Introduce HealthIndicatorRegistry

This commit introduces HealthIndicatorRegistry which handles
registration of HealthIndicator instances. Registering new
HealthIndicator instances is now possible in runtime.

See gh-4965

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthEndpointConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -16,10 +16,13 @@
 
 package org.springframework.boot.actuate.autoconfigure.health;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.actuate.autoconfigure.endpoint.condition.ConditionalOnEnabledEndpoint;
+import org.springframework.boot.actuate.health.HealthAggregator;
 import org.springframework.boot.actuate.health.HealthEndpoint;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
+import org.springframework.boot.actuate.health.OrderedHealthAggregator;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
@@ -27,15 +30,27 @@ import org.springframework.context.annotation.Configuration;
  * Configuration for {@link HealthEndpoint}.
  *
  * @author Stephane Nicoll
+ * @author Vedran Pavic
  */
 @Configuration
 class HealthEndpointConfiguration {
 
+	private final HealthAggregator healthAggregator;
+
+	private final HealthIndicatorRegistry healthIndicatorRegistry;
+
+	HealthEndpointConfiguration(ObjectProvider<HealthAggregator> healthAggregator,
+			ObjectProvider<HealthIndicatorRegistry> healthIndicatorRegistry) {
+		this.healthAggregator = healthAggregator
+				.getIfAvailable(OrderedHealthAggregator::new);
+		this.healthIndicatorRegistry = healthIndicatorRegistry.getObject();
+	}
+
 	@Bean
 	@ConditionalOnMissingBean
 	@ConditionalOnEnabledEndpoint
-	public HealthEndpoint healthEndpoint(ApplicationContext applicationContext) {
-		return new HealthEndpoint(HealthIndicatorBeansComposite.get(applicationContext));
+	public HealthEndpoint healthEndpoint() {
+		return new HealthEndpoint(this.healthAggregator, this.healthIndicatorRegistry);
 	}
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthEndpointWebExtensionConfiguration.java

@@ -36,7 +36,6 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication.Type;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
@@ -107,11 +106,9 @@ class HealthEndpointWebExtensionConfiguration {
 		@ConditionalOnEnabledEndpoint
 		@ConditionalOnBean(HealthEndpoint.class)
 		public HealthEndpointWebExtension healthEndpointWebExtension(
-				ApplicationContext applicationContext,
+				HealthEndpoint healthEndpoint,
 				HealthWebEndpointResponseMapper responseMapper) {
-			return new HealthEndpointWebExtension(
-					HealthIndicatorBeansComposite.get(applicationContext),
-					responseMapper);
+			return new HealthEndpointWebExtension(healthEndpoint, responseMapper);
 		}
 
 	}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthIndicatorAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -16,16 +16,23 @@
 
 package org.springframework.boot.actuate.autoconfigure.health;
 
+import java.util.LinkedHashMap;
+import java.util.Map;
+
 import org.springframework.boot.actuate.health.ApplicationHealthIndicator;
+import org.springframework.boot.actuate.health.DefaultHealthIndicatorRegistry;
 import org.springframework.boot.actuate.health.HealthAggregator;
 import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
 import org.springframework.boot.actuate.health.OrderedHealthAggregator;
 import org.springframework.boot.actuate.health.ReactiveHealthIndicator;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.util.ClassUtils;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for {@link HealthIndicator}s.
@@ -33,6 +40,7 @@ import org.springframework.context.annotation.Configuration;
  * @author Andy Wilkinson
  * @author Stephane Nicoll
  * @author Phillip Webb
+ * @author Vedran Pavic
  * @since 2.0.0
  */
 @Configuration
@@ -61,4 +69,34 @@ public class HealthIndicatorAutoConfiguration {
 		return healthAggregator;
 	}
 
