Add support for gracefully shutting down the web server

This commit adds support for gracefully shutting down the embedded
web server. When a grace period is configured
(server.shutdown.grace-period), upon shutdown, the web server will no
longer permit new requests and will wait for up to the grace period
for active requests to complete.

Closes gh-4657

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

@@ -36,6 +36,7 @@ import org.springframework.boot.context.properties.NestedConfigurationProperty;
 import org.springframework.boot.convert.DurationUnit;
 import org.springframework.boot.web.server.Compression;
 import org.springframework.boot.web.server.Http2;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.servlet.server.Encoding;
 import org.springframework.boot.web.servlet.server.Jsp;
@@ -114,6 +115,9 @@ public class ServerProperties {
 	@NestedConfigurationProperty
 	private final Http2 http2 = new Http2();
 
+	@NestedConfigurationProperty
+	private final Shutdown shutdown = new Shutdown();
+
 	private final Servlet servlet = new Servlet();
 
 	private final Tomcat tomcat = new Tomcat();
@@ -199,6 +203,10 @@ public class ServerProperties {
 		return this.http2;
 	}
 
+	public Shutdown getShutdown() {
+		return this.shutdown;
+	}
+
 	public Servlet getServlet() {
 		return this.servlet;
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/ReactiveWebServerFactoryCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -52,6 +52,7 @@ public class ReactiveWebServerFactoryCustomizer
 		map.from(this.serverProperties::getSsl).to(factory::setSsl);
 		map.from(this.serverProperties::getCompression).to(factory::setCompression);
 		map.from(this.serverProperties::getHttp2).to(factory::setHttp2);
+		map.from(this.serverProperties.getShutdown()).to(factory::setShutdown);
 	}
 
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -60,6 +60,7 @@ public class ServletWebServerFactoryCustomizer
 		map.from(this.serverProperties::getHttp2).to(factory::setHttp2);
 		map.from(this.serverProperties::getServerHeader).to(factory::setServerHeader);
 		map.from(this.serverProperties.getServlet()::getContextParameters).to(factory::setInitParameters);
+		map.from(this.serverProperties.getShutdown()).to(factory::setShutdown);
 	}
 
 }

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/reactive/ReactiveWebServerFactoryCustomizerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -17,14 +17,18 @@
 package org.springframework.boot.autoconfigure.web.reactive;
 
 import java.net.InetAddress;
+import java.time.Duration;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
 
 import org.springframework.boot.autoconfigure.web.ServerProperties;
 import org.springframework.boot.web.reactive.server.ConfigurableReactiveWebServerFactory;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 
@@ -71,4 +75,14 @@ class ReactiveWebServerFactoryCustomizerTests {
 		verify(factory).setSsl(ssl);
 	}
 
+	@Test
+	void whenGracePeriodPropertyIsSetThenGracePeriodIsCustomized() {
+		this.properties.getShutdown().setGracePeriod(Duration.ofSeconds(30));
+		ConfigurableReactiveWebServerFactory factory = mock(ConfigurableReactiveWebServerFactory.class);
+		this.customizer.customize(factory);
+		ArgumentCaptor<Shutdown> shutdownCaptor = ArgumentCaptor.forClass(Shutdown.class);
+		verify(factory).setShutdown(shutdownCaptor.capture());
+		assertThat(shutdownCaptor.getValue().getGracePeriod()).isEqualTo(Duration.ofSeconds(30));
+	}
+
 }

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/ServletWebServerFactoryCustomizerTests.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.autoconfigure.web.servlet;
 
 import java.io.File;
+import java.time.Duration;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -29,6 +30,7 @@ import org.springframework.boot.context.properties.bind.Bindable;
 import org.springframework.boot.context.properties.bind.Binder;
 import org.springframework.boot.context.properties.source.ConfigurationPropertySource;
 import org.springframework.boot.context.properties.source.MapConfigurationPropertySource;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.servlet.server.ConfigurableServletWebServerFactory;
 import org.springframework.boot.web.servlet.server.Jsp;
@@ -154,6 +156,18 @@ class ServletWebServerFactoryCustomizerTests {
 		assertThat(sessionCaptor.getValue().getStoreDir()).isEqualTo(new File("myfolder"));
 	}
 
+	@Test
+	void whenGracePeriodPropertyIsSetThenGracePeriodIsCustomized() {
+		Map<String, String> map = new HashMap<>();
+		map.put("server.shutdown.grace-period", "30s");
+		bindProperties(map);
+		ConfigurableServletWebServerFactory factory = mock(ConfigurableServletWebServerFactory.class);
+		this.customizer.customize(factory);
+		ArgumentCaptor<Shutdown> shutdownCaptor = ArgumentCaptor.forClass(Shutdown.class);
+		verify(factory).setShutdown(shutdownCaptor.capture());
+		assertThat(shutdownCaptor.getValue().getGracePeriod()).isEqualTo(Duration.ofSeconds(30));
+	}
+
 	private void bindProperties(Map<String, String> map) {
 		ConfigurationPropertySource source = new MapConfigurationPropertySource(map);
 		new Binder(source).bind("server", Bindable.ofInstance(this.properties));

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

@@ -2960,6 +2960,26 @@ You can learn more about the resource configuration on the client side in the <<
 
 
 
+[[boot-features-graceful-shutdown]]
+== Graceful shutdown
+Graceful shutdown is supported with all four embedded web servers (Jetty, Reactor Netty, Tomcat, and Undertow) and with both reactive and Servlet-based web applications.
+When enabled, shutdown of the application will include a grace period of configurable duration.
+During this grace period, existing requests will be allowed to complete but no new requests will be permitted.
+The exact way in which new requests are not permitted varies depending on the web server that is being used.
+Jetty, Reactor Netty, and Tomcat will stop accepting requests at the network layer.
+Undertow will accept requests but respond immediately with a service unavailable (503) response.
+
+Graceful shutdown occurs as one of the first steps during application close processing and before any beans have been destroyed.
+This ensures that the beans are available for use by any processing that occurs while in-flight requests are being allowed to complete.
+To enable graceful shutdown, configure the configprop:server.shutdown.grace-period[] property, as shown in the following example:
+
+[source,properties,indent=0,configprops]
+----
+server.shutdown.grace-period=30s
+----
+
+
+
 [[boot-features-rsocket]]
 == RSocket
 https://rsocket.io[RSocket] is a binary protocol for use on byte stream transports.

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyGracefulShutdown.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.embedded.jetty;
+
+import java.time.Duration;
+import java.util.function.Supplier;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.eclipse.jetty.server.Connector;
+import org.eclipse.jetty.server.Server;
+import org.eclipse.jetty.server.ServerConnector;
+
+import org.springframework.boot.web.server.GracefulShutdown;
+
+/**
+ * {@link GracefulShutdown} for Jetty.
+ *
+ * @author Andy Wilkinson
+ */
+class JettyGracefulShutdown implements GracefulShutdown {
+
+	private static final Log logger = LogFactory.getLog(JettyGracefulShutdown.class);
+
+	private final Server server;
+
+	private final Supplier<Integer> activeRequests;
+
+	private final Duration period;
+
+	private volatile boolean shuttingDown = false;
+
+	JettyGracefulShutdown(Server server, Supplier<Integer> activeRequests, Duration period) {
+		this.server = server;
+		this.activeRequests = activeRequests;
+		this.period = period;
+	}
+
+	@Override
+	public boolean shutDownGracefully() {
+		logger.info("Commencing graceful shutdown, allowing up to " + this.period.getSeconds()
+				+ "s for active requests to complete");
+		for (Connector connector : this.server.getConnectors()) {
+			((ServerConnector) connector).setAccepting(false);
+		}
+		this.shuttingDown = true;
+		long end = System.currentTimeMillis() + this.period.toMillis();
+		while (System.currentTimeMillis() < end && (this.activeRequests.get() > 0)) {
+			try {
+				Thread.sleep(100);
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
+		}
+		this.shuttingDown = false;
+		long activeRequests = this.activeRequests.get();
+		if (activeRequests == 0) {
+			logger.info("Graceful shutdown complete");
+			return true;
+		}
+		if (logger.isInfoEnabled()) {
+			logger.info("Grace period elaped with " + activeRequests + " request(s) still active");
+		}
+		return activeRequests == 0;
+	}
+
+	@Override
+	public boolean isShuttingDown() {
+		return this.shuttingDown;
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyReactiveWebServerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -103,7 +103,7 @@ public class JettyReactiveWebServerFactory extends AbstractReactiveWebServerFact
 	public WebServer getWebServer(HttpHandler httpHandler) {
 		JettyHttpHandlerAdapter servlet = new JettyHttpHandlerAdapter(httpHandler);
 		Server server = createJettyServer(servlet);
-		return new JettyWebServer(server, getPort() >= 0);
+		return new JettyWebServer(server, getPort() >= 0, getShutdown().getGracePeriod());
 	}
 
 	@Override

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyServletWebServerFactory.java

@@ -398,7 +398,7 @@ public class JettyServletWebServerFactory extends AbstractServletWebServerFactor
 	 * @return a new {@link JettyWebServer} instance
 	 */
 	protected JettyWebServer getJettyWebServer(Server server) {
-		return new JettyWebServer(server, getPort() >= 0);
+		return new JettyWebServer(server, getPort() >= 0, getShutdown().getGracePeriod());
 	}
 
 	@Override

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyWebServer.java

@@ -18,6 +18,7 @@ package org.springframework.boot.web.embedded.jetty;
 
 import java.io.IOException;
 import java.net.BindException;
+import java.time.Duration;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
@@ -32,8 +33,11 @@ import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.handler.ContextHandler;
 import org.eclipse.jetty.server.handler.HandlerCollection;
 import org.eclipse.jetty.server.handler.HandlerWrapper;
+import org.eclipse.jetty.server.handler.StatisticsHandler;
 import org.eclipse.jetty.util.component.AbstractLifeCycle;
 
