From b5a6a1cf36bc8ea0cd430da97cd8efbb9915609d Mon Sep 17 00:00:00 2001
From: doronkopit5 <doron.kopit@fiverr.com>
Date: Mon, 14 Mar 2022 13:46:26 +0200
Subject: [PATCH] fix(opentelemtry-core): fix header extraction

---
 .../propagation/W3CBaggagePropagator.ts       |  3 +-
 .../test/baggage/W3CBaggagePropagator.test.ts | 30 ++++++++++++++-----
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/packages/opentelemetry-core/src/baggage/propagation/W3CBaggagePropagator.ts b/packages/opentelemetry-core/src/baggage/propagation/W3CBaggagePropagator.ts
index 652cc14c3a..d38b92c77d 100644
--- a/packages/opentelemetry-core/src/baggage/propagation/W3CBaggagePropagator.ts
+++ b/packages/opentelemetry-core/src/baggage/propagation/W3CBaggagePropagator.ts
@@ -58,7 +58,8 @@ export class W3CBaggagePropagator implements TextMapPropagator {
   }
 
   extract(context: Context, carrier: unknown, getter: TextMapGetter): Context {
-    const headerValue: string = getter.get(carrier, BAGGAGE_HEADER) as string;
+    const headerBaggage = getter.get(carrier, BAGGAGE_HEADER);
+    const headerValue: string = (headerBaggage instanceof Array)? headerBaggage[0]: headerBaggage as string;
     if (!headerValue) return context;
     const baggage: Record<string, BaggageEntry> = {};
     if (headerValue.length === 0) {
diff --git a/packages/opentelemetry-core/test/baggage/W3CBaggagePropagator.test.ts b/packages/opentelemetry-core/test/baggage/W3CBaggagePropagator.test.ts
index 38de668087..8f5fc3cf9d 100644
--- a/packages/opentelemetry-core/test/baggage/W3CBaggagePropagator.test.ts
+++ b/packages/opentelemetry-core/test/baggage/W3CBaggagePropagator.test.ts
@@ -175,9 +175,29 @@ describe('W3CBaggagePropagator', () => {
   });
 
   describe('.extract()', () => {
+    const baggageValue = 'key1=d4cda95b,key3=c88815a7, keyn   = valn, keym =valm';
+    const expected = propagation.createBaggage({
+      key1: { value: 'd4cda95b' },
+      key3: { value: 'c88815a7' },
+      keyn: { value: 'valn' },
+      keym: { value: 'valm' },
+    });
+
     it('should extract context of a sampled span from carrier', () => {
-      carrier[BAGGAGE_HEADER] =
-        'key1=d4cda95b,key3=c88815a7, keyn   = valn, keym =valm';
+      carrier[BAGGAGE_HEADER] = baggageValue;
+      const extractedBaggage = propagation.getBaggage(
+        httpBaggagePropagator.extract(
+          ROOT_CONTEXT,
+          carrier,
+          defaultTextMapGetter
+        )
+      );
+
+      assert.deepStrictEqual(extractedBaggage, expected);
+    });
+
+    it('should extract context of a sampled span when the headerValue comes as array', () => {
+      carrier[BAGGAGE_HEADER] = [baggageValue];
       const extractedBaggage = propagation.getBaggage(
         httpBaggagePropagator.extract(
           ROOT_CONTEXT,
@@ -186,12 +206,6 @@ describe('W3CBaggagePropagator', () => {
         )
       );
 
-      const expected = propagation.createBaggage({
-        key1: { value: 'd4cda95b' },
-        key3: { value: 'c88815a7' },
-        keyn: { value: 'valn' },
-        keym: { value: 'valm' },
-      });
       assert.deepStrictEqual(extractedBaggage, expected);
     });
   });