Configure Undertow to eagerly initialize Filters by default

Closes gh-9232

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

@@ -1129,6 +1129,11 @@ public class ServerProperties {
 		 */
 		private Boolean directBuffers;
 
+		/**
+		 * Whether servlet filters should be initialized on startup.
+		 */
+		private boolean eagerFilterInit = true;
+
 		private final Accesslog accesslog = new Accesslog();
 
 		public long getMaxHttpPostSize() {
@@ -1171,6 +1176,14 @@ public class ServerProperties {
 			this.directBuffers = directBuffers;
 		}
 
+		public boolean isEagerFilterInit() {
+			return this.eagerFilterInit;
+		}
+
+		public void setEagerFilterInit(boolean eagerFilterInit) {
+			this.eagerFilterInit = eagerFilterInit;
+		}
+
 		public Accesslog getAccesslog() {
 			return this.accesslog;
 		}

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

@@ -472,11 +472,12 @@ public class DefaultServletWebServerFactoryCustomizer
 				customizeMaxHttpPostSize(factory,
 						undertowProperties.getMaxHttpPostSize());
 			}
-
 			if (serverProperties.getConnectionTimeout() != null) {
 				customizeConnectionTimeout(factory,
 						serverProperties.getConnectionTimeout());
 			}
+			factory.addDeploymentInfoCustomizers((deploymentInfo) -> deploymentInfo
+					.setEagerFilterInit(undertowProperties.isEagerFilterInit()));
 		}
 
 		private static void customizeConnectionTimeout(

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

@@ -246,6 +246,7 @@ content into your application; rather pick only the properties that you need.
 	server.undertow.buffer-size= # Size of each buffer in bytes.
 	server.undertow.direct-buffers= # Allocate buffers outside the Java heap.
 	server.undertow.io-threads= # Number of I/O threads to create for the worker.
+	server.undertow.eager-filter-init=true # Whether servlet filters should be initialized on startup.
 	server.undertow.max-http-post-size=0 # Maximum size in bytes of the HTTP post content.
 	server.undertow.worker-threads= # Number of worker threads.
 

spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowServletWebServerFactory.java

@@ -137,6 +137,8 @@ public class UndertowServletWebServerFactory extends AbstractServletWebServerFac
 
 	private boolean useForwardHeaders;
 
+	private boolean eagerInitFilters = true;
+
 	/**
 	 * Create a new {@link UndertowServletWebServerFactory} instance.
 	 */
@@ -392,6 +394,7 @@ public class UndertowServletWebServerFactory extends AbstractServletWebServerFac
 		configureErrorPages(deployment);
 		deployment.setServletStackTraces(ServletStackTraces.NONE);
 		deployment.setResourceManager(getDocumentRootResourceManager());
+		deployment.setEagerFilterInit(this.eagerInitFilters);
 		configureMimeMappings(deployment);
 		for (UndertowDeploymentInfoCustomizer customizer : this.deploymentInfoCustomizers) {
 			customizer.customize(deployment);
@@ -637,6 +640,25 @@ public class UndertowServletWebServerFactory extends AbstractServletWebServerFac
 		this.useForwardHeaders = useForwardHeaders;
 	}
 
+	/**
+	 * Return if filters should be initialized eagerly.
+	 * @return {@code true} if filters are initialized eagerly, otherwise {@code false}.
+	 * @since 2.0.0
+	 */
+	public boolean isEagerInitFilters() {
+		return this.eagerInitFilters;
+	}
+
+	/**
+	 * Set whether filters should be initialized eagerly.
+	 * @param eagerInitFilters {@code true} if filters are initialized eagerly, otherwise
+	 * {@code false}.
+	 * @since 2.0.0
+	 */
+	public void setEagerInitFilters(boolean eagerInitFilters) {
+		this.eagerInitFilters = eagerInitFilters;
+	}
+
 	/**
 	 * {@link ResourceManager} that exposes resource in {@code META-INF/resources}
 	 * directory of nested (in {@code BOOT-INF/lib} or {@code WEB-INF/lib}) jars.

spring-boot/src/test/java/org/springframework/boot/web/embedded/jetty/JettyServletWebServerFactoryTests.java

@@ -23,13 +23,7 @@ import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
-import javax.servlet.Filter;
-import javax.servlet.FilterChain;
-import javax.servlet.FilterConfig;
-import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -51,8 +45,6 @@ import org.mockito.InOrder;
 import org.springframework.boot.web.server.Compression;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.Ssl;
-import org.springframework.boot.web.server.WebServerException;
-import org.springframework.boot.web.servlet.ServletContextInitializer;
 import org.springframework.boot.web.servlet.ServletRegistrationBean;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactory;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactoryTests;
@@ -285,38 +277,6 @@ public class JettyServletWebServerFactoryTests
 				.isSameAs(threadPool);
 	}
 
