feat: stabilize ServiceInstanceIdResourceProvider by moving to autoco…

sdk-extensions/autoconfigure/src/main/java/io/opentelemetry/sdk/autoconfigure/EnvironmentResourceProvider.java

@@ -23,8 +23,7 @@ public Resource createResource(ConfigProperties config) {
 
   @Override
   public int order() {
-    // Environment resource takes precedent over all other ResourceProviders except
-    // ServiceInstanceIdResourceProvider.
+    // Environment resource takes precedent over all other ResourceProviders.
     return Integer.MAX_VALUE - 1;
   }
 }

sdk-extensions/incubator/src/main/java/io/opentelemetry/sdk/extension/incubator/resources/ServiceInstanceIdResourceProvider.java → sdk-extensions/autoconfigure/src/main/java/io/opentelemetry/sdk/autoconfigure/internal/ServiceInstanceIdResourceProvider.java

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.sdk.extension.incubator.resources;
+package io.opentelemetry.sdk.autoconfigure.internal;
 
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.common.Attributes;
@@ -14,13 +14,20 @@
 import java.util.UUID;
 
 /**
- * A {@link ConditionalResourceProvider} for {@code service.instance.id}. It implements {@link
- * ConditionalResourceProvider} rather than a plain {@link ResourceProvider} because it depends on
- * the attributes discovered by the other providers.
+ * A {@link ResourceProvider} for {@code service.instance.id}. This provider generates a random
+ * UUID for {@code service.instance.id} if not already set by the user or another resource provider.
+ * The value is stable across calls to this provider within the same JVM instance.
+ *
+ * <p>This provider implements the internal {@link ConditionalResourceProvider} interface to
+ * conditionally apply the resource only when service.instance.id is not already set by other
+ * providers.
+ *
+ * <p>This class is internal and is not intended for public use.
  */
-public final class ServiceInstanceIdResourceProvider implements ConditionalResourceProvider {
+final class ServiceInstanceIdResourceProvider
+    implements ResourceProvider, ConditionalResourceProvider {
 
-  public static final AttributeKey<String> SERVICE_INSTANCE_ID =
+  static final AttributeKey<String> SERVICE_INSTANCE_ID =
       AttributeKey.stringKey("service.instance.id");
 
   // multiple calls to this resource provider should return the same value

sdk-extensions/autoconfigure/src/main/resources/META-INF/services/io.opentelemetry.sdk.autoconfigure.spi.ResourceProvider

@@ -1 +1,2 @@
 io.opentelemetry.sdk.autoconfigure.EnvironmentResourceProvider
+io.opentelemetry.sdk.autoconfigure.internal.ServiceInstanceIdResourceProvider

sdk-extensions/autoconfigure/src/test/java/io/opentelemetry/sdk/autoconfigure/ResourceConfigurationTest.java

@@ -54,6 +54,21 @@ void customConfigResourceWithDisabledKeys() {
                 .build());
   }
 
+  @Test
+  void serviceInstanceIdAddedByDefault() {
+    Map<String, String> props = new HashMap<>();
+    props.put("otel.service.name", "test-service");
+
+    Resource result =
+        ResourceConfiguration.configureResource(
+            DefaultConfigProperties.create(props, componentLoader),
+            SpiHelper.create(ResourceConfigurationTest.class.getClassLoader()),
+            (r, c) -> r);
+
+    // Verify service.instance.id is added by default via ServiceInstanceIdResourceProvider
+    assertThat(result.getAttribute(stringKey("service.instance.id"))).isNotNull();
+  }
+
   @ParameterizedTest
   @MethodSource("decodeResourceAttributesArgs")
   void decodeResourceAttributes(String input, String expectedKey, String expectedValue) {

sdk-extensions/autoconfigure/src/test/java/io/opentelemetry/sdk/autoconfigure/internal/ServiceInstanceIdResourceProviderTest.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.autoconfigure.internal;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
+import io.opentelemetry.sdk.resources.Resource;
+import java.util.Collections;
+import org.junit.jupiter.api.Test;
+
+class ServiceInstanceIdResourceProviderTest {
+
+  @Test
+  void createResource_generatesStableValue() {
+    ServiceInstanceIdResourceProvider provider = new ServiceInstanceIdResourceProvider();
+    DefaultConfigProperties config = DefaultConfigProperties.createFromMap(Collections.emptyMap());
+
+    // Multiple calls should return the same value
+    Resource resource1 = provider.createResource(config);
+    Resource resource2 = provider.createResource(config);
+
+    assertThat(resource1.getAttribute(ServiceInstanceIdResourceProvider.SERVICE_INSTANCE_ID))
+        .isNotNull();
+    assertThat(resource2.getAttribute(ServiceInstanceIdResourceProvider.SERVICE_INSTANCE_ID))
+        .isEqualTo(resource1.getAttribute(ServiceInstanceIdResourceProvider.SERVICE_INSTANCE_ID));
+  }
+
+  @Test
+  void shouldApply_returnsFalseWhenAlreadySet() {
+    ServiceInstanceIdResourceProvider provider = new ServiceInstanceIdResourceProvider();
+    DefaultConfigProperties config = DefaultConfigProperties.createFromMap(Collections.emptyMap());
+    Resource existing = Resource.empty();
+
+    assertThat(provider.shouldApply(config, existing)).isTrue();
+
+    Resource withId = existing.toBuilder()
+        .put(ServiceInstanceIdResourceProvider.SERVICE_INSTANCE_ID, "custom")
+        .build();
+
+    assertThat(provider.shouldApply(config, withId)).isFalse();
+  }
+
+  @Test
+  void order_returnsMaxValue() {
+    ServiceInstanceIdResourceProvider provider = new ServiceInstanceIdResourceProvider();
+    assertThat(provider.order()).isEqualTo(Integer.MAX_VALUE);
+  }
+}