Add ObservationRegistry support to ConfigClientRequestTemplateFactory

spring-cloud-config-client/pom.xml

@@ -58,6 +58,11 @@
 			<artifactId>spring-boot-starter-actuator</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-restclient</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-aspectj</artifactId>

spring-cloud-config-client/src/main/java/org/springframework/cloud/config/client/ConfigServerBootstrapper.java

@@ -35,7 +35,7 @@ public class ConfigServerBootstrapper implements BootstrapRegistryInitializer {
 
 	private LoaderInterceptor loaderInterceptor;
 
-	static ConfigServerBootstrapper create() {
+	public static ConfigServerBootstrapper create() {
 		return new ConfigServerBootstrapper();
 	}
 

spring-cloud-config-client/src/main/java/org/springframework/cloud/config/client/ConfigServerConfigDataLocationResolver.java

@@ -240,8 +240,14 @@ public List<ConfigServerConfigDataResource> resolveProfileSpecific(
 			.registerSingleton("configDataConfigClientProperties",
 					event.getBootstrapContext().get(ConfigClientProperties.class)));
 
-		bootstrapContext.registerIfAbsent(ConfigClientRequestTemplateFactory.class,
-				context -> new ConfigClientRequestTemplateFactory(log, context.get(ConfigClientProperties.class)));
+		bootstrapContext.registerIfAbsent(ConfigClientRequestTemplateFactory.class, context -> {
+			ConfigClientProperties props = context.get(ConfigClientProperties.class);
+			if (ClassUtils
+				.isPresent("org.springframework.boot.restclient.observation.ObservationRestTemplateCustomizer", null)) {
+				return ObservationConfigClientRequestTemplateFactory.createWithObservation(context, log, props);
+			}
+			return new ConfigClientRequestTemplateFactory(log, props);
+		});
 
 		bootstrapContext.registerIfAbsent(RestTemplate.class, context -> {
 			ConfigClientRequestTemplateFactory factory = context.get(ConfigClientRequestTemplateFactory.class);

spring-cloud-config-client/src/main/java/org/springframework/cloud/config/client/ObservationConfigClientRequestTemplateFactory.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2026-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.cloud.config.client;
+
+import io.micrometer.observation.ObservationRegistry;
+import org.apache.commons.logging.Log;
+
+import org.springframework.boot.bootstrap.BootstrapContext;
+import org.springframework.boot.restclient.observation.ObservationRestTemplateCustomizer;
+import org.springframework.http.client.observation.DefaultClientRequestObservationConvention;
+import org.springframework.web.client.RestTemplate;
+
+public class ObservationConfigClientRequestTemplateFactory extends ConfigClientRequestTemplateFactory {
+
+	private final ObservationRestTemplateCustomizer observationRestTemplateCustomizer;
+
+	public ObservationConfigClientRequestTemplateFactory(Log log, ConfigClientProperties properties,
+			ObservationRegistry observationRegistry) {
+		super(log, properties);
+		this.observationRestTemplateCustomizer = observationRegistry != ObservationRegistry.NOOP
+				? new ObservationRestTemplateCustomizer(observationRegistry,
+						new DefaultClientRequestObservationConvention())
+				: null;
+	}
+
+	@Override
+	public RestTemplate create() {
+		RestTemplate template = super.create();
+		if (observationRestTemplateCustomizer != null) {
+			observationRestTemplateCustomizer.customize(template);
+		}
+		return template;
+	}
+
+	static ConfigClientRequestTemplateFactory createWithObservation(BootstrapContext context, Log log,
+			ConfigClientProperties props) {
+		ObservationRegistry registry = context.getOrElse(ObservationRegistry.class, ObservationRegistry.NOOP);
+		return new ObservationConfigClientRequestTemplateFactory(log, props, registry);
+	}
+
+}

spring-cloud-config-client/src/main/java/org/springframework/cloud/config/client/ObservationConfigServerBootstrapper.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2026-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.cloud.config.client;
+
+import io.micrometer.observation.ObservationRegistry;
+
+import org.springframework.boot.bootstrap.BootstrapRegistry;
+
+public class ObservationConfigServerBootstrapper extends ConfigServerBootstrapper {
+
+	private ObservationRegistry observationRegistry;
+
+	public static ObservationConfigServerBootstrapper create() {
+		return new ObservationConfigServerBootstrapper();
+	}
+
+	public ObservationConfigServerBootstrapper withObservationRegistry(ObservationRegistry observationRegistry) {
+		this.observationRegistry = observationRegistry;
+		return this;
+	}
+
+	@Override
+	public void initialize(BootstrapRegistry registry) {
+		super.initialize(registry);
+		if (observationRegistry != null) {
+			registry.register(ObservationRegistry.class, BootstrapRegistry.InstanceSupplier.of(observationRegistry));
+		}
+	}
+
+}

