
@@ -422,6 +428,14 @@ public class ServerProperties
 			this.persistent = persistent;
 		}
 
+		public File getStoreDir() {
+			return this.storeDir;
+		}
+
+		public void setStoreDir(File storeDir) {
+			this.storeDir = storeDir;
+		}
+
 		public static class Cookie {
 
 			/**

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ServerPropertiesTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.autoconfigure.web;
 
+import java.io.File;
 import java.net.InetAddress;
 import java.nio.charset.Charset;
 import java.util.Collections;
@@ -384,6 +385,17 @@ public class ServerPropertiesTests {
 		verify(container).setUseForwardHeaders(true);
 	}
 
+	@Test
+	public void sessionStoreDir() throws Exception {
+		Map<String, String> map = new HashMap<String, String>();
+		map.put("server.session.store-dir", "myfolder");
+		bindProperties(map);
+		JettyEmbeddedServletContainerFactory container = spy(
+				new JettyEmbeddedServletContainerFactory());
+		this.properties.customize(container);
+		verify(container).setSessionStoreDir(new File("myfolder"));
+	}
+
 	private void bindProperties(Map<String, String> map) {
 		new RelaxedDataBinder(this.properties, "server")
 				.bind(new MutablePropertyValues(map));

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

@@ -87,6 +87,7 @@ content into your application; rather pick only the properties that you need.
 	server.display-name= # the display name of the application
 	server.use-forward-headers= # if X-Forwarded-* headers should be used (default is off unless running in a known cloud)
 	server.session.persistent=false # true if session should be saved across restarts
+	server.session.store-dir= # dir used to save session data
 	server.session.timeout= # session timeout in seconds
 	server.session.tracking-modes= # tracking modes (one or more of "cookie" ,"url", "ssl")
 	server.session.cookie.name= # session cookie name

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

@@ -3584,7 +3584,7 @@ Spring Session provides support for managing a user's session information. If yo
 writing a web application and Spring Session and Spring Data Redis are both on the
 classpath, Spring Boot will auto-configure Spring Session through its
 `@EnableRedisHttpSession`. Session data will be stored in Redis and the session timeout
-can be configured using the `server.session-timeout` property.
+can be configured using the `server.session.timeout` property.
 
 
 

spring-boot/src/main/java/org/springframework/boot/context/embedded/AbstractConfigurableEmbeddedServletContainer.java

@@ -66,6 +66,8 @@ public abstract class AbstractConfigurableEmbeddedServletContainer
 
 	private boolean persistSession;
 
+	private File sessionStoreDir;
+
 	private Ssl ssl;
 
 	private JspServlet jspServlet = new JspServlet();
@@ -191,6 +193,15 @@ public abstract class AbstractConfigurableEmbeddedServletContainer
 		return this.persistSession;
 	}
 
+	@Override
+	public void setSessionStoreDir(File sessionStoreDir) {
+		this.sessionStoreDir = sessionStoreDir;
+	}
+
+	public File getSessionStoreDir() {
+		return this.sessionStoreDir;
+	}
+
 	@Override
 	public void setInitializers(List<? extends ServletContextInitializer> initializers) {
 		Assert.notNull(initializers, "Initializers must not be null");

spring-boot/src/main/java/org/springframework/boot/context/embedded/AbstractEmbeddedServletContainerFactory.java

@@ -26,6 +26,9 @@ import java.util.Arrays;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.springframework.boot.ApplicationHome;
+import org.springframework.boot.ApplicationTemp;
+import org.springframework.util.Assert;
 
 /**
  * Abstract base class for {@link EmbeddedServletContainerFactory} implementations.
@@ -140,4 +143,24 @@ public abstract class AbstractEmbeddedServletContainerFactory
 		}
 	}
 
+	protected final File getValidSessionStoreDir() {
+		return getValidSessionStoreDir(true);
+	}
+
+	protected final File getValidSessionStoreDir(boolean mkdirs) {
+		File dir = getSessionStoreDir();
+		if (dir == null) {
+			return new ApplicationTemp().getFolder("servlet-sessions");
+		}
+		if (!dir.isAbsolute()) {
+			dir = new File(new ApplicationHome().getDir(), dir.getPath());
+		}
+		if (!dir.exists() && mkdirs) {
+			dir.mkdirs();
+		}
+		Assert.state(!mkdirs || dir.exists(), "Session dir " + dir + " does not exist");
+		Assert.state(!dir.isFile(), "Session dir " + dir + " points to a file");
+		return dir;
+	}
+
 }

spring-boot/src/main/java/org/springframework/boot/context/embedded/ConfigurableEmbeddedServletContainer.java

@@ -79,6 +79,12 @@ public interface ConfigurableEmbeddedServletContainer {
 	 */
 	void setPersistSession(boolean persistSession);
 
+	/**
+	 * Set the directory used to store serialized session data.
+	 * @param sessionStoreDir the directory or {@code null} to use a default location.
+	 */
+	void setSessionStoreDir(File sessionStoreDir);
+
 	/**
 	 * Sets the specific network address that the server should bind to.
 	 * @param address the address to set (defaults to {@code null})

spring-boot/src/main/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainerFactory.java

@@ -53,7 +53,6 @@ import org.eclipse.jetty.util.ssl.SslContextFactory;
 import org.eclipse.jetty.webapp.AbstractConfiguration;
 import org.eclipse.jetty.webapp.Configuration;
 import org.eclipse.jetty.webapp.WebAppContext;
-import org.springframework.boot.ApplicationTemp;
 import org.springframework.boot.context.embedded.AbstractEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.Compression;
 import org.springframework.boot.context.embedded.EmbeddedServletContainer;
@@ -304,8 +303,8 @@ public class JettyEmbeddedServletContainerFactory
 
 	private void configurePersistSession(SessionManager sessionManager) {
 		try {
-			File storeDirectory = new ApplicationTemp().getFolder("jetty-sessions");
-			((HashSessionManager) sessionManager).setStoreDirectory(storeDirectory);
+			((HashSessionManager) sessionManager)
+					.setStoreDirectory(getValidSessionStoreDir());
 		}
 		catch (IOException ex) {
 			throw new IllegalStateException(ex);

