Read declarative thread_details flag from ConfigProvider

- configureDeclarativeConfig now takes ConfigProvider and reads
  java.spring_starter.thread_details.enabled from the instrumentation config.
  The call site in OpenTelemetryAutoConfiguration passes SpringConfigProvider,
  which coerces Spring's flattened String values back to Boolean; the previous
  attempts via SdkConfigProvider/YamlDeclarativeConfigProperties silently dropped
  the flag because Spring's application.yaml pipeline stores every scalar as a
  String and YamlDeclarativeConfigProperties refuses to coerce.
- configureProperties keeps reading otel.instrumentation.common.thread-details.enabled
  from Environment for the properties-based path; no legacy fallback in the
  declarative path.
- Add declarative-config smoke test assertion: enable thread_details in the
  testDeclarativeConfig application.yaml and assert thread.id / thread.name
  appear on the server span.
- Simplify segments[0] == "agent" guard in ConfigPropertiesBackedDeclarativeConfigProperties
  (drop dead segments.length check, work off translatedPath).

Author: trask

declarative-config-bridge/src/main/java/io/opentelemetry/instrumentation/config/bridge/ConfigPropertiesBackedDeclarativeConfigProperties.java

@@ -226,14 +226,15 @@ private String resolvePropertyKey(String name) {
     }
 
     // java.agent.* maps to otel.javaagent.* (not otel.instrumentation.agent.*)
-    if (segments.length > 0 && segments[0].equals("agent")) {
-      if (translatedPath.length() == "agent".length()) {
-        return "otel.javaagent";
-      }
-      return "otel.javaagent." + translatedPath.substring("agent.".length());
+    String translated = translatedPath.toString();
+    if (translated.equals("agent")) {
+      return "otel.javaagent";
+    }
+    if (translated.startsWith("agent.")) {
+      return "otel.javaagent." + translated.substring("agent.".length());
     }
 
-    return "otel.instrumentation." + translatedPath;
+    return "otel.instrumentation." + translated;
   }
 
   private String pathWithName(String name) {

instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/OpenTelemetryAutoConfiguration.java

@@ -168,14 +168,14 @@ public OpenTelemetryConfigurationModel openTelemetryConfigurationModel(
       @Bean
       public OpenTelemetry openTelemetry(
           OpenTelemetryConfigurationModel model, ApplicationContext applicationContext) {
-        ThreadDetailsInstrumenterCustomizerProvider.configureDeclarativeConfig(
-            applicationContext.getEnvironment());
         OpenTelemetrySdkComponentLoader componentLoader =
             new OpenTelemetrySdkComponentLoader(applicationContext);
+        SpringConfigProvider configProvider = SpringConfigProvider.create(model, componentLoader);
+        ThreadDetailsInstrumenterCustomizerProvider.configureDeclarativeConfig(configProvider);
         OpenTelemetrySdk sdk = DeclarativeConfiguration.create(model, componentLoader).getSdk();
         Runtime.getRuntime().addShutdownHook(new Thread(sdk::close));
         logStart();
-        return new SpringOpenTelemetrySdk(sdk, SpringConfigProvider.create(model, componentLoader));
+        return new SpringOpenTelemetrySdk(sdk, configProvider);
       }
 
       /**

instrumentation/spring/spring-boot-autoconfigure/src/main/java/io/opentelemetry/instrumentation/spring/autoconfigure/internal/instrumentation/thread/ThreadDetailsInstrumenterCustomizerProvider.java

@@ -5,6 +5,7 @@
 
 package io.opentelemetry.instrumentation.spring.autoconfigure.internal.instrumentation.thread;
 
+import io.opentelemetry.api.incubator.config.ConfigProvider;
 import io.opentelemetry.instrumentation.api.incubator.instrumenter.InstrumenterCustomizer;
 import io.opentelemetry.instrumentation.api.incubator.instrumenter.InstrumenterCustomizerProvider;
 import io.opentelemetry.instrumentation.api.incubator.thread.ThreadDetailsAttributesExtractor;
@@ -17,8 +18,6 @@
 public class ThreadDetailsInstrumenterCustomizerProvider implements InstrumenterCustomizerProvider {
   private static final String LEGACY_PROPERTY =
       "otel.instrumentation.common.thread-details.enabled";
-  private static final String DECLARATIVE_PROPERTY =
-      "otel.distribution.spring_starter.thread_details_enabled";
 
   // Static because this class is loaded via ServiceLoader (SPI), not managed by Spring DI.
   // Set by OpenTelemetryAutoConfiguration#openTelemetry before instrumenters are built,
@@ -27,17 +26,19 @@ public class ThreadDetailsInstrumenterCustomizerProvider implements Instrumenter
   private static volatile boolean enabled;
 
   /** Called from OpenTelemetryAutoConfiguration for declarative config. */
-  public static void configureDeclarativeConfig(Environment environment) {
-    // Declarative config uses the distro-scoped key, but we still accept the legacy property so
-    // both Spring configuration paths resolve the same feature flag.
-    enabled = readEnabled(environment, DECLARATIVE_PROPERTY, LEGACY_PROPERTY);
+  public static void configureDeclarativeConfig(ConfigProvider configProvider) {
+    enabled =
+        configProvider
+            .getInstrumentationConfig()
+            .get("java")
+            .get("spring_starter")
+            .get("thread_details")
+            .getBoolean("enabled", false);
   }
 
