Deprecate NewSpanXXX in the favor of StartSpan (#708)

Required to support the Go execution tracer spans.

Fixes #694.

Author: rakyll

exporter/stackdriver/stackdriver_test.go

@@ -53,14 +53,13 @@ func TestExport(t *testing.T) {
 
 	trace.ApplyConfig(trace.Config{DefaultSampler: trace.AlwaysSample()})
 
-	span := trace.NewSpan("custom-span", nil, trace.StartOptions{})
+	_, span := trace.StartSpan(context.Background(), "custom-span")
 	time.Sleep(10 * time.Millisecond)
 	span.End()
 
 	// Test HTTP spans
 
 	handler := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
-
 		_, backgroundSpan := trace.StartSpan(context.Background(), "BackgroundWork")
 		spanContext := backgroundSpan.SpanContext()
 		time.Sleep(10 * time.Millisecond)

exporter/stackdriver/stats.go

@@ -155,12 +155,11 @@ func (e *statsExporter) Flush() {
 }
 
 func (e *statsExporter) uploadStats(vds []*view.Data) error {
-	span := trace.NewSpan(
+	ctx, span := trace.StartSpan(
+		context.Background(),
 		"go.opencensus.io/exporter/stackdriver.uploadStats",
-		nil,
-		trace.StartOptions{Sampler: trace.NeverSample()},
+		trace.WithSampler(trace.NeverSample()),
 	)
-	ctx := trace.WithSpan(context.Background(), span)
 	defer span.End()
 
 	for _, vd := range vds {

exporter/stackdriver/trace.go

@@ -117,11 +117,14 @@ func (e *traceExporter) uploadSpans(spans []*trace.SpanData) {
 		req.Spans = append(req.Spans, protoFromSpanData(span, e.projectID))
 	}
 	// Create a never-sampled span to prevent traces associated with exporter.
-	span := trace.NewSpan("go.opencensus.io/exporter/stackdriver.uploadSpans", nil, trace.StartOptions{Sampler: trace.NeverSample()})
+	ctx, span := trace.StartSpan( // TODO: add timeouts
+		context.Background(),
+		"go.opencensus.io/exporter/stackdriver.uploadSpans",
+		trace.WithSampler(trace.NeverSample()),
+	)
 	defer span.End()
 	span.AddAttributes(trace.Int64Attribute("num_spans", int64(len(spans))))
 
-	ctx := trace.WithSpan(context.Background(), span) // TODO: add timeouts
 	err := e.client.BatchWriteSpans(ctx, &req)
 	if err != nil {
 		span.SetStatus(trace.Status{Code: 2, Message: err.Error()})

exporter/stackdriver/trace_proto_test.go

@@ -57,19 +57,21 @@ func (t *testExporter) ExportSpan(s *trace.SpanData) {
 }
 
 func TestExportTrace(t *testing.T) {
+	ctx := context.Background()
+
 	var te testExporter
 	trace.RegisterExporter(&te)
 	defer trace.UnregisterExporter(&te)
 
-	span0 := trace.NewSpanWithRemoteParent(
+	ctx, span0 := trace.StartSpanWithRemoteParent(
+		ctx,
 		"span0",
 		trace.SpanContext{
 			TraceID:      traceID,
 			SpanID:       spanID,
 			TraceOptions: 1,
 		},
-		trace.StartOptions{})
-	ctx := trace.WithSpan(context.Background(), span0)
+	)
 	{
 		ctx1, span1 := trace.StartSpan(ctx, "span1")
 		{

exporter/stackdriver/trace_test.go

@@ -35,9 +35,8 @@ func TestBundling(t *testing.T) {
 	}
 	trace.RegisterExporter(exporter)
 
-	trace.ApplyConfig(trace.Config{DefaultSampler: trace.AlwaysSample()})
 	for i := 0; i < 35; i++ {
-		_, span := trace.StartSpan(context.Background(), "span")
+		_, span := trace.StartSpan(context.Background(), "span", trace.WithSampler(trace.AlwaysSample()))
 		span.End()
 	}