Configure MeterBinders after beans have been created

Update `MeterRegistryPostProcessor` to configure `MeterRegistry` beans
in two distinct sweeps. The first sweep applies customizers and filters
as the `MeterRegistry` bean is initialized, the second sweep applies
`MeterBinder` beans once all singletons have been instantiated.

Prior to this commit, it was not possible for a `MeterBinder` bean to
directly or indirectly use a `MeterRegistry`. It was also possible for
bound meters to cause a deadlock during refresh processing if those
meters could be updated on a thread other than main, such as GC
notifications.

Fixes gh-30636
Fixes gh-33070

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

@@ -1,86 +0,0 @@
-/*
- * Copyright 2012-2022 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
- *
- *      https://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.MeterRegistry;
-import io.micrometer.core.instrument.Metrics;
-import io.micrometer.core.instrument.binder.MeterBinder;
-import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
-import io.micrometer.core.instrument.config.MeterFilter;
-
-import org.springframework.beans.factory.ObjectProvider;
-import org.springframework.boot.util.LambdaSafe;
-
-/**
- * Configurer to apply {@link MeterRegistryCustomizer customizers}, {@link MeterFilter
- * filters}, {@link MeterBinder binders} and {@link Metrics#addRegistry global
- * registration} to {@link MeterRegistry meter registries}.
- *
- * @author Jon Schneider
- * @author Phillip Webb
- */
-class MeterRegistryConfigurer {
-
-	private final ObjectProvider<MeterRegistryCustomizer<?>> customizers;
-
-	private final ObjectProvider<MeterFilter> filters;
-
-	private final ObjectProvider<MeterBinder> binders;
-
-	private final boolean addToGlobalRegistry;
-
-	private final boolean hasCompositeMeterRegistry;
-
-	MeterRegistryConfigurer(ObjectProvider<MeterRegistryCustomizer<?>> customizers, ObjectProvider<MeterFilter> filters,
-			ObjectProvider<MeterBinder> binders, boolean addToGlobalRegistry, boolean hasCompositeMeterRegistry) {
-		this.customizers = customizers;
-		this.filters = filters;
-		this.binders = binders;
-		this.addToGlobalRegistry = addToGlobalRegistry;
-		this.hasCompositeMeterRegistry = hasCompositeMeterRegistry;
-	}
-
-	void configure(MeterRegistry registry) {
-		// Customizers must be applied before binders, as they may add custom
-		// tags or alter timer or summary configuration.
-		customize(registry);
-		if (!(registry instanceof AutoConfiguredCompositeMeterRegistry)) {
-			addFilters(registry);
-		}
-		if (!this.hasCompositeMeterRegistry || registry instanceof CompositeMeterRegistry) {
-			addBinders(registry);
-		}
-		if (this.addToGlobalRegistry && registry != Metrics.globalRegistry) {
-			Metrics.addRegistry(registry);
-		}
-	}
-
-	@SuppressWarnings("unchecked")
-	private void customize(MeterRegistry registry) {
-		LambdaSafe.callbacks(MeterRegistryCustomizer.class, this.customizers.orderedStream().toList(), registry)
-				.withLogger(MeterRegistryConfigurer.class).invoke((customizer) -> customizer.customize(registry));
-	}
-
-	private void addFilters(MeterRegistry registry) {
-		this.filters.orderedStream().forEach(registry.config()::meterFilter);
-	}
-
-	private void addBinders(MeterRegistry registry) {
-		this.binders.orderedStream().forEach((binder) -> binder.bindTo(registry));
-	}
-
-}

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

@@ -16,65 +16,138 @@
 
 package org.springframework.boot.actuate.autoconfigure.metrics;
 
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Set;
+
 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 io.micrometer.core.instrument.config.MeterFilter;
 
 import org.springframework.beans.BeansException;
 import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.boot.util.LambdaSafe;
 import org.springframework.context.ApplicationContext;
 
 /**
- * {@link BeanPostProcessor} that delegates to a lazily created
- * {@link MeterRegistryConfigurer} to post-process {@link MeterRegistry} beans.
+ * {@link BeanPostProcessor} for {@link MeterRegistry} beans.
  *
  * @author Jon Schneider
  * @author Phillip Webb
  * @author Andy Wilkinson
  */
-class MeterRegistryPostProcessor implements BeanPostProcessor {
+class MeterRegistryPostProcessor implements BeanPostProcessor, SmartInitializingSingleton {
 
-	private final ObjectProvider<MeterBinder> meterBinders;
+	private final boolean hasNoCompositeMeterRegistryBeans;
 
