Change DiscoveryHealthIndicator to an interface and create a DiscoveryCompositeHealthIndicator

fixes gh-1

src/main/java/org/springframework/cloud/client/CommonsClientAutoConfiguration.java

@@ -1,12 +1,17 @@
 package org.springframework.cloud.client;
 
+import org.springframework.boot.actuate.health.HealthAggregator;
 import org.springframework.boot.actuate.health.HealthIndicator;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.cloud.client.discovery.DiscoveryClientHealthIndicator;
+import org.springframework.cloud.client.discovery.DiscoveryCompositeHealthIndicator;
 import org.springframework.cloud.client.discovery.DiscoveryHealthIndicator;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.annotation.Order;
 
+import java.util.List;
+
 /**
  * @author Spencer Gibb
  */
@@ -15,8 +20,13 @@ import org.springframework.core.annotation.Order;
 @Order(0)
 public class CommonsClientAutoConfiguration {
 
+	@Bean
+	public DiscoveryClientHealthIndicator instancesHealthIndicator() {
+		return new DiscoveryClientHealthIndicator();
+	}
+
     @Bean
-    public DiscoveryHealthIndicator discoveryHealthIndicator() {
-        return new DiscoveryHealthIndicator();
+    public DiscoveryCompositeHealthIndicator discoveryHealthIndicator(HealthAggregator aggregator, List<DiscoveryHealthIndicator> indicators) {
+        return new DiscoveryCompositeHealthIndicator(aggregator, indicators);
     }
 }

src/main/java/org/springframework/cloud/client/discovery/DiscoveryClient.java

@@ -9,6 +9,8 @@ import java.util.List;
  */
 //TODO: merge with LoadBalancerClient?
 public interface DiscoveryClient {
+	public String description();
+
     /**
      * @return ServiceInstance with information used to register the local service
      */

src/main/java/org/springframework/cloud/client/discovery/DiscoveryClientHealthIndicator.java

@@ -0,0 +1,61 @@
+package org.springframework.cloud.client.discovery;
+
+import java.util.List;
+
+import lombok.extern.slf4j.Slf4j;
+
+import org.springframework.beans.BeansException;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.Status;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.core.Ordered;
+
+/**
+ * @author Spencer Gibb
+ */
+@Slf4j
+public class DiscoveryClientHealthIndicator implements ApplicationContextAware, DiscoveryHealthIndicator, Ordered {
+
+    private ApplicationContext context;
+
+	private int order = Ordered.HIGHEST_PRECEDENCE;
+
+	@Override
+	public Health health() {
+		Health.Builder builder = new Health.Builder();
+        try {
+			DiscoveryClient client = context.getBean(DiscoveryClient.class);
+            if (client == null) {
+                builder.unknown().withDetail("warning", "No DiscoveryClient found");
+                return builder.build();
+            }
+			List<String> services = client.getServices();
+            builder.status(new Status("UP", client.description()))
+					.withDetail("services", services);
+        } catch (Exception e) {
+            log.error("Error", e);
+            builder.down(e);
+        }
+		return builder.build();
+    }
+
+	@Override
+	public String getName() {
+		return "discoveryClient";
+	}
+
+	@Override
+    public void setApplicationContext(ApplicationContext context) throws BeansException {
+        this.context = context;
+    }
+
+	@Override
+	public int getOrder() {
+		return order;
+	}
+
+	public void setOrder(int order) {
+		this.order = order;
+	}
+}

src/main/java/org/springframework/cloud/client/discovery/DiscoveryCompositeHealthIndicator.java

@@ -0,0 +1,36 @@
+package org.springframework.cloud.client.discovery;
+
+import java.util.List;
+
+import lombok.extern.slf4j.Slf4j;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.health.*;
+
+/**
+ * @author Spencer Gibb
+ */
+@Slf4j
+public class DiscoveryCompositeHealthIndicator extends CompositeHealthIndicator {
+
+	@Autowired
+	public DiscoveryCompositeHealthIndicator(HealthAggregator healthAggregator, List<DiscoveryHealthIndicator> indicators) {
+		super(healthAggregator);
+		for (DiscoveryHealthIndicator indicator : indicators) {
+			addHealthIndicator(indicator.getName(), new Holder(indicator));
+		}
+	}
+
+	public static class Holder implements HealthIndicator {
+		DiscoveryHealthIndicator delegate;
+
+		public Holder(DiscoveryHealthIndicator delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public Health health() {
+			return delegate.health();
+		}
+	}
+}

src/main/java/org/springframework/cloud/client/discovery/DiscoveryHealthIndicator.java