+	@Bean
+	@ConditionalOnMissingBean(HealthIndicatorRegistry.class)
+	public HealthIndicatorRegistry healthIndicatorRegistry(
+			ApplicationContext applicationContext) {
+		HealthIndicatorRegistry registry = new DefaultHealthIndicatorRegistry();
+		Map<String, HealthIndicator> indicators = new LinkedHashMap<>();
+		indicators.putAll(applicationContext.getBeansOfType(HealthIndicator.class));
+		if (ClassUtils.isPresent("reactor.core.publisher.Flux", null)) {
+			new ReactiveHealthIndicators().get(applicationContext)
+					.forEach(indicators::putIfAbsent);
+		}
+		indicators.forEach(registry::register);
+		return registry;
+	}
+
+	private static class ReactiveHealthIndicators {
+
+		public Map<String, HealthIndicator> get(ApplicationContext applicationContext) {
+			Map<String, HealthIndicator> indicators = new LinkedHashMap<>();
+			applicationContext.getBeansOfType(ReactiveHealthIndicator.class)
+					.forEach((name, indicator) -> indicators.put(name, adapt(indicator)));
+			return indicators;
+		}
+
+		private HealthIndicator adapt(ReactiveHealthIndicator indicator) {
+			return () -> indicator.health().block();
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/health/HealthIndicatorBeansComposite.java

@@ -1,80 +0,0 @@
-/*
- * Copyright 2012-2017 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.boot.actuate.autoconfigure.health;
-
-import java.util.LinkedHashMap;
-import java.util.Map;
-
-import org.springframework.beans.factory.NoSuchBeanDefinitionException;
-import org.springframework.boot.actuate.health.CompositeHealthIndicator;
-import org.springframework.boot.actuate.health.CompositeHealthIndicatorFactory;
-import org.springframework.boot.actuate.health.HealthAggregator;
-import org.springframework.boot.actuate.health.HealthIndicator;
-import org.springframework.boot.actuate.health.OrderedHealthAggregator;
-import org.springframework.boot.actuate.health.ReactiveHealthIndicator;
-import org.springframework.context.ApplicationContext;
-import org.springframework.util.ClassUtils;
-
-/**
- * Creates a {@link CompositeHealthIndicator} from beans in the
- * {@link ApplicationContext}.
- *
- * @author Phillip Webb
- */
-final class HealthIndicatorBeansComposite {
-
-	private HealthIndicatorBeansComposite() {
-	}
-
-	public static HealthIndicator get(ApplicationContext applicationContext) {
-		HealthAggregator healthAggregator = getHealthAggregator(applicationContext);
-		Map<String, HealthIndicator> indicators = new LinkedHashMap<>();
-		indicators.putAll(applicationContext.getBeansOfType(HealthIndicator.class));
-		if (ClassUtils.isPresent("reactor.core.publisher.Flux", null)) {
-			new ReactiveHealthIndicators().get(applicationContext)
-					.forEach(indicators::putIfAbsent);
-		}
-		CompositeHealthIndicatorFactory factory = new CompositeHealthIndicatorFactory();
-		return factory.createHealthIndicator(healthAggregator, indicators);
-	}
-
-	private static HealthAggregator getHealthAggregator(
-			ApplicationContext applicationContext) {
-		try {
-			return applicationContext.getBean(HealthAggregator.class);
-		}
-		catch (NoSuchBeanDefinitionException ex) {
-			return new OrderedHealthAggregator();
-		}
-	}
-
-	private static class ReactiveHealthIndicators {
-
-		public Map<String, HealthIndicator> get(ApplicationContext applicationContext) {
-			Map<String, HealthIndicator> indicators = new LinkedHashMap<>();
-			applicationContext.getBeansOfType(ReactiveHealthIndicator.class)
-					.forEach((name, indicator) -> indicators.put(name, adapt(indicator)));
-			return indicators;
-		}
-
-		private HealthIndicator adapt(ReactiveHealthIndicator indicator) {
-			return () -> indicator.health().block();
-		}
-
-	}
-
-}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/cloudfoundry/CloudFoundryWebEndpointDiscovererTests.java

