Reuse registered global OpenTelemetry

Spring Boot instrumentation will be included when applications are running with OpenTelemetry Java Agent.

Signed-off-by: Yanming Zhou <[email protected]>

Author: quaff

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

@@ -16,6 +16,7 @@
 
 package org.springframework.boot.actuate.autoconfigure.opentelemetry;
 
+import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
@@ -29,23 +30,37 @@
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.autoconfigure.AutoConfiguration;
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.condition.ConditionMessage;
+import org.springframework.boot.autoconfigure.condition.ConditionOutcome;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.autoconfigure.condition.SpringBootCondition;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ConditionContext;
+import org.springframework.context.annotation.Conditional;
 import org.springframework.core.env.Environment;
+import org.springframework.core.type.AnnotatedTypeMetadata;
 
 /**
  * {@link EnableAutoConfiguration Auto-configuration} for OpenTelemetry.
  *
  * @author Moritz Halbritter
+ * @author Yanming Zhou
  * @since 3.2.0
  */
 @AutoConfiguration
 @ConditionalOnClass(OpenTelemetrySdk.class)
 @EnableConfigurationProperties(OpenTelemetryProperties.class)
 public class OpenTelemetryAutoConfiguration {
 
+	@Bean
+	@ConditionalOnMissingBean(OpenTelemetry.class)
+	@Conditional(OnRegisteredGlobalOpenTelemetryCondition.class)
+	OpenTelemetry globalOpenTelemetry() {
+		return GlobalOpenTelemetry.get();
+	}
+
 	@Bean
 	@ConditionalOnMissingBean(OpenTelemetry.class)
 	OpenTelemetrySdk openTelemetry(ObjectProvider<SdkTracerProvider> tracerProvider,
@@ -72,4 +87,15 @@ private Resource toResource(Environment environment, OpenTelemetryProperties pro
 		return builder.build();
 	}
 
+	static class OnRegisteredGlobalOpenTelemetryCondition extends SpringBootCondition {
+
+		@Override
+		public ConditionOutcome getMatchOutcome(ConditionContext context, AnnotatedTypeMetadata metadata) {
+			boolean globalOpenTelemetryRegistered = GlobalOpenTelemetry.get() != OpenTelemetry.noop();
+			return new ConditionOutcome(globalOpenTelemetryRegistered, ConditionMessage
+				.of("GlobalOpenTelemetry is" + (globalOpenTelemetryRegistered ? "not" : "") + " NOOP"));
+		}
+
+	}
+
 }

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

@@ -16,14 +16,18 @@
 
 package org.springframework.boot.actuate.autoconfigure.opentelemetry;
 
+import io.opentelemetry.api.GlobalOpenTelemetry;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.trace.Tracer;
+import io.opentelemetry.api.trace.TracerProvider;
 import io.opentelemetry.context.propagation.ContextPropagators;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.logs.SdkLoggerProvider;
 import io.opentelemetry.sdk.metrics.SdkMeterProvider;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.autoconfigure.AutoConfiguration;
@@ -36,18 +40,26 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.entry;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 
 /**
  * Tests for {@link OpenTelemetryAutoConfiguration}.
  *
  * @author Moritz Halbritter
+ * @author Yanming Zhou
  */
 class OpenTelemetryAutoConfigurationTests {
 
 	private final ApplicationContextRunner runner = new ApplicationContextRunner()
 		.withConfiguration(AutoConfigurations.of(OpenTelemetryAutoConfiguration.class));
 
+	@BeforeEach
+	void reset() {
+		GlobalOpenTelemetry.resetForTest();
+	}
+
 	@Test
 	void isRegisteredInAutoConfigurationImports() {
 		assertThat(ImportCandidates.load(AutoConfiguration.class, null).getCandidates())
@@ -62,6 +74,20 @@ void shouldProvideBeans() {
 		});
 	}
 
+	@Test
+	void reuseRegisteredGlobalOpenTelemetry() {
+		OpenTelemetry openTelemetry = mock(OpenTelemetry.class);
+		TracerProvider tracerProvider = mock(TracerProvider.class);
+		Tracer tracer = mock(Tracer.class);
+		given(tracerProvider.get(eq("org.springframework.boot"))).willReturn(tracer);
+		given(openTelemetry.getTracerProvider()).willReturn(tracerProvider);
+		GlobalOpenTelemetry.set(openTelemetry);
+		this.runner.run((context) -> {
+			assertThat(context).doesNotHaveBean(OpenTelemetrySdk.class);
+			assertThat(context.getBean(OpenTelemetry.class).getTracer("org.springframework.boot")).isSameAs(tracer);
+		});
+	}
+
 	@Test
 	void shouldBackOffIfOpenTelemetryIsNotOnClasspath() {
 		this.runner.withClassLoader(new FilteredClassLoader("io.opentelemetry")).run((context) -> {