-	private final ObjectProvider<MeterFilter> meterFilters;
+	private final boolean useGlobalRegistry;
 
-	private final ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers;
+	private final ObjectProvider<MeterRegistryCustomizer<?>> customizers;
 
-	private final ObjectProvider<MetricsProperties> metricsProperties;
+	private final ObjectProvider<MeterFilter> filters;
 
-	private volatile MeterRegistryConfigurer configurer;
+	private final ObjectProvider<MeterBinder> binders;
 
-	private final ApplicationContext applicationContext;
+	private volatile boolean deferBinding = true;
+
+	private final Set<MeterRegistry> deferredBindings = new LinkedHashSet<>();
+
+	MeterRegistryPostProcessor(ApplicationContext applicationContext, MetricsProperties metricsProperties,
+			ObjectProvider<MeterRegistryCustomizer<?>> customizers, ObjectProvider<MeterFilter> filters,
+			ObjectProvider<MeterBinder> binders) {
+		this(hasNoCompositeMeterRegistryBeans(applicationContext), metricsProperties.isUseGlobalRegistry(), customizers,
+				filters, binders);
+	}
+
+	private static boolean hasNoCompositeMeterRegistryBeans(ApplicationContext applicationContext) {
+		return applicationContext.getBeanNamesForType(CompositeMeterRegistry.class, false, false).length == 0;
+	}
+
+	MeterRegistryPostProcessor(boolean hasNoCompositeMeterRegistryBeans, boolean useGlobalRegistry,
+			ObjectProvider<MeterRegistryCustomizer<?>> customizers, ObjectProvider<MeterFilter> filters,
+			ObjectProvider<MeterBinder> binders) {
+		this.hasNoCompositeMeterRegistryBeans = hasNoCompositeMeterRegistryBeans;
+		this.useGlobalRegistry = useGlobalRegistry;
+		this.customizers = customizers;
+		this.filters = filters;
+		this.binders = binders;
 
-	MeterRegistryPostProcessor(ObjectProvider<MeterBinder> meterBinders, ObjectProvider<MeterFilter> meterFilters,
-			ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers,
-			ObjectProvider<MetricsProperties> metricsProperties, ApplicationContext applicationContext) {
-		this.meterBinders = meterBinders;
-		this.meterFilters = meterFilters;
-		this.meterRegistryCustomizers = meterRegistryCustomizers;
-		this.metricsProperties = metricsProperties;
-		this.applicationContext = applicationContext;
 	}
 
 	@Override
 	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
 		if (bean instanceof MeterRegistry meterRegistry) {
-			getConfigurer().configure(meterRegistry);
+			postProcessMeterRegistry(meterRegistry);
 		}
 		return bean;
 	}
 
-	private MeterRegistryConfigurer getConfigurer() {
-		if (this.configurer == null) {
-			boolean hasCompositeMeterRegistry = this.applicationContext
-					.getBeanNamesForType(CompositeMeterRegistry.class, false, false).length != 0;
-			this.configurer = new MeterRegistryConfigurer(this.meterRegistryCustomizers, this.meterFilters,
-					this.meterBinders, this.metricsProperties.getObject().isUseGlobalRegistry(),
-					hasCompositeMeterRegistry);
+	@Override
+	public void afterSingletonsInstantiated() {
+		synchronized (this.deferredBindings) {
+			this.deferBinding = false;
+			this.deferredBindings.forEach(this::applyBinders);
 		}
-		return this.configurer;
+	}
+
+	private void postProcessMeterRegistry(MeterRegistry meterRegistry) {
+		// Customizers must be applied before binders, as they may add custom tags or
+		// alter timer or summary configuration.
+		applyCustomizers(meterRegistry);
+		applyFilters(meterRegistry);
+		addToGlobalRegistryIfNecessary(meterRegistry);
+		if (isBindable(meterRegistry)) {
+			applyBinders(meterRegistry);
+		}
+	}
+
+	@SuppressWarnings("unchecked")
+	private void applyCustomizers(MeterRegistry meterRegistry) {
+		List<MeterRegistryCustomizer<?>> customizers = this.customizers.orderedStream().toList();
+		LambdaSafe.callbacks(MeterRegistryCustomizer.class, customizers, meterRegistry)
+				.withLogger(MeterRegistryPostProcessor.class)
+				.invoke((customizer) -> customizer.customize(meterRegistry));
+	}
+
+	private void applyFilters(MeterRegistry meterRegistry) {
+		if (meterRegistry instanceof AutoConfiguredCompositeMeterRegistry) {
+			return;
+		}
+		this.filters.orderedStream().forEach(meterRegistry.config()::meterFilter);
+	}
+
+	private void addToGlobalRegistryIfNecessary(MeterRegistry meterRegistry) {
+		if (this.useGlobalRegistry && !isGlobalRegistry(meterRegistry)) {
+			Metrics.addRegistry(meterRegistry);
+		}
+	}
+
+	private boolean isGlobalRegistry(MeterRegistry meterRegistry) {
+		return meterRegistry == Metrics.globalRegistry;
+	}
+
+	private boolean isBindable(MeterRegistry meterRegistry) {
+		return this.hasNoCompositeMeterRegistryBeans || isCompositeMeterRegistry(meterRegistry);
+	}
+
+	private boolean isCompositeMeterRegistry(MeterRegistry meterRegistry) {
+		return meterRegistry instanceof CompositeMeterRegistry;
+	}
+
+	void applyBinders(MeterRegistry meterRegistry) {
+		if (this.deferBinding) {
+			synchronized (this.deferredBindings) {
+				if (this.deferBinding) {
+					this.deferredBindings.add(meterRegistry);
+					return;
+				}
+			}
+		}
+		this.binders.orderedStream().forEach((binder) -> binder.bindTo(meterRegistry));
 	}
 