@@ -1,42 +1,15 @@
 package org.springframework.cloud.client.discovery;
 
-import java.util.List;
-
-import lombok.extern.slf4j.Slf4j;
-
-import org.springframework.beans.BeansException;
-import org.springframework.boot.actuate.health.AbstractHealthIndicator;
 import org.springframework.boot.actuate.health.Health;
-import org.springframework.cloud.client.ServiceInstance;
-import org.springframework.context.ApplicationContext;
-import org.springframework.context.ApplicationContextAware;
 
 /**
  * @author Spencer Gibb
  */
-@Slf4j
-public class DiscoveryHealthIndicator extends AbstractHealthIndicator implements ApplicationContextAware {
-
-    private ApplicationContext context;
-
-    @Override
-    protected void doHealthCheck(Health.Builder builder) throws Exception {
-        try {
-            DiscoveryClient client = context.getBean(DiscoveryClient.class);
-            if (client == null) {
-                builder.unknown().withDetail("warning", "No DiscoveryClient found");
-                return;
-            }
-            List<ServiceInstance> instances = client.getAllInstances();
-            builder.up().withDetail("instances", instances);
-        } catch (Exception e) {
-            log.error("Error", e);
-            builder.down(e);
-        }
-    }
+public interface DiscoveryHealthIndicator {
+	public String getName();
 
-    @Override
-    public void setApplicationContext(ApplicationContext context) throws BeansException {
-        this.context = context;
-    }
+	/**
+	 * @return an indication of health
+	 */
+	Health health();
 }

src/test/java/org/springframework/cloud/client/discovery/DiscoveryCompositeHealthIndicatorTests.java

@@ -0,0 +1,71 @@
+package org.springframework.cloud.client.discovery;
+
+import com.google.common.collect.Lists;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthAggregator;
+import org.springframework.boot.actuate.health.OrderedHealthAggregator;
+import org.springframework.boot.actuate.health.Status;
+import org.springframework.cloud.client.CommonsClientAutoConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+import static org.mockito.Mockito.*;
+import static org.junit.Assert.*;
+
+/**
+ * @author Spencer Gibb
+ */
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = {DiscoveryCompositeHealthIndicatorTests.Config.class, CommonsClientAutoConfiguration.class})
+public class DiscoveryCompositeHealthIndicatorTests {
+
+	@Autowired
+	DiscoveryCompositeHealthIndicator healthIndicator;
+
+	@Configuration
+	public static class Config {
+		@Bean
+		public HealthAggregator healthAggregator() {
+			return new OrderedHealthAggregator();
+		}
+
+		@Bean
+		public DiscoveryClient discoveryClient() {
+			DiscoveryClient mock = mock(DiscoveryClient.class);
+			when(mock.description()).thenReturn("TestDiscoveryClient");
+			when(mock.getServices()).thenReturn(Lists.newArrayList("TestService1"));
+			return mock;
+		}
+
+		@Bean
+		public DiscoveryHealthIndicator discoveryHealthIndicator() {
+			return new DiscoveryHealthIndicator() {
+				@Override
+				public String getName() {
+					return "testDiscoveryHealthIndicator";
+				}
+
+				@Override
+				public Health health() {
+					return new Health.Builder().up().build();
+				}
+			};
+		}
+	}
+
+	@Test
+	public void testHealthIndicator() {
+		assertNotNull("healthIndicator was null", healthIndicator);
+		Health health = healthIndicator.health();
+		assertNotNull("health was null", health);
+		Status status = health.getStatus();
+		assertNotNull("status was null", status);
+		assertEquals("status code was wrong", "UP", status.getCode());
+		assertEquals("status desciption was wrong", "TestDiscoveryClient", status.getDescription());
+	}
+}