@@ -34,8 +34,9 @@ import org.springframework.boot.actuate.endpoint.web.ExposableWebEndpoint;
 import org.springframework.boot.actuate.endpoint.web.PathMapper;
 import org.springframework.boot.actuate.endpoint.web.WebOperation;
 import org.springframework.boot.actuate.endpoint.web.annotation.EndpointWebExtension;
+import org.springframework.boot.actuate.health.HealthAggregator;
 import org.springframework.boot.actuate.health.HealthEndpoint;
-import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -109,7 +110,8 @@ public class CloudFoundryWebEndpointDiscovererTests {
 
 		@Bean
 		public HealthEndpoint healthEndpoint() {
-			return new HealthEndpoint(mock(HealthIndicator.class));
+			return new HealthEndpoint(mock(HealthAggregator.class),
+					mock(HealthIndicatorRegistry.class));
 		}
 
 		@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/cloudfoundry/reactive/ReactiveCloudFoundryActuatorAutoConfigurationTests.java

@@ -32,6 +32,7 @@ import reactor.ipc.netty.http.HttpResources;
 import org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.health.HealthEndpointAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.health.HealthIndicatorAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.web.server.ManagementContextAutoConfiguration;
 import org.springframework.boot.actuate.endpoint.ExposableEndpoint;
 import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
@@ -87,6 +88,7 @@ public class ReactiveCloudFoundryActuatorAutoConfigurationTests {
 					WebClientCustomizerConfig.class, WebClientAutoConfiguration.class,
 					ManagementContextAutoConfiguration.class,
 					EndpointAutoConfiguration.class, WebEndpointAutoConfiguration.class,
+					HealthIndicatorAutoConfiguration.class,
 					HealthEndpointAutoConfiguration.class,
 					ReactiveCloudFoundryActuatorAutoConfiguration.class));
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/cloudfoundry/servlet/CloudFoundryActuatorAutoConfigurationTests.java

@@ -24,6 +24,7 @@ import org.junit.Test;
 import org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.health.HealthEndpointAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.health.HealthIndicatorAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.web.server.ManagementContextAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.web.servlet.ServletManagementContextAutoConfiguration;
 import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
@@ -270,7 +271,8 @@ public class CloudFoundryActuatorAutoConfigurationTests {
 						"vcap.application.application_id:my-app-id",
 						"vcap.application.cf_api:http://my-cloud-controller.com")
 				.withConfiguration(
-						AutoConfigurations.of(HealthEndpointAutoConfiguration.class))
+						AutoConfigurations.of(HealthIndicatorAutoConfiguration.class,
+								HealthEndpointAutoConfiguration.class))
 				.run((context) -> {
 					Collection<ExposableWebEndpoint> endpoints = context
 							.getBean("cloudFoundryWebEndpointServletHandlerMapping",

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/endpoint/web/documentation/HealthEndpointDocumentationTests.java

@@ -23,9 +23,10 @@ import javax.sql.DataSource;
 
 import org.junit.Test;
 
-import org.springframework.boot.actuate.health.CompositeHealthIndicator;
+import org.springframework.boot.actuate.health.DefaultHealthIndicatorRegistry;
 import org.springframework.boot.actuate.health.HealthEndpoint;
 import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.actuate.health.HealthIndicatorRegistry;
 import org.springframework.boot.actuate.health.OrderedHealthAggregator;
 import org.springframework.boot.actuate.jdbc.DataSourceHealthIndicator;
 import org.springframework.boot.actuate.system.DiskSpaceHealthIndicator;
@@ -72,8 +73,9 @@ public class HealthEndpointDocumentationTests extends MockMvcEndpointDocumentati
 
 		@Bean
 		public HealthEndpoint endpoint(Map<String, HealthIndicator> healthIndicators) {
-			return new HealthEndpoint(new CompositeHealthIndicator(
-					new OrderedHealthAggregator(), healthIndicators));
+			HealthIndicatorRegistry registry = new DefaultHealthIndicatorRegistry();
+			healthIndicators.forEach(registry::register);
+			return new HealthEndpoint(new OrderedHealthAggregator(), registry);
 		}
 
