Ensured reusability of Feign components

Tests have been refactored to ensure that the custom components registered as beans are working properly.

fixes #374

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

@@ -16,8 +16,10 @@
 
 package org.springframework.cloud.sleuth.instrument.web.client.feign;
 
+import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 
+import feign.Client;
 import feign.Feign;
 
 /**
@@ -34,6 +36,15 @@ final class SleuthFeignBuilder {
 
 	static Feign.Builder builder(BeanFactory beanFactory) {
 		return Feign.builder()
-				.client(new TraceFeignClient(beanFactory));
+				.client(client(beanFactory));
+	}
+
+	private static Client client(BeanFactory beanFactory) {
+		try {
+			Client client = beanFactory.getBean(Client.class);
+			return (Client) new TraceFeignObjectWrapper(beanFactory).wrap(client);
+		} catch (BeansException e) {
+			return new TraceFeignClient(beanFactory);
+		}
 	}
 }

spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/web/client/feign/SleuthHystrixFeignBuilder.java

@@ -16,8 +16,10 @@
 
 package org.springframework.cloud.sleuth.instrument.web.client.feign;
 
+import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.BeanFactory;
 
+import feign.Client;
 import feign.Feign;
 import feign.hystrix.HystrixFeign;
 
@@ -36,6 +38,15 @@ final class SleuthHystrixFeignBuilder {
 
 	static Feign.Builder builder(BeanFactory beanFactory) {
 		return HystrixFeign.builder()
-				.client(new TraceFeignClient(beanFactory));
+				.client(client(beanFactory));
+	}
+
+	private static Client client(BeanFactory beanFactory) {
+		try {
+			Client client = beanFactory.getBean(Client.class);
+			return (Client) new TraceFeignObjectWrapper(beanFactory).wrap(client);
+		} catch (BeansException e) {
+			return new TraceFeignClient(beanFactory);
+		}
 	}
 }

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/AdhocTestSuite.java

@@ -21,7 +21,7 @@ import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 import org.junit.runners.Suite.SuiteClasses;
 import org.springframework.cloud.sleuth.instrument.web.RestTemplateTraceAspectIntegrationTests;
-import org.springframework.cloud.sleuth.instrument.web.client.WebClientDiscoveryExceptionTests;
+import org.springframework.cloud.sleuth.instrument.web.client.discoveryexception.WebClientDiscoveryExceptionTests;
 
 /**
  * A test suite for probing weird ordering problems in the tests.

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/discoveryexception/WebClientDiscoveryExceptionTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.instrument.web.client;
+package org.springframework.cloud.sleuth.instrument.web.client.discoveryexception;
 
 import java.io.IOException;
 import java.util.Map;

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/exception/WebClientExceptionTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.instrument.web.client;
+package org.springframework.cloud.sleuth.instrument.web.client.exception;
 
 import java.io.IOException;
 import java.util.Collections;

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/feign/issues/issue307/Issue307Tests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.instrument.web.client.feign.issues;
+package org.springframework.cloud.sleuth.instrument.web.client.feign.issues.issue307;
 
 import java.util.ArrayList;
 import java.util.List;

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/feign/issues/issue362/Issue362Tests.java

@@ -16,7 +16,10 @@
 
 package org.springframework.cloud.sleuth.instrument.web.client.feign.issues.issue362;
 
+import java.io.IOException;
 import java.util.Date;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutionException;
 
 import org.junit.Before;
@@ -43,6 +46,7 @@ import org.springframework.web.client.RestTemplate;
 
 import feign.Client;
 import feign.Logger;
+import feign.Request;
 import feign.Response;
 import feign.RetryableException;
 import feign.Retryer;
@@ -61,9 +65,11 @@ import static org.assertj.core.api.BDDAssertions.then;
 public class Issue362Tests {
 
 	RestTemplate template = new RestTemplate();
+	@Autowired FeignComponentAsserter feignComponentAsserter;
 
 	@Before
 	public void setup() {
+		this.feignComponentAsserter.executedComponents.clear();
 		ExceptionUtils.setFail(true);
 	}
 
@@ -75,6 +81,7 @@ public class Issue362Tests {
 
 		SleuthAssertions.then(response.getBody()).isEqualTo("I'm OK");
 		then(ExceptionUtils.getLastException()).isNull();
+		then(this.feignComponentAsserter.executedComponents).containsEntry(Client.class, true);
 	}
 
 	@Test
@@ -87,6 +94,9 @@ public class Issue362Tests {
 		} catch (Exception e) { }
 
 		then(ExceptionUtils.getLastException()).isNull();
+		then(this.feignComponentAsserter.executedComponents)
+				.containsEntry(ErrorDecoder.class, true)
+				.containsEntry(Client.class, true);
 	}
 }
 
@@ -117,17 +127,20 @@ class Application {
 	}
 
 	@Bean
-	public Client client() {
-		return new Client.Default(null, null);
-	}
+	public FeignComponentAsserter testHolder() { return new FeignComponentAsserter(); }
+
+}
+
+class FeignComponentAsserter {
+	Map<Class, Boolean> executedComponents = new ConcurrentHashMap<>();
 }
 
 @Configuration
 class CustomConfig {
 
 	@Bean
-	public ErrorDecoder errorDecoder() {
-		return new CustomErrorDecoder();
+	public ErrorDecoder errorDecoder(FeignComponentAsserter feignComponentAsserter) {
+		return new CustomErrorDecoder(feignComponentAsserter);
 	}
 
 	@Bean
@@ -137,18 +150,42 @@ class CustomConfig {
 
 	public static class CustomErrorDecoder extends ErrorDecoder.Default {
 
-		public CustomErrorDecoder() {
+		private final FeignComponentAsserter feignComponentAsserter;
+
+		public CustomErrorDecoder(FeignComponentAsserter feignComponentAsserter) {
+			this.feignComponentAsserter = feignComponentAsserter;
 		}
 
 		@Override
 		public Exception decode(String methodKey, Response response) {
+			this.feignComponentAsserter.executedComponents.put(ErrorDecoder.class, true);
 			if (response.status() == 409) {
 				return new RetryableException("Article not Ready", new Date());
 			} else {
 				return super.decode(methodKey, response);
 			}
 		}
+	}
 
+	@Bean
+	public Client client(FeignComponentAsserter feignComponentAsserter) {
+		return new CustomClient(feignComponentAsserter);
+	}
+
+	public static class CustomClient extends Client.Default {
+
+		private final FeignComponentAsserter feignComponentAsserter;
+
+		public CustomClient(FeignComponentAsserter feignComponentAsserter) {
+			super(null, null);
+			this.feignComponentAsserter = feignComponentAsserter;
+		}
+
+		@Override public Response execute(Request request, Request.Options options)
+				throws IOException {
+			this.feignComponentAsserter.executedComponents.put(Client.class, true);
+			return super.execute(request, options);
+		}
 	}
 }
 

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/feign/servererrors/FeignClientServerErrorTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.instrument.web.client.feign;
+package org.springframework.cloud.sleuth.instrument.web.client.feign.servererrors;
 
 import java.util.ArrayList;
 import java.util.Collections;

spring-cloud-sleuth-core/src/test/java/org/springframework/cloud/sleuth/instrument/web/client/integration/WebClientTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.cloud.sleuth.instrument.web.client;
+package org.springframework.cloud.sleuth.instrument.web.client.integration;
 
 import java.lang.invoke.MethodHandles;
 import java.util.ArrayList;