Prevent Micrometer global registry from pinning application contexts

core/spring-boot-test/src/main/java/org/springframework/boot/test/metrics/DisableGlobalMeterRegistryContextCustomizerFactory.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2012-present 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.test.metrics;
+
+import java.util.List;
+
+import org.jspecify.annotations.Nullable;
+
+import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.test.context.ContextConfigurationAttributes;
+import org.springframework.test.context.ContextCustomizer;
+import org.springframework.test.context.ContextCustomizerFactory;
+import org.springframework.test.context.MergedContextConfiguration;
+import org.springframework.util.ClassUtils;
+
+/**
+ * {@link ContextCustomizerFactory} to disable the use of Micrometer's
+ * {@link io.micrometer.core.instrument.Metrics#globalRegistry global registry} in tests,
+ * preventing {@link io.micrometer.core.instrument.MeterRegistry meter registries} from
+ * pinning application contexts when many test contexts are cached.
+ */
+class DisableGlobalMeterRegistryContextCustomizerFactory implements ContextCustomizerFactory {
+
+	private static final String METRICS_CLASS = "io.micrometer.core.instrument.Metrics";
+
+	private static final String USE_GLOBAL_REGISTRY_PROPERTY = "management.metrics.use-global-registry";
+
+	@Override
+	public @Nullable ContextCustomizer createContextCustomizer(Class<?> testClass,
+			List<ContextConfigurationAttributes> configAttributes) {
+		if (ClassUtils.isPresent(METRICS_CLASS, testClass.getClassLoader())) {
+			return new DisableGlobalMeterRegistryContextCustomizer();
+		}
+		return null;
+	}
+
+	static final class DisableGlobalMeterRegistryContextCustomizer implements ContextCustomizer {
+
+		@Override
+		public void customizeContext(ConfigurableApplicationContext context, MergedContextConfiguration mergedConfig) {
+			ConfigurableEnvironment environment = context.getEnvironment();
+			if (environment.getProperty(USE_GLOBAL_REGISTRY_PROPERTY) == null) {
+				TestPropertyValues.of(USE_GLOBAL_REGISTRY_PROPERTY + "=false").applyTo(environment);
+			}
+		}
+
+		@Override
+		public boolean equals(@Nullable Object obj) {
+			return obj instanceof DisableGlobalMeterRegistryContextCustomizer;
+		}
+
+		@Override
+		public int hashCode() {
+			return getClass().hashCode();
+		}
+
+	}
+
+}

core/spring-boot-test/src/main/java/org/springframework/boot/test/metrics/package-info.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2012-present 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.
+ */
+
+/**
+ * Spring Boot support for metrics testing.
+ */
+@NullMarked
+package org.springframework.boot.test.metrics;
+
+import org.jspecify.annotations.NullMarked;

core/spring-boot-test/src/main/resources/META-INF/spring.factories

@@ -5,7 +5,8 @@ org.springframework.boot.test.context.PropertyMappingContextCustomizerFactory,\
 org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizerFactory,\
 org.springframework.boot.test.context.filter.annotation.TypeExcludeFiltersContextCustomizerFactory,\
 org.springframework.boot.test.http.client.DisableReactorResourceFactoryGlobalResourcesContextCustomizerFactory,\
-org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory
+org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory,\
+org.springframework.boot.test.metrics.DisableGlobalMeterRegistryContextCustomizerFactory
 
 # Application Context Initializers
 org.springframework.context.ApplicationContextInitializer=\

core/spring-boot-test/src/test/java/org/springframework/boot/test/metrics/DisableGlobalMeterRegistryContextCustomizerFactoryTests.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-present 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.test.metrics;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.test.context.MergedContextConfiguration;
+
+import org.springframework.boot.test.util.TestPropertyValues;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.core.env.StandardEnvironment;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link DisableGlobalMeterRegistryContextCustomizerFactory}.
+ */
+class DisableGlobalMeterRegistryContextCustomizerFactoryTests {
+
+	@Test
+	void disablesGlobalMeterRegistryByDefault() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		context.setEnvironment(new StandardEnvironment());
+		new DisableGlobalMeterRegistryContextCustomizerFactory.DisableGlobalMeterRegistryContextCustomizer()
+			.customizeContext(context, mock(MergedContextConfiguration.class));
+		assertThat(context.getEnvironment().getProperty("management.metrics.use-global-registry"))
+			.isEqualTo("false");
+	}
+
+	@Test
+	void doesNotOverrideExplicitProperty() {
+		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+		StandardEnvironment environment = new StandardEnvironment();
+		TestPropertyValues.of("management.metrics.use-global-registry=true").applyTo(environment);
+		context.setEnvironment(environment);
+		new DisableGlobalMeterRegistryContextCustomizerFactory.DisableGlobalMeterRegistryContextCustomizer()
+			.customizeContext(context, mock(MergedContextConfiguration.class));
+		assertThat(context.getEnvironment().getProperty("management.metrics.use-global-registry"))
+			.isEqualTo("true");
+	}
+
+}

module/spring-boot-micrometer-metrics/src/main/java/org/springframework/boot/micrometer/metrics/autoconfigure/MeterRegistryPostProcessor.java

@@ -54,25 +54,31 @@ class MeterRegistryPostProcessor implements BeanPostProcessor, SmartInitializing
 
 	private final ObjectProvider<MeterBinder> binders;
 