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -63,6 +67,8 @@ public class JettyWebServer implements WebServer {
 
 	private final boolean autoStart;
 
+	private final GracefulShutdown gracefulShutdown;
+
 	private Connector[] connectors;
 
 	private volatile boolean started;
@@ -81,9 +87,31 @@ public class JettyWebServer implements WebServer {
 	 * @param autoStart if auto-starting the server
 	 */
 	public JettyWebServer(Server server, boolean autoStart) {
+		this(server, autoStart, null);
+	}
+
+	/**
+	 * Create a new {@link JettyWebServer} instance.
+	 * @param server the underlying Jetty server
+	 * @param autoStart if auto-starting the server
+	 * @param shutdownGracePeriod grace period to use when shutting down
+	 * @since 2.3.0
+	 */
+	public JettyWebServer(Server server, boolean autoStart, Duration shutdownGracePeriod) {
 		this.autoStart = autoStart;
 		Assert.notNull(server, "Jetty Server must not be null");
 		this.server = server;
+		GracefulShutdown gracefulShutdown = null;
+		if (shutdownGracePeriod != null) {
+			StatisticsHandler handler = new StatisticsHandler();
+			handler.setHandler(server.getHandler());
+			server.setHandler(handler);
+			gracefulShutdown = new JettyGracefulShutdown(server, handler::getRequestsActive, shutdownGracePeriod);
+		}
+		else {
+			gracefulShutdown = new ImmediateGracefulShutdown();
+		}
+		this.gracefulShutdown = gracefulShutdown;
 		initialize();
 	}
 
@@ -261,6 +289,15 @@ public class JettyWebServer implements WebServer {
 		return 0;
 	}
 
+	@Override
+	public boolean shutDownGracefully() {
+		return this.gracefulShutdown.shutDownGracefully();
+	}
+
+	boolean inGracefulShutdown() {
+		return this.gracefulShutdown.isShuttingDown();
+	}
+
 	/**
 	 * Returns access to the underlying Jetty Server.
 	 * @return the Jetty server

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyGracefulShutdown.java

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.embedded.netty;
+
+import java.time.Duration;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.BiFunction;
+import java.util.function.Supplier;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.reactivestreams.Publisher;
+import reactor.netty.DisposableServer;
+import reactor.netty.http.server.HttpServerRequest;
+import reactor.netty.http.server.HttpServerResponse;
+
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;
+
+/**
+ * {@link GracefulShutdown} for a Reactor Netty {@link DisposableServer}.
+ *
+ * @author Andy Wilkinson
+ */
+final class NettyGracefulShutdown implements GracefulShutdown {
+
+	private static final Log logger = LogFactory.getLog(NettyGracefulShutdown.class);
+
+	private final Supplier<DisposableServer> disposableServer;
+
+	private final Duration lifecycleTimeout;
+
+	private final Duration period;
+
+	private final AtomicLong activeRequests = new AtomicLong();
+
+	private volatile boolean shuttingDown;
+
+	NettyGracefulShutdown(Supplier<DisposableServer> disposableServer, Duration lifecycleTimeout, Duration period) {
+		this.disposableServer = disposableServer;
+		this.lifecycleTimeout = lifecycleTimeout;
+		this.period = period;
+	}
+
+	@Override
+	public boolean shutDownGracefully() {
+		logger.info("Commencing graceful shutdown, allowing up to " + this.period.getSeconds()
+				+ "s for active requests to complete");
+		DisposableServer server = this.disposableServer.get();
+		if (server == null) {
+			return false;
+		}
+		if (this.lifecycleTimeout != null) {
+			server.disposeNow(this.lifecycleTimeout);
+		}
+		else {
+			server.disposeNow();
+		}
+		this.shuttingDown = true;
+		long end = System.currentTimeMillis() + this.period.toMillis();
+		try {
+			while (this.activeRequests.get() > 0 && System.currentTimeMillis() < end) {
+				try {
+					Thread.sleep(50);
+				}
+				catch (InterruptedException ex) {
+					Thread.currentThread().interrupt();
+					break;
+				}
+			}
+			long activeRequests = this.activeRequests.get();
+			if (activeRequests == 0) {
+				logger.info("Graceful shutdown complete");
+				return true;
+			}
+			if (logger.isInfoEnabled()) {
+				logger.info("Grace period elaped with " + activeRequests + " request(s) still active");
+			}
+			return false;
+		}
+		finally {
+			this.shuttingDown = false;
+		}
+	}
+
+	@Override
+	public boolean isShuttingDown() {
+		return this.shuttingDown;
+	}
+
+	BiFunction<? super HttpServerRequest, ? super HttpServerResponse, ? extends Publisher<Void>> wrapHandler(
+			ReactorHttpHandlerAdapter handlerAdapter) {
+		if (this.period == null) {
+			return handlerAdapter;
+		}
+		return (request, response) -> {
+			this.activeRequests.incrementAndGet();
+			return handlerAdapter.apply(request, response).doOnTerminate(() -> this.activeRequests.decrementAndGet());
+		};
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyReactiveWebServerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -31,6 +31,7 @@ import reactor.netty.resources.LoopResources;
 
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.ReactiveWebServerFactory;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.http.client.reactive.ReactorResourceFactory;
 import org.springframework.http.server.reactive.HttpHandler;
@@ -55,6 +56,8 @@ public class NettyReactiveWebServerFactory extends AbstractReactiveWebServerFact
 
 	private ReactorResourceFactory resourceFactory;
 
+	private Shutdown shutdown;
+
 	public NettyReactiveWebServerFactory() {
 	}
 
@@ -66,7 +69,8 @@ public class NettyReactiveWebServerFactory extends AbstractReactiveWebServerFact
 	public WebServer getWebServer(HttpHandler httpHandler) {
 		HttpServer httpServer = createHttpServer();
 		ReactorHttpHandlerAdapter handlerAdapter = new ReactorHttpHandlerAdapter(httpHandler);
-		NettyWebServer webServer = new NettyWebServer(httpServer, handlerAdapter, this.lifecycleTimeout);
+		NettyWebServer webServer = new NettyWebServer(httpServer, handlerAdapter, this.lifecycleTimeout,
+				(this.shutdown == null) ? null : this.shutdown.getGracePeriod());
 		webServer.setRouteProviders(this.routeProviders);
 		return webServer;
 	}
@@ -136,6 +140,16 @@ public class NettyReactiveWebServerFactory extends AbstractReactiveWebServerFact
 		this.resourceFactory = resourceFactory;
 	}
 
+	@Override
+	public void setShutdown(Shutdown shutdown) {
+		this.shutdown = shutdown;
+	}
+
+	@Override
+	public Shutdown getShutdown() {
+		return this.shutdown;
+	}
+
 	private HttpServer createHttpServer() {
 		HttpServer server = HttpServer.create();
 		if (this.resourceFactory != null) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/netty/NettyWebServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -19,16 +19,21 @@ package org.springframework.boot.web.embedded.netty;
 import java.time.Duration;
 import java.util.Collections;
 import java.util.List;
+import java.util.function.BiFunction;
 import java.util.function.Predicate;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.reactivestreams.Publisher;
 import reactor.netty.ChannelBindException;
 import reactor.netty.DisposableServer;
 import reactor.netty.http.server.HttpServer;
 import reactor.netty.http.server.HttpServerRequest;
+import reactor.netty.http.server.HttpServerResponse;
 import reactor.netty.http.server.HttpServerRoutes;
 
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -53,20 +58,44 @@ public class NettyWebServer implements WebServer {
 
 	private final HttpServer httpServer;
 
-	private final ReactorHttpHandlerAdapter handlerAdapter;
+	private final BiFunction<? super HttpServerRequest, ? super HttpServerResponse, ? extends Publisher<Void>> handler;
 
 	private final Duration lifecycleTimeout;
 
+	private final GracefulShutdown shutdown;
+
 	private List<NettyRouteProvider> routeProviders = Collections.emptyList();
 
-	private DisposableServer disposableServer;
+	private volatile DisposableServer disposableServer;
 
 	public NettyWebServer(HttpServer httpServer, ReactorHttpHandlerAdapter handlerAdapter, Duration lifecycleTimeout) {
+		this(httpServer, handlerAdapter, lifecycleTimeout, null);
+	}
+
+	/**
+	 * Creates a {@code NettyWebServer}.
+	 * @param httpServer the Reactor Netty HTTP server
+	 * @param handlerAdapter the Spring WebFlux handler adapter
+	 * @param lifecycleTimeout lifecycle timeout
+	 * @param shutdownGracePeriod grace period for handler for graceful shutdown
+	 * @since 2.3.0
+	 */
+	public NettyWebServer(HttpServer httpServer, ReactorHttpHandlerAdapter handlerAdapter, Duration lifecycleTimeout,
+			Duration shutdownGracePeriod) {
 		Assert.notNull(httpServer, "HttpServer must not be null");
 		Assert.notNull(handlerAdapter, "HandlerAdapter must not be null");
 		this.httpServer = httpServer;
-		this.handlerAdapter = handlerAdapter;
 		this.lifecycleTimeout = lifecycleTimeout;
+		if (shutdownGracePeriod != null) {
+			NettyGracefulShutdown gracefulShutdown = new NettyGracefulShutdown(() -> this.disposableServer,
+					lifecycleTimeout, shutdownGracePeriod);
+			this.handler = gracefulShutdown.wrapHandler(handlerAdapter);
+			this.shutdown = gracefulShutdown;
+		}
+		else {
+			this.handler = handlerAdapter;
+			this.shutdown = new ImmediateGracefulShutdown();
+		}
 	}
 
 	public void setRouteProviders(List<NettyRouteProvider> routeProviders) {
@@ -91,10 +120,19 @@ public class NettyWebServer implements WebServer {
 		}
 	}
 
