Adds Feign Logger factory interface (#1411)

Fixes gh-1363

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/DefaultFeignLoggerFactory.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2016 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.netflix.feign;
+
+import feign.Logger;
+import feign.slf4j.Slf4jLogger;
+
+/**
+ * @author Venil Noronha
+ */
+public class DefaultFeignLoggerFactory implements FeignLoggerFactory {
+
+	private Logger logger;
+
+	public DefaultFeignLoggerFactory(Logger logger) {
+		this.logger = logger;
+	}
+
+	@Override
+	public Logger create(Class<?> type) {
+		return this.logger != null ? this.logger : new Slf4jLogger(type);
+	}
+
+}

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/FeignClientFactoryBean.java

@@ -39,7 +39,6 @@ import feign.Target.HardCodedTarget;
 import feign.codec.Decoder;
 import feign.codec.Encoder;
 import feign.codec.ErrorDecoder;
-import feign.slf4j.Slf4jLogger;
 import lombok.Data;
 import lombok.EqualsAndHashCode;
 
@@ -83,11 +82,8 @@ class FeignClientFactoryBean implements FactoryBean<Object>, InitializingBean,
 	}
 
 	protected Feign.Builder feign(FeignContext context) {
-		Logger logger = getOptional(context, Logger.class);
-
-		if (logger == null) {
-			logger = new Slf4jLogger(this.type);
-		}
+		FeignLoggerFactory loggerFactory = get(context, FeignLoggerFactory.class);
+		Logger logger = loggerFactory.create(this.type);
 
 		// @formatter:off
 		Feign.Builder builder = get(context, Feign.Builder.class)

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/FeignClientsConfiguration.java

@@ -19,7 +19,6 @@ package org.springframework.cloud.netflix.feign;
 import java.util.ArrayList;
 import java.util.List;
 
-import org.apache.http.client.HttpClient;
 import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
@@ -39,16 +38,16 @@ import org.springframework.format.support.FormattingConversionService;
 
 import com.netflix.hystrix.HystrixCommand;
 
-import feign.Client;
 import feign.Contract;
 import feign.Feign;
+import feign.Logger;
 import feign.codec.Decoder;
 import feign.codec.Encoder;
-import feign.httpclient.ApacheHttpClient;
 import feign.hystrix.HystrixFeign;
 
 /**
  * @author Dave Syer
+ * @author Venil Noronha
  */
 @Configuration
 public class FeignClientsConfiguration {
@@ -62,6 +61,9 @@ public class FeignClientsConfiguration {
 	@Autowired(required = false)
 	private List<FeignFormatterRegistrar> feignFormatterRegistrars = new ArrayList<>();
 
+	@Autowired(required = false)
+	private Logger logger;
+
 	@Bean
 	@ConditionalOnMissingBean
 	public Decoder feignDecoder() {
@@ -108,4 +110,10 @@ public class FeignClientsConfiguration {
 		return Feign.builder();
 	}
 
+	@Bean
+	@ConditionalOnMissingBean(FeignLoggerFactory.class)
+	public FeignLoggerFactory feignLoggerFactory() {
+		return new DefaultFeignLoggerFactory(logger);
+	}
+
 }

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/feign/FeignLoggerFactory.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2016 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.netflix.feign;
+
+import feign.Logger;
+
+/**
+ * Allows an application to use a custom Feign {@link Logger}.
+ *
+ * @author Venil Noronha
+ */
+public interface FeignLoggerFactory {
+
+	/**
+	 * Factory method to provide a {@link Logger} for a given {@link Class}.
+	 *
+	 * @param type the {@link Class} for which a {@link Logger} instance is to be created
+	 * @return a {@link Logger} instance
+	 */
+	public Logger create(Class<?> type);
+
+}

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/feign/FeignLoggerFactoryTests.java

@@ -0,0 +1,126 @@
+/*
+ * Copyright 2016 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.netflix.feign;
+
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+import feign.Logger;
+import feign.slf4j.Slf4jLogger;
+
+/**
+ * @author Venil Noronha
+ */
+public class FeignLoggerFactoryTests {
+
+	@Test
+	public void testDefaultLogger() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SampleConfiguration1.class);
+		FeignLoggerFactory loggerFactory = context.getBean(FeignLoggerFactory.class);
+		assertNotNull(loggerFactory);
+		Logger logger = loggerFactory.create(Object.class);
+		assertNotNull(logger);
+		assertTrue(logger instanceof Slf4jLogger);
+		context.close();
+	}
+
+	@Configuration
+	@Import(FeignClientsConfiguration.class)
+	protected static class SampleConfiguration1 {
+
+	}
+
+	@Test
+	public void testCustomLogger() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SampleConfiguration2.class);
+		FeignLoggerFactory loggerFactory = context.getBean(FeignLoggerFactory.class);
+		assertNotNull(loggerFactory);
+		Logger logger = loggerFactory.create(Object.class);
+		assertNotNull(logger);
+		assertTrue(logger instanceof LoggerImpl1);
+		context.close();
+	}
+
+	@Configuration
+	@Import(FeignClientsConfiguration.class)
+	protected static class SampleConfiguration2 {
+
+		@Bean
+		public Logger logger() {
+			return new LoggerImpl1();
+		}
+
+	}
+
+	static class LoggerImpl1 extends Logger {
+
+		@Override
+		protected void log(String arg0, String arg1, Object... arg2) {
+			// noop
+		}
+
+	}
+
+	@Test
+	public void testCustomLoggerFactory() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SampleConfiguration3.class);
+		FeignLoggerFactory loggerFactory = context.getBean(FeignLoggerFactory.class);
+		assertNotNull(loggerFactory);
+		assertTrue(loggerFactory instanceof LoggerFactoryImpl);
+		Logger logger = loggerFactory.create(Object.class);
+		assertNotNull(logger);
+		assertTrue(logger instanceof LoggerImpl2);
+		context.close();
+	}
+
+	@Configuration
+	@Import(FeignClientsConfiguration.class)
+	protected static class SampleConfiguration3 {
+
+		@Bean
+		public FeignLoggerFactory feignLoggerFactory() {
+			return new LoggerFactoryImpl();
+		}
+
+	}
+
+	static class LoggerFactoryImpl implements FeignLoggerFactory {
+
+		@Override
+		public Logger create(Class<?> type) {
+			return new LoggerImpl2();
+		}
+
+	}
+
+	static class LoggerImpl2 extends Logger {
+
+		@Override
+		protected void log(String arg0, String arg1, Object... arg2) {
+			// noop
+		}
+
+	}
+
+}