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainerFactory.java

@@ -52,7 +52,6 @@ import org.apache.coyote.ProtocolHandler;
 import org.apache.coyote.http11.AbstractHttp11JsseProtocol;
 import org.apache.coyote.http11.AbstractHttp11Protocol;
 import org.springframework.beans.BeanUtils;
-import org.springframework.boot.ApplicationTemp;
 import org.springframework.boot.context.embedded.AbstractEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.Compression;
 import org.springframework.boot.context.embedded.EmbeddedServletContainer;
@@ -411,7 +410,7 @@ public class TomcatEmbeddedServletContainerFactory
 		Assert.state(manager instanceof StandardManager,
 				"Unable to persist HTTP session state using manager type "
 						+ manager.getClass().getName());
-		File folder = new ApplicationTemp().getFolder("tomcat-sessions");
+		File folder = getValidSessionStoreDir();
 		File file = new File(folder, "SESSIONS.ser");
 		((StandardManager) manager).setPathname(file.getAbsolutePath());
 	}

spring-boot/src/main/java/org/springframework/boot/context/embedded/undertow/UndertowEmbeddedServletContainerFactory.java

@@ -38,7 +38,6 @@ import javax.servlet.ServletContainerInitializer;
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 
-import org.springframework.boot.ApplicationTemp;
 import org.springframework.boot.context.embedded.AbstractEmbeddedServletContainerFactory;
 import org.springframework.boot.context.embedded.EmbeddedServletContainer;
 import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
@@ -360,7 +359,7 @@ public class UndertowEmbeddedServletContainerFactory
 			configureAccessLog(deployment);
 		}
 		if (isPersistSession()) {
-			File folder = new ApplicationTemp().getFolder("undertow-sessions");
+			File folder = getValidSessionStoreDir();
 			deployment.setSessionPersistenceManager(new FileSessionPersistence(folder));
 		}
 		DeploymentManager manager = Servlets.defaultContainer().addDeployment(deployment);

spring-boot/src/test/java/org/springframework/boot/context/embedded/AbstractEmbeddedServletContainerFactoryTests.java

@@ -19,6 +19,7 @@ package org.springframework.boot.context.embedded;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileWriter;
+import java.io.FilenameFilter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.PrintWriter;
@@ -58,6 +59,8 @@ import org.junit.Test;
 import org.junit.rules.ExpectedException;
 import org.junit.rules.TemporaryFolder;
 import org.mockito.InOrder;
+import org.springframework.boot.ApplicationHome;
+import org.springframework.boot.ApplicationTemp;
 import org.springframework.boot.context.embedded.Ssl.ClientAuth;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
@@ -72,6 +75,7 @@ import org.springframework.util.concurrent.ListenableFuture;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.lessThan;
 import static org.hamcrest.Matchers.notNullValue;
@@ -564,6 +568,54 @@ public abstract class AbstractEmbeddedServletContainerFactoryTests {
 		assertThat(message, s3.split(":")[0], equalTo(s2.split(":")[1]));
 	}
 
+	@Test
+	public void persistSessionInSpecificSessionStoreDir() throws Exception {
+		AbstractEmbeddedServletContainerFactory factory = getFactory();
+		File sessionStoreDir = this.temporaryFolder.newFolder();
+		factory.setPersistSession(true);
+		factory.setSessionStoreDir(sessionStoreDir);
+		this.container = factory
+				.getEmbeddedServletContainer(sessionServletRegistration());
+		this.container.start();
+		getResponse(getLocalUrl("/session"));
+		this.container.stop();
+		File[] dirContents = sessionStoreDir.listFiles(new FilenameFilter() {
+
+			@Override
+			public boolean accept(File dir, String name) {
+				return !(".".equals(name) || "..".equals(name));
+			}
+
+		});
+		assertThat(dirContents.length, greaterThan(0));
+	}
+
+	@Test
+	public void getValidSessionStoreWhenSessionStoreNotSet() throws Exception {
+		AbstractEmbeddedServletContainerFactory factory = getFactory();
+		File dir = factory.getValidSessionStoreDir(false);
+		assertThat(dir.getName(), equalTo("servlet-sessions"));
+		assertThat(dir.getParentFile(), equalTo(new ApplicationTemp().getFolder()));
+	}
+
+	@Test
+	public void getValidSessionStoreWhenSessionStoreIsRelative() throws Exception {
+		AbstractEmbeddedServletContainerFactory factory = getFactory();
+		factory.setSessionStoreDir(new File("sessions"));
+		File dir = factory.getValidSessionStoreDir(false);
+		assertThat(dir.getName(), equalTo("sessions"));
+		assertThat(dir.getParentFile(), equalTo(new ApplicationHome().getDir()));
+	}
+
+	@Test
+	public void getValidSessionStoreWhenSessionStoreReferencesFile() throws Exception {
+		AbstractEmbeddedServletContainerFactory factory = getFactory();
+		factory.setSessionStoreDir(this.temporaryFolder.newFile());
+		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expectMessage("points to a file");
+		factory.getValidSessionStoreDir(false);
+	}
+
 	@Test
 	public void compression() throws Exception {
 		assertTrue(doTestCompression(10000, null, null));