+	private final ObjectProvider<MetricsAutoConfiguration.MeterRegistryCloser> meterRegistryCloser;
+
 	private volatile boolean deferBinding = true;
 
 	private final Set<MeterRegistry> deferredBindings = new LinkedHashSet<>();
 
 	MeterRegistryPostProcessor(ApplicationContext applicationContext,
-			ObjectProvider<MetricsProperties> metricsProperties, ObjectProvider<MeterRegistryCustomizer<?>> customizers,
-			ObjectProvider<MeterFilter> filters, ObjectProvider<MeterBinder> binders) {
-		this(CompositeMeterRegistries.of(applicationContext), metricsProperties, customizers, filters, binders);
+			ObjectProvider<MetricsProperties> metricsProperties,
+			ObjectProvider<MeterRegistryCustomizer<?>> customizers, ObjectProvider<MeterFilter> filters,
+			ObjectProvider<MeterBinder> binders,
+			ObjectProvider<MetricsAutoConfiguration.MeterRegistryCloser> meterRegistryCloser) {
+		this(CompositeMeterRegistries.of(applicationContext), metricsProperties, customizers, filters, binders,
+				meterRegistryCloser);
 	}
 
 	MeterRegistryPostProcessor(CompositeMeterRegistries compositeMeterRegistries,
 			ObjectProvider<MetricsProperties> properties, ObjectProvider<MeterRegistryCustomizer<?>> customizers,
-			ObjectProvider<MeterFilter> filters, ObjectProvider<MeterBinder> binders) {
+			ObjectProvider<MeterFilter> filters, ObjectProvider<MeterBinder> binders,
+			ObjectProvider<MetricsAutoConfiguration.MeterRegistryCloser> meterRegistryCloser) {
 		this.compositeMeterRegistries = compositeMeterRegistries;
 		this.properties = properties;
 		this.customizers = customizers;
 		this.filters = filters;
 		this.binders = binders;
-
+		this.meterRegistryCloser = meterRegistryCloser;
 	}
 
 	@Override
@@ -123,6 +129,7 @@ private void applyFilters(MeterRegistry meterRegistry) {
 	private void addToGlobalRegistryIfNecessary(MeterRegistry meterRegistry) {
 		if (this.properties.getObject().isUseGlobalRegistry() && !isGlobalRegistry(meterRegistry)) {
 			Metrics.addRegistry(meterRegistry);
+			this.meterRegistryCloser.getObject().track(meterRegistry);
 		}
 	}
 

module/spring-boot-micrometer-metrics/src/main/java/org/springframework/boot/micrometer/metrics/autoconfigure/MetricsAutoConfiguration.java

@@ -16,6 +16,9 @@
 
 package org.springframework.boot.micrometer.metrics.autoconfigure;
 
+import java.util.LinkedHashSet;
+import java.util.Set;
+
 import io.micrometer.core.annotation.Timed;
 import io.micrometer.core.instrument.Clock;
 import io.micrometer.core.instrument.MeterRegistry;
@@ -65,9 +68,10 @@ Clock micrometerClock() {
 	static MeterRegistryPostProcessor meterRegistryPostProcessor(ApplicationContext applicationContext,
 			ObjectProvider<MetricsProperties> metricsProperties,
 			ObjectProvider<MeterRegistryCustomizer<?>> meterRegistryCustomizers,
-			ObjectProvider<MeterFilter> meterFilters, ObjectProvider<MeterBinder> meterBinders) {
+			ObjectProvider<MeterFilter> meterFilters, ObjectProvider<MeterBinder> meterBinders,
+			ObjectProvider<MeterRegistryCloser> meterRegistryCloser) {
 		return new MeterRegistryPostProcessor(applicationContext, metricsProperties, meterRegistryCustomizers,
-				meterFilters, meterBinders);
+				meterFilters, meterBinders, meterRegistryCloser);
 	}
 
 	@Bean
@@ -102,20 +106,25 @@ static class MeterRegistryCloser implements ApplicationListener<ContextClosedEve
 
 		private final ApplicationContext context;
 
-		private final Iterable<MeterRegistry> meterRegistries;
-
 		private final boolean useGlobalRegistry;
 
+		private final Set<MeterRegistry> trackedRegistries = new LinkedHashSet<>();
+
 		MeterRegistryCloser(ApplicationContext context, boolean useGlobalRegistry) {
-			this.meterRegistries = context.getBeansOfType(MeterRegistry.class).values();
 			this.context = context;
 			this.useGlobalRegistry = useGlobalRegistry;
 		}
 
+		void track(MeterRegistry meterRegistry) {
+			this.trackedRegistries.add(meterRegistry);
+		}
+
 		@Override
 		public void onApplicationEvent(ContextClosedEvent event) {
 			if (this.context.equals(event.getApplicationContext())) {
-				for (MeterRegistry meterRegistry : this.meterRegistries) {
+				Set<MeterRegistry> meterRegistries = new LinkedHashSet<>(this.trackedRegistries);
+				meterRegistries.addAll(this.context.getBeansOfType(MeterRegistry.class).values());
+				for (MeterRegistry meterRegistry : meterRegistries) {
 					if (this.useGlobalRegistry) {
 						Metrics.globalRegistry.remove(meterRegistry);
 					}