Add fields method (#226)

Co-authored-by: (Eliseo) Nathaniel Ruiz Nowell <enruizno@uwaterloo.ca>

.github/workflows/test.yml

@@ -6,7 +6,7 @@ on:
     - 'release/*'
   pull_request:
 env:
-  CORE_REPO_SHA: bce2aa649c9f3541a57b115ceb6694c5a00ca856
+  CORE_REPO_SHA: 5de7ffd7cbb555fb04d0138361a188496557080d
 
 jobs:
   build:

exporter/opentelemetry-exporter-datadog/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- Add fields method
+  ([#226](https://github.com/open-telemetry/opentelemetry-python/pull/226))
+
 ## Version 0.15b0
 
 Released 2020-11-02

exporter/opentelemetry-exporter-datadog/src/opentelemetry/exporter/datadog/propagator.py

@@ -106,6 +106,19 @@ class DatadogFormat(TextMapPropagator):
                 span.context.trace_state[constants.DD_ORIGIN],
             )
 
+    def fields(self):
+        """Returns a set with the fields set in `inject`.
+
+        See
+        `opentelemetry.trace.propagation.textmap.TextMapPropagator.fields`
+        """
+        return {
+            self.TRACE_ID_KEY,
+            self.PARENT_ID_KEY,
+            self.SAMPLING_PRIORITY_KEY,
+            self.ORIGIN_KEY,
+        }
+
 
 def format_trace_id(trace_id: int) -> str:
     """Format the trace id for Datadog."""

sdk-extension/opentelemetry-sdk-extension-aws/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- Add method to return fields injected by propagator
+  ([#226](https://github.com/open-telemetry/opentelemetry-python/pull/226))
+
 ## Version 0.16b0
 
 Released 2020-11-25

sdk-extension/opentelemetry-sdk-extension-aws/src/opentelemetry/sdk/extension/aws/trace/propagation/aws_xray_format.py

@@ -274,3 +274,12 @@ class AwsXRayFormat(TextMapPropagator):
         set_in_carrier(
             carrier, TRACE_HEADER_KEY, trace_header,
         )
+
+    def fields(self):
+        """Returns a set with the fields set in `inject`.
+
+        See
+        `opentelemetry.trace.propagation.textmap.TextMapPropagator.fields`
+        """
+
+        return {TRACE_HEADER_KEY}