add spring starter span logging

Author: zeitlinger

instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/internal/instrumentation/logging/LoggingExporterAutoConfiguration.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.spring.autoconfigure.internal.instrumentation.logging;
+
+import static java.util.Collections.emptyList;
+
+import io.opentelemetry.exporter.logging.LoggingSpanExporter;
+import io.opentelemetry.instrumentation.spring.autoconfigure.internal.SdkEnabled;
+import io.opentelemetry.sdk.autoconfigure.spi.AutoConfigurationCustomizerProvider;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.trace.SdkTracerProviderBuilder;
+import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Conditional;
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
+@Conditional(SdkEnabled.class)
+// for forwards compatibility with declarative configuration
+@ConditionalOnProperty(name = "otel.debug", havingValue = "true")
+@ConditionalOnClass(LoggingSpanExporter.class)
+@Configuration
+public class LoggingExporterAutoConfiguration {
+
+  @Bean
+  public AutoConfigurationCustomizerProvider loggingOtelCustomizer() {
+    return p ->
+        p.addTracerProviderCustomizer(
+            (builder, config) -> {
+              enableLoggingExporter(builder, config);
+              return builder;
+            });
+  }
+
+  public static void enableLoggingExporter(
+      SdkTracerProviderBuilder builder, ConfigProperties config) {
+    // don't install another instance if the user has already explicitly requested it.
+    if (loggingExporterIsNotAlreadyConfigured(config)) {
+      builder.addSpanProcessor(SimpleSpanProcessor.create(LoggingSpanExporter.create()));
+    }
+  }
+
+  private static boolean loggingExporterIsNotAlreadyConfigured(ConfigProperties config) {
+    return !config.getList("otel.traces.exporter", emptyList()).contains("logging");
+  }
+}

instrumentation/spring/spring-boot-autoconfigure/src/test/java/io/opentelemetry/instrumentation/spring/autoconfigure/internal/instrumentation/logging/LoggingExporterAutoConfigurationTest.java

@@ -0,0 +1,49 @@
+package io.opentelemetry.instrumentation.spring.autoconfigure.internal.instrumentation.logging;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.opentelemetry.api.OpenTelemetry;
+import io.opentelemetry.instrumentation.spring.autoconfigure.OpenTelemetryAutoConfiguration;
+import io.opentelemetry.instrumentation.testing.junit.InstrumentationExtension;
+import io.opentelemetry.instrumentation.testing.junit.LibraryInstrumentationExtension;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
+import java.util.Collections;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+
+class LoggingExporterAutoConfigurationTest {
+  @RegisterExtension
+  static final InstrumentationExtension testing = LibraryInstrumentationExtension.create();
+
+  private final ApplicationContextRunner runner =
+      new ApplicationContextRunner()
+          .withBean(
+              ConfigProperties.class,
+              () -> DefaultConfigProperties.createFromMap(Collections.emptyMap()))
+          .withConfiguration(
+              AutoConfigurations.of(
+                  LoggingExporterAutoConfiguration.class, OpenTelemetryAutoConfiguration.class));
+
+  @Test
+  void instrumentationEnabled() {
+    runner
+        .withPropertyValues("otel.debug=true")
+        .run(
+            context ->
+                assertThat(context.getBean(OpenTelemetry.class).toString())
+                    .containsOnlyOnce("cntscnt"));
+  }
+
+  @Test
+  void instrumentationDisabled() {
+    runner
+        .withPropertyValues("otel.debug=false")
+        .run(
+            context ->
+                assertThat(context.getBean(OpenTelemetry.class).toString())
+                    .doesNotContain("cntscnt"));
+  }
+}

testing-common/src/main/java/io/opentelemetry/instrumentation/testing/provider/TestExporterCustomizerProvider.java

@@ -26,6 +26,12 @@
 import java.util.List;
 
 public class TestExporterCustomizerProvider implements DeclarativeConfigurationCustomizerProvider {
+
+  @Override
+  public int order() {
+    return Integer.MIN_VALUE; // run before other customizers that might add exporters
+  }
+
   @Override
   public void customize(DeclarativeConfigurationCustomizer customizer) {
     if (TestSpanExporterComponentProvider.getSpanExporter() == null) {