Only use micrometer composites when necessary

Update micrometer auto-configuration so that a `CompositeMeterRegistry`
is only created when more than one `MeterRegistry` bean is declared.
When a composite is crated, it is marked as `@Primary` so that it
can be directly injected. Meter registries can now be defined directly
as beans, and auto-configuration can back off in the usual way.

The `MeterRegistryConfigurer` is now called `MeterRegistryCustomizer`
and is generically types so it's easy to apply customizations to a
particular `MeterRegistry` implementation.

Fixes gh-11799

Co-authored-by: Jon Schneider <jschneider@pivotal.io>

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistriesConfiguration.java

@@ -0,0 +1,44 @@
+/*
+ * 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.autoconfigure.metrics;
+
+import org.springframework.boot.actuate.autoconfigure.metrics.export.atlas.AtlasExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.datadog.DatadogExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.ganglia.GangliaExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.graphite.GraphiteExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.influx.InfluxExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.jmx.JmxExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.prometheus.PrometheusExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleExportConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.statsd.StatsdExportConfiguration;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+/**
+ * Imports for registry configurations.
+ *
+ * @author Jon Schneider
+ */
+@Configuration
+@Import({ AtlasExportConfiguration.class, DatadogExportConfiguration.class,
+		GangliaExportConfiguration.class, GraphiteExportConfiguration.class,
+		InfluxExportConfiguration.class, JmxExportConfiguration.class,
+		PrometheusExportConfiguration.class, SimpleExportConfiguration.class,
+		StatsdExportConfiguration.class })
+class MeterRegistriesConfiguration {
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryCustomizer.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.
@@ -23,19 +23,20 @@ import io.micrometer.core.instrument.MeterRegistry;
  * Callback interface that can be used to customize auto-configured {@link MeterRegistry
  * MeterRegistries}.
  * <p>
- * Configurers are guaranteed to be applied before any {@link Meter} is registered with
+ * Customizers are guaranteed to be applied before any {@link Meter} is registered with
  * the registry.
  *
  * @author Jon Schneider
+ * @param <T> The registry type to customize
  * @since 2.0.0
  */
 @FunctionalInterface
-public interface MeterRegistryConfigurer {
+public interface MeterRegistryCustomizer<T extends MeterRegistry> {
 
 	/**
-	 * Configure the given {@code registry}.
+	 * Customize the given {@code registry}.
-	 * @param registry the registry to configure
+	 * @param registry the registry to customize
 	 */
-	void configureRegistry(MeterRegistry registry);
+	void customize(T registry);
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryPostProcessor.java

@@ -0,0 +1,94 @@
+/*
+ * 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.autoconfigure.metrics;
+
+import java.util.Collection;
+import java.util.Collections;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Metrics;
+import io.micrometer.core.instrument.binder.MeterBinder;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
+
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.boot.util.LambdaSafe;
+
+/**
+ * {@link BeanPostProcessor} to apply {@link MeterRegistryCustomizer customizers} and
+ * {@link MeterBinder binters} and {@link Metrics#addRegistry global registration} to
+ * {@link MeterRegistry meter registries}. This post processor intentionally skips
+ * {@link CompositeMeterRegistry} with the assumptions that the registries it contains are
+ * beans and will be customized directly.
+ *
+ * @author Jon Schneider
+ * @author Phillip Webb
+ */
+class MeterRegistryPostProcessor implements BeanPostProcessor {
+
+	private final Collection<MeterRegistryCustomizer<?>> customizers;
+
+	private final Collection<MeterBinder> binders;
+
+	private final boolean addToGlobalRegistry;
+
+	MeterRegistryPostProcessor(ObjectProvider<Collection<MeterBinder>> binders,
+			ObjectProvider<Collection<MeterRegistryCustomizer<?>>> customizers,
+			boolean addToGlobalRegistry) {
+		this.binders = binders.getIfAvailable(Collections::emptyList);
+		this.customizers = customizers.getIfAvailable(Collections::emptyList);
+		this.addToGlobalRegistry = addToGlobalRegistry;
+	}
+
+	@Override
+	public Object postProcessBeforeInitialization(Object bean, String beanName) {
+		return bean;
+	}
+
+	@Override
+	public Object postProcessAfterInitialization(Object bean, String beanName) {
+		if (bean instanceof MeterRegistry) {
+			postProcess((MeterRegistry) bean);
+		}
+		return bean;
+	}
+
+	private void postProcess(MeterRegistry registry) {
+		if (registry instanceof CompositeMeterRegistry) {
+			return;
+		}
+		// Customizers must be applied before binders, as they may add custom tags or
+		// alter timer or summary configuration.
+		customize(registry);
+		addBinders(registry);
+		if (this.addToGlobalRegistry && registry != Metrics.globalRegistry) {
+			Metrics.addRegistry(registry);
+		}
+	}
+
+	@SuppressWarnings("unchecked")
+	private void customize(MeterRegistry registry) {
+		LambdaSafe.callbacks(MeterRegistryCustomizer.class, this.customizers, registry)
+				.withLogger(MeterRegistryPostProcessor.class)
+				.invoke((customizer) -> customizer.customize(registry));
+	}
+
+	private void addBinders(MeterRegistry registry) {
+		this.binders.forEach((binder) -> binder.bindTo(registry));
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsAutoConfiguration.java

