Features actuator endpoint

Allows modules to declare features and display if they enabled or not.

spring-cloud-commons/src/main/java/org/springframework/cloud/client/CommonsClientAutoConfiguration.java

@@ -16,8 +16,12 @@
 
 package org.springframework.cloud.client;
 
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.endpoint.Endpoint;
 import org.springframework.boot.actuate.health.HealthAggregator;
 import org.springframework.boot.actuate.health.HealthIndicator;
 import org.springframework.boot.autoconfigure.AutoConfigureOrder;
@@ -25,10 +29,13 @@ import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.cloud.client.actuator.FeaturesEndpoint;
+import org.springframework.cloud.client.actuator.HasFeatures;
 import org.springframework.cloud.client.discovery.DiscoveryClient;
 import org.springframework.cloud.client.discovery.health.DiscoveryClientHealthIndicator;
 import org.springframework.cloud.client.discovery.health.DiscoveryCompositeHealthIndicator;
 import org.springframework.cloud.client.discovery.health.DiscoveryHealthIndicator;
+import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
@@ -56,4 +63,22 @@ public class CommonsClientAutoConfiguration {
 		return new DiscoveryCompositeHealthIndicator(aggregator, indicators);
 	}
 
+	@Bean
+	public HasFeatures commonsFeatures() {
+		return HasFeatures.abstractFeatures(DiscoveryClient.class,
+				LoadBalancerClient.class);
+	}
+
+	@Configuration
+	@ConditionalOnClass(Endpoint.class)
+	protected static class ActuatorConfiguration {
+		@Autowired(required = false)
+		private List<HasFeatures> hasFeatures = new ArrayList<>();
+
+		@Bean
+		public FeaturesEndpoint featuresEndpoint() {
+			return new FeaturesEndpoint(hasFeatures);
+		}
+	}
+
 }

spring-cloud-commons/src/main/java/org/springframework/cloud/client/actuator/FeaturesEndpoint.java

@@ -0,0 +1,87 @@
+package org.springframework.cloud.client.actuator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import lombok.Value;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.boot.actuate.endpoint.AbstractEndpoint;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+
+/**
+ * @author Spencer Gibb
+ */
+@ConfigurationProperties(prefix = "endpoints.features", ignoreUnknownFields = false)
+public class FeaturesEndpoint extends AbstractEndpoint<FeaturesEndpoint.Features> implements ApplicationContextAware {
+
+	private final List<HasFeatures> hasFeaturesList;
+	private ApplicationContext context;
+
+	public FeaturesEndpoint(List<HasFeatures> hasFeaturesList) {
+		super("features", false);
+		this.hasFeaturesList = hasFeaturesList;
+	}
+
+	@Override
+	public void setApplicationContext(ApplicationContext context) throws BeansException {
+		this.context = context;
+	}
+
+	@Override
+	public Features invoke() {
+		Features features = new Features();
+
+		for (HasFeatures hasFeatures : hasFeaturesList) {
+			List<Class> abstractFeatures = hasFeatures.getAbstractFeatures();
+			if (abstractFeatures != null) {
+				for (Class clazz : abstractFeatures) {
+					addAbstractFeature(features, clazz);
+				}
+			}
+
+			List<NamedFeature> namedFeatures = hasFeatures.getNamedFeatures();
+			if (namedFeatures != null) {
+				for (NamedFeature namedFeature : namedFeatures) {
+					addFeature(features, namedFeature);
+				}
+			}
+		}
+
+		return features;
+	}
+
+	private void addAbstractFeature(Features features, Class type) {
+		addFeature(features, new NamedFeature(type.getSimpleName(), type));
+	}
+
+	private void addFeature(Features features, NamedFeature feature) {
+		try {
+			Object bean = context.getBean(feature.getType());
+			Class<?> beanClass = bean.getClass();
+			features.getEnabled().add(new Feature(feature.getName(),
+					beanClass.getCanonicalName(),
+					beanClass.getPackage().getImplementationVersion(),
+					beanClass.getPackage().getImplementationVendor()));
+		} catch (NoSuchBeanDefinitionException e) {
+			features.getDisabled().add(feature.getName());
+		}
+	}
+
+	@Value
+	class Features {
+		List<Feature> enabled = new ArrayList<>();
+		List<String> disabled = new ArrayList<>();
+	}
+
+	@Value
+	class Feature {
+		final String type;
+		final String name;
+		final String version;
+		final String vendor;
+	}
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/actuator/HasFeatures.java

