Tomcat keepalive customizations

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

@@ -66,6 +66,7 @@
  * @author HaiTao Zhang
  * @author Victor Mandujano
  * @author Chris Bono
+ * @author Michael Lubavin
  * @since 1.0.0
  */
 @ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
@@ -395,6 +396,19 @@ public static class Tomcat {
 		 */
 		private Duration connectionTimeout;
 
+		/**
+		 * Amount of time a connection is allowed to remain idle until it is closed. Set
+		 * to -1 to indicate idle connections should not be closed.
+		 */
+		private Duration keepAliveTimeout;
+
+		/**
+		 * The maximum number of requests which can be processed on one connection before
+		 * it is closed by the server. Set to -1 for an unlimited number of requests per
+		 * connection. The default is 100, same as Tomcat default.
+		 */
+		private int maxKeepAliveRequests = 100;
+
 		/**
 		 * Static resource configuration.
 		 */
@@ -530,6 +544,22 @@ public void setConnectionTimeout(Duration connectionTimeout) {
 			this.connectionTimeout = connectionTimeout;
 		}
 
+		public Duration getKeepAliveTimeout() {
+			return this.keepAliveTimeout;
+		}
+
+		public void setKeepAliveTimeout(Duration keepAliveTimeout) {
+			this.keepAliveTimeout = keepAliveTimeout;
+		}
+
+		public int getMaxKeepAliveRequests() {
+			return this.maxKeepAliveRequests;
+		}
+
+		public void setMaxKeepAliveRequests(int maxKeepAliveRequests) {
+			this.maxKeepAliveRequests = maxKeepAliveRequests;
+		}
+
 		public Resource getResource() {
 			return this.resource;
 		}

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

@@ -102,6 +102,10 @@ public void customize(ConfigurableTomcatWebServerFactory factory) {
 		propertyMapper.from(tomcatProperties::getUriEncoding).whenNonNull().to(factory::setUriEncoding);
 		propertyMapper.from(tomcatProperties::getConnectionTimeout).whenNonNull()
 				.to((connectionTimeout) -> customizeConnectionTimeout(factory, connectionTimeout));
+		propertyMapper.from(tomcatProperties::getKeepAliveTimeout).whenNonNull()
+				.to((keepAliveTimeout) -> customizeKeepAliveTimeout(factory, keepAliveTimeout));
+		propertyMapper.from(tomcatProperties::getMaxKeepAliveRequests)
+				.to((maxKeepAliveRequests) -> customizeMaxKeepAliveRequests(factory, maxKeepAliveRequests));
 		propertyMapper.from(tomcatProperties::getMaxConnections).when(this::isPositive)
 				.to((maxConnections) -> customizeMaxConnections(factory, maxConnections));
 		propertyMapper.from(tomcatProperties::getAcceptCount).when(this::isPositive)
@@ -159,6 +163,26 @@ private void customizeConnectionTimeout(ConfigurableTomcatWebServerFactory facto
 		});
 	}
 
+	private void customizeKeepAliveTimeout(ConfigurableTomcatWebServerFactory factory, Duration keepAliveTimeout) {
+		factory.addConnectorCustomizers((connector) -> {
+			ProtocolHandler handler = connector.getProtocolHandler();
+			if (handler instanceof AbstractProtocol) {
+				AbstractProtocol<?> protocol = (AbstractProtocol<?>) handler;
+				protocol.setKeepAliveTimeout((int) keepAliveTimeout.toMillis());
+			}
+		});
+	}
+
+	private void customizeMaxKeepAliveRequests(ConfigurableTomcatWebServerFactory factory, int maxKeepAliveRequests) {
+		factory.addConnectorCustomizers((connector) -> {
+			ProtocolHandler handler = connector.getProtocolHandler();
+			if (handler instanceof AbstractHttp11Protocol) {
+				AbstractHttp11Protocol<?> protocol = (AbstractHttp11Protocol<?>) handler;
+				protocol.setMaxKeepAliveRequests(maxKeepAliveRequests);
+			}
+		});
+	}
+
 	private void customizeRelaxedPathChars(ConfigurableTomcatWebServerFactory factory, String relaxedChars) {
 		factory.addConnectorCustomizers((connector) -> connector.setProperty("relaxedPathChars", relaxedChars));
 	}

