Enable Connection Evictor in HttpClient (#4103) (#4258)

docs/modules/ROOT/pages/spring-cloud-netflix.adoc

@@ -110,6 +110,17 @@ eureka:
       socket-timeout: 10000
 ----
 
+When using the default Apache HTTP Client Request Factory, an additional parameter can be used to configure timeout for evicting idle connections. Default value is 30 seconds. Value must be specified in milliseconds.
+
+.application.yml
+[source,yaml]
+----
+eureka:
+  client:
+    rest-template-timeout:
+      idle-timeout: 30000
+----
+
 === Status Page and Health Indicator
 
 The status page and health indicators for a Eureka instance default to `/info` and `/health` respectively, which are the default locations of useful endpoints in a Spring Boot Actuator application.

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/RestTemplateTimeoutProperties.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2022 the original author or authors.
+ * Copyright 2013-2024 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.
@@ -30,6 +30,7 @@ import org.springframework.web.client.RestTemplate;
  * {@link RestTemplateEurekaHttpClient}.
  *
  * @author Jiwon Jeon
+ * @author Armin Krezovic
  * @since 3.1.6
  */
 @ConfigurationProperties("eureka.client.rest-template-timeout")
@@ -45,6 +46,12 @@ public class RestTemplateTimeoutProperties {
 
 	private int socketTimeout = 3 * 60 * 1000;
 
+	/**
+	 * Indicates how long a connection can be idle before it is evicted from the
+	 * connection pool.
+	 */
+	private long idleTimeout = 30 * 60 * 1000L;
+
 	public int getConnectTimeout() {
 		return connectTimeout;
 	}
@@ -69,6 +76,14 @@ public class RestTemplateTimeoutProperties {
 		this.socketTimeout = socketTimeout;
 	}
 
+	public long getIdleTimeout() {
+		return idleTimeout;
+	}
+
+	public void setIdleTimeout(long idleTimeout) {
+		this.idleTimeout = idleTimeout;
+	}
+
 	@Override
 	public boolean equals(Object o) {
 		if (this == o) {
@@ -81,18 +96,18 @@ public class RestTemplateTimeoutProperties {
 		RestTemplateTimeoutProperties that = (RestTemplateTimeoutProperties) o;
 
 		return connectTimeout == that.connectTimeout && connectRequestTimeout == that.connectRequestTimeout
-				&& socketTimeout == that.socketTimeout;
+				&& socketTimeout == that.socketTimeout && idleTimeout == that.idleTimeout;
 	}
 
 	@Override
 	public int hashCode() {
-		return Objects.hash(connectTimeout, connectRequestTimeout, socketTimeout);
+		return Objects.hash(connectTimeout, connectRequestTimeout, socketTimeout, idleTimeout);
 	}
 
 	@Override
 	public String toString() {
 		return "RestTemplateTimeoutProperties{" + ", connectTimeout=" + connectTimeout + ", connectRequestTimeout="
-				+ connectRequestTimeout + ", socketTimeout=" + socketTimeout + '}';
+				+ connectRequestTimeout + ", socketTimeout=" + socketTimeout + ", idleTimeout=" + idleTimeout + '}';
 	}
 
 }

spring-cloud-netflix-eureka-client/src/main/java/org/springframework/cloud/netflix/eureka/http/DefaultEurekaClientHttpRequestFactorySupplier.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2022 the original author or authors.
+ * Copyright 2013-2024 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.cloud.netflix.eureka.http;
 
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLContext;
@@ -29,8 +30,10 @@ import org.apache.hc.client5.http.impl.io.PoolingHttpClientConnectionManagerBuil
 import org.apache.hc.client5.http.io.HttpClientConnectionManager;
 import org.apache.hc.client5.http.ssl.SSLConnectionSocketFactoryBuilder;
 import org.apache.hc.core5.http.io.SocketConfig;
+import org.apache.hc.core5.util.TimeValue;
 import org.apache.hc.core5.util.Timeout;
 
+import org.springframework.beans.factory.DisposableBean;
 import org.springframework.cloud.netflix.eureka.RestTemplateTimeoutProperties;
 import org.springframework.http.client.ClientHttpRequestFactory;
 import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
@@ -43,9 +46,13 @@ import org.springframework.lang.Nullable;
  * @author Marcin Grzejszczak
  * @author Olga Maciaszek-Sharma
  * @author Jiwon Jeon
+ * @author Armin Krezovic
  * @since 3.0.0
  */
-public class DefaultEurekaClientHttpRequestFactorySupplier implements EurekaClientHttpRequestFactorySupplier {
+public class DefaultEurekaClientHttpRequestFactorySupplier
+		implements EurekaClientHttpRequestFactorySupplier, DisposableBean {
+
+	private final AtomicReference<CloseableHttpClient> ref = new AtomicReference<>();
 
 	private final RestTemplateTimeoutProperties restTemplateTimeoutProperties;
 
@@ -64,7 +71,18 @@ public class DefaultEurekaClientHttpRequestFactorySupplier implements EurekaClie
 
 	@Override
 	public ClientHttpRequestFactory get(SSLContext sslContext, @Nullable HostnameVerifier hostnameVerifier) {
-		HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
+		TimeValue timeValue;
+
+		if (restTemplateTimeoutProperties != null) {
+			timeValue = TimeValue.ofMilliseconds(restTemplateTimeoutProperties.getIdleTimeout());
+		}
+		else {
+			timeValue = TimeValue.of(30, TimeUnit.SECONDS);
+		}
+
+		HttpClientBuilder httpClientBuilder = HttpClients.custom().evictExpiredConnections()
+				.evictIdleConnections(timeValue);
+
 		if (sslContext != null || hostnameVerifier != null || restTemplateTimeoutProperties != null) {
 			httpClientBuilder.setConnectionManager(
 					buildConnectionManager(sslContext, hostnameVerifier, restTemplateTimeoutProperties));
@@ -73,7 +91,11 @@ public class DefaultEurekaClientHttpRequestFactorySupplier implements EurekaClie
 			httpClientBuilder.setDefaultRequestConfig(buildRequestConfig());
 		}
 
-		CloseableHttpClient httpClient = httpClientBuilder.build();
+		if (ref.get() == null) {
+			ref.compareAndSet(null, httpClientBuilder.build());
+		}
+
+		CloseableHttpClient httpClient = ref.get();
 		HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
 		requestFactory.setHttpClient(httpClient);
 		return requestFactory;
@@ -108,4 +130,13 @@ public class DefaultEurekaClientHttpRequestFactorySupplier implements EurekaClie
 				.build();
 	}
 
+	@Override
+	public void destroy() throws Exception {
+		CloseableHttpClient httpClient = ref.get();
+
+		if (httpClient != null) {
+			httpClient.close();
+		}
+	}
+
 }