Merge pull request #13 from spring-cloud-incubator/resource_customizer

Resource customizer

Author: marcingrzejszczak

docs/src/main/asciidoc/project-features.adoc

@@ -41,6 +41,11 @@ We're providing an Slf4j integration via a `SpanProcessor` that injects to and r
 If it's there on the classpath, we integrate with the `LoggingSpanExporter`.
 You can disable that integration via the `spring.sleuth.otel.log.exporter.enabled=false` property.
 
+[[features-otel-resource-customization]]
+=== OpenTelemetry Resource Customization
+
+OpenTelemetry provides a `Resource` abstraction which captures identifying information about the entities for which signals (stats or traces) are reported. If you wish to customize that `Resource` you can register as a bean an implementation of the `ResourceCustomizer` interface.
+
 [[features-otel-opentracing]]
 === OpenTelemetry Opentracing
 

spring-cloud-sleuth-otel-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/otel/OtelAutoConfiguration.java

@@ -100,12 +100,18 @@ SdkTracerProvider otelTracerProvider(SpanLimits spanLimits, ObjectProvider<List<
 
 	@Bean
 	@ConditionalOnMissingBean
-	Resource otelResource(Environment env) {
-		// todo: populate the resource with the right stuff (service.name, etc)
-		// this was the code in the zipkin exporter configuration previously:
-		// env.getProperty("spring.application.name", env.getProperty(
-		// "spring.zipkin.service.name", ZipkinSpanExporter.DEFAULT_SERVICE_NAME)
+	Resource otelResource(Environment env, ObjectProvider<List<ResourceCustomizer>> resourceCustomizerProvider) {
 		String applicationName = env.getProperty("spring.application.name");
+		Resource resource = defaultResource(applicationName);
+		List<ResourceCustomizer> resourceCustomizers = resourceCustomizerProvider.getIfAvailable(ArrayList::new);
+		for (ResourceCustomizer customizer : resourceCustomizers) {
+			Resource customized = customizer.customize(resource);
+			resource = resource.merge(customized);
+		}
+		return resource;
+	}
+
+	private Resource defaultResource(String applicationName) {
 		if (applicationName == null) {
 			return Resource.getDefault();
 		}

spring-cloud-sleuth-otel-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/otel/ResourceCustomizer.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2013-2020 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.sleuth.autoconfig.otel;
+
+import io.opentelemetry.sdk.resources.Resource;
+
+/**
+ * Allows to customize the {@link Resource}.
+ *
+ * @author Marcin Grzejszczak
+ * @since 1.0.0
+ */
+@FunctionalInterface
+public interface ResourceCustomizer {
+
+	/**
+	 * Customizes the resource or returns itself if there's nothing to customize.
+	 * @param resource - resource to customize
+	 * @return resource to be merged with the customized resource
+	 */
+	Resource customize(Resource resource);
+
+}

spring-cloud-sleuth-otel-autoconfigure/src/main/java/org/springframework/cloud/sleuth/autoconfig/otel/zipkin2/ZipkinOtelAutoConfiguration.java

@@ -16,15 +16,19 @@
 
 package org.springframework.cloud.sleuth.autoconfig.otel.zipkin2;
 
+import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.trace.Tracer;
 import io.opentelemetry.exporter.zipkin.ZipkinSpanExporter;
+import io.opentelemetry.sdk.resources.Resource;
+import io.opentelemetry.semconv.resource.attributes.ResourceAttributes;
 import zipkin2.reporter.Sender;
 
 import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.boot.autoconfigure.AutoConfigureBefore;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.cloud.sleuth.autoconfig.otel.ResourceCustomizer;
 import org.springframework.cloud.sleuth.autoconfig.zipkin2.ZipkinAutoConfiguration;
 import org.springframework.cloud.sleuth.zipkin2.DefaultZipkinRestTemplateCustomizer;
 import org.springframework.cloud.sleuth.zipkin2.EndpointLocator;
@@ -62,11 +66,22 @@ static class ZipkinConfiguration {
 		@Bean
 		@ConditionalOnMissingBean
 		ZipkinSpanExporter otelZipkinSpanExporter(ZipkinProperties zipkinProperties,
-				@Qualifier(ZipkinAutoConfiguration.SENDER_BEAN_NAME) Sender sender, Environment env) {
+				@Qualifier(ZipkinAutoConfiguration.SENDER_BEAN_NAME) Sender sender) {
 			return ZipkinSpanExporter.builder().setEndpoint(zipkinProperties.getBaseUrl() + "api/v2/spans")
 					.setSender(sender).setEncoder(zipkinProperties.getEncoder()).build();
 		}
 
+		@Bean
+		ResourceCustomizer zipkinResourceCustomizer(Environment environment) {
+			return resource -> {
+				String zipkinServiceName = environment.getProperty("spring.zipkin.service.name");
+				if (zipkinServiceName == null) {
+					return resource;
+				}
+				return Resource.create(Attributes.of(ResourceAttributes.SERVICE_NAME, zipkinServiceName));
+			};
+		}
+
 	}
 
 }

spring-cloud-sleuth-otel-autoconfigure/src/test/java/org/springframework/cloud/sleuth/autoconfig/otel/zipkin2/ZipkinSamplerTests.java

@@ -16,6 +16,8 @@
 
 package org.springframework.cloud.sleuth.autoconfig.otel.zipkin2;
 
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.sdk.resources.Resource;
 import org.assertj.core.api.BDDAssertions;
 import org.junit.jupiter.api.Test;
 
@@ -45,6 +47,19 @@ void should_set_sampler_to_non_off_when_zipkin_handler_on_classpath_for_otel() {
 		});
 	}
 
+	@Test
+	void should_set_service_name_to_zipkin_service_name() {
+		ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+				.withPropertyValues("spring.sleuth.tracer.mode=AUTO", "spring.application.name=foo",
+						"spring.zipkin.service.name=bar")
+				.withConfiguration(AutoConfigurations.of(TestConfig.class));
+
+		contextRunner.run(context -> {
+			Resource resource = context.getBean(Resource.class);
+			BDDAssertions.then(resource.getAttributes().get(AttributeKey.stringKey("service.name"))).isEqualTo("bar");
+		});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@EnableAutoConfiguration
 	static class TestConfig {