DATAES-719 - Add customization hook for reactive WebClient.

Original PR: #363

src/test/java/org/springframework/data/elasticsearch/client/ClientConfigurationUnitTests.java

@@ -20,12 +20,14 @@ import static org.mockito.Mockito.*;
 
 import java.net.InetSocketAddress;
 import java.time.Duration;
+import java.util.function.Function;
 
 import javax.net.ssl.SSLContext;
 
 import org.apache.http.conn.ssl.NoopHostnameVerifier;
 import org.junit.jupiter.api.Test;
 import org.springframework.http.HttpHeaders;
+import org.springframework.web.reactive.function.client.WebClient;
 
 /**
  * Unit tests for {@link ClientConfiguration}.
@@ -143,6 +145,26 @@ public class ClientConfigurationUnitTests {
 		assertThat(clientConfiguration.getHostNameVerifier()).contains(NoopHostnameVerifier.INSTANCE);
 	}
 
+	@Test // DATAES-719
+	void shouldHaveDefaultWebClientConfigurer() {
+		ClientConfiguration clientConfiguration = ClientConfiguration.builder() //
+				.connectedTo("foo", "bar") //
+				.build();
+
+		assertThat(clientConfiguration.getWebClientConfigurer()).isEqualTo(Function.identity());
+	}
+
+	@Test // DATAES-719
+	void shouldUseConfiguredWebClientConfigurer() {
+		Function<WebClient, WebClient> webClientConfigurer = webClient -> webClient;
+		ClientConfiguration clientConfiguration = ClientConfiguration.builder() //
+				.connectedTo("foo", "bar") //
+				.withWebClientConfigurer(webClientConfigurer) //
+				.build();
+
+		assertThat(clientConfiguration.getWebClientConfigurer()).isEqualTo(webClientConfigurer);
+	}
+
 	private static String buildBasicAuth(String username, String password) {
 
 		HttpHeaders headers = new HttpHeaders();

src/test/java/org/springframework/data/elasticsearch/client/reactive/DefaultWebClientProviderUnitTests.java

@@ -18,12 +18,15 @@ package org.springframework.data.elasticsearch.client.reactive;
 import static org.assertj.core.api.Assertions.*;
 
 import java.net.InetSocketAddress;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.function.Function;
 
 import org.junit.jupiter.api.Test;
 import org.springframework.web.reactive.function.client.WebClient;
 
 /**
  * @author Christoph Strobl
+ * @author Peter-Josef Meisch
  */
 public class DefaultWebClientProviderUnitTests {
 
@@ -40,4 +43,18 @@ public class DefaultWebClientProviderUnitTests {
 		assertThat(shouldBeCachedInstanceOfClient1).isSameAs(client1);
 		assertThat(notClient1ButAnotherInstance).isNotSameAs(client1);
 	}
+
+	@Test // DATAES-719
+	void shouldCallWebClientConfigurer() {
+		AtomicReference<Boolean> configurerCalled = new AtomicReference<>(false);
+		Function<WebClient, WebClient> configurer = webClient -> {
+			configurerCalled.set(true);
+			return webClient;
+		};
+		WebClientProvider provider = new DefaultWebClientProvider("http", null).withWebClientConfigurer(configurer);
+
+		provider.get(InetSocketAddress.createUnresolved("localhost", 9200));
+
+		assertThat(configurerCalled).hasValue(true);
+	}
 }

src/test/java/org/springframework/data/elasticsearch/client/reactive/ReactiveMockClientTestsUtils.java

@@ -61,6 +61,7 @@ import org.springframework.web.util.UriBuilder;
  * @author Christoph Strobl
  * @author Huw Ayling-Miller
  * @author Henrique Amaral
+ * @author Peter-Josef Meisch
  */
 public class ReactiveMockClientTestsUtils {
 
@@ -276,6 +277,11 @@ public class ReactiveMockClientTestsUtils {
 			throw new UnsupportedOperationException();
 		}
 
+		@Override
+		public WebClientProvider withWebClientConfigurer(Function<WebClient, WebClient> webClientConfigurer) {
+			throw new UnsupportedOperationException("not implemented");
+		}
+
 		public Send when(String host) {
 			InetSocketAddress inetSocketAddress = getInetSocketAddress(host);
 			return new CallbackImpl(get(host), headersUriSpecMap.get(inetSocketAddress),