Add keepalive configure for elasticsearch autoconfig.

Author: liuhaibo

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/elasticsearch/ElasticsearchProperties.java

@@ -62,6 +62,11 @@ public class ElasticsearchProperties {
 	 */
 	private String pathPrefix;
 
+	/**
+	 * Whether to enable keepalive between client and Elasticsearch.
+	 */
+	private boolean keepalive = true;
+
 	private final Restclient restclient = new Restclient();
 
 	public List<String> getUris() {
@@ -112,6 +117,14 @@ public void setPathPrefix(String pathPrefix) {
 		this.pathPrefix = pathPrefix;
 	}
 
+	public boolean isKeepalive() {
+		return this.keepalive;
+	}
+
+	public void setKeepalive(boolean keepalive) {
+		this.keepalive = keepalive;
+	}
+
 	public Restclient getRestclient() {
 		return this.restclient;
 	}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/elasticsearch/ElasticsearchRestClientConfigurations.java

@@ -27,6 +27,7 @@
 import org.apache.http.client.config.RequestConfig;
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
+import org.apache.http.impl.nio.reactor.IOReactorConfig;
 import org.elasticsearch.client.RestClient;
 import org.elasticsearch.client.RestClientBuilder;
 import org.elasticsearch.client.sniff.Sniffer;
@@ -155,6 +156,8 @@ public void customize(RestClientBuilder builder) {
 		@Override
 		public void customize(HttpAsyncClientBuilder builder) {
 			builder.setDefaultCredentialsProvider(new PropertiesCredentialsProvider(this.properties));
+			map.from(this.properties::isKeepalive).whenTrue()
+					.to(keepalive -> builder.setDefaultIOReactorConfig(IOReactorConfig.custom().setSoKeepAlive(keepalive).build()));
 		}
 
 		@Override

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/elasticsearch/ElasticsearchRestClientAutoConfigurationTests.java

@@ -183,6 +183,16 @@ void configureWithCustomPathPrefix() {
 		});
 	}
 
+	@Test
+	void configureWithKeepalive() {
+		this.contextRunner.withPropertyValues("spring.elasticsearch.keepalive=true").run(
+				context -> {
+					RestClient client = context.getBean(RestClient.class);
+					assertThat(client.getHttpClient()).extracting("connmgr.ioReactor.config.soKeepAlive").isEqualTo(Boolean.TRUE);
+				}
+		);
+	}
+
 	@Test
 	void configureWithoutSnifferLibraryShouldNotCreateSniffer() {
 		this.contextRunner.withClassLoader(new FilteredClassLoader("org.elasticsearch.client.sniff"))