Make auto-config of RestTemplate metrics back off with no builder bean

See gh-15842

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/client/HttpClientMetricsAutoConfiguration.java

@@ -27,6 +27,7 @@ import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
@@ -42,7 +43,7 @@ import org.springframework.core.annotation.Order;
  */
 @Configuration
 @AutoConfigureAfter({ MetricsAutoConfiguration.class,
-		SimpleMetricsExportAutoConfiguration.class })
+		SimpleMetricsExportAutoConfiguration.class, RestTemplateAutoConfiguration.class })
 @ConditionalOnClass(MeterRegistry.class)
 @ConditionalOnBean(MeterRegistry.class)
 @Import({ RestTemplateMetricsConfiguration.class, WebClientMetricsConfiguration.class })

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/web/client/RestTemplateMetricsConfiguration.java

@@ -22,8 +22,10 @@ import org.springframework.boot.actuate.autoconfigure.metrics.MetricsProperties;
 import org.springframework.boot.actuate.metrics.web.client.DefaultRestTemplateExchangeTagsProvider;
 import org.springframework.boot.actuate.metrics.web.client.MetricsRestTemplateCustomizer;
 import org.springframework.boot.actuate.metrics.web.client.RestTemplateExchangeTagsProvider;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.web.client.RestTemplateBuilder;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.client.RestTemplate;
@@ -33,9 +35,11 @@ import org.springframework.web.client.RestTemplate;
  *
  * @author Jon Schneider
  * @author Phillip Webb
+ * @author raheela.aslam
  */
 @Configuration
 @ConditionalOnClass(RestTemplate.class)
+@ConditionalOnBean(RestTemplateBuilder.class)
 class RestTemplateMetricsConfiguration {
 
 	private final MetricsProperties properties;

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/web/client/RestTemplateMetricsConfigurationTests.java

@@ -21,6 +21,7 @@ import org.junit.Rule;
 import org.junit.Test;
 
 import org.springframework.boot.actuate.autoconfigure.metrics.test.MetricsRun;
+import org.springframework.boot.actuate.metrics.web.client.DefaultRestTemplateExchangeTagsProvider;
 import org.springframework.boot.actuate.metrics.web.client.MetricsRestTemplateCustomizer;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
 import org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration;
@@ -41,6 +42,7 @@ import static org.springframework.test.web.client.response.MockRestResponseCreat
  *
  * @author Stephane Nicoll
  * @author Jon Schneider
+ * @author raheela.aslam
  */
 public class RestTemplateMetricsConfigurationTests {
 
@@ -131,4 +133,14 @@ public class RestTemplateMetricsConfigurationTests {
 		return restTemplate;
 	}
 
+	@Test
+	public void backsOffWhenRestTemplateBuilderIsMissing() {
+		new ApplicationContextRunner().with(MetricsRun.simple())
+				.withConfiguration(
+						AutoConfigurations.of(HttpClientMetricsAutoConfiguration.class))
+				.run((context) -> assertThat(context)
+						.doesNotHaveBean(DefaultRestTemplateExchangeTagsProvider.class)
+						.doesNotHaveBean(MetricsRestTemplateCustomizer.class));
+	}
+
 }