Moves EurekaServerConfiguration to auto-configuration

Eureka ServerConfiguration is now auto-configuration based, instead of being explicitly specified via configuration pulled in through @EnableEurekaServer. This way specific beans can be conditionally overridden, configuration can be re-ordered.
Supports PeerEurekaNodes bean to be overridden by the user

Fixes gh-1717

spring-cloud-netflix-eureka-server/src/main/java/org/springframework/cloud/netflix/eureka/server/EnableEurekaServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2014 the original author or authors.
+ * 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.
@@ -22,16 +22,22 @@ import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
 
+import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
 import org.springframework.context.annotation.Import;
 
 /**
+ * Annotation to activate Eureka Server related configuration {@link EurekaServerAutoConfiguration}
+ *
  * @author Dave Syer
+ * @author Biju Kunjummen
  *
  */
+
+@EnableDiscoveryClient
 @Target(ElementType.TYPE)
 @Retention(RetentionPolicy.RUNTIME)
 @Documented
-@Import(EurekaServerConfiguration.class)
+@Import(EurekaServerMarkerConfiguration.class)
 public @interface EnableEurekaServer {
 
 }

spring-cloud-netflix-eureka-server/src/main/java/org/springframework/cloud/netflix/eureka/server/EurekaServerAutoConfiguration.java

@@ -29,12 +29,12 @@ import javax.ws.rs.ext.Provider;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.web.servlet.FilterRegistrationBean;
 import org.springframework.cloud.client.actuator.HasFeatures;
-import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
 import org.springframework.cloud.netflix.eureka.EurekaConstants;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
@@ -66,13 +66,15 @@ import com.sun.jersey.spi.container.servlet.ServletContainer;
 
 /**
  * @author Gunnar Hillert
+ * @author Biju Kunjummen
  */
 @Configuration
 @Import(EurekaServerInitializerConfiguration.class)
-@EnableDiscoveryClient
-@EnableConfigurationProperties({ EurekaDashboardProperties.class, InstanceRegistryProperties.class })
+@ConditionalOnBean(EurekaServerMarkerConfiguration.Marker.class)
+@EnableConfigurationProperties({ EurekaDashboardProperties.class,
+		InstanceRegistryProperties.class })
 @PropertySource("classpath:/eureka/server.properties")
-public class EurekaServerConfiguration extends WebMvcConfigurerAdapter {
+public class EurekaServerAutoConfiguration extends WebMvcConfigurerAdapter {
 	/**
 	 * List of packages containing Jersey resources required by the Eureka server
 	 */
@@ -98,7 +100,8 @@ public class EurekaServerConfiguration extends WebMvcConfigurerAdapter {
 
 	@Bean
 	public HasFeatures eurekaServerFeature() {
-		return HasFeatures.namedFeature("Eureka Server", EurekaServerConfiguration.class);
+		return HasFeatures.namedFeature("Eureka Server",
+				EurekaServerAutoConfiguration.class);
 	}
 
 	@Configuration
@@ -163,6 +166,7 @@ public class EurekaServerConfiguration extends WebMvcConfigurerAdapter {
 	}
 
 	@Bean
+	@ConditionalOnMissingBean
 	public PeerEurekaNodes peerEurekaNodes(PeerAwareInstanceRegistry registry,
 			ServerCodecs serverCodecs) {
 		return new PeerEurekaNodes(registry, this.eurekaServerConfig,

spring-cloud-netflix-eureka-server/src/main/java/org/springframework/cloud/netflix/eureka/server/EurekaServerMarkerConfiguration.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 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.eureka.server;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * Responsible for adding in a marker bean to activate
+ * {@link EurekaServerAutoConfiguration}
+ *
+ * @author Biju Kunjummen
+ */
+@Configuration
+public class EurekaServerMarkerConfiguration {
+
+	@Bean
+	public Marker eurekaServerMarkerBean() {
+		return new Marker();
+	}
+
+	class Marker {
+	}
+}

spring-cloud-netflix-eureka-server/src/main/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
+  org.springframework.cloud.netflix.eureka.server.EurekaServerAutoConfiguration

spring-cloud-netflix-eureka-server/src/test/java/org/springframework/cloud/netflix/eureka/server/ApplicationTests.java

@@ -106,7 +106,7 @@ public class ApplicationTests {
 	@Test
 	public void customCodecWorks() throws Exception {
 		assertThat("serverCodecs is wrong type", this.serverCodecs,
-				is(instanceOf(EurekaServerConfiguration.CloudServerCodecs.class)));
+				is(instanceOf(EurekaServerAutoConfiguration.CloudServerCodecs.class)));
 		CodecWrapper codec = this.serverCodecs.getFullJsonCodec();
 		assertThat("codec is wrong type", codec, is(instanceOf(CloudJacksonJson.class)));
 

spring-cloud-netflix-eureka-server/src/test/java/org/springframework/cloud/netflix/eureka/server/EurekaCustomPeerNodesTest.java

@@ -0,0 +1,87 @@
+/*
+ * 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.eureka.server;
+
+import static org.junit.Assert.*;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import com.netflix.appinfo.ApplicationInfoManager;
+import com.netflix.discovery.EurekaClientConfig;
+import com.netflix.eureka.EurekaServerConfig;
+import com.netflix.eureka.cluster.PeerEurekaNodes;
+import com.netflix.eureka.registry.PeerAwareInstanceRegistry;
+import com.netflix.eureka.resources.ServerCodecs;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = EurekaCustomPeerNodesTest.Application.class, webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, value = {
+		"spring.application.name=eureka", "server.contextPath=/context",
+		"management.security.enabled=false" })
+public class EurekaCustomPeerNodesTest {
+
+	 @Autowired
+	 private PeerEurekaNodes peerEurekaNodes;
+
+	@Test
+	public void testCustomPeerNodesShouldTakePrecedenceOverDefault() {
+		assertTrue("PeerEurekaNodes should be the user created one",
+				peerEurekaNodes instanceof CustomEurekaPeerNodes);
+	}
+
+	@Configuration
+	@EnableAutoConfiguration
+	@EnableEurekaServer
+	protected static class Application {
+
+		public static void main(String[] args) {
+			new SpringApplicationBuilder(ApplicationContextTests.Application.class)
+					.properties("spring.application.name=eureka",
+							"server.contextPath=/context")
+					.run(args);
+		}
+
+		@Bean
+		public PeerEurekaNodes myPeerEurekaNodes(PeerAwareInstanceRegistry registry,
+				EurekaServerConfig eurekaServerConfig,
+				EurekaClientConfig eurekaClientConfig, ServerCodecs serverCodecs,
+				ApplicationInfoManager applicationInfoManager) {
+			return new CustomEurekaPeerNodes(registry, eurekaServerConfig,
+					eurekaClientConfig, serverCodecs, applicationInfoManager);
+		}
+
+	}
+
+	private static class CustomEurekaPeerNodes extends PeerEurekaNodes {
+
+		public CustomEurekaPeerNodes(PeerAwareInstanceRegistry registry,
+				EurekaServerConfig serverConfig, EurekaClientConfig clientConfig,
+				ServerCodecs serverCodecs,
+				ApplicationInfoManager applicationInfoManager) {
+			super(registry, serverConfig, clientConfig, serverCodecs,
+					applicationInfoManager);
+		}
+	}
+
+}