 		@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/health/HealthEndpointAutoConfigurationTests.java

@@ -46,7 +46,8 @@ public class HealthEndpointAutoConfigurationTests {
 
 	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
 			.withConfiguration(
-					AutoConfigurations.of(HealthEndpointAutoConfiguration.class));
+					AutoConfigurations.of(HealthIndicatorAutoConfiguration.class,
+							HealthEndpointAutoConfiguration.class));
 
 	@Test
 	public void healthEndpointShowDetailsDefault() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/integrationtest/JmxEndpointIntegrationTests.java

@@ -28,6 +28,7 @@ import org.junit.Test;
 
 import org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.endpoint.jmx.JmxEndpointAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.health.HealthIndicatorAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.trace.http.HttpTraceAutoConfiguration;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration;
@@ -47,7 +48,7 @@ public class JmxEndpointIntegrationTests {
 	private final WebApplicationContextRunner contextRunner = new WebApplicationContextRunner()
 			.withConfiguration(AutoConfigurations.of(JmxAutoConfiguration.class,
 					EndpointAutoConfiguration.class, JmxEndpointAutoConfiguration.class,
-					HttpTraceAutoConfiguration.class))
+					HttpTraceAutoConfiguration.class, HealthIndicatorAutoConfiguration.class))
 			.withConfiguration(
 					AutoConfigurations.of(EndpointAutoConfigurationClasses.ALL));
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/integrationtest/WebMvcEndpointExposureIntegrationTests.java

@@ -28,6 +28,7 @@ import org.junit.Test;
 
 import org.springframework.boot.actuate.autoconfigure.endpoint.EndpointAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.endpoint.web.WebEndpointAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.health.HealthIndicatorAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.trace.http.HttpTraceAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.web.server.ManagementContextAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.web.servlet.ServletManagementContextAutoConfiguration;
@@ -73,7 +74,8 @@ public class WebMvcEndpointExposureIntegrationTests {
 							ServletManagementContextAutoConfiguration.class,
 							ManagementContextAutoConfiguration.class,
 							ServletManagementContextAutoConfiguration.class,
-							HttpTraceAutoConfiguration.class))
+							HttpTraceAutoConfiguration.class,
+							HealthIndicatorAutoConfiguration.class))
 					.withConfiguration(
 							AutoConfigurations.of(EndpointAutoConfigurationClasses.ALL))
 					.withUserConfiguration(CustomMvcEndpoint.class,

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/DefaultHealthIndicatorRegistry.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2012-2018 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.boot.actuate.health;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.util.Assert;
+
+/**
+ * Default implementation of {@link HealthIndicatorRegistry}.
+ *
+ * @author Vedran Pavic
+ * @since 2.1.0
+ */
+public class DefaultHealthIndicatorRegistry implements HealthIndicatorRegistry {
+
+	private final Map<String, HealthIndicator> healthIndicators = new HashMap<>();
+
+	@Override
+	public void register(String name, HealthIndicator healthIndicator) {
+		Assert.notNull(healthIndicator, "HealthIndicator must not be null");
+		synchronized (this.healthIndicators) {
+			if (this.healthIndicators.get(name) != null) {
+				throw new IllegalStateException(
+						"HealthIndicator with name '" + name + "' already registered");
+			}
+			this.healthIndicators.put(name, healthIndicator);
+		}
+	}
+
+	@Override
+	public HealthIndicator unregister(String name) {
+		synchronized (this.healthIndicators) {
+			return this.healthIndicators.remove(name);
+		}
+	}
+
+	@Override
+	public HealthIndicator get(String name) {
+		synchronized (this.healthIndicators) {
+			return this.healthIndicators.get(name);
+		}
+	}
+
+	@Override
+	public Map<String, HealthIndicator> getAll() {
+		synchronized (this.healthIndicators) {
+			return Collections.unmodifiableMap(new HashMap<>(this.healthIndicators));
+		}
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/HealthEndpoint.java

