Set Schema URL when exporting traces to OTLP

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.

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]