@@ -17,28 +17,17 @@
 package org.springframework.boot.actuate.autoconfigure.metrics;
 
 import java.util.Collection;
-import java.util.Collections;
 
 import io.micrometer.core.annotation.Timed;
+import io.micrometer.core.instrument.Clock;
 import io.micrometer.core.instrument.MeterRegistry;
-import io.micrometer.core.instrument.Metrics;
 import io.micrometer.core.instrument.binder.MeterBinder;
-import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
 
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.actuate.autoconfigure.endpoint.condition.ConditionalOnEnabledEndpoint;
 import org.springframework.boot.actuate.autoconfigure.metrics.amqp.RabbitMetricsConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.cache.CacheMetricsConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.CompositeMeterRegistryConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.atlas.AtlasExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.datadog.DatadogExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.ganglia.GangliaExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.graphite.GraphiteExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.influx.InfluxExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.jmx.JmxExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.prometheus.PrometheusExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleExportConfiguration;
-import org.springframework.boot.actuate.autoconfigure.metrics.export.statsd.StatsdExportConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.jdbc.DataSourcePoolMetricsConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.reactive.server.WebFluxMetricsConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.web.client.RestTemplateMetricsConfiguration;
@@ -61,14 +50,13 @@ import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 import org.springframework.integration.config.EnableIntegrationManagement;
 import org.springframework.integration.support.management.IntegrationManagementConfigurer;
-import org.springframework.util.Assert;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for Micrometer-based metrics.
  *
- * @since 2.0.0
  * @author Jon Schneider
  * @author Stephane Nicoll
+ * @since 2.0.0
  */
 @Configuration
 @ConditionalOnClass(Timed.class)
@@ -76,32 +64,19 @@ import org.springframework.util.Assert;
 @Import({ MeterBindersConfiguration.class, WebMvcMetricsConfiguration.class,
 		WebFluxMetricsConfiguration.class, RestTemplateMetricsConfiguration.class,
 		CacheMetricsConfiguration.class, DataSourcePoolMetricsConfiguration.class,
-		RabbitMetricsConfiguration.class, AtlasExportConfiguration.class,
+		RabbitMetricsConfiguration.class, MeterRegistriesConfiguration.class,
-		DatadogExportConfiguration.class, GangliaExportConfiguration.class,
+		CompositeMeterRegistryConfiguration.class })
-		GraphiteExportConfiguration.class, InfluxExportConfiguration.class,
-		JmxExportConfiguration.class, PrometheusExportConfiguration.class,
-		SimpleExportConfiguration.class, StatsdExportConfiguration.class })
 @AutoConfigureAfter({ CacheAutoConfiguration.class, DataSourceAutoConfiguration.class,
 		RabbitAutoConfiguration.class, RestTemplateAutoConfiguration.class })
 public class MetricsAutoConfiguration {
 
 	@Bean
-	@ConditionalOnMissingBean(MeterRegistry.class)
+	public static MeterRegistryPostProcessor meterRegistryPostProcessor(
-	public CompositeMeterRegistry compositeMeterRegistry(
+			ObjectProvider<Collection<MeterBinder>> binders,
-			MetricsProperties metricsProperties,
+			ObjectProvider<Collection<MeterRegistryCustomizer<?>>> customizers,
-			ObjectProvider<Collection<MetricsExporter>> exporters,
+			MetricsProperties properties) {
-			ObjectProvider<Collection<MeterRegistryConfigurer>> configurers) {
+		return new MeterRegistryPostProcessor(binders, customizers,
-		CompositeMeterRegistry composite = metricsProperties.isUseGlobalRegistry()
+				properties.isUseGlobalRegistry());
-				? Metrics.globalRegistry : new CompositeMeterRegistry();
-		configurers.getIfAvailable(Collections::emptyList)
-				.forEach((configurer) -> configurer.configureRegistry(composite));
-		exporters.getIfAvailable(Collections::emptyList).forEach((exporter) -> {
-			MeterRegistry childRegistry = exporter.registry();
-			Assert.state(composite != childRegistry,
-					"cannot add a CompositeMeterRegistry to itself");
-			composite.add(childRegistry);
-		});
-		return composite;
 	}
 
 	@Bean
@@ -112,6 +87,15 @@ public class MetricsAutoConfiguration {
 		return new MetricsEndpoint(registry);
 	}
 
+	@Bean
+	@ConditionalOnMissingBean
+	public Clock micrometerClock() {
+		return Clock.SYSTEM;
+	}
+
+	/**
+	 * Binds metrics from Spring Integration.
+	 */
 	@Configuration
 	@ConditionalOnClass(EnableIntegrationManagement.class)
 	static class MetricsIntegrationConfiguration {
@@ -133,19 +117,4 @@ public class MetricsAutoConfiguration {
 
 	}
 
-	@Configuration
-	static class MeterRegistryConfigurationSupport {
-
-		MeterRegistryConfigurationSupport(MeterRegistry registry,
-				MetricsProperties config,
-				ObjectProvider<Collection<MeterBinder>> binders) {
-			binders.getIfAvailable(Collections::emptyList)
-					.forEach((binder) -> binder.bindTo(registry));
-			if (config.isUseGlobalRegistry() && registry != Metrics.globalRegistry) {
-				Metrics.addRegistry(registry);
-			}
-		}
-
-	}
-
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/CompositeMeterRegistryConfiguration.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.
@@ -16,23 +16,21 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics.export;
 
