Add customizer for SdkTracerProviderBuilder

See gh-34945

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/OpenTelemetryAutoConfiguration.java

@@ -70,6 +70,7 @@ import org.springframework.core.env.Environment;
  * {@link EnableAutoConfiguration Auto-configuration} for OpenTelemetry.
  *
  * @author Moritz Halbritter
+ * @author Yanming Zhou
  * @since 3.0.0
  */
 @AutoConfiguration(before = MicrometerTracingAutoConfiguration.class)
@@ -101,12 +102,13 @@ public class OpenTelemetryAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	SdkTracerProvider otelSdkTracerProvider(Environment environment, ObjectProvider<SpanProcessor> spanProcessors,
-			Sampler sampler) {
+			Sampler sampler, ObjectProvider<SdkTracerProviderCustomizer> customizers) {
 		String applicationName = environment.getProperty("spring.application.name", DEFAULT_APPLICATION_NAME);
 		SdkTracerProviderBuilder builder = SdkTracerProvider.builder()
 			.setSampler(sampler)
 			.setResource(Resource.create(Attributes.of(ResourceAttributes.SERVICE_NAME, applicationName)));
 		spanProcessors.orderedStream().forEach(builder::addSpanProcessor);
+		customizers.forEach((customizer) -> customizer.customize(builder));
 		return builder.build();
 	}
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/SdkTracerProviderCustomizer.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2012-2023 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.boot.actuate.autoconfigure.tracing;
+
+import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
+
+/**
+ * Callback interface that can be used to customize auto-configured
+ * {@link SdkTracerProviderBuilder}.
+ *
+ * @author Yanming Zhou
+ * @since 3.1.0
+ */
+@FunctionalInterface
+public interface SdkTracerProviderCustomizer {
+
+	/**
+	 * Customize the given {@code builder}.
+	 * @param builder the builder to customize
+	 */
+	void customize(SdkTracerProviderBuilder builder);
+
+}

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

@@ -34,6 +34,7 @@ import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.context.propagation.TextMapPropagator;
 import io.opentelemetry.extension.trace.propagation.B3Propagator;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import io.opentelemetry.sdk.trace.SpanLimits;
 import io.opentelemetry.sdk.trace.SpanProcessor;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
 import org.junit.jupiter.api.Test;
@@ -54,6 +55,7 @@ import static org.mockito.Mockito.mock;
  *
  * @author Moritz Halbritter
  * @author Andy Wilkinson
+ * @author Yanming Zhou
  */
 class OpenTelemetryAutoConfigurationTests {
 
@@ -203,6 +205,14 @@ class OpenTelemetryAutoConfigurationTests {
 			.run((context) -> assertThat(context).hasBean("w3cTextMapPropagatorWithoutBaggage"));
 	}
 
+	@Test
+	void shouldCustomizeSdkTracerProvider() {
+		this.contextRunner.withUserConfiguration(SdkTracerProviderCustomizationConfiguration.class).run((context) -> {
+			SdkTracerProvider tracerProvider = context.getBean(SdkTracerProvider.class);
+			assertThat(tracerProvider.getSpanLimits().getMaxNumberOfEvents()).isEqualTo(42);
+		});
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	private static class CustomConfiguration {
 
@@ -278,4 +288,17 @@ class OpenTelemetryAutoConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	private static class SdkTracerProviderCustomizationConfiguration {
+
+		@Bean
+		SdkTracerProviderCustomizer sdkTracerProviderBuilderCustomizer() {
+			return (builder) -> {
+				SpanLimits spanLimits = SpanLimits.builder().setMaxNumberOfEvents(42).build();
+				builder.setSpanLimits(spanLimits);
+			};
+		}
+
+	}
+
 }