 }

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

@@ -50,12 +50,11 @@ public class MetricsAutoConfiguration {
 	}
 
 	@Bean
-	public static MeterRegistryPostProcessor meterRegistryPostProcessor(ObjectProvider<MeterBinder> meterBinders,
-			ObjectProvider<MeterFilter> meterFilters,
-			ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers,
-			ObjectProvider<MetricsProperties> metricsProperties, ApplicationContext applicationContext) {
-		return new MeterRegistryPostProcessor(meterBinders, meterFilters, meterRegistryCustomizers, metricsProperties,
-				applicationContext);
+	public static MeterRegistryPostProcessor meterRegistryPostProcessor(ApplicationContext applicationContext,
+			MetricsProperties metricsProperties, ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers,
+			ObjectProvider<MeterFilter> meterFilters, ObjectProvider<MeterBinder> meterBinders) {
+		return new MeterRegistryPostProcessor(applicationContext, metricsProperties, meterRegistryCustomizers,
+				meterFilters, meterBinders);
 	}
 
 	@Bean

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/amqp/RabbitMetricsAutoConfigurationMeterBinderCycleIntegrationTests.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2012-2022 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
+ *
+ *      https://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.amqp;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.binder.MeterBinder;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.amqp.rabbit.core.RabbitTemplate;
+import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.amqp.RabbitMetricsAutoConfiguration;
+import org.springframework.boot.actuate.autoconfigure.metrics.export.simple.SimpleMetricsExportAutoConfiguration;
+import org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+/**
+ * Integration test to check that {@link RabbitMetricsAutoConfiguration} does not cause a
+ * dependency cycle when used with {@link MeterBinder}.
+ *
+ * @author Phillip Webb
+ * @see <a href="https://github.com/spring-projects/spring-boot/issues/30636">gh-30636</a>
+ */
+class RabbitMetricsAutoConfigurationMeterBinderCycleIntegrationTests {
+
+	@Test
+	void doesNotFormCycle() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(TestConfig.class);
+		context.getBean(TestService.class);
+		context.close();
+	}
+
+	@Configuration
+	@Import({ TestService.class, RabbitAutoConfiguration.class, MetricsAutoConfiguration.class,
+			SimpleMetricsExportAutoConfiguration.class, RabbitMetricsAutoConfiguration.class })
+	static class TestConfig {
+
+	}
+
+	static class TestService implements MeterBinder {
+
+		TestService(RabbitTemplate rabbitTemplate) {
+		}
+
+		@Override
+		public void bindTo(MeterRegistry registry) {
+		}
+
+	}
+
+}

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

@@ -40,28 +40,28 @@ import static org.mockito.Mockito.inOrder;
 import static org.mockito.Mockito.mock;
 
 /**
- * Tests for {@link MeterRegistryConfigurer}.
+ * Tests for {@link MeterRegistryPostProcessor}.
  *
  * @author Phillip Webb
  * @author Andy Wilkinson
  */
 @ExtendWith(MockitoExtension.class)
-class MeterRegistryConfigurerTests {
-
-	private List<MeterBinder> binders = new ArrayList<>();
-
-	private List<MeterFilter> filters = new ArrayList<>();
+class MeterRegistryPostProcessorTests {
 
 	private List<MeterRegistryCustomizer<?>> customizers = new ArrayList<>();
 
