service.instance.id implementation (#6226)

Co-authored-by: Jack Berg <jberg@newrelic.com>

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

@@ -22,7 +22,8 @@ public Resource createResource(ConfigProperties config) {
 
   @Override
   public int order() {
-    // Environment resource takes precedent over all other ResourceProviders
-    return Integer.MAX_VALUE;
+    // Environment resource takes precedent over all other ResourceProviders except
+    // ServiceInstanceIdResourceProvider.
+    return Integer.MAX_VALUE - 1;
   }
 }

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

@@ -0,0 +1,47 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.extension.incubator.resources;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.sdk.autoconfigure.spi.ConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.ResourceProvider;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.ConditionalResourceProvider;
+import io.opentelemetry.sdk.resources.Resource;
+import java.util.UUID;
+
+/**
+ * does not implement {@link ResourceProvider}, because it depends on all attributes discovered by
+ * the other providers.
+ */
+public final class ServiceInstanceIdResourceProvider implements ConditionalResourceProvider {
+
+  public static final AttributeKey<String> SERVICE_INSTANCE_ID =
+      AttributeKey.stringKey("service.instance.id");
+
+  // multiple calls to this resource provider should return the same value
+  private static final Resource RANDOM =
+      Resource.create(Attributes.of(SERVICE_INSTANCE_ID, UUID.randomUUID().toString()));
+
+  static final int ORDER = Integer.MAX_VALUE;
+
+  @Override
+  public Resource createResource(ConfigProperties config) {
+    return RANDOM;
+  }
+
+  @Override
+  public boolean shouldApply(ConfigProperties config, Resource existing) {
+    return existing.getAttribute(SERVICE_INSTANCE_ID) == null;
+  }
+
+  @Override
+  public int order() {
+    // Run after environment resource provider - only set the service instance ID if it
+    // hasn't been set by any other provider or the user.
+    return ORDER;
+  }
+}

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

@@ -0,0 +1 @@
+io.opentelemetry.sdk.extension.incubator.resources.ServiceInstanceIdResourceProvider

sdk-extensions/incubator/src/test/java/io/opentelemetry/sdk/extension/incubator/resources/ServiceInstanceIdResourceProviderTest.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.extension.incubator.resources;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.google.common.collect.ImmutableMap;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.common.AttributesBuilder;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.DefaultConfigProperties;
+import io.opentelemetry.sdk.resources.Resource;
+import java.util.Collections;
+import java.util.Map;
+import java.util.stream.Stream;
+import org.junit.jupiter.api.DynamicTest;
+import org.junit.jupiter.api.TestFactory;
+
+class ServiceInstanceIdResourceProviderTest {
+
+  private static class TestCase {
+    private final String name;
+    final String expectedValue;
+    final Map<String, String> attributes;
+
+    TestCase(String name, String expectedValue, Map<String, String> attributes) {
+      this.name = name;
+      this.expectedValue = expectedValue;
+      this.attributes = attributes;
+    }
+  }
+
+  @TestFactory
+  Stream<DynamicTest> createResource() {
+    return Stream.of(
+            new TestCase(
+                "user provided service.instance.id",
+                null,
+                ImmutableMap.of("service.instance.id", "custom")),
+            new TestCase("random value", "random", Collections.emptyMap()))
+        .map(
+            testCase ->
+                DynamicTest.dynamicTest(
+                    testCase.name,
+                    () -> {
+                      ServiceInstanceIdResourceProvider provider =
+                          new ServiceInstanceIdResourceProvider();
+                      DefaultConfigProperties config =
+                          DefaultConfigProperties.createFromMap(Collections.emptyMap());
+                      AttributesBuilder builder = Attributes.builder();
+                      testCase.attributes.forEach(builder::put);
+                      Resource existing = Resource.create(builder.build());
+                      Resource resource =
+                          provider.shouldApply(config, existing)
+                              ? provider.createResource(config)
+                              : Resource.empty();
+
+                      String actual =
+                          resource
+                              .getAttributes()
+                              .get(ServiceInstanceIdResourceProvider.SERVICE_INSTANCE_ID);
+                      if ("random".equals(testCase.expectedValue)) {
+                        assertThat(actual).isNotNull();
+                      } else {
+                        assertThat(actual).isEqualTo(testCase.expectedValue);
+                      }
+                    }));
+  }
+}