10702 - rest client instrumentation

instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/RestClientBeanPostProcessor

@@ -0,0 +1,34 @@
+package io.opentelemetry.instrumentation.spring.autoconfigure.instrumentation.web;
+
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.spring.web.v3_1.SpringWebTelemetry;
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.web.client.RestClient;
+
+final class RestClientBeanPostProcessor implements BeanPostProcessor {
+
+    private final ObjectProvider<OpenTelemetry> openTelemetryProvider;
+
+    public RestClientBeanPostProcessor(ObjectProvider<OpenTelemetry> openTelemetryProvider) {
+        this.openTelemetryProvider = openTelemetryProvider;
+    }
+
+    @Override
+    public Object postProcessAfterInitialization(Object bean, String beanName) {
+        if (!(bean instanceof RestClient restClient)) {
+            return bean;
+        }
+        ClientHttpRequestInterceptor interceptor = SpringWebTelemetry.create(openTelemetryProvider.getObject()).newInterceptor();
+        return addRestClientInterceptorIfNotPresent(restClient, interceptor);
+    }
+
+    private static RestClient addRestClientInterceptorIfNotPresent(RestClient restClient, ClientHttpRequestInterceptor instrumentationInterceptor) {
+        return restClient.mutate().requestInterceptors(interceptors -> {
+            if (interceptors.stream().noneMatch(interceptor -> interceptor.getClass() == instrumentationInterceptor.getClass())) {
+                interceptors.addFirst(instrumentationInterceptor);
+            }
+        }).build();
+    }
+}

instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/SpringWebInstrumentationAutoConfiguration.java

@@ -14,25 +14,33 @@
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Conditional;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.RestClient;
 import org.springframework.web.client.RestTemplate;
 
 /**
- * Configures {@link RestTemplate} for tracing.
+ * Configures {@link RestTemplate} and {@link RestClient} for tracing.
  *
- * <p>Adds Open Telemetry instrumentation to RestTemplate beans after initialization
+ * <p>Adds Open Telemetry instrumentation to RestTemplate and RestClient beans after initialization
  */
 @ConditionalOnBean(OpenTelemetry.class)
-@ConditionalOnClass(RestTemplate.class)
 @ConditionalOnProperty(name = "otel.instrumentation.spring-web.enabled", matchIfMissing = true)
 @Conditional(SdkEnabled.class)
 @Configuration
 public class SpringWebInstrumentationAutoConfiguration {
 
   public SpringWebInstrumentationAutoConfiguration() {}
 
+  @ConditionalOnClass(RestTemplate.class)
   @Bean
   static RestTemplateBeanPostProcessor otelRestTemplateBeanPostProcessor(
       ObjectProvider<OpenTelemetry> openTelemetryProvider) {
     return new RestTemplateBeanPostProcessor(openTelemetryProvider);
   }
+
+  @ConditionalOnClass(RestClient.class)
+  @Bean
+  static RestClientBeanPostProcessor otelRestClientBeanPostProcessor(
+    ObjectProvider<OpenTelemetry> openTelemetryProvider) {
+      return new RestClientBeanPostProcessor(openTelemetryProvider);
+  }
 }

instrumentation/spring/spring-boot-autoconfigure/src/test/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/RestClientBeanPostProcessorTest

@@ -0,0 +1,62 @@
+package io.opentelemetry.instrumentation.spring.autoconfigure.instrumentation.web;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.opentelemetry.api.OpenTelemetry;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.web.client.RestClient;
+
+class RestClienteBeanPostProcessorTest {
+  private static final DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory();
+
+  static {
+    beanFactory.registerSingleton("openTelemetry", OpenTelemetry.noop());
+  }
+
+  @Test
+  @DisplayName("when processed bean is not of type RestClient should return object")
+  void returnsObject() {
+    BeanPostProcessor underTest =
+        new RestClientBeanPostProcessor(beanFactory.getBeanProvider(OpenTelemetry.class));
+
+    assertThat(underTest.postProcessAfterInitialization(new Object(), "testObject"))
+        .isExactlyInstanceOf(Object.class);
+  }
+
+  @Test
+  @DisplayName("when processed bean is of type RestClient should return RestClient")
+  void returnsRestClient() {
+    BeanPostProcessor underTest =
+        new RestClientBeanPostProcessor(beanFactory.getBeanProvider(OpenTelemetry.class));
+
+    assertThat(underTest.postProcessAfterInitialization(new RestClient(), "testRestClient"))
+        .isInstanceOf(RestClient.class);
+  }
+
+  @Test
+  @DisplayName("when processed bean is of type RestClient should add ONE RestClientInterceptor")
+  void addsRestClientInterceptor() {
+    BeanPostProcessor underTest =
+        new RestClientBeanPostProcessor(beanFactory.getBeanProvider(OpenTelemetry.class));
+
+    RestClient restClient = new RestClient();
+
+    underTest.postProcessAfterInitialization(restClient, "testRestClient");
+    underTest.postProcessAfterInitialization(restClient, "testRestClient");
+    underTest.postProcessAfterInitialization(restClient, "testRestClient");
+
+    assertThat(
+            restClient.getInterceptors().stream()
+                .filter(RestClientBeanPostProcessorTest::isOtelInstrumentationInterceptor)
+                .count())
+        .isEqualTo(1);
+  }
+
+  private static boolean isOtelInstrumentationInterceptor(ClientHttpRequestInterceptor rti) {
+    return rti.getClass().getName().startsWith("io.opentelemetry.instrumentation");
+  }
+}

instrumentation/spring/spring-boot-autoconfigure/src/test/java/io/opentelemetry/instrumentation/spring/autoconfigure/instrumentation/web/SpringWebInstrumentationAutoConfigurationTest.java

@@ -25,30 +25,43 @@ void instrumentationEnabled() {
     contextRunner
         .withPropertyValues("otel.instrumentation.spring-web.enabled=true")
         .run(
-            context ->
+            context -> {
                 assertThat(
                         context.getBean(
                             "otelRestTemplateBeanPostProcessor",
                             RestTemplateBeanPostProcessor.class))
-                    .isNotNull());
+                    .isNotNull(); 
+                 assertThat(
+                        context.getBean(
+                            "otelRestClientBeanPostProcessor",
+                            RestClientBeanPostProcessor.class))
+                    .isNotNull();
+           });
   }
 
   @Test
   void instrumentationDisabled() {
     contextRunner
         .withPropertyValues("otel.instrumentation.spring-web.enabled=false")
         .run(
-            context ->
-                assertThat(context.containsBean("otelRestTemplateBeanPostProcessor")).isFalse());
+            context -> {
+                assertThat(context.containsBean("otelRestTemplateBeanPostProcessor")).isFalse();
+                assertThat(context.containsBean("otelRestClientBeanPostProcessor")).isFalse()
+        });
   }
 
   @Test
   void defaultConfiguration() {
     contextRunner.run(
-        context ->
+        context -> {
             assertThat(
                     context.getBean(
                         "otelRestTemplateBeanPostProcessor", RestTemplateBeanPostProcessor.class))
-                .isNotNull());
+                .isNotNull();
+            assertThat(
+                    context.getBean(
+                        "otelRestClientBeanPostProcessor", RestClientBeanPostProcessor.class))
+                .isNotNull()
+        });
   }
 }