+	@Override
+	public boolean shutDownGracefully() {
+		return this.shutdown.shutDownGracefully();
+	}
+
+	boolean inGracefulShutdown() {
+		return this.shutdown.isShuttingDown();
+	}
+
 	private DisposableServer startHttpServer() {
 		HttpServer server = this.httpServer;
 		if (this.routeProviders.isEmpty()) {
-			server = server.handle(this.handlerAdapter);
+			server = server.handle(this.handler);
 		}
 		else {
 			server = server.route(this::applyRouteProviders);
@@ -109,7 +147,7 @@ public class NettyWebServer implements WebServer {
 		for (NettyRouteProvider provider : this.routeProviders) {
 			routes = provider.apply(routes);
 		}
-		routes.route(ALWAYS, this.handlerAdapter);
+		routes.route(ALWAYS, this.handler);
 	}
 
 	private ChannelBindException findBindException(Exception ex) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatGracefulShutdown.java

@@ -0,0 +1,126 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.embedded.tomcat;
+
+import java.lang.reflect.Field;
+import java.time.Duration;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.apache.catalina.Container;
+import org.apache.catalina.Service;
+import org.apache.catalina.connector.Connector;
+import org.apache.catalina.core.StandardWrapper;
+import org.apache.catalina.startup.Tomcat;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.util.ReflectionUtils;
+
+/**
+ * {@link GracefulShutdown} for {@link Tomcat}.
+ *
+ * @author Andy Wilkinson
+ */
+class TomcatGracefulShutdown implements GracefulShutdown {
+
+	private static final Log logger = LogFactory.getLog(TomcatGracefulShutdown.class);
+
+	private final Tomcat tomcat;
+
+	private final Duration period;
+
+	private volatile boolean shuttingDown = false;
+
+	TomcatGracefulShutdown(Tomcat tomcat, Duration period) {
+		this.tomcat = tomcat;
+		this.period = period;
+	}
+
+	@Override
+	public boolean shutDownGracefully() {
+		logger.info("Commencing graceful shutdown, allowing up to " + this.period.getSeconds()
+				+ "s for active requests to complete");
+		List<Connector> connectors = getConnectors();
+		for (Connector connector : connectors) {
+			connector.pause();
+			connector.getProtocolHandler().closeServerSocketGraceful();
+		}
+		this.shuttingDown = true;
+		try {
+			long end = System.currentTimeMillis() + this.period.toMillis();
+			for (Container host : this.tomcat.getEngine().findChildren()) {
+				for (Container context : host.findChildren()) {
+					while (active(context)) {
+						if (System.currentTimeMillis() > end) {
+							logger.info("Grace period elaped with one or more requests still active");
+							return false;
+						}
+						Thread.sleep(50);
+					}
+				}
+			}
+
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+		finally {
+			this.shuttingDown = false;
+		}
+		logger.info("Graceful shutdown complete");
+		return true;
+	}
+
+	private boolean active(Container context) {
+		try {
+			Field field = ReflectionUtils.findField(context.getClass(), "inProgressAsyncCount");
+			field.setAccessible(true);
+			AtomicLong inProgressAsyncCount = (AtomicLong) field.get(context);
+			if (inProgressAsyncCount.get() > 0) {
+				return true;
+			}
+			for (Container wrapper : context.findChildren()) {
+				if (((StandardWrapper) wrapper).getCountAllocated() > 0) {
+					return true;
+				}
+			}
+			return false;
+		}
+		catch (Exception ex) {
+			throw new RuntimeException(ex);
+		}
+	}
+
+	private List<Connector> getConnectors() {
+		List<Connector> connectors = new ArrayList<>();
+		for (Service service : this.tomcat.getServer().findServices()) {
+			for (Connector connector : service.findConnectors()) {
+				connectors.add(connector);
+			}
+		}
+		return connectors;
+	}
+
+	@Override
+	public boolean isShuttingDown() {
+		return this.shuttingDown;
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatReactiveWebServerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -131,7 +131,7 @@ public class TomcatReactiveWebServerFactory extends AbstractReactiveWebServerFac
 		}
 		TomcatHttpHandlerAdapter servlet = new TomcatHttpHandlerAdapter(httpHandler);
 		prepareContext(tomcat.getHost(), servlet);
-		return new TomcatWebServer(tomcat, getPort() >= 0);
+		return getTomcatWebServer(tomcat);
 	}
 
 	private void configureEngine(Engine engine) {
@@ -413,7 +413,7 @@ public class TomcatReactiveWebServerFactory extends AbstractReactiveWebServerFac
 	 * @return a new {@link TomcatWebServer} instance
 	 */
 	protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) {
-		return new TomcatWebServer(tomcat, getPort() >= 0);
+		return new TomcatWebServer(tomcat, getPort() >= 0, getShutdown().getGracePeriod());
 	}
 
 	/**

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatServletWebServerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -435,7 +435,7 @@ public class TomcatServletWebServerFactory extends AbstractServletWebServerFacto
 	 * @return a new {@link TomcatWebServer} instance
 	 */
 	protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) {
-		return new TomcatWebServer(tomcat, getPort() >= 0);
+		return new TomcatWebServer(tomcat, getPort() >= 0, getShutdown().getGracePeriod());
 	}
 
 	@Override

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -17,6 +17,7 @@
 package org.springframework.boot.web.embedded.tomcat;
 
 import java.net.BindException;
+import java.time.Duration;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Map;
@@ -38,6 +39,8 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.naming.ContextBindings;
 
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -66,6 +69,8 @@ public class TomcatWebServer implements WebServer {
 
 	private final boolean autoStart;
 
+	private final GracefulShutdown gracefulShutdown;
+
 	private volatile boolean started;
 
 	/**
@@ -82,9 +87,22 @@ public class TomcatWebServer implements WebServer {
 	 * @param autoStart if the server should be started
 	 */
 	public TomcatWebServer(Tomcat tomcat, boolean autoStart) {
+		this(tomcat, autoStart, null);
+	}
+
+	/**
+	 * Create a new {@link TomcatWebServer} instance.
+	 * @param tomcat the underlying Tomcat server
+	 * @param autoStart if the server should be started
+	 * @param shutdownGracePeriod grace period to use when shutting down
+	 * @since 2.3.0
+	 */
+	public TomcatWebServer(Tomcat tomcat, boolean autoStart, Duration shutdownGracePeriod) {
 		Assert.notNull(tomcat, "Tomcat Server must not be null");
 		this.tomcat = tomcat;
 		this.autoStart = autoStart;
+		this.gracefulShutdown = (shutdownGracePeriod != null) ? new TomcatGracefulShutdown(tomcat, shutdownGracePeriod)
+				: new ImmediateGracefulShutdown();
 		initialize();
 	}
 
@@ -374,4 +392,13 @@ public class TomcatWebServer implements WebServer {
 		return this.tomcat;
 	}
 
+	@Override
+	public boolean shutDownGracefully() {
+		return this.gracefulShutdown.shutDownGracefully();
+	}
+
+	boolean inGracefulShutdown() {
+		return this.gracefulShutdown.isShuttingDown();
+	}
+
 }

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

@@ -0,0 +1,76 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.embedded.undertow;
+
+import java.time.Duration;
+
+import io.undertow.server.handlers.GracefulShutdownHandler;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.boot.web.server.GracefulShutdown;
+
+/**
+ * {@link GracefulShutdown} for Undertow.
+ *
+ * @author Andy Wilkinson
+ */
+class UndertowGracefulShutdown implements GracefulShutdown {
+
+	private static final Log logger = LogFactory.getLog(UndertowGracefulShutdown.class);
+
+	private final GracefulShutdownHandler gracefulShutdownHandler;
+
+	private final Duration period;
+
+	private volatile boolean shuttingDown;
+
+	UndertowGracefulShutdown(GracefulShutdownHandler gracefulShutdownHandler, Duration period) {
+		this.gracefulShutdownHandler = gracefulShutdownHandler;
+		this.period = period;
+	}
+
+	@Override
+	public boolean shutDownGracefully() {
+		logger.info("Commencing graceful shutdown, allowing up to " + this.period.getSeconds()
+				+ "s for active requests to complete");
+		this.gracefulShutdownHandler.shutdown();
+		this.shuttingDown = true;
+		boolean graceful = false;
+		try {
+			graceful = this.gracefulShutdownHandler.awaitShutdown(this.period.toMillis());
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+		}
+		finally {
+			this.shuttingDown = false;
+		}
+		if (graceful) {
+			logger.info("Graceful shutdown complete");
+			return true;
+		}
+		logger.info("Grace period elaped with one or more requests still active");
+		return graceful;
+	}
+
+	@Override
+	public boolean isShuttingDown() {
+		return this.shuttingDown;
+	}
+
+}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -19,6 +19,7 @@ package org.springframework.boot.web.embedded.undertow;
 import java.io.Closeable;
 import java.io.File;
 import java.io.IOException;
+import java.time.Duration;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.LinkedHashSet;
@@ -29,6 +30,7 @@ import io.undertow.Handlers;
 import io.undertow.Undertow;
 import io.undertow.UndertowOptions;
 import io.undertow.server.HttpHandler;
+import io.undertow.server.handlers.GracefulShutdownHandler;
 import io.undertow.server.handlers.accesslog.AccessLogHandler;
 import io.undertow.server.handlers.accesslog.DefaultAccessLogReceiver;
 import org.xnio.OptionMap;
@@ -38,6 +40,8 @@ import org.xnio.XnioWorker;
 
