Provide a config prop for Elasticsearch client's path prefix

Closes gh-25010

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

@@ -74,6 +74,7 @@ public class ReactiveElasticsearchRestClientAutoConfiguration {
 				.to((credentials) -> builder.withBasicAuth(credentials.getUsername(), credentials.getPassword()));
 		map.from(this.properties.getConnectionTimeout()).to(builder::withConnectTimeout);
 		map.from(this.properties.getSocketTimeout()).to(builder::withSocketTimeout);
+		map.from(this.properties.getPathPrefix()).to(builder::withPathPrefix);
 		configureExchangeStrategies(map, builder);
 		return builder.build();
 	}
@@ -164,6 +165,10 @@ public class ReactiveElasticsearchRestClientAutoConfiguration {
 					: this.restClientProperties.getMaxInMemorySize();
 		}
 
+		private String getPathPrefix() {
+			return this.deprecatedProperties.isCustomized() ? null : this.properties.getPathPrefix();
+		}
+
 		private static final class Credentials {
 
 			private final String username;

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

@@ -57,6 +57,11 @@ public class ElasticsearchProperties {
 	 */
 	private Duration socketTimeout = Duration.ofSeconds(30);
 
+	/**
+	 * Prefix added to the path of every request sent to Elasticsearch.
+	 */
+	private String pathPrefix;
+
 	public List<String> getUris() {
 		return this.uris;
 	}
@@ -97,4 +102,12 @@ public class ElasticsearchProperties {
 		this.socketTimeout = socketTimeout;
 	}
 
+	public String getPathPrefix() {
+		return this.pathPrefix;
+	}
+
+	public void setPathPrefix(String pathPrefix) {
+		this.pathPrefix = pathPrefix;
+	}
+
 }

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

@@ -80,6 +80,9 @@ class ElasticsearchRestClientConfigurations {
 				builderCustomizers.orderedStream().forEach((customizer) -> customizer.customize(requestConfigBuilder));
 				return requestConfigBuilder;
 			});
+			if (this.properties.getPathPrefix() != null) {
+				builder.setPathPrefix(this.properties.properties.getPathPrefix());
+			}
 			builderCustomizers.orderedStream().forEach((customizer) -> customizer.customize(builder));
 			return builder;
 		}
@@ -253,6 +256,10 @@ class ElasticsearchRestClientConfigurations {
 					: this.properties.getSocketTimeout();
 		}
 
+		private String getPathPrefix() {
+			return this.deprecatedProperties.isCustomized() ? null : this.properties.getPathPrefix();
+		}
+
 	}
 
 }

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

@@ -256,6 +256,13 @@ class ReactiveElasticsearchRestClientAutoConfigurationTests {
 						.isEqualTo(Duration.ofSeconds(2)));
 	}
 
+	@Test
+	void whenPathPrefixIsConfiguredThenClientConfigurationHasPathPrefix() {
+		this.contextRunner.withPropertyValues("spring.elasticsearch.path-prefix=/some/prefix")
+				.run((context) -> assertThat(context.getBean(ClientConfiguration.class).getPathPrefix())
+						.isEqualTo("/some/prefix"));
+	}
+
 	@ParameterizedPropertyPrefixTest
 	void whenCredentialsAreConfiguredThenClientConfigurationHasDefaultAuthorizationHeader(String prefix) {
 		this.contextRunner.withPropertyValues(prefix + "username=alice", prefix + "password=secret")

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

@@ -201,6 +201,14 @@ class ElasticsearchRestClientAutoConfigurationTests {
 				});
 	}
 
+	@Test
+	void configureWithCustomPathPrefix() {
+		this.contextRunner.withPropertyValues("spring.elasticsearch.path-prefix=/some/prefix").run((context) -> {
+			RestClient client = context.getBean(RestHighLevelClient.class).getLowLevelClient();
+			assertThat(client).extracting("pathPrefix").isEqualTo("/some/prefix");
+		});
+	}
+
 	@Test
 	void configureWithoutSnifferLibraryShouldNotCreateSniffer() {
 		this.contextRunner.withClassLoader(new FilteredClassLoader("org.elasticsearch.client.sniff"))