-	@Test
-	public void faultyFilterCausesStartFailure() throws Exception {
-		JettyServletWebServerFactory factory = getFactory();
-		factory.addInitializers(new ServletContextInitializer() {
-
-			@Override
-			public void onStartup(ServletContext servletContext) throws ServletException {
-				servletContext.addFilter("faulty", new Filter() {
-
-					@Override
-					public void init(FilterConfig filterConfig) throws ServletException {
-						throw new ServletException("Faulty filter");
-					}
-
-					@Override
-					public void doFilter(ServletRequest request, ServletResponse response,
-							FilterChain chain) throws IOException, ServletException {
-						chain.doFilter(request, response);
-					}
-
-					@Override
-					public void destroy() {
-					}
-
-				});
-			}
-
-		});
-		this.thrown.expect(WebServerException.class);
-		factory.getWebServer().start();
-	}
-
 	@Override
 	@SuppressWarnings("serial")
 	// Workaround for Jetty issue - https://bugs.eclipse.org/bugs/show_bug.cgi?id=470646

spring-boot/src/test/java/org/springframework/boot/web/embedded/tomcat/TomcatServletWebServerFactoryTests.java

@@ -26,13 +26,7 @@ import java.util.concurrent.TimeUnit;
 
 import javax.naming.InitialContext;
 import javax.naming.NamingException;
-import javax.servlet.Filter;
-import javax.servlet.FilterChain;
-import javax.servlet.FilterConfig;
-import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
 
 import org.apache.catalina.Container;
 import org.apache.catalina.Context;
@@ -57,7 +51,6 @@ import org.mockito.InOrder;
 import org.springframework.boot.testutil.InternalOutputCapture;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.WebServerException;
-import org.springframework.boot.web.servlet.ServletContextInitializer;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactory;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactoryTests;
 import org.springframework.test.util.ReflectionTestUtils;
@@ -451,38 +444,6 @@ public class TomcatServletWebServerFactoryTests
 		assertThat(sessionIdGenerator.getJvmRoute()).isEqualTo("test");
 	}
 
-	@Test
-	public void faultyFilterCausesStartFailure() throws Exception {
-		TomcatServletWebServerFactory factory = getFactory();
-		factory.addInitializers(new ServletContextInitializer() {
-
-			@Override
-			public void onStartup(ServletContext servletContext) throws ServletException {
-				servletContext.addFilter("faulty", new Filter() {
-
-					@Override
-					public void init(FilterConfig filterConfig) throws ServletException {
-						throw new ServletException("Faulty filter");
-					}
-
-					@Override
-					public void doFilter(ServletRequest request, ServletResponse response,
-							FilterChain chain) throws IOException, ServletException {
-						chain.doFilter(request, response);
-					}
-
-					@Override
-					public void destroy() {
-					}
-
-				});
-			}
-
-		});
-		this.thrown.expect(WebServerException.class);
-		factory.getWebServer().start();
-	}
-
 	@Override
 	protected JspServlet getJspServlet() throws ServletException {
 		Tomcat tomcat = ((TomcatWebServer) this.webServer).getTomcat();

spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java

@@ -50,6 +50,9 @@ import java.util.zip.GZIPInputStream;
 
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLException;
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
 import javax.servlet.GenericServlet;
 import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
@@ -88,6 +91,7 @@ import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.Ssl.ClientAuth;
 import org.springframework.boot.web.server.SslStoreProvider;
 import org.springframework.boot.web.server.WebServer;
+import org.springframework.boot.web.server.WebServerException;
 import org.springframework.boot.web.servlet.FilterRegistrationBean;
 import org.springframework.boot.web.servlet.ServletContextInitializer;
 import org.springframework.boot.web.servlet.ServletRegistrationBean;
@@ -944,6 +948,38 @@ public abstract class AbstractServletWebServerFactoryTests {
 		assertThat(options.getDevelopment()).isEqualTo(false);
 	}
 
+	@Test
+	public void faultyFilterCausesStartFailure() throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		factory.addInitializers(new ServletContextInitializer() {
+
+			@Override
+			public void onStartup(ServletContext servletContext) throws ServletException {
+				servletContext.addFilter("faulty", new Filter() {
+
+					@Override
+					public void init(FilterConfig filterConfig) throws ServletException {
+						throw new ServletException("Faulty filter");
+					}
+
+					@Override
+					public void doFilter(ServletRequest request, ServletResponse response,
+							FilterChain chain) throws IOException, ServletException {
+						chain.doFilter(request, response);
+					}
+
+					@Override
+					public void destroy() {
+					}
+
+				});
+			}
+
+		});
+		this.thrown.expect(WebServerException.class);
+		factory.getWebServer().start();
+	}
+
 	protected abstract void addConnector(int port,
 			AbstractServletWebServerFactory factory);