Move X-Ray Env Variable propagation to span link instead of parent

open-telemetry/opentelemetry-specification#3166

Per discussion in the FAAS SIG, we decided that the AWS X-Ray environment variable should be moved to a span link to avoid interfering with the configured propagators.

instrumentation/aws-lambda/aws-lambda-core-1.0/library/src/main/java/io/opentelemetry/instrumentation/awslambdacore/v1_0/internal/ApiGatewayProxyRequest.java

@@ -30,14 +30,7 @@ public abstract class ApiGatewayProxyRequest {
  private static boolean noHttpPropagationNeeded() {
  Collection<String> fields =
  GlobalOpenTelemetry.getPropagators().getTextMapPropagator().fields();
- return fields.isEmpty() || xrayPropagationFieldsOnly(fields);
- }
-
- private static boolean xrayPropagationFieldsOnly(Collection<String> fields) {
- // ugly but faster than typical convert-to-set-and-check-contains-only
- return (fields.size() == 1)
- && ParentContextExtractor.AWS_TRACE_HEADER_PROPAGATOR_KEY.equalsIgnoreCase(
- fields.iterator().next());
+ return fields.isEmpty();
  }
 
  public static ApiGatewayProxyRequest forStream(InputStream source) {

instrumentation/aws-lambda/aws-lambda-core-1.0/library/src/main/java/io/opentelemetry/instrumentation/awslambdacore/v1_0/internal/AwsLambdaFunctionInstrumenter.java

@@ -11,6 +11,7 @@
 import io.opentelemetry.instrumentation.api.instrumenter.Instrumenter;
 import io.opentelemetry.instrumentation.api.internal.ContextPropagationDebug;
 import io.opentelemetry.instrumentation.awslambdacore.v1_0.AwsLambdaRequest;
+import java.util.Locale;
 import java.util.Map;
 import javax.annotation.Nullable;
 
@@ -46,15 +47,25 @@ public void end(
  }
 
  public Context extract(AwsLambdaRequest input) {
- return ParentContextExtractor.extract(input.getHeaders(), this);
- }
-
- public Context extract(Map<String, String> headers, TextMapGetter<Map<String, String>> getter) {
  ContextPropagationDebug.debugContextLeakIfEnabled();
 
  return openTelemetry
  .getPropagators()
  .getTextMapPropagator()
- .extract(Context.root(), headers, getter);
+ .extract(Context.root(), input.getHeaders(), MapGetter.INSTANCE);
+ }
+
+ private enum MapGetter implements TextMapGetter<Map<String, String>> {
+ INSTANCE;
+
+ @Override
+ public Iterable<String> keys(Map<String, String> map) {
+ return map.keySet();
+ }
+
+ @Override
+ public String get(Map<String, String> map, String s) {
+ return map.get(s.toLowerCase(Locale.ROOT));
+ }
  }
 }

instrumentation/aws-lambda/aws-lambda-core-1.0/library/src/main/java/io/opentelemetry/instrumentation/awslambdacore/v1_0/internal/AwsLambdaFunctionInstrumenterFactory.java

@@ -23,6 +23,7 @@ public static AwsLambdaFunctionInstrumenter createInstrumenter(OpenTelemetry ope
  openTelemetry,
  "io.opentelemetry.aws-lambda-core-1.0",
  AwsLambdaFunctionInstrumenterFactory::spanName)
+ .addSpanLinksExtractor(new AwsXRayEnvSpanLinksExtractor())
  .addAttributesExtractor(new AwsLambdaFunctionAttributesExtractor())
  .buildInstrumenter(SpanKindExtractor.alwaysServer()));
  }

instrumentation/aws-lambda/aws-lambda-core-1.0/library/src/main/java/io/opentelemetry/instrumentation/awslambdacore/v1_0/internal/AwsXRayEnvSpanLinksExtractor.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.awslambdacore.v1_0.internal;
+
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.propagation.TextMapGetter;
+import io.opentelemetry.contrib.awsxray.propagator.AwsXrayPropagator;
+import io.opentelemetry.instrumentation.api.instrumenter.SpanLinksBuilder;
+import io.opentelemetry.instrumentation.api.instrumenter.SpanLinksExtractor;
+import io.opentelemetry.instrumentation.awslambdacore.v1_0.AwsLambdaRequest;
+import java.util.Collections;
+import java.util.Locale;
+import java.util.Map;
+
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
+public final class AwsXRayEnvSpanLinksExtractor implements SpanLinksExtractor<AwsLambdaRequest> {
+
+ private static final String AWS_TRACE_HEADER_ENV_KEY = "_X_AMZN_TRACE_ID";
+
+ // lower-case map getter used for extraction
+ private static final String AWS_TRACE_HEADER_PROPAGATOR_KEY = "x-amzn-trace-id";
+
+ @Override
+ public void extract(
+ SpanLinksBuilder spanLinks,
+ io.opentelemetry.context.Context parentContext,
+ AwsLambdaRequest awsLambdaRequest) {
+ extract(spanLinks);
+ }
+
+ public static void extract(SpanLinksBuilder spanLinks) {
+ String parentTraceHeader = System.getenv(AWS_TRACE_HEADER_ENV_KEY);
+ if (parentTraceHeader == null || parentTraceHeader.isEmpty()) {
+ return;
+ }
+ Context parentCtx =
+ AwsXrayPropagator.getInstance()
+ .extract(
+ // see BaseTracer#extract() on why we're using root() here
+ Context.root(),
+ Collections.singletonMap(AWS_TRACE_HEADER_PROPAGATOR_KEY, parentTraceHeader),
+ MapGetter.INSTANCE);
+ SpanContext parent = Span.fromContext(parentCtx).getSpanContext();
+ if (parent.isValid()) {
+ spanLinks.addLink(parent);
+ }
+ }
+
+ private enum MapGetter implements TextMapGetter<Map<String, String>> {
+ INSTANCE;
+
+ @Override
+ public Iterable<String> keys(Map<String, String> map) {
+ return map.keySet();
+ }
+
+ @Override
+ public String get(Map<String, String> map, String s) {
+ return map.get(s.toLowerCase(Locale.ROOT));
+ }
+ }
+}