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.ReactiveWebServerFactory;
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.http.server.reactive.UndertowHttpHandlerAdapter;
 import org.springframework.util.Assert;
@@ -93,8 +97,29 @@ public class UndertowReactiveWebServerFactory extends AbstractReactiveWebServerF
 	@Override
 	public WebServer getWebServer(org.springframework.http.server.reactive.HttpHandler httpHandler) {
 		Undertow.Builder builder = createBuilder(getPort());
-		Closeable closeable = configureHandler(builder, httpHandler);
-		return new UndertowWebServer(builder, getPort() >= 0, closeable);
+		HttpHandler handler = new UndertowHttpHandlerAdapter(httpHandler);
+		if (this.useForwardHeaders) {
+			handler = Handlers.proxyPeerAddress(handler);
+		}
+		handler = UndertowCompressionConfigurer.configureCompression(getCompression(), handler);
+		Closeable closeable = null;
+		GracefulShutdown gracefulShutdown = null;
+		if (isAccessLogEnabled()) {
+			AccessLogHandlerConfiguration accessLogHandlerConfiguration = configureAccessLogHandler(builder, handler);
+			closeable = accessLogHandlerConfiguration.closeable;
+			handler = accessLogHandlerConfiguration.accessLogHandler;
+		}
+		GracefulShutdownHandler gracefulShutdownHandler = Handlers.gracefulShutdown(handler);
+		Duration gracePeriod = getShutdown().getGracePeriod();
+		if (gracePeriod != null) {
+			gracefulShutdown = new UndertowGracefulShutdown(gracefulShutdownHandler, gracePeriod);
+			handler = gracefulShutdownHandler;
+		}
+		else {
+			gracefulShutdown = new ImmediateGracefulShutdown();
+		}
+		builder.setHandler(handler);
+		return new UndertowWebServer(builder, getPort() >= 0, closeable, gracefulShutdown);
 	}
 
 	private Undertow.Builder createBuilder(int port) {
@@ -123,24 +148,7 @@ public class UndertowReactiveWebServerFactory extends AbstractReactiveWebServerF
 		return builder;
 	}
 
-	private Closeable configureHandler(Undertow.Builder builder,
-			org.springframework.http.server.reactive.HttpHandler httpHandler) {
-		HttpHandler handler = new UndertowHttpHandlerAdapter(httpHandler);
-		if (this.useForwardHeaders) {
-			handler = Handlers.proxyPeerAddress(handler);
-		}
-		handler = UndertowCompressionConfigurer.configureCompression(getCompression(), handler);
-		Closeable closeable = null;
-		if (isAccessLogEnabled()) {
-			closeable = configureAccessLogHandler(builder, handler);
-		}
-		else {
-			builder.setHandler(handler);
-		}
-		return closeable;
-	}
-
-	private Closeable configureAccessLogHandler(Undertow.Builder builder, HttpHandler handler) {
+	private AccessLogHandlerConfiguration configureAccessLogHandler(Undertow.Builder builder, HttpHandler handler) {
 		try {
 			createAccessLogDirectoryIfNecessary();
 			XnioWorker worker = createWorker();
@@ -148,9 +156,9 @@ public class UndertowReactiveWebServerFactory extends AbstractReactiveWebServerF
 			DefaultAccessLogReceiver accessLogReceiver = new DefaultAccessLogReceiver(worker, this.accessLogDirectory,
 					prefix, this.accessLogSuffix, this.accessLogRotate);
 			String formatString = ((this.accessLogPattern != null) ? this.accessLogPattern : "common");
-			builder.setHandler(
-					new AccessLogHandler(handler, accessLogReceiver, formatString, Undertow.class.getClassLoader()));
-			return () -> {
+			AccessLogHandler accessLogHandler = new AccessLogHandler(handler, accessLogReceiver, formatString,
+					Undertow.class.getClassLoader());
+			return new AccessLogHandlerConfiguration(accessLogHandler, () -> {
 				try {
 					accessLogReceiver.close();
 					worker.shutdown();
@@ -162,7 +170,7 @@ public class UndertowReactiveWebServerFactory extends AbstractReactiveWebServerF
 				catch (InterruptedException ex) {
 					Thread.currentThread().interrupt();
 				}
-			};
+			});
 		}
 		catch (IOException ex) {
 			throw new IllegalStateException("Failed to create AccessLogHandler", ex);
@@ -289,4 +297,17 @@ public class UndertowReactiveWebServerFactory extends AbstractReactiveWebServerF
 		this.builderCustomizers.addAll(Arrays.asList(customizers));
 	}
 
+	private static final class AccessLogHandlerConfiguration {
+
+		private final AccessLogHandler accessLogHandler;
+
+		private final Closeable closeable;
+
+		private AccessLogHandlerConfiguration(AccessLogHandler accessLogHandler, Closeable closeable) {
+			this.accessLogHandler = accessLogHandler;
+			this.closeable = closeable;
+		}
+
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -20,6 +20,7 @@ import java.lang.reflect.Field;
 import java.net.BindException;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
+import java.time.Duration;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -29,12 +30,15 @@ import io.undertow.Handlers;
 import io.undertow.Undertow;
 import io.undertow.Undertow.Builder;
 import io.undertow.server.HttpHandler;
+import io.undertow.server.handlers.GracefulShutdownHandler;
 import io.undertow.servlet.api.DeploymentManager;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.xnio.channels.BoundChannel;
 
 import org.springframework.boot.web.server.Compression;
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -74,10 +78,14 @@ public class UndertowServletWebServer implements WebServer {
 
 	private final String serverHeader;
 
+	private final Duration shutdownGracePeriod;
+
 	private Undertow undertow;
 
 	private volatile boolean started = false;
 
+	private volatile GracefulShutdown gracefulShutdown;
+
 	/**
 	 * Create a new {@link UndertowServletWebServer} instance.
 	 * @param builder the builder
@@ -117,6 +125,25 @@ public class UndertowServletWebServer implements WebServer {
 	 */
 	public UndertowServletWebServer(Builder builder, DeploymentManager manager, String contextPath,
 			boolean useForwardHeaders, boolean autoStart, Compression compression, String serverHeader) {
+		this(builder, manager, contextPath, useForwardHeaders, autoStart, compression, serverHeader, null);
+	}
+
+	/**
+	 * Create a new {@link UndertowServletWebServer} instance.
+	 * @param builder the builder
+	 * @param manager the deployment manager
+	 * @param contextPath the root context path
+	 * @param useForwardHeaders if x-forward headers should be used
+	 * @param autoStart if the server should be started
+	 * @param compression compression configuration
+	 * @param serverHeader string to be used in HTTP header
+	 * @param shutdownGracePeriod the period to wait for activity to cease when shutting
+	 * down the server gracefully
+	 * @since 2.3.0
+	 */
+	public UndertowServletWebServer(Builder builder, DeploymentManager manager, String contextPath,
+			boolean useForwardHeaders, boolean autoStart, Compression compression, String serverHeader,
+			Duration shutdownGracePeriod) {
 		this.builder = builder;
 		this.manager = manager;
 		this.contextPath = contextPath;
@@ -124,6 +151,7 @@ public class UndertowServletWebServer implements WebServer {
 		this.autoStart = autoStart;
 		this.compression = compression;
 		this.serverHeader = serverHeader;
+		this.shutdownGracePeriod = shutdownGracePeriod;
 	}
 
 	@Override
@@ -200,6 +228,14 @@ public class UndertowServletWebServer implements WebServer {
 		if (StringUtils.hasText(this.serverHeader)) {
 			httpHandler = Handlers.header(httpHandler, "Server", this.serverHeader);
 		}
+		if (this.shutdownGracePeriod != null) {
+			GracefulShutdownHandler gracefulShutdownHandler = Handlers.gracefulShutdown(httpHandler);
+			this.gracefulShutdown = new UndertowGracefulShutdown(gracefulShutdownHandler, this.shutdownGracePeriod);
+			httpHandler = gracefulShutdownHandler;
+		}
+		else {
+			this.gracefulShutdown = new ImmediateGracefulShutdown();
+		}
 		this.builder.setHandler(httpHandler);
 		return this.builder.build();
 	}
@@ -314,6 +350,15 @@ public class UndertowServletWebServer implements WebServer {
 		return ports.get(0).getNumber();
 	}
 
+	@Override
+	public boolean shutDownGracefully() {
+		return this.gracefulShutdown.shutDownGracefully();
+	}
+
+	boolean inGracefulShutdown() {
+		return this.gracefulShutdown.isShuttingDown();
+	}
+
 	/**
 	 * An active Undertow port.
 	 */

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -449,7 +449,7 @@ public class UndertowServletWebServerFactory extends AbstractServletWebServerFac
 	 */
 	protected UndertowServletWebServer getUndertowWebServer(Builder builder, DeploymentManager manager, int port) {
 		return new UndertowServletWebServer(builder, manager, getContextPath(), isUseForwardHeaders(), port >= 0,
-				getCompression(), getServerHeader());
+				getCompression(), getServerHeader(), getShutdown().getGracePeriod());
 	}
 
 	@Override

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -29,6 +29,8 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.xnio.channels.BoundChannel;
 
+import org.springframework.boot.web.server.GracefulShutdown;
+import org.springframework.boot.web.server.ImmediateGracefulShutdown;
 import org.springframework.boot.web.server.PortInUseException;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.boot.web.server.WebServerException;
@@ -59,6 +61,8 @@ public class UndertowWebServer implements WebServer {
 
 	private final Closeable closeable;
 
+	private final GracefulShutdown gracefulShutdown;
+
 	private Undertow undertow;
 
 	private volatile boolean started = false;
@@ -80,9 +84,23 @@ public class UndertowWebServer implements WebServer {
 	 * @since 2.0.4
 	 */
 	public UndertowWebServer(Undertow.Builder builder, boolean autoStart, Closeable closeable) {
+		this(builder, autoStart, closeable, new ImmediateGracefulShutdown());
+	}
+
+	/**
+	 * Create a new {@link UndertowWebServer} instance.
+	 * @param builder the builder
+	 * @param autoStart if the server should be started
+	 * @param closeable called when the server is stopped
+	 * @param gracefulShutdown handler for graceful shutdown
+	 * @since 2.3.0
+	 */
+	public UndertowWebServer(Undertow.Builder builder, boolean autoStart, Closeable closeable,
+			GracefulShutdown gracefulShutdown) {
 		this.builder = builder;
 		this.autoStart = autoStart;
 		this.closeable = closeable;
+		this.gracefulShutdown = gracefulShutdown;
 	}
 