-import io.micrometer.core.instrument.MeterRegistry;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 /**
- * A {@code MetricsExporter} can be used to export metrics, typically to an external
+ * Conditionally build a composite registry when more than one registry present.
- * server running as a separate process.
  *
  * @author Jon Schneider
- * @author Andy Wilkinson
  * @since 2.0.0
  */
-@FunctionalInterface
+@Configuration
-public interface MetricsExporter {
+public class CompositeMeterRegistryConfiguration {
 
-	/**
+	@Bean
-	 * Returns the {@link MeterRegistry} used to register metrics with the exporter.
+	public static CompositeMeterRegistryPostProcessor compositeMeterRegistryPostProcessor() {
-	 * @return the meter registry
+		return new CompositeMeterRegistryPostProcessor();
-	 */
+	}
-	MeterRegistry registry();
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/CompositeMeterRegistryPostProcessor.java

@@ -0,0 +1,122 @@
+/*
+ * 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.autoconfigure.metrics.export;
+
+import java.util.Arrays;
+
+import io.micrometer.core.instrument.Clock;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.config.ConstructorArgumentValues;
+import org.springframework.beans.factory.config.ConstructorArgumentValues.ValueHolder;
+import org.springframework.beans.factory.config.RuntimeBeanReference;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
+import org.springframework.beans.factory.support.GenericBeanDefinition;
+import org.springframework.beans.factory.support.ManagedList;
+import org.springframework.core.Ordered;
+import org.springframework.core.annotation.Order;
+import org.springframework.util.ObjectUtils;
+
+/**
+ * {@link BeanFactoryPostProcessor} to register a {@link CompositeMeterRegistry} when
+ * necessary.
+ *
+ * @author Jon Schneider
+ * @author Phillip Webb
+ */
+@Order(Ordered.LOWEST_PRECEDENCE - 1)
+class CompositeMeterRegistryPostProcessor
+		implements BeanDefinitionRegistryPostProcessor, BeanFactoryAware {
+
+	private static final String COMPOSITE_BEAN_NAME = "compositeMeterRegistry";
+
+	private ConfigurableListableBeanFactory beanFactory;
+
+	@Override
+	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
+		if (beanFactory instanceof ConfigurableListableBeanFactory) {
+			this.beanFactory = (ConfigurableListableBeanFactory) beanFactory;
+		}
+	}
+
+	@Override
+	public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory)
+			throws BeansException {
+	}
+
+	@Override
+	public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry)
+			throws BeansException {
+		if (this.beanFactory == null) {
+			return;
+		}
+		String[] registryBeans = this.beanFactory.getBeanNamesForType(MeterRegistry.class,
+				true, false);
+		registerCompositeIfNecessary(registry, registryBeans);
+	}
+
+	private void registerCompositeIfNecessary(BeanDefinitionRegistry registry,
+			String[] registryBeans) {
+		if (ObjectUtils.isEmpty(registryBeans)) {
+			registerNoOpMeterRegistry(registry);
+		}
+		if (registryBeans.length > 1 && !hasPrimaryDefinition(registryBeans)) {
+			registerPrimaryCompositeMeterRegistry(registry, registryBeans);
+		}
+	}
+
+	private boolean hasPrimaryDefinition(String[] registryBeans) {
+		return Arrays.stream(registryBeans).map(this.beanFactory::getBeanDefinition)
+				.anyMatch(BeanDefinition::isPrimary);
+	}
+
+	private void registerNoOpMeterRegistry(BeanDefinitionRegistry registry) {
+		// If there are no meter registries configured, we register an empty composite
+		// that effectively no-ops metrics instrumentation throughout the app.
+		GenericBeanDefinition definition = new GenericBeanDefinition();
+		definition.setBeanClass(CompositeMeterRegistry.class);
+		registry.registerBeanDefinition(COMPOSITE_BEAN_NAME, definition);
+	}
+
+	private void registerPrimaryCompositeMeterRegistry(BeanDefinitionRegistry registry,
+			String[] registryBeans) {
+		GenericBeanDefinition definition = new GenericBeanDefinition();
+		definition.setBeanClass(CompositeMeterRegistry.class);
+		definition.setPrimary(true);
+		ConstructorArgumentValues arguments = new ConstructorArgumentValues();
+		arguments.addIndexedArgumentValue(0,
+				new ValueHolder(null, Clock.class.getName()));
+		arguments.addIndexedArgumentValue(1, getBeanReferences(registryBeans));
+		definition.setConstructorArgumentValues(arguments);
+		registry.registerBeanDefinition(COMPOSITE_BEAN_NAME, definition);
+	}
+
+	private ManagedList<RuntimeBeanReference> getBeanReferences(String[] names) {
+		ManagedList<RuntimeBeanReference> references = new ManagedList<>(names.length);
+		Arrays.stream(names).map(RuntimeBeanReference::new).forEach(references::add);
+		return references;
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/atlas/AtlasExportConfiguration.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.
@@ -20,7 +20,6 @@ import com.netflix.spectator.atlas.AtlasConfig;
 import io.micrometer.atlas.AtlasMeterRegistry;
 import io.micrometer.core.instrument.Clock;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -48,14 +47,8 @@ public class AtlasExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.atlas.enabled", matchIfMissing = true)
-	public MetricsExporter atlasExporter(AtlasConfig atlasConfig, Clock clock) {
+	public AtlasMeterRegistry atlasMeterRegistry(AtlasConfig atlasConfig, Clock clock) {
-		return () -> new AtlasMeterRegistry(atlasConfig, clock);
+		return new AtlasMeterRegistry(atlasConfig, clock);
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/datadog/DatadogExportConfiguration.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.
@@ -20,7 +20,6 @@ import io.micrometer.core.instrument.Clock;
 import io.micrometer.datadog.DatadogConfig;
 import io.micrometer.datadog.DatadogMeterRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -48,14 +47,9 @@ public class DatadogExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.datadog.enabled", matchIfMissing = true)
-	public MetricsExporter datadogExporter(DatadogConfig datadogConfig, Clock clock) {
+	public DatadogMeterRegistry datadogMeterRegistry(DatadogConfig datadogConfig,
-		return () -> new DatadogMeterRegistry(datadogConfig, clock);
+			Clock clock) {
-	}
+		return new DatadogMeterRegistry(datadogConfig, clock);
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/ganglia/GangliaExportConfiguration.java

