Merge pull request #28875 from polarbear567

* pr/28875:
  Polish "Add server.netty.max-keep-alive-requests"
  Add server.netty.max-keep-alive-requests

Closes gh-28875

Author: snicoll

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -1340,6 +1340,12 @@ public static class Netty {
 		 */
 		private DataSize maxInitialLineLength = DataSize.ofKilobytes(4);
 
+		/**
+		 * Maximum number of requests that can be made per connection. By default, a
+		 * connection serves unlimited number of requests.
+		 */
+		private Integer maxKeepAliveRequests;
+
 		/**
 		 * Whether to validate headers when decoding requests.
 		 */
@@ -1391,6 +1397,14 @@ public void setMaxInitialLineLength(DataSize maxInitialLineLength) {
 			this.maxInitialLineLength = maxInitialLineLength;
 		}
 
+		public Integer getMaxKeepAliveRequests() {
+			return this.maxKeepAliveRequests;
+		}
+
+		public void setMaxKeepAliveRequests(Integer maxKeepAliveRequests) {
+			this.maxKeepAliveRequests = maxKeepAliveRequests;
+		}
+
 		public boolean isValidateHeaders() {
 			return this.validateHeaders;
 		}

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -62,6 +62,8 @@ public void customize(NettyReactiveWebServerFactory factory) {
 				.to((connectionTimeout) -> customizeConnectionTimeout(factory, connectionTimeout));
 		propertyMapper.from(nettyProperties::getIdleTimeout).whenNonNull()
 				.to((idleTimeout) -> customizeIdleTimeout(factory, idleTimeout));
+		propertyMapper.from(nettyProperties::getMaxKeepAliveRequests)
+				.to((maxKeepAliveRequests) -> customizeMaxKeepAliveRequests(factory, maxKeepAliveRequests));
 		customizeRequestDecoder(factory, propertyMapper);
 	}
 
@@ -104,4 +106,8 @@ private void customizeIdleTimeout(NettyReactiveWebServerFactory factory, Duratio
 		factory.addServerCustomizers((httpServer) -> httpServer.idleTimeout(idleTimeout));
 	}
 
+	private void customizeMaxKeepAliveRequests(NettyReactiveWebServerFactory factory, int maxKeepAliveRequests) {
+		factory.addServerCustomizers((httpServer) -> httpServer.maxKeepAliveRequests(maxKeepAliveRequests));
+	}
+
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -339,6 +339,12 @@ void testCustomizeNettyIdleTimeout() {
 		assertThat(this.properties.getNetty().getIdleTimeout()).isEqualTo(Duration.ofSeconds(10));
 	}
 
+	@Test
+	void testCustomizeNettyMaxKeepAliveRequests() {
+		bind("server.netty.max-keep-alive-requests", "100");
+		assertThat(this.properties.getNetty().getMaxKeepAliveRequests()).isEqualTo(100);
+	}
+
 	@Test
 	void tomcatAcceptCountMatchesProtocolDefault() throws Exception {
 		assertThat(this.properties.getTomcat().getAcceptCount()).isEqualTo(getDefaultProtocol().getAcceptCount());

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2021 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -48,6 +48,7 @@
  *
  * @author Brian Clozel
  * @author Artsiom Yudovin
+ * @author Leo Li
  */
 @ExtendWith(MockitoExtension.class)
 class NettyWebServerFactoryCustomizerTests {
@@ -117,6 +118,14 @@ void setIdleTimeout() {
 		verifyIdleTimeout(factory, Duration.ofSeconds(1));
 	}
 
+	@Test
+	void setMaxKeepAliveRequests() {
+		this.serverProperties.getNetty().setMaxKeepAliveRequests(100);
+		NettyReactiveWebServerFactory factory = mock(NettyReactiveWebServerFactory.class);
+		this.customizer.customize(factory);
+		verifyMaxKeepAliveRequests(factory, 100);
+	}
+
 	@Test
 	void configureHttpRequestDecoder() {
 		ServerProperties.Netty nettyProperties = this.serverProperties.getNetty();
@@ -162,4 +171,12 @@ private void verifyIdleTimeout(NettyReactiveWebServerFactory factory, Duration e
 		assertThat(idleTimeout).isEqualTo(expected);
 	}
 
+	private void verifyMaxKeepAliveRequests(NettyReactiveWebServerFactory factory, int expected) {
+		verify(factory, times(2)).addServerCustomizers(this.customizerCaptor.capture());
+		NettyServerCustomizer serverCustomizer = this.customizerCaptor.getAllValues().get(0);
+		HttpServer httpServer = serverCustomizer.apply(HttpServer.create());
+		int maxKeepAliveRequests = httpServer.configuration().maxKeepAliveRequests();
+		assertThat(maxKeepAliveRequests).isEqualTo(expected);
+	}
+
 }