Add getActiveBaggage API (#3385)

Co-authored-by: Valentin Marchaud <contact@vmarchaud.fr>
Resolves #3354

CHANGELOG.md

@@ -11,6 +11,8 @@ For experimental package changes, see the [experimental CHANGELOG](experimental/
 
 ### :rocket: (Enhancement)
 
+* feat(api): add `getActiveBaggage` API [#3385](https://github.com/open-telemetry/opentelemetry-js/pull/3385)
+
 ### :bug: (Bug Fix)
 
 * fix(sdk-metrics): use default Resource to comply with semantic conventions [#3411](https://github.com/open-telemetry/opentelemetry-js/pull/3411) @pichlermarc

api/src/api/propagation.ts

@@ -30,6 +30,7 @@ import {
 } from '../propagation/TextMapPropagator';
 import {
   getBaggage,
+  getActiveBaggage,
   setBaggage,
   deleteBaggage,
 } from '../baggage/context-helpers';
@@ -112,6 +113,8 @@ export class PropagationAPI {
 
   public getBaggage = getBaggage;
 
+  public getActiveBaggage = getActiveBaggage;
+
   public setBaggage = setBaggage;
 
   public deleteBaggage = deleteBaggage;

api/src/baggage/context-helpers.ts

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import { ContextAPI } from '../api/context';
 import { createContextKey } from '../context/context';
 import { Context } from '../context/types';
 import { Baggage } from './types';
@@ -33,6 +34,15 @@ export function getBaggage(context: Context): Baggage | undefined {
   return (context.getValue(BAGGAGE_KEY) as Baggage) || undefined;
 }
 
+/**
+ * Retrieve the current baggage from the active/current context
+ *
+ * @returns {Baggage} Extracted baggage from the context
+ */
+export function getActiveBaggage(): Baggage | undefined {
+  return getBaggage(ContextAPI.getInstance().active());
+}
+
 /**
  * Store a baggage in the given context
  *

api/test/common/baggage/Baggage.test.ts

@@ -16,6 +16,7 @@
 
 import * as assert from 'assert';
 import {
+  context,
   ROOT_CONTEXT,
   propagation,
   baggageEntryMetadataFromString,
@@ -131,6 +132,20 @@ describe('Baggage', () => {
 
       assert.strictEqual(bag, propagation.getBaggage(ctx));
     });
+
+    it('should get the current baggage', () => {
+      const entries = {
+        'banana': {value: 'boats'}
+      };
+      const bag = propagation.createBaggage(entries);
+      const ctx = propagation.setBaggage(ROOT_CONTEXT, bag);
+
+      context.setGlobalContextManager({ active: () => ctx, disable: () => {} } as any);
+
+      assert.strictEqual(bag, propagation.getActiveBaggage());
+
+      context.disable();
+    });
   });
 
   describe('metadata', () => {