Add ObservationContextSource

Closes gh-991

Author: jzheaux

core/build.gradle

@@ -17,6 +17,7 @@ dependencies {
     api "org.springframework:spring-core"
     api "org.springframework:spring-beans"
     api "org.springframework:spring-tx"
+    api "io.micrometer:micrometer-core"
 
     implementation "org.slf4j:slf4j-api"
 
@@ -31,6 +32,10 @@ dependencies {
     optional "commons-pool:commons-pool"
     optional "org.apache.commons:commons-pool2"
 
+    testImplementation ("io.micrometer:micrometer-test") {
+        exclude group: 'org.mockito'
+        exclude group: 'org.assertj'
+    }
     testImplementation platform('org.junit:junit-bom')
     testImplementation "org.junit.vintage:junit-vintage-engine"
 

core/src/main/java/org/springframework/ldap/core/support/ContextSourceObservationPostProcessor.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2002-2025 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.ldap.core.support;
+
+import io.micrometer.observation.ObservationRegistry;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.ldap.core.ContextSource;
+
+/**
+ * A {@link BeanPostProcessor} that makes any {@link ContextSource} bean observable by
+ * Micrometer
+ *
+ * @author Josh Cummings
+ * @since 3.3
+ */
+public final class ContextSourceObservationPostProcessor implements BeanPostProcessor {
+
+	private final ObjectProvider<ObservationRegistry> observationRegistry;
+
+	public ContextSourceObservationPostProcessor(ObjectProvider<ObservationRegistry> observationRegistry) {
+		this.observationRegistry = observationRegistry;
+	}
+
+	@Override
+	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+		if (bean instanceof ObservationContextSource) {
+			return bean;
+		}
+		if (!(bean instanceof BaseLdapPathContextSource ldap)) {
+			return bean;
+		}
+		ObservationRegistry observationRegistry = this.observationRegistry
+			.getIfAvailable(() -> ObservationRegistry.NOOP);
+		if (observationRegistry.isNoop()) {
+			return bean;
+		}
+		return new ObservationContextSource(ldap, observationRegistry);
+	}
+
+}