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));