@@ -21,7 +21,6 @@ import io.micrometer.core.instrument.util.HierarchicalNameMapper;
 import io.micrometer.ganglia.GangliaConfig;
 import io.micrometer.ganglia.GangliaMeterRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -48,15 +47,9 @@ public class GangliaExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.ganglia.enabled", matchIfMissing = true)
-	public MetricsExporter gangliaExporter(GangliaConfig gangliaConfig,
+	public GangliaMeterRegistry gangliaMeterRegistry(GangliaConfig gangliaConfig,
 			HierarchicalNameMapper nameMapper, Clock clock) {
-		return () -> new GangliaMeterRegistry(gangliaConfig, clock, nameMapper);
+		return new GangliaMeterRegistry(gangliaConfig, clock, nameMapper);
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 	@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/graphite/GraphiteExportConfiguration.java

@@ -21,7 +21,6 @@ import io.micrometer.core.instrument.util.HierarchicalNameMapper;
 import io.micrometer.graphite.GraphiteConfig;
 import io.micrometer.graphite.GraphiteMeterRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -48,15 +47,9 @@ public class GraphiteExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.graphite.enabled", matchIfMissing = true)
-	public MetricsExporter graphiteExporter(GraphiteConfig graphiteConfig,
+	public GraphiteMeterRegistry graphiteMeterRegistry(GraphiteConfig graphiteConfig,
 			HierarchicalNameMapper nameMapper, Clock clock) {
-		return () -> new GraphiteMeterRegistry(graphiteConfig, clock, nameMapper);
+		return new GraphiteMeterRegistry(graphiteConfig, clock, nameMapper);
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 	@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/influx/InfluxExportConfiguration.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.
@@ -20,7 +20,6 @@ import io.micrometer.core.instrument.Clock;
 import io.micrometer.influx.InfluxConfig;
 import io.micrometer.influx.InfluxMeterRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -47,14 +46,9 @@ public class InfluxExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.influx.enabled", matchIfMissing = true)
-	public MetricsExporter influxExporter(InfluxConfig influxConfig, Clock clock) {
+	public InfluxMeterRegistry influxMeterRegistry(InfluxConfig influxConfig,
-		return () -> new InfluxMeterRegistry(influxConfig, clock);
+			Clock clock) {
-	}
+		return new InfluxMeterRegistry(influxConfig, clock);
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 }

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/jmx/JmxExportConfiguration.java

@@ -21,7 +21,6 @@ import io.micrometer.core.instrument.util.HierarchicalNameMapper;
 import io.micrometer.jmx.JmxConfig;
 import io.micrometer.jmx.JmxMeterRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -48,15 +47,9 @@ public class JmxExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.jmx.enabled", matchIfMissing = true)
-	public MetricsExporter jmxExporter(JmxConfig config,
+	public JmxMeterRegistry jmxMeterRegistry(JmxConfig config,
 			HierarchicalNameMapper nameMapper, Clock clock) {
-		return () -> new JmxMeterRegistry(config, clock, nameMapper);
+		return new JmxMeterRegistry(config, clock, nameMapper);
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 	@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/prometheus/PrometheusExportConfiguration.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.
@@ -21,7 +21,6 @@ import io.micrometer.prometheus.PrometheusConfig;
 import io.micrometer.prometheus.PrometheusMeterRegistry;
 import io.prometheus.client.CollectorRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.actuate.autoconfigure.web.ManagementContextConfiguration;
 import org.springframework.boot.actuate.metrics.export.prometheus.PrometheusScrapeEndpoint;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
@@ -50,10 +49,10 @@ public class PrometheusExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.prometheus.enabled", matchIfMissing = true)
-	public MetricsExporter prometheusExporter(PrometheusConfig prometheusConfig,
+	public PrometheusMeterRegistry prometheusMeterRegistry(
-			CollectorRegistry collectorRegistry, Clock clock) {
+			PrometheusConfig prometheusConfig, CollectorRegistry collectorRegistry,
-		return () -> new PrometheusMeterRegistry(prometheusConfig, collectorRegistry,
+			Clock clock) {
-				clock);
+		return new PrometheusMeterRegistry(prometheusConfig, collectorRegistry, clock);
 	}
 
 	@Bean
@@ -62,12 +61,6 @@ public class PrometheusExportConfiguration {
 		return new CollectorRegistry(true);
 	}
 
