use new w3c phase 3 spec

DataDog · May 13, 2024 · c6de4f0 · c6de4f0
1 parent 0e3a0f1
commit c6de4f0
Showing 1 changed file with 9 additions and 7 deletions.
diff --git a/lib/datadog/tracing/distributed/propagation.rb b/lib/datadog/tracing/distributed/propagation.rb
@@ -101,17 +101,19 @@ def extract(data)
               # Only parse if it represent the same trace as the successfully extracted one
               next unless tracecontext_digest.trace_id == extracted_trace_digest.trace_id
 
-              distributed_tags = extracted_trace_digest.trace_distributed_tags
-              unless tracecontext_digest.span_id == extracted_trace_digest.span_id
-                distributed_tags = distributed_tags&.dup || {}
+              if tracecontext_digest.span_id == extracted_trace_digest.span_id
+                parent_id = extracted_trace_digest.span_id
+                distributed_tags = extracted_trace_digest.trace_distributed_tags
+              else
+                # span_id in the tracecontext header takes precedence over the value in datadog headers
+                parent_id = tracecontext_digest.span_id
+                distributed_tags = extracted_trace_digest.trace_distributed_tags&.dup || {}
                 distributed_tags[Tracing::Metadata::Ext::Distributed::TAG_DD_PARENT_ID] =
-                  tracecontext_digest.trace_distributed_tags.fetch(
-                    Tracing::Metadata::Ext::Distributed::TAG_DD_PARENT_ID,
-                    Tracing::Metadata::Ext::Distributed::DD_PARENT_ID_DEFAULT
-                  )
+                  format('%016x', extracted_trace_digest.span_id)
               end
               # Preserve the trace state and last datadog span id
               extracted_trace_digest = extracted_trace_digest.merge(
+                span_id: parent_id,
                 trace_state: tracecontext_digest.trace_state,
                 trace_state_unknown_fields: tracecontext_digest.trace_state_unknown_fields,
                 trace_distributed_tags: distributed_tags