fix(instrumentation-aws-sdk): make empty context when SQS message has no propagation fields (#1889)

* fix(instrumentation-aws-sdk): make empty context when SQS message has no propagation fields

* style: lint fix

---------

Co-authored-by: Amir Blum <amirgiraffe@gmail.com>

Author: zl4bv

plugins/node/opentelemetry-instrumentation-aws-sdk/src/services/MessageAttributes.ts

@@ -55,6 +55,9 @@ class ContextGetter
   keys(
     carrier: SQS.MessageBodyAttributeMap | SNS.MessageAttributeMap
   ): string[] {
+    if (carrier == null) {
+      return [];
+    }
     return Object.keys(carrier);
   }
 

plugins/node/opentelemetry-instrumentation-aws-sdk/test/MessageAttributes.test.ts

@@ -17,10 +17,12 @@
 import { expect } from 'expect';
 import {
   MAX_MESSAGE_ATTRIBUTES,
+  contextGetter,
   contextSetter,
   injectPropagationContext,
   addPropagationFieldsToAttributeNames,
 } from '../src/services/MessageAttributes';
+import { SNS, SQS } from '../src/aws-sdk.types';
 
 describe('MessageAttributes', () => {
   describe('MAX_MESSAGE_ATTRIBUTES', () => {
@@ -29,6 +31,30 @@ describe('MessageAttributes', () => {
     });
   });
 
+  describe('contextGetter', () => {
+    it('returns context keys if there are available attributes', () => {
+      const contextCarrier = {
+        key1: { DataType: 'String', StringValue: 'value1' },
+      };
+      const expectedKeys = ['key1'];
+
+      expect(contextGetter.keys(contextCarrier)).toEqual(expectedKeys);
+    });
+
+    it('returns empty context keys if there are no available attributes', () => {
+      const contextCarrier = undefined;
+      const expectedKeys: string[] = [];
+
+      expect(
+        contextGetter.keys(
+          contextCarrier as unknown as
+            | SQS.MessageBodyAttributeMap
+            | SNS.MessageAttributeMap
+        )
+      ).toEqual(expectedKeys);
+    });
+  });
+
   describe('contextSetter', () => {
     it('should set parent context in sqs receive callback', () => {
       const contextKey = 'key';