Merge pull request #44499 from thecooldrop

* pr/44499:
  Polish "Add support for OpenTelemetry's service.namespace"
  Add support for OpenTelemetry's service.namespace

Closes gh-44499

Author: mhalbritter

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/opentelemetry/OpenTelemetryResourceAttributes.java

@@ -86,7 +86,7 @@ public OpenTelemetryResourceAttributes(Environment environment, Map<String, Stri
 	 * <p>
 	 * Additionally, {@code spring.application.name} or {@code unknown_service} will be
 	 * used as the default for {@code service.name}, and {@code spring.application.group}
-	 * will serve as the default for {@code service.group}.
+	 * will serve as the default for {@code service.group} and {@code service.namespace}.
 	 * @param consumer the {@link BiConsumer} to apply
 	 */
 	public void applyTo(BiConsumer<String, String> consumer) {
@@ -97,20 +97,31 @@ public void applyTo(BiConsumer<String, String> consumer) {
 				attributes.put(name, value);
 			}
 		});
-		attributes.computeIfAbsent("service.name", (k) -> getApplicationName());
-		attributes.computeIfAbsent("service.group", (k) -> getApplicationGroup());
+		attributes.computeIfAbsent("service.name", (key) -> getApplicationName());
+		attributes.computeIfAbsent("service.group", (key) -> getApplicationGroup());
+		attributes.computeIfAbsent("service.namespace", (key) -> getServiceNamespace());
 		attributes.forEach(consumer);
 	}
 
 	private String getApplicationName() {
 		return this.environment.getProperty("spring.application.name", DEFAULT_SERVICE_NAME);
 	}
 
+	/**
+	 * Returns the application group.
+	 * @return the application group
+	 * @deprecated since 3.5.0 for removal in 3.7.0
+	 */
+	@Deprecated(since = "3.5.0", forRemoval = true)
 	private String getApplicationGroup() {
 		String applicationGroup = this.environment.getProperty("spring.application.group");
 		return (StringUtils.hasLength(applicationGroup)) ? applicationGroup : null;
 	}
 
+	private String getServiceNamespace() {
+		return this.environment.getProperty("spring.application.group");
+	}
+
 	/**
 	 * Parses resource attributes from the {@link System#getenv()}. This method fetches
 	 * attributes defined in the {@code OTEL_RESOURCE_ATTRIBUTES} and

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/opentelemetry/OpenTelemetryAutoConfigurationTests.java

@@ -106,6 +106,23 @@ void shouldNotApplySpringApplicationGroupIfNotSet() {
 		});
 	}
 
+	@Test
+	void shouldApplyServiceNamespaceIfApplicationGroupIsSet() {
+		this.runner.withPropertyValues("spring.application.group=my-group").run((context) -> {
+			Resource resource = context.getBean(Resource.class);
+			assertThat(resource.getAttributes().asMap()).containsEntry(AttributeKey.stringKey("service.namespace"),
+					"my-group");
+		});
+	}
+
+	@Test
+	void shouldNotApplyServiceNamespaceIfApplicationGroupIsNotSet() {
+		this.runner.run(((context) -> {
+			Resource resource = context.getBean(Resource.class);
+			assertThat(resource.getAttributes().asMap()).doesNotContainKey(AttributeKey.stringKey("service.namespace"));
+		}));
+	}
+
 	@Test
 	void shouldFallbackToDefaultApplicationNameIfSpringApplicationNameIsNotSet() {
 		this.runner.run((context) -> {
@@ -156,7 +173,7 @@ void shouldRegisterSdkMeterProviderIfAvailable() {
 	}
 
 	@Configuration(proxyBeanMethods = false)
-	private static final class UserConfiguration {
+	static class UserConfiguration {
 
 		@Bean
 		OpenTelemetry customOpenTelemetry() {

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/opentelemetry/OpenTelemetryResourceAttributesTests.java