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

@@ -38,6 +38,8 @@
 import org.apache.catalina.valves.AccessLogValve;
 import org.apache.catalina.valves.RemoteIpValve;
 import org.apache.coyote.AbstractProtocol;
+import org.apache.coyote.http11.Http11NioProtocol;
+import org.apache.tomcat.util.net.NioEndpoint;
 import org.eclipse.jetty.server.HttpChannel;
 import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Server;
@@ -82,6 +84,7 @@
  * @author HaiTao Zhang
  * @author Rafiullah Hamedy
  * @author Chris Bono
+ * @author Michael Lubavin
  */
 class ServerPropertiesTests {
 
@@ -132,6 +135,8 @@ void testTomcatBinding() {
 		map.put("server.tomcat.relaxed-path-chars", "|,<");
 		map.put("server.tomcat.relaxed-query-chars", "^  ,  | ");
 		map.put("server.tomcat.use-relative-redirects", "true");
+		map.put("server.tomcat.keep-alive-timeout", "100s");
+		map.put("server.tomcat.max-keep-alive-requests", "-1");
 		bind(map);
 		ServerProperties.Tomcat tomcat = this.properties.getTomcat();
 		Accesslog accesslog = tomcat.getAccesslog();
@@ -154,6 +159,8 @@ void testTomcatBinding() {
 		assertThat(tomcat.getRelaxedPathChars()).containsExactly('|', '<');
 		assertThat(tomcat.getRelaxedQueryChars()).containsExactly('^', '|');
 		assertThat(tomcat.isUseRelativeRedirects()).isTrue();
+		assertThat(tomcat.getKeepAliveTimeout()).hasSeconds(100);
+		assertThat(tomcat.getMaxKeepAliveRequests()).isEqualTo(-1);
 	}
 
 	@Test
@@ -325,6 +332,16 @@ void tomcatMaxThreadsMatchesProtocolDefault() throws Exception {
 		assertThat(this.properties.getTomcat().getThreads().getMax()).isEqualTo(getDefaultProtocol().getMaxThreads());
 	}
 
+	@Test
+	void tomcatMaxKeepAliveRequestsMatchesProtocolDefault() throws Exception {
+		Http11NioProtocol http11NioProtocol = (Http11NioProtocol) getDefaultProtocol();
+		NioEndpoint endpoint = (NioEndpoint) ReflectionTestUtils.getField(http11NioProtocol, "endpoint");
+		// cannot use getter since it returns 1 when endpoint is not bound,
+		// so using reflection to fetch the default maxKeepAliveRequests instead
+		int defaultMaxKeepAliveRequests = (int) ReflectionTestUtils.getField(endpoint, "maxKeepAliveRequests");
+		assertThat(this.properties.getTomcat().getMaxKeepAliveRequests()).isEqualTo(defaultMaxKeepAliveRequests);
+	}
+
 	@Test
 	void tomcatMinSpareThreadsMatchesProtocolDefault() throws Exception {
 		assertThat(this.properties.getTomcat().getThreads().getMinSpare())

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/embedded/TomcatWebServerFactoryCustomizerTests.java

@@ -324,6 +324,29 @@ void customConnectionTimeout() {
 						.isEqualTo(30000));
 	}
 
+	@Test
+	void customKeepAliveTimeout() {
+		bind("server.tomcat.keep-alive-timeout=50s");
+		customizeAndRunServer((server) -> assertThat(
+				((AbstractProtocol<?>) server.getTomcat().getConnector().getProtocolHandler()).getKeepAliveTimeout())
+						.isEqualTo(50000));
+	}
+
+	@Test
+	void defaultMaxKeepAliveRequests() {
+		customizeAndRunServer((server) -> assertThat(
+				((AbstractHttp11Protocol<?>) server.getTomcat().getConnector().getProtocolHandler())
+						.getMaxKeepAliveRequests()).isEqualTo(100));
+	}
+
+	@Test
+	void customMaxKeepAliveRequests() {
+		bind("server.tomcat.max-keep-alive-requests=-1");
+		customizeAndRunServer((server) -> assertThat(
+				((AbstractHttp11Protocol<?>) server.getTomcat().getConnector().getProtocolHandler())
+						.getMaxKeepAliveRequests()).isEqualTo(-1));
+	}
+
 	@Test
 	void accessLogBufferingCanBeDisabled() {
 		bind("server.tomcat.accesslog.enabled=true", "server.tomcat.accesslog.buffered=false");