+	private List<MeterFilter> filters = new ArrayList<>();
+
+	private List<MeterBinder> binders = new ArrayList<>();
+
 	@Mock
-	private MeterBinder mockBinder;
+	private MeterRegistryCustomizer<MeterRegistry> mockCustomizer;
 
 	@Mock
 	private MeterFilter mockFilter;
 
 	@Mock
-	private MeterRegistryCustomizer<MeterRegistry> mockCustomizer;
+	private MeterBinder mockBinder;
 
 	@Mock
 	private MeterRegistry mockRegistry;
@@ -70,73 +70,79 @@ class MeterRegistryConfigurerTests {
 	private Config mockConfig;
 
 	@Test
-	void configureWhenCompositeShouldApplyCustomizer() {
+	void postProcessAndInitializeWhenCompositeAppliesCustomizer() {
 		this.customizers.add(this.mockCustomizer);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), false, false);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(false, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
 		CompositeMeterRegistry composite = new CompositeMeterRegistry();
-		configurer.configure(composite);
+		postProcessAndInitialize(processor, composite);
 		then(this.mockCustomizer).should().customize(composite);
 	}
 
 	@Test
-	void configureShouldApplyCustomizer() {
+	void postProcessAndInitializeAppliesCustomizer() {
 		given(this.mockRegistry.config()).willReturn(this.mockConfig);
 		this.customizers.add(this.mockCustomizer);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), false, false);
-		configurer.configure(this.mockRegistry);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(true, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
+		postProcessAndInitialize(processor, this.mockRegistry);
 		then(this.mockCustomizer).should().customize(this.mockRegistry);
 	}
 
 	@Test
-	void configureShouldApplyFilter() {
+	void postProcessAndInitializeAppliesFilter() {
 		given(this.mockRegistry.config()).willReturn(this.mockConfig);
 		this.filters.add(this.mockFilter);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), false, false);
-		configurer.configure(this.mockRegistry);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(true, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
+		postProcessAndInitialize(processor, this.mockRegistry);
 		then(this.mockConfig).should().meterFilter(this.mockFilter);
 	}
 
 	@Test
-	void configureShouldApplyBinder() {
+	void postProcessAndInitializeBindsTo() {
 		given(this.mockRegistry.config()).willReturn(this.mockConfig);
 		this.binders.add(this.mockBinder);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), false, false);
-		configurer.configure(this.mockRegistry);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(true, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
+		postProcessAndInitialize(processor, this.mockRegistry);
 		then(this.mockBinder).should().bindTo(this.mockRegistry);
 	}
 
 	@Test
-	void configureShouldApplyBinderToComposite() {
+	void postProcessAndInitializeWhenCompositeBindsTo() {
 		this.binders.add(this.mockBinder);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), false, true);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(false, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
 		CompositeMeterRegistry composite = new CompositeMeterRegistry();
-		configurer.configure(composite);
+		postProcessAndInitialize(processor, composite);
 		then(this.mockBinder).should().bindTo(composite);
 	}
 
 	@Test
-	void configureShouldNotApplyBinderWhenCompositeExists() {
+	void postProcessAndInitializeWhenCompositeExistsDoesNotBindTo() {
 		given(this.mockRegistry.config()).willReturn(this.mockConfig);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), null, false, true);
-		configurer.configure(this.mockRegistry);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(false, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters), null);
+		postProcessAndInitialize(processor, this.mockRegistry);
 		then(this.mockBinder).shouldHaveNoInteractions();
 	}
 
 	@Test
-	void configureShouldBeCalledInOrderCustomizerFilterBinder() {
+	void postProcessAndInitializeBeOrderedCustomizerThenFilterThenBindTo() {
 		given(this.mockRegistry.config()).willReturn(this.mockConfig);
 		this.customizers.add(this.mockCustomizer);
 		this.filters.add(this.mockFilter);
 		this.binders.add(this.mockBinder);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), false, false);
-		configurer.configure(this.mockRegistry);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(true, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
+		postProcessAndInitialize(processor, this.mockRegistry);
 		InOrder ordered = inOrder(this.mockBinder, this.mockConfig, this.mockCustomizer);
 		then(this.mockCustomizer).should(ordered).customize(this.mockRegistry);
 		then(this.mockConfig).should(ordered).meterFilter(this.mockFilter);
@@ -144,12 +150,13 @@ class MeterRegistryConfigurerTests {
 	}
 