@@ -156,9 +156,10 @@ void unknownServiceShouldBeUsedAsDefaultServiceName() {
 	@Test
 	void springApplicationGroupNameShouldBeUsedAsDefaultServiceGroup() {
 		this.environment.setProperty("spring.application.group", "spring-boot");
-		assertThat(getAttributes()).hasSize(2)
+		assertThat(getAttributes()).hasSize(3)
 			.containsEntry("service.name", "unknown_service")
-			.containsEntry("service.group", "spring-boot");
+			.containsEntry("service.group", "spring-boot")
+			.containsEntry("service.namespace", "spring-boot");
 	}
 
 	@Test
@@ -167,6 +168,11 @@ void springApplicationNameShouldBeUsedAsDefaultServiceName() {
 		assertThat(getAttributes()).hasSize(1).containsEntry("service.name", "spring-boot-app");
 	}
 
+	@Test
+	void serviceNamespaceShouldNotBePresentByDefault() {
+		assertThat(getAttributes()).hasSize(1).doesNotContainKey("service.namespace");
+	}
+
 	@Test
 	void resourceAttributesShouldTakePrecedenceOverSpringApplicationName() {
 		this.resourceAttributes.put("service.name", "spring-boot");
@@ -192,18 +198,49 @@ void otelServiceNameShouldTakePrecedenceOverSpringApplicationName() {
 	void resourceAttributesShouldTakePrecedenceOverSpringApplicationGroupName() {
 		this.resourceAttributes.put("service.group", "spring-boot-app");
 		this.environment.setProperty("spring.application.group", "spring-boot");
-		assertThat(getAttributes()).hasSize(2)
+		assertThat(getAttributes()).hasSize(3)
 			.containsEntry("service.name", "unknown_service")
 			.containsEntry("service.group", "spring-boot-app");
 	}
 
+	@Test
+	void resourceAttributesShouldTakePrecedenceOverApplicationGroupNameForPopulatingServiceNamespace() {
+		this.resourceAttributes.put("service.namespace", "spring-boot-app");
+		this.environment.setProperty("spring.application.group", "overriden");
+		assertThat(getAttributes()).hasSize(3)
+			.containsEntry("service.name", "unknown_service")
+			.containsEntry("service.group", "overriden")
+			.containsEntry("service.namespace", "spring-boot-app");
+	}
+
 	@Test
 	void otelResourceAttributesShouldTakePrecedenceOverSpringApplicationGroupName() {
 		this.environmentVariables.put("OTEL_RESOURCE_ATTRIBUTES", "service.group=spring-boot");
 		this.environment.setProperty("spring.application.group", "spring-boot-app");
-		assertThat(getAttributes()).hasSize(2)
+		assertThat(getAttributes()).hasSize(3)
 			.containsEntry("service.name", "unknown_service")
-			.containsEntry("service.group", "spring-boot");
+			.containsEntry("service.group", "spring-boot")
+			.containsEntry("service.namespace", "spring-boot-app");
+	}
+
+	@Test
+	void otelResourceAttributesShouldTakePrecedenceOverSpringApplicationGroupNameForServiceNamespace() {
+		this.environmentVariables.put("OTEL_RESOURCE_ATTRIBUTES", "service.namespace=spring-boot");
+		this.environment.setProperty("spring.application.group", "overriden");
+		assertThat(getAttributes()).hasSize(3)
+			.containsEntry("service.group", "overriden")
+			.containsEntry("service.namespace", "spring-boot");
+	}
+
+	@Test
+	void shouldUseServiceGroupForServiceNamespaceIfServiceGroupIsSet() {
+		this.environment.setProperty("spring.application.group", "alpha");
+		assertThat(getAttributes()).containsEntry("service.namespace", "alpha");
+	}
+
+	@Test
+	void shouldNotSetServiceNamespaceIfServiceGroupIsNotSet() {
+		assertThat(getAttributes()).doesNotContainKey("service.namespace");
 	}
 
 	private Map<String, String> getAttributes() {