@@ -0,0 +1,29 @@
+package org.springframework.cloud.client.actuator;
+
+import lombok.Builder;
+import lombok.Singular;
+import lombok.Value;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * @author Spencer Gibb
+ */
+@Value
+@Builder
+public class HasFeatures {
+	@Singular
+	private final List<Class> abstractFeatures;
+	@Singular
+	private final List<NamedFeature> namedFeatures;
+
+	public static HasFeatures abstractFeatures(Class... abstractFeatures) {
+		return new HasFeatures(Arrays.asList(abstractFeatures), Collections.<NamedFeature>emptyList());
+	}
+
+	public static HasFeatures namedFeatures(NamedFeature... namedFeatures) {
+		return new HasFeatures(Collections.<Class>emptyList(), Arrays.asList(namedFeatures));
+	}
+}

spring-cloud-commons/src/main/java/org/springframework/cloud/client/actuator/NamedFeature.java

@@ -0,0 +1,12 @@
+package org.springframework.cloud.client.actuator;
+
+import lombok.Value;
+
+/**
+ * @author Spencer Gibb
+ */
+@Value
+public class NamedFeature {
+	private final String name;
+	private final Class<?> type;
+}

spring-cloud-commons/src/test/java/org/springframework/cloud/client/actuator/FeaturesEndpointTests.java

@@ -0,0 +1,89 @@
+package org.springframework.cloud.client.actuator;
+
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
+import static org.hamcrest.Matchers.notNullValue;
+import static org.junit.Assert.assertThat;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author Spencer Gibb
+ */
+public class FeaturesEndpointTests {
+
+	private AnnotationConfigApplicationContext context;
+
+	@Before
+	public void setup() {
+		this.context = new AnnotationConfigApplicationContext();
+		this.context.register(JacksonAutoConfiguration.class, FeaturesConfig.class, Config.class);
+		this.context.refresh();
+	}
+
+	@After
+	public void close() {
+		if (this.context != null) {
+			this.context.close();
+		}
+	}
+
+	@Test
+	public void invokeWorks() {
+		FeaturesEndpoint.Features features = this.context.getBean(FeaturesEndpoint.class).invoke();
+		assertThat(features, is(notNullValue()));
+		assertThat(features.getEnabled().size(), is(equalTo(2)));
+		assertThat(features.getDisabled().size(), is(equalTo(1)));
+	}
+
+	@Configuration
+	public static class FeaturesConfig {
+		@Bean
+		Foo foo() {
+			return new Foo();
+		}
+
+		@Bean
+		Bar bar() {
+			return new Bar();
+		}
+
+		@Bean
+		HasFeatures localFeatures() {
+			return HasFeatures.builder()
+					.abstractFeature(Foo.class)
+					.namedFeature(new NamedFeature("Bar Feature", Bar.class))
+					.abstractFeature(Baz.class)
+					.build();
+		}
+
+	}
+
+	@Configuration
+	@EnableConfigurationProperties
+	public static class Config {
+		@Autowired(required = false)
+		private List<HasFeatures> hasFeatures = new ArrayList<>();
+
+		@Bean
+		public FeaturesEndpoint cloudEndpoint() {
+			return new FeaturesEndpoint(hasFeatures);
+		}
+	}
+
+	public static class Foo {}
+	public static class Bar {}
+	public static class Baz {}
+}