Add @FeignClient(primary)

docs/src/main/asciidoc/spring-cloud-netflix.adoc

@@ -1127,6 +1127,18 @@ static class HystrixClientFallbackFactory implements FallbackFactory<HystrixClie
 
 WARNING: There is a limitation with the implementation of fallbacks in Feign and how Hystrix fallbacks work. Fallbacks are currently not supported for methods that return `com.netflix.hystrix.HystrixCommand` and `rx.Observable`.
 
+=== Feign and `@Primary`
+
+When using Feign with Hystrix fallbacks, there are multiple beans in the `ApplicationContext` of the same type. This will cause `@Autowired` to work because there isn't exactly one bean, or one marked as primary. To work around this, Spring Cloud Netflix marks all Feign instances as `@Primary`, so Spring Framework will know which bean to inject. In some cases, this may not be desirable. To turn off this behavior set the `primary` attribute of `@FeignClient` to false.
+
+[source,java,indent=0]
+----
+@FeignClient(name = "hello", primary = false)
+public interface HelloClient {
+	// methods here
+}
+----
+
 [[spring-cloud-feign-inheritance]]
 === Feign Inheritance Support
 

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

@@ -106,4 +106,9 @@ public @interface FeignClient {
 	 */
 	String path() default "";
 
+	/**
+	 * Whether to mark the feign proxy as a primary bean. Defaults to false.
+	 */
+	boolean primary() default true;
+
 }

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

@@ -188,7 +188,10 @@ class FeignClientsRegistrar implements ImportBeanDefinitionRegistrar,
 
 		String alias = name + "FeignClient";
 		AbstractBeanDefinition beanDefinition = definition.getBeanDefinition();
-		beanDefinition.setPrimary(true);
+
+		boolean primary = (Boolean)attributes.get("primary"); // has a default, won't be null
+
+		beanDefinition.setPrimary(primary);
 
 		String qualifier = getQualifier(attributes);
 		if (StringUtils.hasText(qualifier)) {

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

+/*
+ * Copyright 2013-2017 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.valid;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.cloud.netflix.feign.EnableFeignClients;
+import org.springframework.cloud.netflix.feign.FeignClient;
+import org.springframework.cloud.netflix.ribbon.RibbonClient;
+import org.springframework.cloud.netflix.ribbon.StaticServerList;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
+import org.springframework.test.annotation.DirtiesContext;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.netflix.loadbalancer.Server;
+import com.netflix.loadbalancer.ServerList;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.Assert.assertNull;
+
+import feign.Logger;
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import java.util.List;
+
+/**
+ * @author Spencer Gibb
+ * @author Jakub Narloch
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringBootTest(classes = FeignClientNotPrimaryTests.Application.class, webEnvironment = WebEnvironment.RANDOM_PORT, value = {
+		"spring.application.name=feignclientnotprimarytest",
+		"logging.level.org.springframework.cloud.netflix.feign.valid=DEBUG",
+		"feign.httpclient.enabled=false", "feign.okhttp.enabled=false" })
+@DirtiesContext
+public class FeignClientNotPrimaryTests {
+
+	public static final String HELLO_WORLD_1 = "hello world 1";
+	public static final String OI_TERRA_2 = "oi terra 2";
+	public static final String MYHEADER1 = "myheader1";
+	public static final String MYHEADER2 = "myheader2";
+
+	@Value("${local.server.port}")
+	private int port = 0;
+
+	@Autowired
+	private TestClient testClient;
+
+	@Autowired
+	private List<TestClient> testClients;
+
+	@FeignClient(name = "localapp", primary = false)
+	protected interface TestClient {
+		@RequestMapping(method = RequestMethod.GET, path = "/hello")
+		Hello getHello();
+
+	}
+
+	@Configuration
+	@EnableAutoConfiguration
+	@RestController
+	@EnableFeignClients(clients = { TestClient.class} ,
+			defaultConfiguration = TestDefaultFeignConfig.class)
+	@RibbonClient(name = "localapp", configuration = LocalRibbonClientConfiguration.class)
+	protected static class Application {
+
+		@Bean
+		@Primary
+		public PrimaryTestClient primaryTestClient() {
+			return new PrimaryTestClient();
+		}
+
+		@RequestMapping(method = RequestMethod.GET, path = "/hello")
+		public Hello getHello() {
+			return new Hello(HELLO_WORLD_1);
+		}
+
+		public static void main(String[] args) {
+			new SpringApplicationBuilder(Application.class)
+					.properties("spring.application.name=feignclienttest",
+							"management.contextPath=/admin")
+					.run(args);
+		}
+	}
+
+	@Test
+	public void testClientType() {
+		assertThat(this.testClient).as("testClient was of wrong type").isInstanceOf(PrimaryTestClient.class);
+	}
+
+	@Test
+	public void testClientCount() {
+		assertThat(this.testClients).as("testClients was wrong").hasSize(2);
+	}
+
+	@Test
+	public void testSimpleType() {
+		Hello hello = this.testClient.getHello();
+		assertNull("hello was null", hello);
+	}
+
+	protected static class PrimaryTestClient implements TestClient {
+		@Override
+		public Hello getHello() {
+			return null;
+		}
+	}
+
+	@Data
+	@AllArgsConstructor
+	@NoArgsConstructor
+	public static class Hello {
+		private String message;
+	}
+
+	@Configuration
+	public static class TestDefaultFeignConfig {
+		@Bean
+		Logger.Level feignLoggerLevel() {
+			return Logger.Level.FULL;
+		}
+	}
+
+	// Load balancer with fixed server list for "local" pointing to localhost
+	@Configuration
+	public static class LocalRibbonClientConfiguration {
+
+		@Value("${local.server.port}")
+		private int port = 0;
+
+		@Bean
+		public ServerList<Server> ribbonServerList() {
+			return new StaticServerList<>(new Server("localhost", this.port));
+		}
+
+	}
+}