@@ -26,25 +26,35 @@ import org.springframework.util.Assert;
  * @author Dave Syer
  * @author Christian Dupuis
  * @author Andy Wilkinson
+ * @author Vedran Pavic
  * @since 2.0.0
  */
 @Endpoint(id = "health")
 public class HealthEndpoint {
 
-	private final HealthIndicator healthIndicator;
+	private final HealthAggregator healthAggregator;
+
+	private final HealthIndicatorRegistry healthIndicatorRegistry;
 
 	/**
 	 * Create a new {@link HealthEndpoint} instance.
-	 * @param healthIndicator the health indicator
+	 * @param healthAggregator the health aggregator
+	 * @param healthIndicatorRegistry the health indicator registry
 	 */
-	public HealthEndpoint(HealthIndicator healthIndicator) {
-		Assert.notNull(healthIndicator, "HealthIndicator must not be null");
-		this.healthIndicator = healthIndicator;
+	public HealthEndpoint(HealthAggregator healthAggregator,
+			HealthIndicatorRegistry healthIndicatorRegistry) {
+		Assert.notNull(healthAggregator, "healthAggregator must not be null");
+		Assert.notNull(healthIndicatorRegistry, "healthIndicatorRegistry must not be null");
+		this.healthAggregator = healthAggregator;
+		this.healthIndicatorRegistry = healthIndicatorRegistry;
 	}
 
 	@ReadOperation
 	public Health health() {
-		return this.healthIndicator.health();
+		CompositeHealthIndicatorFactory factory = new CompositeHealthIndicatorFactory();
+		CompositeHealthIndicator healthIndicator = factory.createHealthIndicator(
+				this.healthAggregator, this.healthIndicatorRegistry.getAll());
+		return healthIndicator.health();
 	}
 
 }

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/HealthEndpointWebExtension.java

@@ -35,11 +35,11 @@ import org.springframework.boot.actuate.endpoint.web.annotation.EndpointWebExten
 @EndpointWebExtension(endpoint = HealthEndpoint.class)
 public class HealthEndpointWebExtension {
 
-	private final HealthIndicator delegate;
+	private final HealthEndpoint delegate;
 
 	private final HealthWebEndpointResponseMapper responseMapper;
 
-	public HealthEndpointWebExtension(HealthIndicator delegate,
+	public HealthEndpointWebExtension(HealthEndpoint delegate,
 			HealthWebEndpointResponseMapper responseMapper) {
 		this.delegate = delegate;
 		this.responseMapper = responseMapper;