 	@Override
@@ -245,6 +263,15 @@ public class UndertowWebServer implements WebServer {
 		return ports.get(0).getNumber();
 	}
 
+	@Override
+	public boolean shutDownGracefully() {
+		return (this.gracefulShutdown != null) ? this.gracefulShutdown.shutDownGracefully() : false;
+	}
+
+	boolean inGracefulShutdown() {
+		return (this.gracefulShutdown != null) ? this.gracefulShutdown.isShuttingDown() : false;
+	}
+
 	/**
 	 * An active Undertow port.
 	 */

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/reactive/context/ReactiveWebServerApplicationContext.java

@@ -146,6 +146,15 @@ public class ReactiveWebServerApplicationContext extends GenericReactiveWebAppli
 		return getBeanFactory().getBean(beanNames[0], HttpHandler.class);
 	}
 
+	@Override
+	protected void doClose() {
+		WebServer webServer = getWebServer();
+		if (webServer != null) {
+			webServer.shutDownGracefully();
+		}
+		super.doClose();
+	}
+
 	@Override
 	protected void onClose() {
 		super.onClose();

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/AbstractConfigurableWebServerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -55,6 +55,8 @@ public abstract class AbstractConfigurableWebServerFactory implements Configurab
 
 	private String serverHeader;
 
+	private Shutdown shutdown = new Shutdown();
+
 	/**
 	 * Create a new {@link AbstractConfigurableWebServerFactory} instance.
 	 */
@@ -162,6 +164,20 @@ public abstract class AbstractConfigurableWebServerFactory implements Configurab
 		this.serverHeader = serverHeader;
 	}
 
+	@Override
+	public void setShutdown(Shutdown shutdown) {
+		this.shutdown = shutdown;
+	}
+
+	/**
+	 * Returns the shutdown configuration that will be applied to the server.
+	 * @return the shutdown configuration
+	 * @since 2.3.0
+	 */
+	public Shutdown getShutdown() {
+		return this.shutdown;
+	}
+
 	/**
 	 * Return the absolute temp dir for given web server.
 	 * @param prefix server name

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/ConfigurableWebServerFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -80,4 +80,13 @@ public interface ConfigurableWebServerFactory extends WebServerFactory, ErrorPag
 	 */
 	void setServerHeader(String serverHeader);
 
+	/**
+	 * Sets the shutdown configuration that will be applied to the server.
+	 * @param shutdown the shutdown configuration
+	 * @since 2.3.0
+	 */
+	default void setShutdown(Shutdown shutdown) {
+
+	}
+
 }

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/GracefulShutdown.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.server;
+
+/**
+ * Handles graceful shutdown of a {@link WebServer}.
+ *
+ * @author Andy Wilkinson
+ * @since 2.3.0
+ */
+public interface GracefulShutdown {
+
+	/**
+	 * Shuts down the {@link WebServer}, returning {@code true} if activity ceased during
+	 * the grace period, otherwise {@code false}.
+	 * @return {@code true} if activity ceased during the grace period, otherwise
+	 * {@code false}
+	 */
+	boolean shutDownGracefully();
+
+	/**
+	 * Returns whether the handler is in the process of gracefully shutting down the web
+	 * server.
+	 * @return {@code true} is graceful shutdown is in progress, otherwise {@code false}.
+	 */
+	boolean isShuttingDown();
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/ImmediateGracefulShutdown.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.server;
+
+/**
+ * A {@link GracefulShutdown} that returns immediately with no grace period.
+ *
+ * @author Andy Wilkinson
+ * @since 2.3.0
+ */
+public class ImmediateGracefulShutdown implements GracefulShutdown {
+
+	@Override
+	public boolean shutDownGracefully() {
+		return false;
+	}
+
+	@Override
+	public boolean isShuttingDown() {
+		return false;
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/Shutdown.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2012-2020 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
+ *
+ *      https://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.web.server;
+
+import java.time.Duration;
+
+/**
+ * Configuration for shutting down a {@link WebServer}.
+ *
+ * @author Andy Wilkinson
+ * @since 2.3.0
+ */
+public class Shutdown {
+
+	/**
+	 * Time to wait for web activity to cease before shutting down the application. By
+	 * default, shutdown will proceed immediately.
+	 */
+	private Duration gracePeriod;
+
+	public Duration getGracePeriod() {
+		return this.gracePeriod;
+	}
+
+	public void setGracePeriod(Duration period) {
+		this.gracePeriod = period;
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/server/WebServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -47,4 +47,15 @@ public interface WebServer {
 	 */
 	int getPort();
 
+	/**
+	 * Gracefully shuts down the web server by preventing the handling of new requests and
+	 * waiting for a configurable period for there to be no active requests.
+	 * @return {@code true} if graceful shutdown completed within the period, otherwise
+	 * {@code false}
+	 * @since 2.3.0
+	 */
+	default boolean shutDownGracefully() {
+		return false;
+	}
+
 }

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/context/ServletWebServerApplicationContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -166,6 +166,15 @@ public class ServletWebServerApplicationContext extends GenericWebApplicationCon
 		}
 	}
 
+	@Override
+	protected void doClose() {
+		WebServer webServer = this.webServer;
+		if (webServer != null) {
+			webServer.shutDownGracefully();
+		}
+		super.doClose();
+	}
+
 	@Override
 	protected void onClose() {
 		super.onClose();

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

@@ -91,6 +91,11 @@ abstract class AbstractJettyServletWebServerFactoryTests extends AbstractServlet
 		this.handleExceptionCausedByBlockedPortOnPrimaryConnector(ex, blockedPort);
 	}
 
+	@Override
+	protected boolean inGracefulShutdown() {
+		return ((JettyWebServer) this.webServer).inGracefulShutdown();
+	}
+
 	@Test
 	void contextPathIsLoggedOnStartupWhenCompressionIsEnabled(CapturedOutput output) {
 		AbstractServletWebServerFactory factory = getFactory();

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -16,8 +16,14 @@
 
 package org.springframework.boot.web.embedded.jetty;
 
+import java.io.IOException;
 import java.net.InetAddress;
+import java.time.Duration;
 import java.util.Arrays;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 import org.eclipse.jetty.server.Connector;
 import org.eclipse.jetty.server.Server;
@@ -26,11 +32,13 @@ import org.junit.jupiter.api.Test;
 import org.mockito.InOrder;
 
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactoryTests;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.http.client.reactive.JettyResourceFactory;
 import org.springframework.http.server.reactive.HttpHandler;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.awaitility.Awaitility.await;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
@@ -110,4 +118,38 @@ class JettyReactiveWebServerFactoryTests extends AbstractReactiveWebServerFactor
 		assertThat(connector.getScheduler()).isEqualTo(resourceFactory.getScheduler());
 	}
 
+	@Test
+	void whenServerIsShuttingDownGracefullyThenNewConnectionsCannotBeMade() throws Exception {
+		JettyReactiveWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingHandler blockingHandler = new BlockingHandler();
+		this.webServer = factory.getWebServer(blockingHandler);
+		this.webServer.start();
+		getWebClient().build().get().retrieve().toBodilessEntity().subscribe();
+		blockingHandler.awaitQueue();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		// We need to make two requests as Jetty accepts one additional request after a
+		// connector has been told to stop accepting requests
+		CountDownLatch responseLatch = new CountDownLatch(1);
+		AtomicReference<Throwable> errorReference = new AtomicReference<>();
+		getWebClient().build().get().retrieve().toBodilessEntity().doOnSuccess((response) -> responseLatch.countDown())
+				.doOnError(errorReference::set).subscribe();
+		getWebClient().build().get().retrieve().toBodilessEntity().doOnSuccess((response) -> responseLatch.countDown())
+				.doOnError(errorReference::set).subscribe();
+		assertThat(shutdownResult.get()).isEqualTo(false);
+		blockingHandler.completeOne();
+		blockingHandler.completeOne();
+		responseLatch.await(5, TimeUnit.SECONDS);
+		this.webServer.stop();
+		Throwable error = await().atMost(Duration.ofSeconds(5)).until(errorReference::get, (ex) -> ex != null);
+		assertThat(error).isInstanceOf(IOException.class);
+	}
+
+	@Override
+	protected boolean inGracefulShutdown() {
+		return ((JettyWebServer) this.webServer).inGracefulShutdown();
+	}
+
 }

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

@@ -21,12 +21,17 @@ import java.time.Duration;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.Future;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 import javax.servlet.ServletContextEvent;
 import javax.servlet.ServletContextListener;
+import javax.servlet.ServletRegistration.Dynamic;
 
+import org.apache.http.HttpResponse;
+import org.apache.http.conn.HttpHostConnectException;
 import org.eclipse.jetty.server.Connector;
 import org.eclipse.jetty.server.Handler;
 import org.eclipse.jetty.server.Server;
@@ -44,8 +49,10 @@ import org.eclipse.jetty.webapp.WebAppContext;
 import org.junit.jupiter.api.Test;
 import org.mockito.InOrder;
 
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.WebServerException;
+import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactory;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@@ -169,6 +176,34 @@ class JettyServletWebServerFactoryTests extends AbstractJettyServletWebServerFac
 		assertThat(connectionFactory.getSslContextFactory().getIncludeProtocols()).containsExactly("TLSv1.1");
 	}
 
