Set Schema URL when exporting traces to OTLP (#2242)

We previously were recording the Schema URL but were not setting
the recorded value when exporting. This change now uses the recorded
value when exporting to OTLP.

CHANGELOG.md

@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Added
+
+- OTLP trace exporter now sets the SchemaURL field in the exported telemetry if the Tracer has WithSchemaURL option. (#2242)
+
 ### Changed
 
 - NoopMeterProvider is now private and NewNoopMeterProvider must be used to obtain a noopMeterProvider. (#2237)

exporters/otlp/otlptrace/internal/tracetransform/span.go

@@ -60,6 +60,7 @@ func Spans(sdl []tracesdk.ReadOnlySpan) []*tracepb.ResourceSpans {
 			ils = &tracepb.InstrumentationLibrarySpans{
 				InstrumentationLibrary: InstrumentationLibrary(sd.InstrumentationLibrary()),
 				Spans:                  []*tracepb.Span{},
+				SchemaUrl:              sd.InstrumentationLibrary().SchemaURL,
 			}
 		}
 		ils.Spans = append(ils.Spans, span(sd))
@@ -72,6 +73,7 @@ func Spans(sdl []tracesdk.ReadOnlySpan) []*tracepb.ResourceSpans {
 			rs = &tracepb.ResourceSpans{
 				Resource:                    Resource(sd.Resource()),
 				InstrumentationLibrarySpans: []*tracepb.InstrumentationLibrarySpans{ils},
+				SchemaUrl:                   sd.Resource().SchemaURL(),
 			}
 			rsm[rKey] = rs
 			continue

exporters/otlp/otlptrace/internal/tracetransform/span_test.go

@@ -25,14 +25,14 @@ import (
 	"google.golang.org/protobuf/proto"
 
 	"go.opentelemetry.io/otel/attribute"
-	"go.opentelemetry.io/otel/trace"
-	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
-
 	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/sdk/instrumentation"
 	"go.opentelemetry.io/otel/sdk/resource"
 	tracesdk "go.opentelemetry.io/otel/sdk/trace"
 	"go.opentelemetry.io/otel/sdk/trace/tracetest"
+	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
+	"go.opentelemetry.io/otel/trace"
+	tracepb "go.opentelemetry.io/proto/otlp/trace/v1"
 )
 
 func TestSpanKind(t *testing.T) {
@@ -266,10 +266,16 @@ func TestSpanData(t *testing.T) {
 		DroppedAttributes: 1,
 		DroppedEvents:     2,
 		DroppedLinks:      3,
-		Resource:          resource.NewSchemaless(attribute.String("rk1", "rv1"), attribute.Int64("rk2", 5), attribute.StringSlice("rk3", []string{"sv1", "sv2"})),
+		Resource: resource.NewWithAttributes(
+			"http://example.com/custom-resource-schema",
+			attribute.String("rk1", "rv1"),
+			attribute.Int64("rk2", 5),
+			attribute.StringSlice("rk3", []string{"sv1", "sv2"}),
+		),
 		InstrumentationLibrary: instrumentation.Library{
-			Name:    "go.opentelemetry.io/test/otel",
-			Version: "v0.0.1",
+			Name:      "go.opentelemetry.io/test/otel",
+			Version:   "v0.0.1",
+			SchemaURL: semconv.SchemaURL,
 		},
 	}
 
@@ -298,8 +304,10 @@ func TestSpanData(t *testing.T) {
 	require.Len(t, got, 1)
 
 	assert.Equal(t, got[0].GetResource(), Resource(spanData.Resource))
+	assert.Equal(t, got[0].SchemaUrl, spanData.Resource.SchemaURL())
 	ilSpans := got[0].GetInstrumentationLibrarySpans()
 	require.Len(t, ilSpans, 1)
+	assert.Equal(t, ilSpans[0].SchemaUrl, spanData.InstrumentationLibrary.SchemaURL)
 	assert.Equal(t, ilSpans[0].GetInstrumentationLibrary(), InstrumentationLibrary(spanData.InstrumentationLibrary))
 	require.Len(t, ilSpans[0].Spans, 1)
 	actualSpan := ilSpans[0].Spans[0]