feat(propagator/aws-xray): Extract X-Ray header in a case-insensitive fashion (#1328)

* Extract X-Ray header in a case-insensitive fashion

* Back to apostrophes

* Switch to 1 tab = 2 spaces

* Add semis

* Apply prettier to tests as well

* chore: fix lint

---------

Co-authored-by: Amir Blum <[email protected]>
Co-authored-by: Daniel Dyla <[email protected]>

Author: 3 people

src/AWSXRayPropagator.ts

@@ -92,9 +92,18 @@ export class AWSXRayPropagator implements TextMapPropagator {
     carrier: unknown,
     getter: TextMapGetter
   ): SpanContext {
-    const traceHeader = getter.get(carrier, AWSXRAY_TRACE_ID_HEADER);
-    if (!traceHeader || typeof traceHeader !== 'string')
+    const headerKeys = getter.keys(carrier);
+    const relevantHeaderKey = headerKeys.find(e => {
+      return e.toLowerCase() === AWSXRAY_TRACE_ID_HEADER;
+    });
+    if (!relevantHeaderKey) {
       return INVALID_SPAN_CONTEXT;
+    }
+    const traceHeader = getter.get(carrier, relevantHeaderKey);
+
+    if (!traceHeader || typeof traceHeader !== 'string') {
+      return INVALID_SPAN_CONTEXT;
+    }
 
     let pos = 0;
     let trimmedPart: string;

test/AWSXRayPropagator.test.ts

@@ -299,6 +299,24 @@ describe('AWSXRayPropagator', () => {
 
       assert.deepStrictEqual(extractedSpanContext, undefined);
     });
+
+    it('extracts context in a case-insensitive fashion', () => {
+      carrier[AWSXRAY_TRACE_ID_HEADER.toUpperCase()] =
+        'Root=1-8a3c60f7-d188f8fa79d48a391a778fa6;Parent=53995c3f42cd8ad8;Sampled=1;Foo=Bar';
+      const extractedSpanContext = trace
+        .getSpan(
+          xrayPropagator.extract(ROOT_CONTEXT, carrier, defaultTextMapGetter)
+        )
+        ?.spanContext();
+
+      assert.deepStrictEqual(extractedSpanContext, {
+        traceId: TRACE_ID,
+        spanId: SPAN_ID,
+        isRemote: true,
+        traceFlags: TraceFlags.SAMPLED,
+      });
+    });
+
     describe('.fields()', () => {
       it('should return a field with AWS X-Ray Trace ID header', () => {
         const expectedField = xrayPropagator.fields();