   /** Called from OpenTelemetryAutoConfiguration for properties-based config. */
   public static void configureProperties(Environment environment) {
-    // Properties-based config keeps the legacy toggle, but we fall back to the declarative key so
-    // a single setting still works if it is shared across config styles.
-    enabled = readEnabled(environment, LEGACY_PROPERTY, DECLARATIVE_PROPERTY);
+    enabled = Boolean.TRUE.equals(environment.getProperty(LEGACY_PROPERTY, Boolean.class));
   }
 
   @Override
@@ -46,14 +47,4 @@ public void customize(InstrumenterCustomizer customizer) {
       customizer.addAttributesExtractor(new ThreadDetailsAttributesExtractor<>());
     }
   }
-
-  private static boolean readEnabled(
-      Environment environment, String primaryProperty, String fallbackProperty) {
-    Boolean enabled = environment.getProperty(primaryProperty, Boolean.class);
-    if (enabled != null) {
-      return enabled;
-    }
-    enabled = environment.getProperty(fallbackProperty, Boolean.class);
-    return Boolean.TRUE.equals(enabled);
-  }
 }

instrumentation/spring/spring-boot-autoconfigure/src/test/java/io/opentelemetry/instrumentation/spring/autoconfigure/internal/instrumentation/thread/ThreadDetailsInstrumenterCustomizerProviderTest.java

@@ -5,12 +5,17 @@
 
 package io.opentelemetry.instrumentation.spring.autoconfigure.internal.instrumentation.thread;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoInteractions;
 
 import io.opentelemetry.instrumentation.api.incubator.instrumenter.InstrumenterCustomizer;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.DeclarativeConfiguration;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfigurationModel;
+import io.opentelemetry.sdk.internal.SdkConfigProvider;
+import java.io.ByteArrayInputStream;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.springframework.mock.env.MockEnvironment;
@@ -36,11 +41,20 @@ void configurePropertiesUsesLegacyProperty() {
   }
 
   @Test
-  void configureDeclarativeConfigUsesDistributionProperty() {
-    MockEnvironment environment =
-        new MockEnvironment()
-            .withProperty("otel.distribution.spring_starter.thread_details_enabled", "true");
-    ThreadDetailsInstrumenterCustomizerProvider.configureDeclarativeConfig(environment);
+  @SuppressWarnings("StringConcatToTextBlock")
+  void configureDeclarativeConfigReadsFromModel() {
+    String yaml =
+        "file_format: \"1.0\"\n"
+            + "instrumentation/development:\n"
+            + "  java:\n"
+            + "    spring_starter:\n"
+            + "      thread_details:\n"
+            + "        enabled: true\n";
+    OpenTelemetryConfigurationModel model =
+        DeclarativeConfiguration.parse(new ByteArrayInputStream(yaml.getBytes(UTF_8)));
+
+    ThreadDetailsInstrumenterCustomizerProvider.configureDeclarativeConfig(
+        SdkConfigProvider.create(DeclarativeConfiguration.toConfigProperties(model)));
 
     InstrumenterCustomizer customizer = mock(InstrumenterCustomizer.class);
     new ThreadDetailsInstrumenterCustomizerProvider().customize(customizer);

smoke-tests-otel-starter/spring-boot-2/src/testDeclarativeConfig/java/io/opentelemetry/spring/smoketest/OtelSpringStarterSmokeTest.java

@@ -11,6 +11,8 @@
 import static io.opentelemetry.semconv.ServiceAttributes.SERVICE_NAME;
 import static io.opentelemetry.semconv.incubating.TelemetryIncubatingAttributes.TELEMETRY_DISTRO_NAME;
 import static io.opentelemetry.semconv.incubating.TelemetryIncubatingAttributes.TELEMETRY_DISTRO_VERSION;
+import static io.opentelemetry.semconv.incubating.ThreadIncubatingAttributes.THREAD_ID;
+import static io.opentelemetry.semconv.incubating.ThreadIncubatingAttributes.THREAD_NAME;
 
 import io.opentelemetry.api.trace.SpanKind;
 import org.assertj.core.api.AbstractCharSequenceAssert;
@@ -72,7 +74,10 @@ void restTemplate() {
                                         satisfies(
                                             SERVICE_INSTANCE_ID,
                                             AbstractCharSequenceAssert::isNotBlank)))
-                        .hasAttribute(HTTP_ROUTE, "/ping"),
+                        .hasAttribute(HTTP_ROUTE, "/ping")
+                        .hasAttributesSatisfying(
+                            satisfies(THREAD_ID, val -> val.isNotZero()),
+                            satisfies(THREAD_NAME, val -> val.isNotBlank())),
                 AbstractSpringStarterSmokeTest::withSpanAssert));
   }
 }

smoke-tests-otel-starter/spring-boot-2/src/testDeclarativeConfig/resources/application.yaml

@@ -46,3 +46,6 @@ otel:
             emit_experimental_telemetry/development: true
       runtime_telemetry:
         emit_experimental_metrics/development: true
+      spring_starter:
+        thread_details:
+          enabled: true