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/health/HealthIndicatorRegistry.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2012-2018 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.boot.actuate.health;
+
+import java.util.Map;
+
+/**
+ * A registry of {@link HealthIndicator}s.
+ * <p>
+ * Implementations <strong>must</strong> be thread-safe.
+ *
+ * @author Andy Wilkinson
+ * @author Vedran Pavic
+ * @since 2.1.0
+ */
+public interface HealthIndicatorRegistry {
+
+	/**
+	 * Registers the given {@code healthIndicator}, associating it with the given
+	 * {@code name}.
+	 * @param name the name of the indicator
+	 * @param healthIndicator the indicator
+	 * @throws IllegalStateException if an indicator with the given {@code name} is
+	 * already registered.
+	 */
+	void register(String name, HealthIndicator healthIndicator);
+
+	/**
+	 * Unregisters the {@code HealthIndicator} previously registered with the given
+	 * {@code name}.
+	 * @param name the name of the indicator
+	 * @return the unregistered indicator, or {@code null} if no indicator was found in
+	 * the registry for the given {@code name}.
+	 */
+	HealthIndicator unregister(String name);
+
+	/**
+	 * Returns the health indicator registered with the given {@code name}.
+	 * @param name the name of the indicator
+	 * @return the health indicator, or {@code null} if no indicator was registered with
+	 * the given {@code name}.
+	 */
+	HealthIndicator get(String name);
+
+	/**
+	 * Returns a snapshot of the registered health indicators and their names. The
+	 * contents of the map do not reflect subsequent changes to the registry.
+	 * @return the snapshot of registered health indicators
+	 */
+	Map<String, HealthIndicator> getAll();
+
+}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/health/DefaultHealthIndicatorRegistryTest.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2012-2018 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.boot.actuate.health;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link DefaultHealthIndicatorRegistry}.
+ *
+ * @author Vedran Pavic
+ */
+public class DefaultHealthIndicatorRegistryTest {
+
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
+	private HealthIndicator one = mock(HealthIndicator.class);
+
+	private HealthIndicator two = mock(HealthIndicator.class);
+
+	private DefaultHealthIndicatorRegistry registry;
+
+	@Before
+	public void setUp() {
+		given(this.one.health()).willReturn(new Health.Builder().up().build());
+		given(this.two.health()).willReturn(new Health.Builder().unknown().build());
+
+		this.registry = new DefaultHealthIndicatorRegistry();
+	}
+
+	@Test
+	public void register() {
+		this.registry.register("one", this.one);
+		this.registry.register("two", this.two);
+		assertThat(this.registry.getAll()).hasSize(2);
+		assertThat(this.registry.get("one")).isSameAs(this.one);
+		assertThat(this.registry.get("two")).isSameAs(this.two);
+	}
+
+	@Test
+	public void registerAlreadyUsedName() {
+		this.thrown.expect(IllegalStateException.class);
+		this.thrown.expectMessage("HealthIndicator with name 'one' already registered");
+		this.registry.register("one", this.one);
+		this.registry.register("one", this.two);
+	}
+
+	@Test
+	public void unregister() {
+		this.registry.register("one", this.one);
+		this.registry.register("two", this.two);
+		assertThat(this.registry.getAll()).hasSize(2);
+		HealthIndicator two = this.registry.unregister("two");
+		assertThat(two).isSameAs(this.two);
+		assertThat(this.registry.getAll()).hasSize(1);
+	}
+
+	@Test
+	public void unregisterNotKnown() {
+		this.registry.register("one", this.one);
+		assertThat(this.registry.getAll()).hasSize(1);
+		HealthIndicator two = this.registry.unregister("two");
+		assertThat(two).isNull();
+		assertThat(this.registry.getAll()).hasSize(1);
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/health/HealthEndpointTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2017 the original author or authors.
+ * Copyright 2012-2018 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.
@@ -30,6 +30,7 @@ import static org.assertj.core.api.Assertions.entry;
  * @author Phillip Webb
  * @author Christian Dupuis
  * @author Andy Wilkinson
+ * @author Vedran Pavic
  */
 public class HealthEndpointTests {
 
@@ -40,8 +41,8 @@ public class HealthEndpointTests {
 				.withDetail("first", "1").build());
 		healthIndicators.put("upAgain", () -> new Health.Builder().status(Status.UP)
 				.withDetail("second", "2").build());
-		HealthEndpoint endpoint = new HealthEndpoint(
-				createHealthIndicator(healthIndicators));
+		HealthEndpoint endpoint = new HealthEndpoint(new OrderedHealthAggregator(),
+				createHealthIndicatorRegistry(healthIndicators));
 		Health health = endpoint.health();
 		assertThat(health.getStatus()).isEqualTo(Status.UP);
 		assertThat(health.getDetails()).containsOnlyKeys("up", "upAgain");
@@ -51,10 +52,11 @@ public class HealthEndpointTests {
 		assertThat(upAgainHealth.getDetails()).containsOnly(entry("second", "2"));
 	}
 
-	private HealthIndicator createHealthIndicator(
+	private HealthIndicatorRegistry createHealthIndicatorRegistry(
 			Map<String, HealthIndicator> healthIndicators) {
-		return new CompositeHealthIndicatorFactory()
-				.createHealthIndicator(new OrderedHealthAggregator(), healthIndicators);
+		HealthIndicatorRegistry registry = new DefaultHealthIndicatorRegistry();
+		healthIndicators.forEach(registry::register);
+		return registry;
 	}
 