+	@Test
+	void whenServerIsShuttingDownGracefullyThenNewConnectionsCannotBeMade() throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingServlet blockingServlet = new BlockingServlet();
+		this.webServer = factory.getWebServer((context) -> {
+			Dynamic registration = context.addServlet("blockingServlet", blockingServlet);
+			registration.addMapping("/blocking");
+			registration.setAsyncSupported(true);
+		});
+		this.webServer.start();
+		Future<Object> request = initiateGetRequest("/blocking");
+		blockingServlet.awaitQueue();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		// Jetty accepts one additional request after a connector has been told to stop
+		// accepting requests
+		Future<Object> unconnectableRequest1 = initiateGetRequest("/");
+		Future<Object> unconnectableRequest2 = initiateGetRequest("/");
+		assertThat(shutdownResult.get()).isEqualTo(false);
+		blockingServlet.admitOne();
+		assertThat(request.get()).isInstanceOf(HttpResponse.class);
+		this.webServer.stop();
+		List<Object> results = Arrays.asList(unconnectableRequest1.get(), unconnectableRequest2.get());
+		assertThat(results).anySatisfy((result) -> assertThat(result).isInstanceOf(HttpHostConnectException.class));
+	}
+
 	private Ssl getSslSettings(String... enabledProtocols) {
 		Ssl ssl = new Ssl();
 		ssl.setKeyStore("src/test/resources/test.jks");

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/netty/NettyReactiveWebServerFactoryTests.java

@@ -16,8 +16,11 @@
 
 package org.springframework.boot.web.embedded.netty;
 
+import java.net.ConnectException;
 import java.time.Duration;
 import java.util.Arrays;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicReference;
 
 import org.junit.jupiter.api.Test;
 import org.mockito.InOrder;
@@ -28,6 +31,7 @@ import reactor.test.StepVerifier;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactoryTests;
 import org.springframework.boot.web.server.PortInUseException;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.http.MediaType;
 import org.springframework.http.client.reactive.ReactorClientHttpConnector;
@@ -99,6 +103,27 @@ class NettyReactiveWebServerFactoryTests extends AbstractReactiveWebServerFactor
 		StepVerifier.create(result).expectNext("Hello World").verifyComplete();
 	}
 
+	@Test
+	void whenServerIsShuttingDownGracefullyThenNewConnectionsCannotBeMade() throws Exception {
+		NettyReactiveWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingHandler blockingHandler = new BlockingHandler();
+		this.webServer = factory.getWebServer(blockingHandler);
+		this.webServer.start();
+		WebClient webClient = getWebClient().build();
+		webClient.get().retrieve().toBodilessEntity().subscribe();
+		blockingHandler.awaitQueue();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		AtomicReference<Throwable> errorReference = new AtomicReference<>();
+		webClient.get().retrieve().toBodilessEntity().doOnError(errorReference::set).subscribe();
+		assertThat(shutdownResult.get()).isEqualTo(false);
+		blockingHandler.completeOne();
+		this.webServer.stop();
+		assertThat(errorReference.get()).hasCauseInstanceOf(ConnectException.class);
+	}
+
 	protected Mono<String> testSslWithAlias(String alias) {
 		String keyStore = "classpath:test.jks";
 		String keyPassword = "password";
@@ -117,4 +142,9 @@ class NettyReactiveWebServerFactoryTests extends AbstractReactiveWebServerFactor
 				.exchange().flatMap((response) -> response.bodyToMono(String.class));
 	}
 
+	@Override
+	protected boolean inGracefulShutdown() {
+		return ((NettyWebServer) this.webServer).inGracefulShutdown();
+	}
+
 }

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

@@ -17,10 +17,14 @@
 package org.springframework.boot.web.embedded.tomcat;
 
 import java.io.IOException;
+import java.net.ConnectException;
 import java.net.InetSocketAddress;
 import java.net.ServerSocket;
+import java.time.Duration;
 import java.util.Arrays;
 import java.util.Map;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicReference;
 
 import org.apache.catalina.Context;
 import org.apache.catalina.LifecycleEvent;
@@ -41,10 +45,12 @@ import org.mockito.InOrder;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactory;
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactoryTests;
 import org.springframework.boot.web.server.PortInUseException;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.WebServerException;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.util.SocketUtils;
+import org.springframework.web.reactive.function.client.WebClient;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
@@ -256,6 +262,27 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 				.isInstanceOf(WebServerException.class);
 	}
 
+	@Test
+	void whenServerIsShuttingDownGracefullyThenNewConnectionsCannotBeMade() throws Exception {
+		TomcatReactiveWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingHandler blockingHandler = new BlockingHandler();
+		this.webServer = factory.getWebServer(blockingHandler);
+		this.webServer.start();
+		WebClient webClient = getWebClient().build();
+		webClient.get().retrieve().toBodilessEntity().subscribe();
+		blockingHandler.awaitQueue();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		AtomicReference<Throwable> errorReference = new AtomicReference<>();
+		webClient.get().retrieve().toBodilessEntity().doOnError(errorReference::set).subscribe();
+		assertThat(shutdownResult.get()).isEqualTo(false);
+		blockingHandler.completeOne();
+		this.webServer.stop();
+		assertThat(errorReference.get()).hasCauseInstanceOf(ConnectException.class);
+	}
+
 	private void doWithBlockedPort(BlockedPortAction action) throws IOException {
 		int port = SocketUtils.findAvailableTcpPort(40000);
 		ServerSocket serverSocket = new ServerSocket();
@@ -280,6 +307,11 @@ class TomcatReactiveWebServerFactoryTests extends AbstractReactiveWebServerFacto
 		assertThat(((PortInUseException) ex).getPort()).isEqualTo(blockedPort);
 	}
 
+	@Override
+	protected boolean inGracefulShutdown() {
+		return ((TomcatWebServer) this.webServer).inGracefulShutdown();
+	}
+
 	interface BlockedPortAction {
 
 		void run(int port);

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

@@ -26,6 +26,7 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
+import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicReference;
 
 import javax.naming.InitialContext;
@@ -55,6 +56,8 @@ import org.apache.catalina.util.CharsetMapper;
 import org.apache.catalina.valves.RemoteIpValve;
 import org.apache.coyote.ProtocolHandler;
 import org.apache.coyote.http11.AbstractHttp11Protocol;
+import org.apache.http.HttpResponse;
+import org.apache.http.conn.HttpHostConnectException;
 import org.apache.jasper.servlet.JspServlet;
 import org.apache.tomcat.JarScanFilter;
 import org.apache.tomcat.JarScanType;
@@ -66,6 +69,7 @@ import org.mockito.InOrder;
 import org.springframework.boot.testsupport.system.CapturedOutput;
 import org.springframework.boot.testsupport.web.servlet.ExampleServlet;
 import org.springframework.boot.web.server.PortInUseException;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.WebServerException;
 import org.springframework.boot.web.servlet.ServletRegistrationBean;
@@ -557,6 +561,30 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 		assertThatThrownBy(() -> factory.getWebServer(registration).start()).isInstanceOf(WebServerException.class);
 	}
 
+	@Test
+	void whenServerIsShuttingDownGracefullyThenNewConnectionsCannotBeMade() throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingServlet blockingServlet = new BlockingServlet();
+		this.webServer = factory.getWebServer((context) -> {
+			Dynamic registration = context.addServlet("blockingServlet", blockingServlet);
+			registration.addMapping("/blocking");
+			registration.setAsyncSupported(true);
+		});
+		this.webServer.start();
+		Future<Object> request = initiateGetRequest("/blocking");
+		blockingServlet.awaitQueue();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		Future<Object> unconnectableRequest = initiateGetRequest("/");
+		assertThat(shutdownResult.get()).isEqualTo(false);
+		blockingServlet.admitOne();
+		assertThat(request.get()).isInstanceOf(HttpResponse.class);
+		this.webServer.stop();
+		assertThat(unconnectableRequest.get()).isInstanceOf(HttpHostConnectException.class);
+	}
+
 	@Override
 	protected JspServlet getJspServlet() throws ServletException {
 		Tomcat tomcat = ((TomcatWebServer) this.webServer).getTomcat();
@@ -610,4 +638,9 @@ class TomcatServletWebServerFactoryTests extends AbstractServletWebServerFactory
 		assertThat(((ConnectorStartFailedException) ex).getPort()).isEqualTo(blockedPort);
 	}
 
+	@Override
+	protected boolean inGracefulShutdown() {
+		return ((TomcatWebServer) this.webServer).inGracefulShutdown();
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/undertow/UndertowReactiveWebServerFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -21,6 +21,8 @@ import java.io.IOException;
 import java.net.URISyntaxException;
 import java.time.Duration;
 import java.util.Arrays;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicReference;
 
 import io.undertow.Undertow;
 import org.awaitility.Awaitility;
@@ -30,10 +32,12 @@ import org.mockito.InOrder;
 import reactor.core.publisher.Mono;
 
 import org.springframework.boot.web.reactive.server.AbstractReactiveWebServerFactoryTests;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.http.MediaType;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.web.reactive.function.BodyInserters;
 import org.springframework.web.reactive.function.client.WebClient;
+import org.springframework.web.reactive.function.client.WebClientResponseException.ServiceUnavailable;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
@@ -105,6 +109,32 @@ class UndertowReactiveWebServerFactoryTests extends AbstractReactiveWebServerFac
 		testAccessLog("my_access.", "logz", "my_access.logz");
 	}
 
+	@Test
+	void whenServerIsShuttingDownGracefullyThenNewConnectionsAreRejectedWithServiceUnavailable() throws Exception {
+		UndertowReactiveWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingHandler blockingHandler = new BlockingHandler();
+		this.webServer = factory.getWebServer(blockingHandler);
+		this.webServer.start();
+		WebClient webClient = getWebClient().build();
+		webClient.get().retrieve().toBodilessEntity().subscribe();
+		blockingHandler.awaitQueue();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		AtomicReference<Throwable> errorReference = new AtomicReference<>();
+		webClient.get().retrieve().toBodilessEntity().doOnError(errorReference::set).subscribe();
+		assertThat(shutdownResult.get()).isEqualTo(false);
+		blockingHandler.completeOne();
+		this.webServer.stop();
+		assertThat(errorReference.get()).isInstanceOf(ServiceUnavailable.class);
+	}
+
+	@Override
+	protected boolean inGracefulShutdown() {
+		return ((UndertowWebServer) this.webServer).inGracefulShutdown();
+	}
+
 	private void testAccessLog(String prefix, String suffix, String expectedFile)
 			throws IOException, URISyntaxException, InterruptedException {
 		UndertowReactiveWebServerFactory factory = getFactory();