 	@Test
-	void configureWhenAddToGlobalRegistryShouldAddToGlobalRegistry() {
+	void postProcessAndInitializeWhenUseGlobalRegistryTrueAddsToGlobalRegistry() {
 		given(this.mockRegistry.config()).willReturn(this.mockConfig);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), true, false);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(true, true,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
 		try {
-			configurer.configure(this.mockRegistry);
+			postProcessAndInitialize(processor, this.mockRegistry);
 			assertThat(Metrics.globalRegistry.getRegistries()).contains(this.mockRegistry);
 		}
 		finally {
@@ -158,14 +165,33 @@ class MeterRegistryConfigurerTests {
 	}
 
 	@Test
-	void configureWhenNotAddToGlobalRegistryShouldAddToGlobalRegistry() {
+	void postProcessAndInitializeWhenUseGlobalRegistryFalseDoesNotAddToGlobalRegistry() {
 		given(this.mockRegistry.config()).willReturn(this.mockConfig);
-		MeterRegistryConfigurer configurer = new MeterRegistryConfigurer(createObjectProvider(this.customizers),
-				createObjectProvider(this.filters), createObjectProvider(this.binders), false, false);
-		configurer.configure(this.mockRegistry);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(true, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
+		postProcessAndInitialize(processor, this.mockRegistry);
 		assertThat(Metrics.globalRegistry.getRegistries()).doesNotContain(this.mockRegistry);
 	}
 
+	@Test
+	void postProcessDoesNotBindToUntilSingletonsInitialized() {
+		given(this.mockRegistry.config()).willReturn(this.mockConfig);
+		this.binders.add(this.mockBinder);
+		MeterRegistryPostProcessor processor = new MeterRegistryPostProcessor(true, false,
+				createObjectProvider(this.customizers), createObjectProvider(this.filters),
+				createObjectProvider(this.binders));
+		processor.postProcessAfterInitialization(this.mockRegistry, "meterRegistry");
+		then(this.mockBinder).shouldHaveNoInteractions();
+		processor.afterSingletonsInstantiated();
+		then(this.mockBinder).should().bindTo(this.mockRegistry);
+	}
+
+	private void postProcessAndInitialize(MeterRegistryPostProcessor processor, MeterRegistry registry) {
+		processor.postProcessAfterInitialization(registry, "meterRegistry");
+		processor.afterSingletonsInstantiated();
+	}
+
 	@SuppressWarnings("unchecked")
 	private <T> ObjectProvider<T> createObjectProvider(List<T> objects) {
 		ObjectProvider<T> objectProvider = mock(ObjectProvider.class);

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

@@ -41,11 +41,12 @@ import org.springframework.context.annotation.Configuration;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
- * Integration tests for {@link MeterRegistryConfigurer}.
+ * Integration tests for {@link MeterRegistryPostProcessor} configured by
+ * {@link MetricsAutoConfiguration}.
  *
  * @author Jon Schneider
  */
-class MeterRegistryConfigurerIntegrationTests {
+class MetricsAutoConfigurationMeterRegistryPostProcessorIntegrationTests {
 
 	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
 			.with(MetricsRun.limitedTo(AtlasMetricsExportAutoConfiguration.class,
@@ -68,7 +69,6 @@ class MeterRegistryConfigurerIntegrationTests {
 				.withConfiguration(AutoConfigurations.of(MetricsAutoConfiguration.class,
 						SimpleMetricsExportAutoConfiguration.class))
 				.withUserConfiguration(TestConfiguration.class).run((context) -> {
-
 				});
 	}
 

src/checkstyle/checkstyle-suppressions.xml

@@ -11,7 +11,7 @@
 	<suppress files="LogbackLoggingSystem\.java" checks="IllegalImport" />
 	<suppress files="LogbackLoggingSystemTests\.java" checks="IllegalImport" />
 	<suppress files="LogbackConfigurationAotContributionTests\.java" checks="IllegalImport" />
-	<suppress files="MeterRegistryConfigurerIntegrationTests\.java" checks="IllegalImport" />
+	<suppress files="MetricsAutoConfigurationMeterRegistryPostProcessorIntegrationTests\.java" checks="IllegalImport" message="LoggerFactory"/>
 	<suppress files="SpringApplicationTests\.java" checks="FinalClass" />
 	<suppress files=".+Configuration\.java" checks="HideUtilityClassConstructor" />
 	<suppress files=".+Application\.java" checks="HideUtilityClassConstructor" />