 }

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/health/HealthEndpointWebIntegrationTests.java

@@ -35,6 +35,7 @@ import org.springframework.test.web.reactive.server.WebTestClient;
  * exposed by Jersey, Spring MVC, and WebFlux.
  *
  * @author Andy Wilkinson
+ * @author Vedran Pavic
  */
 @RunWith(WebEndpointRunners.class)
 public class HealthEndpointWebIntegrationTests {
@@ -66,17 +67,15 @@ public class HealthEndpointWebIntegrationTests {
 		@Bean
 		public HealthEndpoint healthEndpoint(
 				Map<String, HealthIndicator> healthIndicators) {
-			return new HealthEndpoint(
-					new CompositeHealthIndicatorFactory().createHealthIndicator(
-							new OrderedHealthAggregator(), healthIndicators));
+			HealthIndicatorRegistry registry = new DefaultHealthIndicatorRegistry();
+			healthIndicators.forEach(registry::register);
+			return new HealthEndpoint(new OrderedHealthAggregator(), registry);
 		}
 
 		@Bean
 		public HealthEndpointWebExtension healthWebEndpointExtension(
-				Map<String, HealthIndicator> healthIndicators) {
-			return new HealthEndpointWebExtension(
-					new CompositeHealthIndicatorFactory().createHealthIndicator(
-							new OrderedHealthAggregator(), healthIndicators),
+				HealthEndpoint healthEndpoint) {
+			return new HealthEndpointWebExtension(healthEndpoint,
 					new HealthWebEndpointResponseMapper(new HealthStatusHttpMapper(),
 							ShowDetails.ALWAYS,
 							new HashSet<>(Arrays.asList("ACTUATOR"))));

spring-boot-project/spring-boot-docs/src/main/asciidoc/production-ready-features.adoc

@@ -726,13 +726,14 @@ configuration must permit access to the health endpoint for both authenticated a
 unauthenticated users.
 
 Health information is collected from all
-{sc-spring-boot-actuator}/health/HealthIndicator.{sc-ext}[`HealthIndicator`] beans
-defined in your `ApplicationContext`. Spring Boot includes a number of auto-configured
-`HealthIndicators`, and you can also write your own. By default, the final system state
-is derived by the `HealthAggregator`, which sorts the statuses from each
-`HealthIndicator` based on an ordered list of statuses. The first status in the sorted
-list is used as the overall health status. If no `HealthIndicator` returns a status that
-is known to the `HealthAggregator`, an `UNKNOWN` status is used.
+{sc-spring-boot-actuator}/health/HealthIndicator.{sc-ext}[`HealthIndicator`] instances
+registered with {sc-spring-boot-actuator}/health/HealthIndicatorRegistry.{sc-ext}[`HealthIndicatorRegistry`].
+Spring Boot includes a number of auto-configured `HealthIndicators` and you can also write
+your own. By default, the final system state is
+derived by the `HealthAggregator` which sorts the statuses from each `HealthIndicator`
+based on an ordered list of statuses. The first status in the sorted list is used as the
+overall health status. If no `HealthIndicator` returns a status that is known to the
+`HealthAggregator`, an `UNKNOWN` status is used.
 
 
 
@@ -818,6 +819,9 @@ NOTE: The identifier for a given `HealthIndicator` is the name of the bean witho
 `HealthIndicator` suffix, if it exists. In the preceding example, the health information
 is available in an entry named `my`.
 
+Additionally, you can register (and unregister) `HealthIndicator` instances in runtime
+using {sc-spring-boot-actuator}/health/HealthIndicatorRegistry.{sc-ext}[`HealthIndicatorRegistry`].
+
 In addition to Spring Boot's predefined
 {sc-spring-boot-actuator}/health/Status.{sc-ext}[`Status`] types, it is also possible for
 `Health` to return a custom `Status` that represents a new system state. In such cases, a