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
-	}
-
 	@ManagementContextConfiguration
 	public static class PrometheusScrapeEndpointConfiguration {
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/simple/SimpleExportConfiguration.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.
@@ -17,10 +17,10 @@
 package org.springframework.boot.actuate.autoconfigure.metrics.export.simple;
 
 import io.micrometer.core.instrument.Clock;
+import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.simple.SimpleConfig;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
@@ -39,15 +39,9 @@ public class SimpleExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.simple.enabled", matchIfMissing = true)
-	@ConditionalOnMissingBean(MetricsExporter.class)
+	@ConditionalOnMissingBean(MeterRegistry.class)
-	public MetricsExporter simpleExporter(SimpleConfig config, Clock clock) {
+	public SimpleMeterRegistry simpleMeterRegistry(SimpleConfig config, Clock clock) {
-		return () -> new SimpleMeterRegistry(config, clock);
+		return new SimpleMeterRegistry(config, clock);
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 	@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/statsd/StatsdExportConfiguration.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.
@@ -21,7 +21,6 @@ import io.micrometer.core.instrument.util.HierarchicalNameMapper;
 import io.micrometer.statsd.StatsdConfig;
 import io.micrometer.statsd.StatsdMeterRegistry;
 
-import org.springframework.boot.actuate.autoconfigure.metrics.export.MetricsExporter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
@@ -48,15 +47,9 @@ public class StatsdExportConfiguration {
 
 	@Bean
 	@ConditionalOnProperty(value = "management.metrics.export.statsd.enabled", matchIfMissing = true)
-	public MetricsExporter statsdExporter(StatsdConfig statsdConfig,
+	public StatsdMeterRegistry statsdMeterRegistry(StatsdConfig statsdConfig,
 			HierarchicalNameMapper hierarchicalNameMapper, Clock clock) {
-		return () -> new StatsdMeterRegistry(statsdConfig, hierarchicalNameMapper, clock);
+		return new StatsdMeterRegistry(statsdConfig, hierarchicalNameMapper, clock);
-	}
-
-	@Bean
-	@ConditionalOnMissingBean
-	public Clock micrometerClock() {
-		return Clock.SYSTEM;
 	}
 
 	@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/SpringApplicationHierarchyTests.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.
@@ -19,6 +19,7 @@ package org.springframework.boot.actuate.autoconfigure;
 import org.junit.After;
 import org.junit.Test;
 
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration;
 import org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration;
@@ -67,8 +68,8 @@ public class SpringApplicationHierarchyTests {
 			CassandraAutoConfiguration.class, CassandraDataAutoConfiguration.class,
 			MongoDataAutoConfiguration.class, Neo4jDataAutoConfiguration.class,
 			Neo4jRepositoriesAutoConfiguration.class, RedisAutoConfiguration.class,
-			RedisRepositoriesAutoConfiguration.class,
+			RedisRepositoriesAutoConfiguration.class, FlywayAutoConfiguration.class,
-			FlywayAutoConfiguration.class }, excludeName = {
+			MetricsAutoConfiguration.class }, excludeName = {
 					"org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration" })
 	public static class Child {
 
@@ -79,8 +80,8 @@ public class SpringApplicationHierarchyTests {
 			CassandraAutoConfiguration.class, CassandraDataAutoConfiguration.class,
 			MongoDataAutoConfiguration.class, Neo4jDataAutoConfiguration.class,
 			Neo4jRepositoriesAutoConfiguration.class, RedisAutoConfiguration.class,
-			RedisRepositoriesAutoConfiguration.class,
+			RedisRepositoriesAutoConfiguration.class, FlywayAutoConfiguration.class,
-			FlywayAutoConfiguration.class }, excludeName = {
+			MetricsAutoConfiguration.class }, excludeName = {
 					"org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration" })
 	public static class Parent {
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryCustomizerTests.java

@@ -17,20 +17,22 @@
 package org.springframework.boot.actuate.autoconfigure.metrics;
 
 import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.MeterRegistry.Config;
 import org.junit.Test;
 
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Tests for applying {@link MeterRegistryConfigurer MeterRegistryConfigurers}.
+ * Tests for applying {@link MeterRegistryCustomizer} beans.
  *
  * @author Jon Schneider
  * @author Andy Wilkinson
  */
-public class MeterRegistryConfigurerTests {
+public class MeterRegistryCustomizerTests {
 
 	private ApplicationContextRunner contextRunner = new ApplicationContextRunner()
 			.with(MetricsRun.simple());
@@ -38,26 +40,35 @@ public class MeterRegistryConfigurerTests {
 	@Test
 	public void commonTagsAreAppliedToAutoConfiguredBinders() {
 		this.contextRunner
-				.withUserConfiguration(MeterRegistryConfigurerConfiguration.class)
+				.withUserConfiguration(MeterRegistryCustomizerConfiguration.class)
-				.run((context) -> assertThat(context.getBean(MeterRegistry.class)
+				.run((context) -> {
-						.get("jvm.memory.used").tags("region", "us-east-1").gauge())
+					MeterRegistry registry = context.getBean(MeterRegistry.class);
-								.isNotNull());
+					assertThat(registry.get("jvm.memory.used").tags("region", "us-east-1")
+							.gauge()).isNotNull();
+				});
 	}
 
 	@Test
 	public void commonTagsAreAppliedBeforeRegistryIsInjectableElsewhere() {
 		this.contextRunner
-				.withUserConfiguration(MeterRegistryConfigurerConfiguration.class)
+				.withUserConfiguration(MeterRegistryCustomizerConfiguration.class)
-				.run((context) -> assertThat(context.getBean(MeterRegistry.class)
+				.run((context) -> {
-						.get("my.thing").tags("region", "us-east-1").gauge())
+					MeterRegistry registry = context.getBean(MeterRegistry.class);
-								.isNotNull());
+					assertThat(
+							registry.get("my.thing").tags("region", "us-east-1").gauge())
+									.isNotNull();
+				});
 	}
 
