Add RefreshScopeHealthIndicator

Repots DOWN if there are errors in RefreshScope or
ConfigurationProperties rebinding, N.B. RefreshScope instantiates
its beans lazily after a refresh by default, so you won't see an
error until the bean is used.

Fixes gh-85

spring-cloud-context/src/main/java/org/springframework/cloud/autoconfigure/RefreshEndpointAutoConfiguration.java

@@ -34,9 +34,11 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.ConfigurationProperties;
 import org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration;
 import org.springframework.cloud.context.environment.EnvironmentChangeEvent;
+import org.springframework.cloud.context.properties.ConfigurationPropertiesRebinder;
 import org.springframework.cloud.context.restart.RestartEndpoint;
 import org.springframework.cloud.context.scope.refresh.RefreshScope;
 import org.springframework.cloud.endpoint.RefreshEndpoint;
+import org.springframework.cloud.health.RefreshScopeHealthIndicator;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.Bean;
@@ -55,6 +57,13 @@ public class RefreshEndpointAutoConfiguration {
 		return new InfoEndpointRebinderConfiguration();
 	}
 
+	@ConditionalOnMissingBean
+	@Bean
+	RefreshScopeHealthIndicator refreshScopeHealthIndicator(RefreshScope scope,
+			ConfigurationPropertiesRebinder rebinder) {
+		return new RefreshScopeHealthIndicator(scope, rebinder);
+	}
+
 	@ConditionalOnClass(IntegrationMBeanExporter.class)
 	protected static class RestartEndpointWithIntegration {
 

spring-cloud-context/src/main/java/org/springframework/cloud/context/properties/ConfigurationPropertiesRebinder.java

@@ -16,7 +16,9 @@
 package org.springframework.cloud.context.properties;
 
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.springframework.beans.BeansException;
 import org.springframework.boot.context.properties.ConfigurationProperties;
@@ -46,8 +48,8 @@ import org.springframework.stereotype.Component;
  */
 @Component
 @ManagedResource
-public class ConfigurationPropertiesRebinder implements ApplicationContextAware,
-ApplicationListener<EnvironmentChangeEvent> {
+public class ConfigurationPropertiesRebinder
+		implements ApplicationContextAware, ApplicationListener<EnvironmentChangeEvent> {
 
 	private ConfigurationPropertiesBeans beans;
 
@@ -55,6 +57,8 @@ ApplicationListener<EnvironmentChangeEvent> {
 
 	private ApplicationContext applicationContext;
 
+	private Map<String, Exception> errors = new ConcurrentHashMap<>();
+
 	public ConfigurationPropertiesRebinder(
 			ConfigurationPropertiesBindingPostProcessor binder,
 			ConfigurationPropertiesBeans beans) {
@@ -68,8 +72,18 @@ ApplicationListener<EnvironmentChangeEvent> {
 		this.applicationContext = applicationContext;
 	}
 
+	/**
+	 * A map of bean name to errors when instantiating the bean.
+	 *
+	 * @return the errors accumulated since the latest destroy
+	 */
+	public Map<String, Exception> getErrors() {
+		return this.errors;
+	}
+
 	@ManagedOperation
 	public void rebind() {
+		this.errors.clear();
 		for (String name : this.beans.getBeanNames()) {
 			rebind(name);
 		}
@@ -81,11 +95,17 @@ ApplicationListener<EnvironmentChangeEvent> {
 			return false;
 		}
 		if (this.applicationContext != null) {
-			Object bean = this.applicationContext.getBean(name);
-			this.binder.postProcessBeforeInitialization(bean, name);
-			this.applicationContext.getAutowireCapableBeanFactory().initializeBean(bean,
-					name);
-			return true;
+			try {
+				Object bean = this.applicationContext.getBean(name);
+				this.binder.postProcessBeforeInitialization(bean, name);
+				this.applicationContext.getAutowireCapableBeanFactory()
+						.initializeBean(bean, name);
+				return true;
+			}
+			catch (RuntimeException e) {
+				this.errors.put(name, e);
+				throw e;
+			}
 		}
 		return false;
 	}

spring-cloud-context/src/main/java/org/springframework/cloud/context/scope/GenericScope.java

@@ -18,7 +18,9 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -70,6 +72,8 @@ public class GenericScope implements Scope, BeanFactoryPostProcessor, Disposable
 
 	private BeanLifecycleDecorator<?> lifecycle;
 
+	private Map<String, Exception> errors = new ConcurrentHashMap<>();
+
 	/**
 	 * Manual override for the serialization id that will be used to identify the bean
 	 * factory. The default is a unique key based on the bean names in the bean factory.
@@ -117,6 +121,15 @@ public class GenericScope implements Scope, BeanFactoryPostProcessor, Disposable
 		this.lifecycle = lifecycle;
 	}
 