instrumentation/aws-lambda/aws-lambda-core-1.0/library/src/test/java/io/opentelemetry/instrumentation/awslambdacore/v1_0/internal/AwsXRayEnvSpanLinksExtractorTest.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.instrumentation.awslambdacore.v1_0.internal;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoInteractions;
+
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.instrumentation.api.instrumenter.SpanLinksBuilder;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.ArgumentCaptor;
+import uk.org.webcompere.systemstubs.environment.EnvironmentVariables;
+import uk.org.webcompere.systemstubs.jupiter.SystemStub;
+import uk.org.webcompere.systemstubs.jupiter.SystemStubsExtension;
+
+/**
+ * This class is internal and is hence not for public use. Its APIs are unstable and can change at
+ * any time.
+ */
+@ExtendWith(SystemStubsExtension.class)
+class AwsXRayEnvSpanLinksExtractorTest {
+
+ @SystemStub final EnvironmentVariables environmentVariables = new EnvironmentVariables();
+
+ @Test
+ void shouldIgnoreIfEnvVarEmpty() {
+ // given
+ SpanLinksBuilder spanLinksBuilder = mock(SpanLinksBuilder.class);
+ environmentVariables.set("_X_AMZN_TRACE_ID", "");
+
+ // when
+ AwsXRayEnvSpanLinksExtractor.extract(spanLinksBuilder);
+ // then
+ verifyNoInteractions(spanLinksBuilder);
+ }
+
+ @Test
+ void shouldLinkAwsParentHeaderIfValidAndNotSampled() {
+ // given
+ SpanLinksBuilder spanLinksBuilder = mock(SpanLinksBuilder.class);
+ environmentVariables.set(
+ "_X_AMZN_TRACE_ID",
+ "Root=1-8a3c60f7-d188f8fa79d48a391a778fa6;Parent=0000000000000456;Sampled=0");
+
+ // when
+ AwsXRayEnvSpanLinksExtractor.extract(spanLinksBuilder);
+ // then
+ ArgumentCaptor<SpanContext> captor = ArgumentCaptor.forClass(SpanContext.class);
+ verify(spanLinksBuilder).addLink(captor.capture());
+ SpanContext spanContext = captor.getValue();
+ assertThat(spanContext.isValid()).isTrue();
+ assertThat(spanContext.isSampled()).isFalse();
+ assertThat(spanContext.getSpanId()).isEqualTo("0000000000000456");
+ assertThat(spanContext.getTraceId()).isEqualTo("8a3c60f7d188f8fa79d48a391a778fa6");
+ }
+
+ @Test
+ void shouldLinkAwsParentHeaderIfValidAndSampled() {
+ // given
+ SpanLinksBuilder spanLinksBuilder = mock(SpanLinksBuilder.class);
+ environmentVariables.set(
+ "_X_AMZN_TRACE_ID",
+ "Root=1-8a3c60f7-d188f8fa79d48a391a778fa6;Parent=0000000000000456;Sampled=1");
+
+ // when
+ AwsXRayEnvSpanLinksExtractor.extract(spanLinksBuilder);
+ // then
+ ArgumentCaptor<SpanContext> captor = ArgumentCaptor.forClass(SpanContext.class);
+ verify(spanLinksBuilder).addLink(captor.capture());
+ SpanContext spanContext = captor.getValue();
+ assertThat(spanContext.isValid()).isTrue();
+ assertThat(spanContext.isSampled()).isTrue();
+ assertThat(spanContext.getSpanId()).isEqualTo("0000000000000456");
+ assertThat(spanContext.getTraceId()).isEqualTo("8a3c60f7d188f8fa79d48a391a778fa6");
+ }
+}