-	static class MeterRegistryConfigurerConfiguration {
+	@Configuration
+	static class MeterRegistryCustomizerConfiguration {
 
 		@Bean
-		public MeterRegistryConfigurer registryConfigurer() {
+		public MeterRegistryCustomizer<MeterRegistry> commonTags() {
-			return (registry) -> registry.config().commonTags("region", "us-east-1");
+			return (registry) -> {
+				Config config = registry.config();
+				config.commonTags("region", "us-east-1");
+			};
 		}
 
 		@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/MeterRegistryPostProcessorTests.java

@@ -0,0 +1,184 @@
+/*
+ * 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.autoconfigure.metrics;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Metrics;
+import io.micrometer.core.instrument.binder.MeterBinder;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InOrder;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.util.Assert;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.inOrder;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyZeroInteractions;
+
+/**
+ * Tests for {@link MeterRegistryPostProcessor}.
+ *
+ * @author Phillip Webb
+ */
+public class MeterRegistryPostProcessorTests {
+
+	private List<MeterBinder> binderBeans = new ArrayList<>();
+
+	private List<MeterRegistryCustomizer<?>> customizerBeans = new ArrayList<>();
+
+	private ObjectProvider<Collection<MeterBinder>> binders = TestObjectProvider
+			.of(this.binderBeans);
+
+	private ObjectProvider<Collection<MeterRegistryCustomizer<?>>> customizers = TestObjectProvider
+			.of(this.customizerBeans);
+
+	@Mock
+	private MeterBinder mockBinder;
+
+	@Mock
+	private MeterRegistryCustomizer<MeterRegistry> mockCustomizer;
+
+	@Mock
+	private MeterRegistry mockRegistry;
+
+	@Before
+	public void setup() {
+		MockitoAnnotations.initMocks(this);
+	}
+
+	@Test
+	public void postProcessWhenNotRegistryShouldReturnBean() {
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(
+				this.binders, this.customizers, false);
+		Object bean = new Object();
+		String beanName = "name";
+		assertThat(processor.postProcessBeforeInitialization(bean, beanName))
+				.isEqualTo(bean);
+		assertThat(processor.postProcessAfterInitialization(bean, beanName))
+				.isEqualTo(bean);
+	}
+
+	@Test
+	public void postProcessorWhenCompositeShouldSkip() {
+		this.binderBeans.add(this.mockBinder);
+		this.customizerBeans.add(this.mockCustomizer);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(
+				this.binders, this.customizers, false);
+		assertThat(processor.postProcessAfterInitialization(new CompositeMeterRegistry(),
+				"name"));
+		verifyZeroInteractions(this.mockBinder, this.mockCustomizer);
+	}
+
+	@Test
+	public void postProcessShouldApplyCustomizer() {
+		this.customizerBeans.add(this.mockCustomizer);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(
+				this.binders, this.customizers, false);
+		assertThat(processor.postProcessAfterInitialization(this.mockRegistry, "name"));
+		verify(this.mockCustomizer).customize(this.mockRegistry);
+	}
+
+	@Test
+	public void postProcessShouldApplyBinder() {
+		this.binderBeans.add(this.mockBinder);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(
+				this.binders, this.customizers, false);
+		assertThat(processor.postProcessAfterInitialization(this.mockRegistry, "name"));
+		verify(this.mockBinder).bindTo(this.mockRegistry);
+	}
+
+	@Test
+	public void postProcessShouldCustomizeBeforeApplyingBinder() {
+		this.binderBeans.add(this.mockBinder);
+		this.customizerBeans.add(this.mockCustomizer);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(
+				this.binders, this.customizers, false);
+		processor.postProcessAfterInitialization(this.mockRegistry, "name");
+		InOrder ordered = inOrder(this.mockCustomizer, this.mockBinder);
+		ordered.verify(this.mockCustomizer).customize(this.mockRegistry);
+		ordered.verify(this.mockBinder).bindTo(this.mockRegistry);
+	}
+
+	@Test
+	public void postProcessWhenAddToGlobalRegistryShouldAddToGlobalRegistry() {
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(
+				this.binders, this.customizers, true);
+		try {
+			processor.postProcessAfterInitialization(this.mockRegistry, "name");
+			assertThat(Metrics.globalRegistry.getRegistries())
+					.contains(this.mockRegistry);
+		}
+		finally {
+			Metrics.removeRegistry(this.mockRegistry);
+		}
+	}
+
+	@Test
+	public void postProcessWhenNotAddToGlobalRegistryShouldAddToGlobalRegistry() {
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(
+				this.binders, this.customizers, false);
+		processor.postProcessAfterInitialization(this.mockRegistry, "name");
+		assertThat(Metrics.globalRegistry.getRegistries())
+				.doesNotContain(this.mockRegistry);
+	}
+
+	private static class TestObjectProvider<T> implements ObjectProvider<T> {
+
+		private final T value;
+
+		TestObjectProvider(T value) {
+			this.value = value;
+		}
+
+		@Override
+		public T getObject() throws BeansException {
+			Assert.state(this.value != null, "No value");
+			return this.value;
+		}
+
+		@Override
+		public T getObject(Object... args) throws BeansException {
+			return this.value;
+		}
+
+		@Override
+		public T getIfAvailable() throws BeansException {
+			return this.value;
+		}
+
+		@Override
+		public T getIfUnique() throws BeansException {
+			throw new UnsupportedOperationException();
+		}
+
+		public static <T> TestObjectProvider<T> of(T value) {
+			return new TestObjectProvider<>(value);
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsAutoConfigurationIntegrationTests.java

