Auto-configure OtlpMetricsSender if available

A new interface OtlpMetricsSender was introduced to allow users to customize the sending of OTLP metrics using the OtlpMeterRegistry. This configures it, if available as a bean, on the auto-configured OtlpMeterRegistry.

Author: shakuzen

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/metrics/export/otlp/OtlpMetricsExportAutoConfiguration.java

@@ -19,7 +19,10 @@
 import io.micrometer.core.instrument.Clock;
 import io.micrometer.registry.otlp.OtlpConfig;
 import io.micrometer.registry.otlp.OtlpMeterRegistry;
+import io.micrometer.registry.otlp.OtlpMeterRegistry.Builder;
+import io.micrometer.registry.otlp.OtlpMetricsSender;
 
+import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.actuate.autoconfigure.metrics.CompositeMeterRegistryAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.MetricsAutoConfiguration;
 import org.springframework.boot.actuate.autoconfigure.metrics.export.ConditionalOnEnabledMetricsExport;
@@ -76,16 +79,24 @@ OtlpConfig otlpConfig(OpenTelemetryProperties openTelemetryProperties,
 	@Bean
 	@ConditionalOnMissingBean
 	@ConditionalOnThreading(Threading.PLATFORM)
-	public OtlpMeterRegistry otlpMeterRegistry(OtlpConfig otlpConfig, Clock clock) {
-		return new OtlpMeterRegistry(otlpConfig, clock);
+	public OtlpMeterRegistry otlpMeterRegistry(OtlpConfig otlpConfig, Clock clock,
+			ObjectProvider<OtlpMetricsSender> metricsSender) {
+		Builder builder = OtlpMeterRegistry.builder(otlpConfig).clock(clock);
+		metricsSender.ifAvailable(builder::metricsSender);
+		return builder.build();
 	}
 
 	@Bean
 	@ConditionalOnMissingBean
 	@ConditionalOnThreading(Threading.VIRTUAL)
-	public OtlpMeterRegistry otlpMeterRegistryVirtualThreads(OtlpConfig otlpConfig, Clock clock) {
+	public OtlpMeterRegistry otlpMeterRegistryVirtualThreads(OtlpConfig otlpConfig, Clock clock,
+			ObjectProvider<OtlpMetricsSender> metricsSender) {
 		VirtualThreadTaskExecutor taskExecutor = new VirtualThreadTaskExecutor("otlp-meter-registry-");
-		return new OtlpMeterRegistry(otlpConfig, clock, taskExecutor.getVirtualThreadFactory());
+		Builder builder = OtlpMeterRegistry.builder(otlpConfig)
+			.clock(clock)
+			.threadFactory(taskExecutor.getVirtualThreadFactory());
+		metricsSender.ifAvailable(builder::metricsSender);
+		return builder.build();
 	}
 
 	/**

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/metrics/export/otlp/OtlpMetricsExportAutoConfigurationTests.java

@@ -21,6 +21,7 @@
 import io.micrometer.core.instrument.Clock;
 import io.micrometer.registry.otlp.OtlpConfig;
 import io.micrometer.registry.otlp.OtlpMeterRegistry;
+import io.micrometer.registry.otlp.OtlpMetricsSender;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.EnabledForJreRange;
 import org.junit.jupiter.api.condition.JRE;
@@ -132,6 +133,32 @@ void testConnectionFactoryWithOverridesWhenUsingCustomConnectionDetails() {
 			});
 	}
 
+	@Test
+	void allowsCustomMetricsSenderToBeUsed() {
+		this.contextRunner.withUserConfiguration(BaseConfiguration.class, CustomMetricsSenderConfiguration.class)
+			.run((context) -> {
+				assertThat(context).hasSingleBean(OtlpMeterRegistry.class);
+				OtlpMeterRegistry registry = context.getBean(OtlpMeterRegistry.class);
+				assertThat(registry).extracting("metricsSender")
+					.satisfies((sender) -> assertThat(sender)
+						.isSameAs(CustomMetricsSenderConfiguration.customMetricsSender));
+			});
+	}
+
+	@Test
+	@EnabledForJreRange(min = JRE.JAVA_21)
+	void allowsCustomMetricsSenderToBeUsedWithVirtualThreads() {
+		this.contextRunner.withUserConfiguration(BaseConfiguration.class, CustomMetricsSenderConfiguration.class)
+			.withPropertyValues("spring.threads.virtual.enabled=true")
+			.run((context) -> {
+				assertThat(context).hasSingleBean(OtlpMeterRegistry.class);
+				OtlpMeterRegistry registry = context.getBean(OtlpMeterRegistry.class);
+				assertThat(registry).extracting("metricsSender")
+					.satisfies((sender) -> assertThat(sender)
+						.isSameAs(CustomMetricsSenderConfiguration.customMetricsSender));
+			});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class BaseConfiguration {
 
@@ -174,4 +201,17 @@ OtlpMetricsConnectionDetails otlpConnectionDetails() {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	static class CustomMetricsSenderConfiguration {
+
+		static OtlpMetricsSender customMetricsSender = request -> {
+		};
+
+		@Bean
+		OtlpMetricsSender customMetricsSender() {
+			return customMetricsSender;
+		}
+
+	}
+
 }

spring-boot-project/spring-boot-docs/src/docs/antora/modules/reference/pages/actuator/metrics.adoc

@@ -522,6 +522,8 @@ management:
 
 Custom headers, for example for authentication, can also be provided using configprop:management.otlp.metrics.export.headers.*[] properties.
 
+If an `OtlpMetricsSender` bean is available, it will be configured on the `OtlpMeterRegistry` that Spring Boot auto-configures.
+
 
 
 [[actuator.metrics.export.prometheus]]