+	/**
+	 * A map of bean name to errors when instantiating the bean.
+	 *
+	 * @return the errors accumulated since the latest destroy
+	 */
+	public Map<String, Exception> getErrors() {
+		return this.errors;
+	}
+
 	@Override
 	public void destroy() {
 		List<Throwable> errors = new ArrayList<Throwable>();
@@ -132,6 +145,7 @@ public class GenericScope implements Scope, BeanFactoryPostProcessor, Disposable
 		if (!errors.isEmpty()) {
 			throw wrapIfNecessary(errors.get(0));
 		}
+		this.errors.clear();
 	}
 
 	/**
@@ -144,6 +158,7 @@ public class GenericScope implements Scope, BeanFactoryPostProcessor, Disposable
 		BeanLifecycleWrapper wrapper = this.cache.remove(name);
 		if (wrapper != null) {
 			wrapper.destroy();
+			this.errors.remove(name);
 			return true;
 		}
 		return false;
@@ -156,7 +171,13 @@ public class GenericScope implements Scope, BeanFactoryPostProcessor, Disposable
 		}
 		BeanLifecycleWrapper value = this.cache.put(name,
 				new BeanLifecycleWrapper(name, objectFactory, this.lifecycle));
-		return value.getBean();
+		try {
+			return value.getBean();
+		}
+		catch (RuntimeException e) {
+			this.errors.put(name, e);
+			throw e;
+		}
 	}
 
 	@Override

spring-cloud-context/src/main/java/org/springframework/cloud/health/RefreshScopeHealthIndicator.java

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2013-2015 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.health;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.boot.actuate.health.AbstractHealthIndicator;
+import org.springframework.boot.actuate.health.Health.Builder;
+import org.springframework.cloud.context.properties.ConfigurationPropertiesRebinder;
+import org.springframework.cloud.context.scope.refresh.RefreshScope;
+
+/**
+ * Health indicator for the refresh scope and configuration properties rebinding. If an
+ * environment change causes a bean to fail in instantiate or bind this indicator will
+ * generally say what the problem was and switch to DOWN.
+ *
+ * @author Dave Syer
+ */
+public class RefreshScopeHealthIndicator extends AbstractHealthIndicator {
+
+	private RefreshScope scope;
+	private ConfigurationPropertiesRebinder rebinder;
+
+	public RefreshScopeHealthIndicator(RefreshScope scope,
+			ConfigurationPropertiesRebinder rebinder) {
+		this.scope = scope;
+		this.rebinder = rebinder;
+	}
+
+	@Override
+	protected void doHealthCheck(Builder builder) throws Exception {
+		Map<String, Exception> errors = new HashMap<>(this.scope.getErrors());
+		errors.putAll(this.rebinder.getErrors());
+		if (errors.isEmpty()) {
+			builder.up();
+		}
+		else {
+			builder.down();
+			if (errors.size() == 1) {
+				builder.withException(errors.values().iterator().next());
+			}
+			else {
+				for (String name : errors.keySet()) {
+					builder.withDetail(name, errors.get(name));
+				}
+			}
+		}
+	}
+
+}

spring-cloud-context/src/test/java/org/springframework/cloud/health/RefreshScopeHealthIndicatorTests.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2013-2015 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.health;
+
+import java.util.Collections;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.Mockito;
+import org.springframework.boot.actuate.health.Status;
+import org.springframework.cloud.context.properties.ConfigurationPropertiesRebinder;
+import org.springframework.cloud.context.scope.refresh.RefreshScope;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.when;
+
+/**
+ * @author Dave Syer
+ */
+public class RefreshScopeHealthIndicatorTests {
+
+	private ConfigurationPropertiesRebinder rebinder = Mockito
+			.mock(ConfigurationPropertiesRebinder.class);
+	private RefreshScope scope = Mockito.mock(RefreshScope.class);
+	private RefreshScopeHealthIndicator indicator = new RefreshScopeHealthIndicator(
+			this.scope, this.rebinder);
+
+	@Before
+	public void init() {
+		when(this.rebinder.getErrors())
+				.thenReturn(Collections.<String, Exception> emptyMap());
+		when(this.scope.getErrors())
+				.thenReturn(Collections.<String, Exception> emptyMap());
+	}
+
+	@Test
+	public void sunnyDay() {
+		assertEquals(Status.UP, this.indicator.health().getStatus());
+	}
+
+	@Test
+	public void binderError() {
+		when(this.rebinder.getErrors()).thenReturn(Collections
+				.<String, Exception> singletonMap("foo", new RuntimeException("FOO")));
+		assertEquals(Status.DOWN, this.indicator.health().getStatus());
+	}
+
+	@Test
+	public void scopeError() {
+		when(this.scope.getErrors()).thenReturn(Collections
+				.<String, Exception> singletonMap("foo", new RuntimeException("FOO")));
+		assertEquals(Status.DOWN, this.indicator.health().getStatus());
+	}
+
+	@Test
+	public void bothError() {
+		when(this.rebinder.getErrors()).thenReturn(Collections
+				.<String, Exception> singletonMap("foo", new RuntimeException("FOO")));
+		when(this.scope.getErrors()).thenReturn(Collections
+				.<String, Exception> singletonMap("bar", new RuntimeException("BAR")));
+		assertEquals(Status.DOWN, this.indicator.health().getStatus());
+	}
+
+}