Add auto-configuration for OTLP gRPC format when using tracing

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

@@ -36,8 +36,10 @@
  * the future, see: <a href=
  * "https://github.com/open-telemetry/opentelemetry-java/issues/3651">opentelemetry-java#3651</a>.
  * Because this class configures components from the OTel SDK, it can't support HTTP/JSON.
- * To keep things simple, we only auto-configure HTTP/protobuf. If you want to use gRPC,
- * define an {@link OtlpGrpcSpanExporter} and this auto-configuration will back off.
+ * By default, we auto-configure HTTP/protobuf. If you want to use gRPC, you need to set
+ * {@code management.otlp.tracing.exporter=grpc}. If you define a
+ * {@link OtlpHttpSpanExporter} or {@link OtlpGrpcSpanExporter}, this auto-configuration
+ * will back off.
  *
  * @author Jonatan Ivanov
  * @author Moritz Halbritter

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

@@ -44,6 +44,11 @@ public class OtlpProperties {
 	 */
 	private Duration timeout = Duration.ofSeconds(10);
 
+	/**
+	 * Transport used to send the spans. Defaults to HTTP.
+	 */
+	private Transport transport = Transport.HTTP;
+
 	/**
 	 * Method used to compress the payload.
 	 */
@@ -70,6 +75,14 @@ public void setTimeout(Duration timeout) {
 		this.timeout = timeout;
 	}
 
+	public Transport getTransport() {
+		return this.transport;
+	}
+
+	public void setTransport(Transport transport) {
+		this.transport = transport;
+	}
+
 	public Compression getCompression() {
 		return this.compression;
 	}
@@ -86,6 +99,20 @@ public void setHeaders(Map<String, String> headers) {
 		this.headers = headers;
 	}
 
+	enum Transport {
+
+		/**
+		 * HTTP exporter.
+		 */
+		HTTP,
+
+		/**
+		 * gRPC exporter.
+		 */
+		GRPC
+
+	}
+
 	enum Compression {
 
 		/**

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

@@ -20,6 +20,8 @@
 
 import io.opentelemetry.exporter.otlp.http.trace.OtlpHttpSpanExporter;
 import io.opentelemetry.exporter.otlp.http.trace.OtlpHttpSpanExporterBuilder;
+import io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporter;
+import io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporterBuilder;
 
 import org.springframework.boot.actuate.autoconfigure.tracing.ConditionalOnEnabledTracing;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
@@ -69,10 +71,11 @@ public String getUrl() {
 	static class Exporters {
 
 		@Bean
-		@ConditionalOnMissingBean(value = OtlpHttpSpanExporter.class,
-				type = "io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporter")
+		@ConditionalOnMissingBean({ OtlpGrpcSpanExporter.class, OtlpHttpSpanExporter.class })
 		@ConditionalOnBean(OtlpTracingConnectionDetails.class)
 		@ConditionalOnEnabledTracing("otlp")
+		@ConditionalOnProperty(prefix = "management.otlp.tracing", name = "transport", havingValue = "http",
+				matchIfMissing = true)
 		OtlpHttpSpanExporter otlpHttpSpanExporter(OtlpProperties properties,
 				OtlpTracingConnectionDetails connectionDetails) {
 			OtlpHttpSpanExporterBuilder builder = OtlpHttpSpanExporter.builder()
@@ -85,6 +88,23 @@ OtlpHttpSpanExporter otlpHttpSpanExporter(OtlpProperties properties,
 			return builder.build();
 		}
 
+		@Bean
+		@ConditionalOnMissingBean({ OtlpGrpcSpanExporter.class, OtlpHttpSpanExporter.class })
+		@ConditionalOnBean(OtlpTracingConnectionDetails.class)
+		@ConditionalOnEnabledTracing("otlp")
+		@ConditionalOnProperty(prefix = "management.otlp.tracing", name = "transport", havingValue = "grpc")
+		OtlpGrpcSpanExporter otlpGrpcSpanExporter(OtlpProperties properties,
+				OtlpTracingConnectionDetails connectionDetails) {
+			OtlpGrpcSpanExporterBuilder builder = OtlpGrpcSpanExporter.builder()
+				.setEndpoint(connectionDetails.getUrl())
+				.setTimeout(properties.getTimeout())
+				.setCompression(properties.getCompression().name().toLowerCase());
+			for (Entry<String, String> header : properties.getHeaders().entrySet()) {
+				builder.addHeader(header.getKey(), header.getValue());
+			}
+			return builder.build();
+		}
+
 	}
 
 }

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

@@ -51,13 +51,28 @@ void shouldNotSupplyBeansIfPropertyIsNotSet() {
 		this.contextRunner.run((context) -> assertThat(context).doesNotHaveBean(OtlpHttpSpanExporter.class));
 	}
 
+	@Test
+	void shouldNotSupplyBeansIfGrpcTransportIsEnabledButPropertyIsNotSet() {
+		this.contextRunner.withPropertyValues("management.otlp.tracing.transport=grpc")
+			.run((context) -> assertThat(context).doesNotHaveBean(OtlpGrpcSpanExporter.class));
+	}
+
 	@Test
 	void shouldSupplyBeans() {
 		this.contextRunner.withPropertyValues("management.otlp.tracing.endpoint=http://localhost:4318/v1/traces")
 			.run((context) -> assertThat(context).hasSingleBean(OtlpHttpSpanExporter.class)
 				.hasSingleBean(SpanExporter.class));
 	}
 
+	@Test
+	void shouldSupplyBeansIfGrpcTransportIsEnabled() {
+		this.contextRunner
+			.withPropertyValues("management.otlp.tracing.endpoint=http://localhost:4317/v1/traces",
+					"management.otlp.tracing.transport=grpc")
+			.run((context) -> assertThat(context).hasSingleBean(OtlpGrpcSpanExporter.class)
+				.hasSingleBean(SpanExporter.class));
+	}
+
 	@Test
 	void shouldNotSupplyBeansIfGlobalTracingIsDisabled() {
 		this.contextRunner.withPropertyValues("management.tracing.enabled=false")