fix(opentelemetry): preserve span labels in traces (linkerd#3609)

A previous change enabling OpenTelmetry forgot to include attributes from the span itself, in addition to the request level spans as we do in the old OpenCensus exporter. This adds those attributes back in.

Signed-off-by: Scott Fleener <[email protected]>

linkerd/opentelemetry/src/lib.rs

@@ -9,16 +9,20 @@ use linkerd_error::Error;
 use linkerd_trace_context as trace_context;
 use metrics::Registry;
 pub use opentelemetry as otel;
-use opentelemetry::trace::{
-    SpanContext, SpanId, SpanKind, Status, TraceFlags, TraceId, TraceState,
+use opentelemetry::{
+    trace::{SpanContext, SpanId, SpanKind, Status, TraceFlags, TraceId, TraceState},
+    KeyValue,
 };
-use opentelemetry::KeyValue;
 pub use opentelemetry_proto as proto;
-use opentelemetry_proto::proto::collector::trace::v1::trace_service_client::TraceServiceClient;
-use opentelemetry_proto::proto::collector::trace::v1::ExportTraceServiceRequest;
-use opentelemetry_proto::proto::trace::v1::ResourceSpans;
-use opentelemetry_proto::transform::common::ResourceAttributesWithSchema;
-use opentelemetry_proto::transform::trace::group_spans_by_resource_and_scope;
+use opentelemetry_proto::{
+    proto::{
+        collector::trace::v1::{
+            trace_service_client::TraceServiceClient, ExportTraceServiceRequest,
+        },
+        trace::v1::ResourceSpans,
+    },
+    transform::{common::ResourceAttributesWithSchema, trace::group_spans_by_resource_and_scope},
+};
 pub use opentelemetry_sdk as sdk;
 pub use opentelemetry_sdk::export::trace::SpanData;
 use opentelemetry_sdk::trace::SpanLinks;
@@ -235,6 +239,9 @@ fn convert_span(span: ExportSpan) -> Result<SpanData, Error> {
     for (k, v) in labels.iter() {
         attributes.push(KeyValue::new(k.clone(), v.clone()));
     }
+    for (k, v) in span.labels.iter() {
+        attributes.push(KeyValue::new(*k, v.clone()));
+    }
     let is_remote = kind != trace_context::export::SpanKind::Client;
     Ok(SpanData {
         parent_span_id: SpanId::from_bytes(span.parent_id.into_bytes()?),