@@ -51,6 +51,7 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
+import org.springframework.context.annotation.Primary;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.test.context.TestPropertySource;
@@ -140,6 +141,7 @@ public class MetricsAutoConfigurationIntegrationTests {
 	@Import(PersonController.class)
 	static class MetricsApp {
 
+		@Primary
 		@Bean
 		public MeterRegistry registry() {
 			return new SimpleMeterRegistry(SimpleConfig.DEFAULT, new MockClock());

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/MetricsConfigurationCompositeTests.java

@@ -1,47 +0,0 @@
-/*
- * 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.autoconfigure.metrics;
-
-import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
-import io.micrometer.graphite.GraphiteMeterRegistry;
-import io.micrometer.prometheus.PrometheusMeterRegistry;
-import org.junit.Test;
-
-import org.springframework.boot.autoconfigure.AutoConfigurations;
-import org.springframework.boot.test.context.runner.ApplicationContextRunner;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-/**
- * Tests for {@link MetricsAutoConfiguration} creating a {@link CompositeMeterRegistry}.
- *
- * @author Jon Schneider
- */
-public class MetricsConfigurationCompositeTests {
-
-	@Test
-	public void compositeContainsImplementationsOnClasspath() {
-		new ApplicationContextRunner()
-				.withConfiguration(AutoConfigurations.of(MetricsAutoConfiguration.class))
-				.withPropertyValues("management.metrics.use-global-registry=false")
-				.run((context) -> assertThat(
-						context.getBean(CompositeMeterRegistry.class).getRegistries())
-								.hasAtLeastOneElementOfType(PrometheusMeterRegistry.class)
-								.hasAtLeastOneElementOfType(GraphiteMeterRegistry.class));
-	}
-
-}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/export/CompositeMeterRegistryConfigurationTests.java

@@ -0,0 +1,111 @@
+/*
+ * 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.autoconfigure.metrics.export;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.MockClock;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
+import io.micrometer.core.instrument.simple.SimpleConfig;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import io.micrometer.graphite.GraphiteMeterRegistry;
+import io.micrometer.jmx.JmxMeterRegistry;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsRun;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link CompositeMeterRegistryConfiguration}.
+ *
+ * @author Jon Schneider
+ */
+@RunWith(SpringRunner.class)
+public class CompositeMeterRegistryConfigurationTests {
+
+	private ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.with(MetricsRun.simple());
+
+	/**
+	 * The simple registry is off by default UNLESS there is no other registry
+	 * implementation on the classpath, in which case it is on.
+	 */
+	@Test
+	public void simpleWithNoCompositeCreated() {
+		this.contextRunner
+				.run((context) -> assertThat(context.getBean(MeterRegistry.class))
+						.isInstanceOf(SimpleMeterRegistry.class));
+	}
+
+	/**
+	 * An empty composite is created in the absence of any other registry implementation.
+	 * This effectively no-ops instrumentation code throughout the application.
+	 */
+	@Test
+	public void emptyCompositeCreated() {
+		new ApplicationContextRunner().with(MetricsRun.limitedTo()).run((context) -> {
+			MeterRegistry registry = context.getBean(MeterRegistry.class);
+			assertThat(registry).isInstanceOf(CompositeMeterRegistry.class);
+			assertThat(((CompositeMeterRegistry) registry).getRegistries()).isEmpty();
+		});
+	}
+
+	@Test
+	public void noCompositeCreatedWhenSingleImplementationIsEnabled() {
+		new ApplicationContextRunner().with(MetricsRun.limitedTo("graphite"))
+				.run((context) -> assertThat(context.getBean(MeterRegistry.class))
+						.isInstanceOf(GraphiteMeterRegistry.class));
+	}
+
+	@Test
+	public void noCompositeCreatedWhenMultipleRegistriesButOneMarkedAsPrimary() {
+		new ApplicationContextRunner().with(MetricsRun.limitedTo("graphite", "jmx"))
+				.withUserConfiguration(PrimarySimpleMeterRegistryConfiguration.class)
+				.run((context) -> assertThat(context.getBean(MeterRegistry.class))
+						.isInstanceOf(SimpleMeterRegistry.class));
+	}
+
+	@Test
+	public void compositeCreatedWhenMultipleImplementationsAreEnabled() {
+		new ApplicationContextRunner().with(MetricsRun.limitedTo("graphite", "jmx"))
+				.run((context) -> {
+					MeterRegistry registry = context.getBean(MeterRegistry.class);
+					assertThat(registry).isInstanceOf(CompositeMeterRegistry.class);
+					assertThat(((CompositeMeterRegistry) registry).getRegistries())
+							.hasAtLeastOneElementOfType(GraphiteMeterRegistry.class)
+							.hasAtLeastOneElementOfType(JmxMeterRegistry.class);
+				});
+	}
+
+	@Configuration
+	static class PrimarySimpleMeterRegistryConfiguration {
+
+		@Primary
+		@Bean
+		public MeterRegistry simpleMeterRegistry() {
+			return new SimpleMeterRegistry(SimpleConfig.DEFAULT, new MockClock());
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/export/CompositeMeterRegistryPostProcessorTests.java

