Inject span

exporter/trace/cloudtrace.go

@@ -19,6 +19,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
 	traceapi "cloud.google.com/go/trace/apiv2"
@@ -29,6 +30,11 @@ import (
 	export "go.opentelemetry.io/otel/sdk/export/trace"
 )
 
+var (
+	once sync.Once
+	resLabelMap = make(map[string]string)
+)
+
 // Option is function type that is passed to the exporter initialization function.
 type Option func(*options)
 
@@ -206,11 +212,30 @@ func newContextWithTimeout(ctx context.Context, timeout time.Duration) (context.
 	return context.WithTimeout(ctx, timeout)
 }
 
+// SetResLabelMapForOnce intializes ResLabelMap for once since 
+// monitored resources are static
+func (e * Exporter) SetResLabelMapForOnce(input map[string]string) {
+	once.Do(func() {
+		for k,v := range input {
+			resLabelMap[k] = v
+		}
+	})
+}
+
+// injectLabelsIntoSpan injects Monitored Resources labels into a span 
+func injectLabelsIntoSpan(sd *export.SpanData) *export.SpanData {
+	for k, v := range resLabelMap {
+		sd.Attributes = append(sd.Attributes, kv.Key(k).String(v))
+	}
+	return sd
+}
+
 // ExportSpan exports a SpanData to Stackdriver Trace.
 func (e *Exporter) ExportSpan(ctx context.Context, sd *export.SpanData) {
 	if len(e.traceExporter.o.DefaultTraceAttributes) > 0 {
 		sd = e.sdWithDefaultTraceAttributes(sd)
 	}
+	injectLabelsIntoSpan(sd)
 	e.traceExporter.ExportSpan(ctx, sd)
 }
 

exporter/trace/trace_proto.go

@@ -84,7 +84,7 @@ func protoFromSpanData(s *export.SpanData, projectID string) *tracepb.Span {
 		SameProcessAsParentSpan: &wrapperspb.BoolValue{Value: !s.HasRemoteParent},
 	}
 	if s.ParentSpanID != s.SpanContext.SpanID && s.ParentSpanID.IsValid() {
-		sp.ParentSpanId = fmt.Sprintf("%.16x", s.ParentSpanID)
+		sp.ParentSpanId = s.ParentSpanID.String()
 	}
 	if s.StatusCode != codes.OK {
 		sp.Status = &statuspb.Status{Code: int32(s.StatusCode)}