Uses custom WebClientCustomizer rather than one from Boot.

Using the boot WebClientCustomizer caused the auto configured
WebClient.Builder to use the loadbalancer filter function even though
it wasn't annotated with `@LoadBalanced`.

Fixes gh-434

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/reactive/ReactiveLoadBalancerAutoConfiguration.java

@@ -4,7 +4,6 @@ import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
-import org.springframework.boot.web.reactive.function.client.WebClientCustomizer;
 import org.springframework.cloud.client.loadbalancer.LoadBalanced;
 import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
 import org.springframework.context.annotation.Bean;

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/reactive/WebClientCustomizer.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2013-2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.client.loadbalancer.reactive;
+
+import org.springframework.web.reactive.function.client.WebClient;
+
+/**
+ * Callback interface that can be used to customize a
+ * {@link org.springframework.web.reactive.function.client.WebClient.Builder
+ * WebClient.Builder}.
+ *
+ * See original {@link org.springframework.boot.web.reactive.function.client.WebClientCustomizer}
+ *
+ * @author Brian Clozel
+ * @since 2.1.0
+ */
+@FunctionalInterface
+public interface WebClientCustomizer {
+
+	/**
+	 * Callback to customize a
+	 * {@link org.springframework.web.reactive.function.client.WebClient.Builder
+	 * WebClient.Builder} instance.
+	 * @param webClientBuilder the client builder to customize
+	 */
+	void customize(WebClient.Builder webClientBuilder);
+
+}
+

spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/reactive/ReactiveLoadBalancerAutoConfigurationTests.java

@@ -16,9 +16,17 @@
 
 package org.springframework.cloud.client.loadbalancer.reactive;
 
+import java.io.IOException;
+import java.net.URI;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+
 import org.junit.Test;
+
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.cloud.client.DefaultServiceInstance;
 import org.springframework.cloud.client.ServiceInstance;
@@ -34,12 +42,6 @@ import org.springframework.test.util.ReflectionTestUtils;
 import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
 import org.springframework.web.reactive.function.client.WebClient;
 
-import java.io.IOException;
-import java.net.URI;
-import java.util.List;
-import java.util.Map;
-import java.util.Random;
-
 import static org.assertj.core.api.Assertions.assertThat;
 
 
@@ -90,20 +92,29 @@ public class ReactiveLoadBalancerAutoConfigurationTests {
 		assertThat(getFilters(two.nonLoadBalanced)).isNullOrEmpty();
 	}
 
+	@Test
+	public void noCustomWebClientBuilders() {
+		ConfigurableApplicationContext context = init(NoWebClientBuilder.class);
+		final Map<String, WebClient.Builder> webClientBuilders = context
+				.getBeansOfType(WebClient.Builder.class);
+
+		assertThat(webClientBuilders).hasSize(1);
+
+		WebClient.Builder builder = context.getBean(WebClient.Builder.class);
+
+		assertThat(builder).isNotNull();
+		assertThat(getFilters(builder)).isNullOrEmpty();
+	}
+
 	protected ConfigurableApplicationContext init(Class<?> config) {
 		return new SpringApplicationBuilder().web(WebApplicationType.NONE)
 				// .properties("spring.aop.proxyTargetClass=true")
-				.sources(config, ReactiveLoadBalancerAutoConfiguration.class).run();
+				.sources(config, WebClientAutoConfiguration.class,
+						ReactiveLoadBalancerAutoConfiguration.class).run();
 	}
 
 	@Configuration
-	protected static class OneWebClientBuilder {
-
-		@Bean
-		@LoadBalanced
-		WebClient.Builder loadBalancedWebClientBuilder() {
-			return WebClient.builder();
-		}
+	protected static class NoWebClientBuilder {
 
 		@Bean
 		LoadBalancerClient loadBalancerClient() {
@@ -116,23 +127,23 @@ public class ReactiveLoadBalancerAutoConfigurationTests {
 	}
 
 	@Configuration
-	protected static class TwoWebClientBuilders {
+	protected static class OneWebClientBuilder extends NoWebClientBuilder {
 
-		@Primary
 		@Bean
-		WebClient.Builder webClientBuilder() {
-			return WebClient.builder();
-		}
-
 		@LoadBalanced
-		@Bean
 		WebClient.Builder loadBalancedWebClientBuilder() {
 			return WebClient.builder();
 		}
 
+	}
+
+	@Configuration
+	protected static class TwoWebClientBuilders extends OneWebClientBuilder {
+
+		@Primary
 		@Bean
-		LoadBalancerClient loadBalancerClient() {
-			return new NoopLoadBalancerClient();
+		WebClient.Builder webClientBuilder() {
+			return WebClient.builder();
 		}
 
 		@Configuration