spring-cloud-config-client/src/test/java/org/springframework/cloud/config/client/ConfigClientRequestTemplateFactoryTests.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2026-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.cloud.config.client;
+
+import io.micrometer.observation.ObservationRegistry;
+import org.apache.commons.logging.LogFactory;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.web.client.RestTemplate;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Luccas Asaphe
+ *
+ */
+public class ConfigClientRequestTemplateFactoryTests {
+
+	@Test
+	void shouldInstrumentRestTemplateWhenObservationRegistryProvided() {
+		// 1. set up the factory
+		ConfigClientProperties properties = new ConfigClientProperties();
+		ObservationRegistry registry = ObservationRegistry.create();
+		ObservationConfigClientRequestTemplateFactory factory = new ObservationConfigClientRequestTemplateFactory(
+				LogFactory.getLog(getClass()), properties, registry);
+
+		// 2. create the RestTemplate
+		RestTemplate restTemplate = factory.create();
+
+		// 3. verify the observation registry
+		assertThat(restTemplate.getObservationRegistry()).isEqualTo(registry);
+	}
+
+	@Test
+	void shouldNotInstrumentRestTemplateWhenObservationRegistryNotProvided() {
+		// 1. set up the factory
+		ConfigClientProperties properties = new ConfigClientProperties();
+		ConfigClientRequestTemplateFactory factory = new ConfigClientRequestTemplateFactory(
+				LogFactory.getLog(getClass()), properties);
+
+		// 2. create the RestTemplate
+		RestTemplate restTemplate = factory.create();
+
+		// 3. verify the observation registry
+		assertThat(restTemplate.getObservationRegistry()).isEqualTo(ObservationRegistry.NOOP);
+	}
+
+	@Test
+	void shouldNotInstrumentRestTemplateWhenObservationRegistryIsNoop() {
+		// 1. set up the factory
+		ConfigClientProperties properties = new ConfigClientProperties();
+		ObservationRegistry registry = ObservationRegistry.NOOP;
+		ObservationConfigClientRequestTemplateFactory factory = new ObservationConfigClientRequestTemplateFactory(
+				LogFactory.getLog(getClass()), properties, registry);
+
+		// 2. create the RestTemplate
+		RestTemplate restTemplate = factory.create();
+
+		// 3. verify the observation registry
+		assertThat(restTemplate.getObservationRegistry()).isEqualTo(ObservationRegistry.NOOP);
+	}
+
+}

spring-cloud-config-client/src/test/java/org/springframework/cloud/config/client/ConfigServerConfigDataCustomizationIntegrationTests.java

@@ -18,6 +18,7 @@
 
 import java.util.Optional;
 
+import io.micrometer.observation.ObservationRegistry;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
@@ -91,6 +92,34 @@ void customizableRestTemplate() {
 		}
 	}
 
+	@Test
+	void customizableObservationRegistry() {
+		ConfigurableApplicationContext context = null;
+		try {
+			ObservationRegistry registry = ObservationRegistry.create();
+			context = new SpringApplicationBuilder(TestConfig.class)
+				.addBootstrapRegistryInitializer(
+						ObservationConfigServerBootstrapper.create().withObservationRegistry(registry))
+				.addBootstrapRegistryInitializer(reg -> reg.addCloseListener(event -> {
+					BootstrapContext bootstrapContext = event.getBootstrapContext();
+					ConfigurableListableBeanFactory beanFactory = event.getApplicationContext().getBeanFactory();
+
+					RestTemplate restTemplate = bootstrapContext.get(RestTemplate.class);
+					beanFactory.registerSingleton("holder", new RestTemplateHolder(restTemplate));
+				}))
+				.run("--spring.config.import=optional:configserver:");
+
+			RestTemplateHolder holder = context.getBean(RestTemplateHolder.class);
+			assertThat(holder).isNotNull();
+			assertThat(holder.restTemplate.getObservationRegistry()).isEqualTo(registry);
+		}
+		finally {
+			if (context != null) {
+				context.close();
+			}
+		}
+	}
+
 	CustomRestTemplate restTemplate(BootstrapContext context) {
 		ConfigClientProperties properties = context.get(ConfigClientProperties.class);
 		String custom = context.get(Binder.class).bind("custom.prop", String.class).orElse("default-custom-prop");

spring-cloud-config-client/src/test/java/org/springframework/cloud/config/client/ConfigServerConfigDataWithoutMicrometerTests.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2026-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.cloud.config.client;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.builder.SpringApplicationBuilder;
+import org.springframework.cloud.test.ClassPathExclusions;
+import org.springframework.context.ConfigurableApplicationContext;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Luccas Asaphe
+ *
+ */
+@ClassPathExclusions({ "spring-boot-starter-actuator-*.jar", "spring-boot-restclient-*.jar" })
+public class ConfigServerConfigDataWithoutMicrometerTests {
+
+	@Test
+	void contextStartsWithoutMicrometer() {
+		try (ConfigurableApplicationContext context = new SpringApplicationBuilder(TestConfig.class)
+			.web(WebApplicationType.NONE)
+			.run("--spring.config.import=optional:configserver:")) {
+			assertThat(context).isNotNull();
+		}
+	}
+
+	@SpringBootConfiguration
+	@EnableAutoConfiguration
+	static class TestConfig {
+
+	}
+
+}