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/embedded/undertow/UndertowServletWebServerFactoryTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2020 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.
@@ -25,15 +25,18 @@ import java.time.Duration;
 import java.util.Arrays;
 import java.util.Locale;
 import java.util.Map;
+import java.util.concurrent.Future;
 import java.util.concurrent.atomic.AtomicReference;
 
 import javax.net.ssl.SSLException;
 import javax.net.ssl.SSLHandshakeException;
+import javax.servlet.ServletRegistration.Dynamic;
 
 import io.undertow.Undertow;
 import io.undertow.Undertow.Builder;
 import io.undertow.servlet.api.DeploymentInfo;
 import io.undertow.servlet.api.ServletContainer;
+import org.apache.http.HttpResponse;
 import org.apache.jasper.servlet.JspServlet;
 import org.awaitility.Awaitility;
 import org.junit.jupiter.api.Test;
@@ -42,6 +45,7 @@ import org.mockito.InOrder;
 import org.springframework.boot.testsupport.web.servlet.ExampleServlet;
 import org.springframework.boot.web.server.ErrorPage;
 import org.springframework.boot.web.server.PortInUseException;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.servlet.ServletRegistrationBean;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactory;
 import org.springframework.boot.web.servlet.server.AbstractServletWebServerFactoryTests;
@@ -173,6 +177,33 @@ class UndertowServletWebServerFactoryTests extends AbstractServletWebServerFacto
 		testAccessLog("my_access.", "logz", "my_access.logz");
 	}
 
+	@Test
+	void whenServerIsShuttingDownGracefullyThenRequestsAreRejectedWithServiceUnavailable() throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingServlet blockingServlet = new BlockingServlet();
+		this.webServer = factory.getWebServer((context) -> {
+			Dynamic registration = context.addServlet("blockingServlet", blockingServlet);
+			registration.addMapping("/blocking");
+			registration.setAsyncSupported(true);
+		});
+		this.webServer.start();
+		Future<Object> request = initiateGetRequest("/blocking");
+		blockingServlet.awaitQueue();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		Future<Object> rejectedRequest = initiateGetRequest("/");
+		assertThat(shutdownResult.get()).isEqualTo(false);
+		blockingServlet.admitOne();
+		assertThat(request.get()).isInstanceOf(HttpResponse.class);
+		this.webServer.stop();
+		Object requestResult = rejectedRequest.get();
+		assertThat(requestResult).isInstanceOf(HttpResponse.class);
+		assertThat(((HttpResponse) requestResult).getStatusLine().getStatusCode())
+				.isEqualTo(HttpStatus.SERVICE_UNAVAILABLE.value());
+	}
+
 	private void testAccessLog(String prefix, String suffix, String expectedFile)
 			throws IOException, URISyntaxException, InterruptedException {
 		UndertowServletWebServerFactory factory = getFactory();
@@ -278,4 +309,9 @@ class UndertowServletWebServerFactoryTests extends AbstractServletWebServerFacto
 		this.handleExceptionCausedByBlockedPortOnPrimaryConnector(ex, blockedPort);
 	}
 
+	@Override
+	protected boolean inGracefulShutdown() {
+		return ((UndertowServletWebServer) this.webServer).inGracefulShutdown();
+	}
+
 }

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/reactive/server/AbstractReactiveWebServerFactoryTests.java

@@ -23,7 +23,15 @@ import java.nio.charset.StandardCharsets;
 import java.security.KeyStore;
 import java.time.Duration;
 import java.util.Arrays;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.Callable;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
+import java.util.concurrent.RunnableFuture;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 import javax.net.ssl.KeyManagerFactory;
 import javax.net.ssl.SSLException;
@@ -38,11 +46,14 @@ import io.netty.handler.ssl.util.InsecureTrustManagerFactory;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import reactor.core.publisher.Mono;
+import reactor.core.publisher.MonoProcessor;
 import reactor.netty.NettyPipeline;
 import reactor.netty.http.client.HttpClient;
 import reactor.test.StepVerifier;
 
+import org.springframework.boot.web.embedded.netty.NettyReactiveWebServerFactory;
 import org.springframework.boot.web.server.Compression;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.WebServer;
 import org.springframework.core.io.buffer.DataBuffer;
@@ -53,6 +64,7 @@ import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.client.reactive.ReactorClientHttpConnector;
+import org.springframework.http.client.reactive.ReactorResourceFactory;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.http.server.reactive.ServerHttpResponse;
@@ -333,6 +345,78 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 				.hasMessageContaining("Could not load key store 'null'");
 	}
 
+	@Test
+	void whenThereAreNoInFlightRequestsShutDownGracefullyReturnsTrueBeforePeriodElapses() throws Exception {
+		AbstractReactiveWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(30));
+		factory.setShutdown(shutdown);
+		this.webServer = factory.getWebServer(new EchoHandler());
+		this.webServer.start();
+		long start = System.currentTimeMillis();
+		assertThat(this.webServer.shutDownGracefully()).isTrue();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isLessThanOrEqualTo(30000);
+	}
+
+	@Test
+	void whenARequestRemainsInFlightThenShutDownGracefullyReturnsFalseAfterPeriodElapses() throws Exception {
+		AbstractReactiveWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingHandler blockingHandler = new BlockingHandler();
+		this.webServer = factory.getWebServer(blockingHandler);
+		this.webServer.start();
+		Mono<ResponseEntity<Void>> request = getWebClient().build().get().retrieve().toBodilessEntity();
+		AtomicReference<ResponseEntity<Void>> responseReference = new AtomicReference<>();
+		CountDownLatch responseLatch = new CountDownLatch(1);
+		request.subscribe((response) -> {
+			responseReference.set(response);
+			responseLatch.countDown();
+		});
+		blockingHandler.awaitQueue();
+		long start = System.currentTimeMillis();
+		assertThat(this.webServer.shutDownGracefully()).isFalse();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isGreaterThanOrEqualTo(5000);
+		assertThat(responseReference.get()).isNull();
+		blockingHandler.completeOne();
+		assertThat(responseLatch.await(5, TimeUnit.SECONDS)).isTrue();
+	}
+
+	@Test
+	void whenARequestCompletesDuringGracePeriodThenShutDownGracefullyReturnsTrueBeforePeriodElapses() throws Exception {
+		AbstractReactiveWebServerFactory factory = getFactory();
+		if (factory instanceof NettyReactiveWebServerFactory) {
+			ReactorResourceFactory resourceFactory = new ReactorResourceFactory();
+			resourceFactory.afterPropertiesSet();
+			((NettyReactiveWebServerFactory) factory).setResourceFactory(resourceFactory);
+		}
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(30));
+		factory.setShutdown(shutdown);
+		BlockingHandler blockingHandler = new BlockingHandler();
+		this.webServer = factory.getWebServer(blockingHandler);
+		this.webServer.start();
+		Mono<ResponseEntity<Void>> request = getWebClient().build().get().retrieve().toBodilessEntity();
+		AtomicReference<ResponseEntity<Void>> responseReference = new AtomicReference<>();
+		CountDownLatch responseLatch = new CountDownLatch(1);
+		request.subscribe((response) -> {
+			responseReference.set(response);
+			responseLatch.countDown();
+		});
+		blockingHandler.awaitQueue();
+		long start = System.currentTimeMillis();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		assertThat(responseLatch.getCount()).isEqualTo(1);
+		blockingHandler.completeOne();
+		assertThat(shutdownResult.get()).isTrue();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isLessThanOrEqualTo(30000);
+		assertThat(responseLatch.await(5, TimeUnit.SECONDS)).isTrue();
+	}
+
 	protected WebClient prepareCompressionTest() {
 		Compression compression = new Compression();
 		compression.setEnabled(true);
@@ -385,6 +469,26 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 		throw new IllegalStateException("Action was not successful in 10 attempts", lastFailure);
 	}
 
+	protected Future<Boolean> initiateGracefulShutdown() {
+		RunnableFuture<Boolean> future = new FutureTask<Boolean>(() -> this.webServer.shutDownGracefully());
+		new Thread(future).start();
+		awaitInGracefulShutdown();
+		return future;
+	}
+
+	protected void awaitInGracefulShutdown() {
+		while (!this.inGracefulShutdown()) {
+			try {
+				Thread.sleep(100);
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
+		}
+	}
+
+	protected abstract boolean inGracefulShutdown();
+
 	protected static class EchoHandler implements HttpHandler {
 
 		public EchoHandler() {
@@ -398,6 +502,40 @@ public abstract class AbstractReactiveWebServerFactoryTests {
 
 	}
 
+	protected static class BlockingHandler implements HttpHandler {
+
+		private final BlockingQueue<MonoProcessor<Void>> monoProcessors = new ArrayBlockingQueue<>(10);
+
+		public BlockingHandler() {
+
+		}
+
+		@Override
+		public Mono<Void> handle(ServerHttpRequest request, ServerHttpResponse response) {
+			MonoProcessor<Void> completion = MonoProcessor.create();
+			this.monoProcessors.add(completion);
+			return completion.then(Mono.empty());
+		}
+
+		public void completeOne() {
+			try {
+				MonoProcessor<Void> processor = this.monoProcessors.take();
+				System.out.println("Completing " + processor);
+				processor.onComplete();
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
+		}
+
+		public void awaitQueue() throws InterruptedException {
+			while (this.monoProcessors.isEmpty()) {
+				Thread.sleep(100);
+			}
+		}
+
+	}
+
 	static class CompressionDetectionHandler extends ChannelInboundHandlerAdapter {
 
 		@Override

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

@@ -44,7 +44,15 @@ import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.Locale;
 import java.util.Map;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.BrokenBarrierException;
 import java.util.concurrent.Callable;
+import java.util.concurrent.CyclicBarrier;
+import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
+import java.util.concurrent.RunnableFuture;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.Supplier;
@@ -52,6 +60,7 @@ import java.util.zip.GZIPInputStream;
 
