From 53682c025864762be1fb42fba2afe333d381cd49 Mon Sep 17 00:00:00 2001
From: Jakub Malinowski <jmalinowski@splunk.com>
Date: Tue, 24 Nov 2020 15:59:30 +0100
Subject: [PATCH] fix: missing .fields() method in jaeger propagator

---
 .../src/JaegerHttpTracePropagator.ts                |  4 ++++
 .../test/JaegerHttpTracePropagator.test.ts          | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/propagators/opentelemetry-propagator-jaeger/src/JaegerHttpTracePropagator.ts b/propagators/opentelemetry-propagator-jaeger/src/JaegerHttpTracePropagator.ts
index 6cf29e4c72..9b3138eb63 100644
--- a/propagators/opentelemetry-propagator-jaeger/src/JaegerHttpTracePropagator.ts
+++ b/propagators/opentelemetry-propagator-jaeger/src/JaegerHttpTracePropagator.ts
@@ -80,6 +80,10 @@ export class JaegerHttpTracePropagator implements TextMapPropagator {
 
     return setExtractedSpanContext(context, spanContext);
   }
+
+  fields(): string[] {
+    return [this._jaegerTraceHeader];
+  }
 }
 
 /**
diff --git a/propagators/opentelemetry-propagator-jaeger/test/JaegerHttpTracePropagator.test.ts b/propagators/opentelemetry-propagator-jaeger/test/JaegerHttpTracePropagator.test.ts
index fae7c8fe82..29503ba4c2 100644
--- a/propagators/opentelemetry-propagator-jaeger/test/JaegerHttpTracePropagator.test.ts
+++ b/propagators/opentelemetry-propagator-jaeger/test/JaegerHttpTracePropagator.test.ts
@@ -172,6 +172,19 @@ describe('JaegerHttpTracePropagator', () => {
     });
   });
 
+  describe('.fields()', () => {
+    it('returns the default header if not customized', () => {
+      assert.deepStrictEqual(jaegerHttpTracePropagator.fields(), [
+        'uber-trace-id',
+      ]);
+    });
+    it('returns the customized header if customized', () => {
+      assert.deepStrictEqual(customJaegerHttpTracePropagator.fields(), [
+        customHeader,
+      ]);
+    });
+  });
+
   it('should fail gracefully on bad responses from getter', () => {
     const ctx1 = jaegerHttpTracePropagator.extract(
       ROOT_CONTEXT,