@@ -0,0 +1,134 @@
+/*
+ * 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.autoconfigure.metrics.export;
+
+import io.micrometer.core.instrument.Clock;
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.junit.Test;
+
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link CompositeMeterRegistryPostProcessor}.
+ *
+ * @author Phillip Webb
+ */
+public class CompositeMeterRegistryPostProcessorTests {
+
+	private static final String COMPOSITE_NAME = "compositeMeterRegistry";
+
+	private ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withUserConfiguration(BaseConfig.class);
+
+	@Test
+	public void registerWhenHasNoMeterRegistryShouldRegisterEmptyComposite() {
+		this.contextRunner.withUserConfiguration(NoMeterRegistryConfig.class)
+				.run((context) -> {
+					assertThat(context).hasSingleBean(MeterRegistry.class);
+					CompositeMeterRegistry registry = context.getBean(COMPOSITE_NAME,
+							CompositeMeterRegistry.class);
+					assertThat(registry.getRegistries()).isEmpty();
+				});
+	}
+
+	@Test
+	public void registerWhenHasSingleMeterRegistryShouldDoNothing() {
+		this.contextRunner.withUserConfiguration(SingleMeterRegistryConfig.class)
+				.run((context) -> {
+					assertThat(context).hasSingleBean(MeterRegistry.class);
+					MeterRegistry registry = context.getBean(MeterRegistry.class);
+					assertThat(registry).isInstanceOf(TestMeterRegistry.class);
+				});
+	}
+
+	@Test
+	public void registerWhenHasMultipleMeterRegistriesShouldAddPrimaryComposite() {
+		this.contextRunner.withUserConfiguration(MultipleMeterRegistriesConfig.class)
+				.run((context) -> {
+					assertThat(context.getBeansOfType(MeterRegistry.class)).hasSize(3)
+							.containsKeys("meterRegistryOne", "meterRegistryTwo",
+									COMPOSITE_NAME);
+					MeterRegistry primary = context.getBean(MeterRegistry.class);
+					assertThat(primary).isInstanceOf(CompositeMeterRegistry.class);
+					assertThat(((CompositeMeterRegistry) primary).getRegistries())
+							.hasSize(2);
+				});
+	}
+
+	@Test
+	public void registerWhenHasMultipleRegistriesAndOneIsPrimaryShouldDoNothing() {
+
+	}
+
+	@Configuration
+	static class BaseConfig {
+
+		@Bean
+		public CompositeMeterRegistryPostProcessor compositeMeterRegistryPostProcessor() {
+			return new CompositeMeterRegistryPostProcessor();
+		}
+
+		@Bean
+		@ConditionalOnMissingBean
+		public Clock micrometerClock() {
+			return Clock.SYSTEM;
+		}
+
+	}
+
+	@Configuration
+	static class NoMeterRegistryConfig {
+
+	}
+
+	@Configuration
+	static class SingleMeterRegistryConfig {
+
+		@Bean
+		public MeterRegistry meterRegistry() {
+			return new TestMeterRegistry();
+		}
+
+	}
+
+	@Configuration
+	static class MultipleMeterRegistriesConfig {
+
+		@Bean
+		public MeterRegistry meterRegistryOne() {
+			return new TestMeterRegistry();
+		}
+
+		@Bean
+		public MeterRegistry meterRegistryTwo() {
+			return new SimpleMeterRegistry();
+		}
+
+	}
+
+	static class TestMeterRegistry extends SimpleMeterRegistry {
+
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/export/simple/SimpleExportConfigurationTests.java

@@ -1,61 +0,0 @@
-/*
- * 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.autoconfigure.metrics.export.simple;
-
-import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
-import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
-import org.junit.Test;
-import org.junit.runner.RunWith;
-
-import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
-import org.springframework.boot.autoconfigure.AutoConfigurations;
-import org.springframework.boot.test.context.runner.ApplicationContextRunner;
-import org.springframework.test.context.junit4.SpringRunner;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-/**
- * Tests for {@link SimpleExportConfiguration}.
- *
- * @author Jon Schneider
- */
-@RunWith(SpringRunner.class)
-public class SimpleExportConfigurationTests {
-
-	@Test
-	public void simpleMeterRegistryIsInTheCompositeWhenNoOtherRegistryIs() {
-		new ApplicationContextRunner()
-				.withPropertyValues("management.metrics.export.atlas.enabled=false",
-						"management.metrics.export.datadog.enabled=false",
-						"management.metrics.export.ganglia.enabled=false",
-						"management.metrics.export.graphite.enabled=false",
-						"management.metrics.export.influx.enabled=false",
-						"management.metrics.export.jmx.enabled=false",
-						"management.metrics.export.prometheus.enabled=false",
-						"management.metrics.export.statsd.enabled=false",
-						"management.metrics.use-global-registry=false")
-				.withConfiguration(AutoConfigurations.of(MetricsAutoConfiguration.class))
-				.run((context) -> {
-					CompositeMeterRegistry meterRegistry = context
-							.getBean(CompositeMeterRegistry.class);
-					assertThat(meterRegistry.getRegistries()).hasSize(1);
-					assertThat(meterRegistry.getRegistries())
-							.hasOnlyElementsOfType(SimpleMeterRegistry.class);
-				});
-	}
-
-}