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLException;
+import javax.servlet.AsyncContext;
 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
@@ -60,6 +69,7 @@ import javax.servlet.ServletContext;
 import javax.servlet.ServletContextEvent;
 import javax.servlet.ServletContextListener;
 import javax.servlet.ServletException;
+import javax.servlet.ServletRegistration.Dynamic;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.SessionCookieConfig;
@@ -69,8 +79,10 @@ import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 
 import org.apache.catalina.webresources.TomcatURLStreamHandlerFactory;
+import org.apache.http.HttpResponse;
 import org.apache.http.client.HttpClient;
 import org.apache.http.client.entity.InputStreamFactory;
+import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.protocol.HttpClientContext;
 import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
 import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
@@ -99,6 +111,7 @@ import org.springframework.boot.testsupport.web.servlet.ExampleServlet;
 import org.springframework.boot.web.server.Compression;
 import org.springframework.boot.web.server.ErrorPage;
 import org.springframework.boot.web.server.MimeMappings;
+import org.springframework.boot.web.server.Shutdown;
 import org.springframework.boot.web.server.Ssl;
 import org.springframework.boot.web.server.Ssl.ClientAuth;
 import org.springframework.boot.web.server.SslStoreProvider;
@@ -1002,6 +1015,155 @@ public abstract class AbstractServletWebServerFactoryTests {
 				.satisfies(this::wrapsFailingServletException);
 	}
 
+	@Test
+	void whenThereAreNoInFlightRequestsShutDownGracefullyReturnsTrueBeforePeriodElapses() throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(30));
+		factory.setShutdown(shutdown);
+		this.webServer = factory.getWebServer();
+		this.webServer.start();
+		long start = System.currentTimeMillis();
+		assertThat(this.webServer.shutDownGracefully()).isTrue();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isLessThanOrEqualTo(30000);
+	}
+
+	@Test
+	void whenARequestRemainsInFlightThenShutDownGracefullyReturnsFalseAfterPeriodElapses() throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingServlet blockingServlet = new BlockingServlet();
+		this.webServer = factory.getWebServer((context) -> {
+			Dynamic registration = context.addServlet("blockingServlet", blockingServlet);
+			registration.addMapping("/blocking");
+		});
+		this.webServer.start();
+		Future<Object> request = initiateGetRequest("/blocking");
+		blockingServlet.awaitQueue();
+		long start = System.currentTimeMillis();
+		assertThat(this.webServer.shutDownGracefully()).isFalse();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isGreaterThanOrEqualTo(5000);
+		assertThat(request.isDone()).isFalse();
+		blockingServlet.admitOne();
+		assertThat(request.get()).isInstanceOf(HttpResponse.class);
+	}
+
+	@Test
+	void whenARequestCompletesAndTheConnectionIsClosedDuringGracePeriodThenShutDownGracefullyReturnsTrueBeforePeriodElapses()
+			throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(30));
+		factory.setShutdown(shutdown);
+		BlockingServlet blockingServlet = new BlockingServlet();
+		this.webServer = factory.getWebServer((context) -> {
+			Dynamic registration = context.addServlet("blockingServlet", blockingServlet);
+			registration.addMapping("/blocking");
+			registration.setAsyncSupported(true);
+		});
+		this.webServer.start();
+		Future<Object> request = initiateGetRequest("/blocking");
+		blockingServlet.awaitQueue();
+		long start = System.currentTimeMillis();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		blockingServlet.admitOne();
+		assertThat(shutdownResult.get()).isTrue();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isLessThanOrEqualTo(30000);
+		assertThat(request.get()).isInstanceOf(HttpResponse.class);
+	}
+
+	@Test
+	void whenAnAsyncRequestRemainsInFlightThenShutDownGracefullyReturnsFalseAfterPeriodElapses() throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(5));
+		factory.setShutdown(shutdown);
+		BlockingAsyncServlet blockingAsyncServlet = new BlockingAsyncServlet();
+		this.webServer = factory.getWebServer((context) -> {
+			Dynamic registration = context.addServlet("blockingServlet", blockingAsyncServlet);
+			registration.addMapping("/blockingAsync");
+			registration.setAsyncSupported(true);
+		});
+		this.webServer.start();
+		Future<Object> request = initiateGetRequest("/blockingAsync");
+		blockingAsyncServlet.awaitQueue();
+		long start = System.currentTimeMillis();
+		assertThat(this.webServer.shutDownGracefully()).isFalse();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isGreaterThanOrEqualTo(5000);
+		assertThat(request.isDone()).isFalse();
+		blockingAsyncServlet.admitOne();
+		assertThat(request.get()).isInstanceOf(HttpResponse.class);
+	}
+
+	@Test
+	void whenAnAsyncRequestCompletesAndTheConnectionIsClosedDuringGracePeriodThenShutDownGracefullyReturnsTrueBeforePeriodElapses()
+			throws Exception {
+		AbstractServletWebServerFactory factory = getFactory();
+		Shutdown shutdown = new Shutdown();
+		shutdown.setGracePeriod(Duration.ofSeconds(30));
+		factory.setShutdown(shutdown);
+		BlockingAsyncServlet blockingAsyncServlet = new BlockingAsyncServlet();
+		this.webServer = factory.getWebServer((context) -> {
+			Dynamic registration = context.addServlet("blockingServlet", blockingAsyncServlet);
+			registration.addMapping("/blockingAsync");
+			registration.setAsyncSupported(true);
+		});
+		this.webServer.start();
+		Future<Object> request = initiateGetRequest("/blockingAsync");
+		blockingAsyncServlet.awaitQueue();
+		long start = System.currentTimeMillis();
+		Future<Boolean> shutdownResult = initiateGracefulShutdown();
+		blockingAsyncServlet.admitOne();
+		assertThat(shutdownResult.get()).isTrue();
+		long end = System.currentTimeMillis();
+		assertThat(end - start).isLessThanOrEqualTo(30000);
+		assertThat(request.get(30, TimeUnit.SECONDS)).isInstanceOf(HttpResponse.class);
+	}
+
+	protected Future<Boolean> initiateGracefulShutdown() {
+		RunnableFuture<Boolean> future = new FutureTask<Boolean>(() -> this.webServer.shutDownGracefully());
+		new Thread(future).start();
+		awaitInGracefulShutdown();
+		return future;
+	}
+
+	protected Future<Object> initiateGetRequest(String path) {
+		return initiateGetRequest(HttpClients.createDefault(), path);
+	}
+
+	protected Future<Object> initiateGetRequest(HttpClient httpClient, String path) {
+		RunnableFuture<Object> getRequest = new FutureTask<>(() -> {
+			try {
+				HttpResponse response = httpClient
+						.execute(new HttpGet("http://localhost:" + this.webServer.getPort() + path));
+				response.getEntity().getContent().close();
+				return response;
+			}
+			catch (Exception ex) {
+				return ex;
+			}
+		});
+		new Thread(getRequest, "GET " + path).start();
+		return getRequest;
+	}
+
+	protected void awaitInGracefulShutdown() {
+		while (!this.inGracefulShutdown()) {
+			try {
+				Thread.sleep(100);
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
+		}
+	}
+
 	private void wrapsFailingServletException(WebServerException ex) {
 		Throwable cause = ex.getCause();
 		while (cause != null) {
@@ -1151,6 +1313,8 @@ public abstract class AbstractServletWebServerFactoryTests {
 
 	protected abstract org.apache.jasper.servlet.JspServlet getJspServlet() throws Exception;
 
+	protected abstract boolean inGracefulShutdown();
+
 	protected ServletContextInitializer exampleServletRegistration() {
 		return new ServletRegistrationBean<>(new ExampleServlet(), "/hello");
 	}
@@ -1315,4 +1479,96 @@ public abstract class AbstractServletWebServerFactoryTests {
 
 	}
 
+	protected static class BlockingServlet extends HttpServlet {
+
+		private final BlockingQueue<CyclicBarrier> barriers = new ArrayBlockingQueue<>(10);
+
+		public BlockingServlet() {
+
+		}
+
+		@Override
+		protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+			CyclicBarrier barrier = new CyclicBarrier(2);
+			this.barriers.add(barrier);
+			try {
+				barrier.await();
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
+			catch (BrokenBarrierException ex) {
+				throw new ServletException(ex);
+			}
+		}
+
+		public void admitOne() {
+			try {
+				this.barriers.take().await();
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
+			catch (BrokenBarrierException ex) {
+				throw new RuntimeException(ex);
+			}
+		}
+
+		public void awaitQueue() throws InterruptedException {
+			while (this.barriers.isEmpty()) {
+				Thread.sleep(100);
+			}
+		}
+
+		public void awaitQueue(int size) throws InterruptedException {
+			while (this.barriers.size() < size) {
+				Thread.sleep(100);
+			}
+		}
+
+	}
+
+	static class BlockingAsyncServlet extends HttpServlet {
+
+		private final BlockingQueue<CyclicBarrier> barriers = new ArrayBlockingQueue<>(10);
+
+		@Override
+		protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+			CyclicBarrier barrier = new CyclicBarrier(2);
+			this.barriers.add(barrier);
+			AsyncContext async = req.startAsync();
+			new Thread(() -> {
+				try {
+					barrier.await();
+				}
+				catch (InterruptedException ex) {
+					Thread.currentThread().interrupt();
+				}
+				catch (BrokenBarrierException ex) {
+
+				}
+				async.complete();
+			}).start();
+		}
+
+		private void admitOne() {
+			try {
+				this.barriers.take().await();
+			}
+			catch (InterruptedException ex) {
+				Thread.currentThread().interrupt();
+			}
+			catch (BrokenBarrierException ex) {
+				throw new RuntimeException(ex);
+			}
+		}
+
+		private void awaitQueue() throws InterruptedException {
+			while (this.barriers.isEmpty()) {
+				Thread.sleep(100);
+			}
+		}
+
+	}
+
 }