Ability to set a custom Client delegate with SleuthFeignBuilder (#1866)

spring-cloud-sleuth-instrumentation/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/SleuthFeignBuilder.java

@@ -20,7 +20,6 @@ import feign.Client;
 import feign.Feign;
 import feign.Retryer;
 
-import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 
 /**
@@ -36,15 +35,19 @@ public final class SleuthFeignBuilder {
 	}
 
 	public static Feign.Builder builder(BeanFactory beanFactory) {
-		return Feign.builder().retryer(Retryer.NEVER_RETRY).client(client(beanFactory));
+		return builder(beanFactory, null);
 	}
 
-	private static Client client(BeanFactory beanFactory) {
-		try {
+	public static Feign.Builder builder(BeanFactory beanFactory, Client delegate) {
+		return Feign.builder().retryer(Retryer.NEVER_RETRY).client(client(beanFactory, delegate));
+	}
+
+	private static Client client(BeanFactory beanFactory, Client delegate) {
+		if (delegate == null) {
 			return new LazyClient(beanFactory);
 		}
-		catch (BeansException ex) {
-			return new LazyClient(beanFactory, new Client.Default(null, null));
+		else {
+			return new LazyClient(beanFactory, delegate);
 		}
 	}
 

spring-cloud-sleuth-instrumentation/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/feign/SleuthFeignBuilderTests.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright 2013-2021 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
+ *
+ *      https://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.sleuth.instrument.web.client.feign;
+
+import feign.Client;
+import feign.Feign;
+import org.assertj.core.api.BDDAssertions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import org.springframework.beans.factory.BeanFactory;
+
+import static org.mockito.Mockito.mock;
+
+/**
+ * @author Julien Baillagou
+ */
+@ExtendWith(MockitoExtension.class)
+public class SleuthFeignBuilderTests {
+
+	@Mock
+	BeanFactory beanFactory;
+
+	@Test
+	public void should_generate_feign_builder() {
+		BDDAssertions.then(SleuthFeignBuilder.builder(beanFactory)).isExactlyInstanceOf(Feign.Builder.class);
+	}
+
+	@Test
+	public void should_generate_feign_builder_with_given_delegate() {
+		BDDAssertions.then(SleuthFeignBuilder.builder(beanFactory, mock(Client.class)))
+				.isExactlyInstanceOf(Feign.Builder.class);
+	}
+
+}