chore: address PR comments

open-telemetry · May 2, 2021 · bc560ac · bc560ac
1 parent 074471a
commit bc560ac
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diff --git a/packages/opentelemetry-propagator-jaeger/README.md b/packages/opentelemetry-propagator-jaeger/README.md
@@ -36,6 +36,10 @@ provider.register({
 });
 ```
 
+## Baggage Notes
+
+Jeager Baggage is represented as multiple headers where the names are carrier dependent. For this reason, they are omitted from the `fields` method. This behavior should be taken into account if your application relies on the `fields` functionality. See the [specification][fields-spec-url] for more details.
+
 ## Trace on Jaeger UI
 
 ![example image](jaeger-tracing.png)
@@ -59,3 +63,4 @@ Apache 2.0 - See [LICENSE][license-url] for more information.
 [devDependencies-url]: https://david-dm.org/open-telemetry/opentelemetry-js?path=packages%2Fopentelemetry-propagator-jaeger&type=dev
 [npm-url]: https://www.npmjs.com/package/@opentelemetry/propagator-jaeger
 [npm-img]: https://badge.fury.io/js/%40opentelemetry%2Fpropagator-jaeger.svg
+[fields-spec-url]: https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/context/api-propagators.md#fields
diff --git a/packages/opentelemetry-propagator-jaeger/src/JaegerHttpTracePropagator.ts b/packages/opentelemetry-propagator-jaeger/src/JaegerHttpTracePropagator.ts
@@ -90,11 +90,11 @@ export class JaegerHttpTracePropagator implements TextMapPropagator {
       : uberTraceIdHeader;
     const baggageValues = getter
       .keys(carrier)
-      .filter(key => key.includes(UBER_BAGGAGE_HEADER_PREFIX))
+      .filter(key => /^uberctx-(.+)/i.test(key))
       .map(key => {
         const value = getter.get(carrier, key);
         return {
-          key: key.replace(`${UBER_BAGGAGE_HEADER_PREFIX}-`, ''),
+          key: key.substring(UBER_BAGGAGE_HEADER_PREFIX.length + 1),
           value: Array.isArray(value) ? value[0] : value,
         };
       });