exporter/exporterparser/all: update SpanData translator

Update the OpenCensus Proto TraceData
to OpenCensus-Go SpanData translator by:
* Name from:
    "exportSpans"
to
    "ocProtoSpansToOCSpanDataInstrumented"
to make it more intuitive but also declare
its intentions and add a reminder that we
should get vendors to start using OpenCensus Proto

* Added tracing for each export with a span that'll
record the errors and number of spans

Author: odeke-em

exporter/exporterparser/aws_xray.go

@@ -172,7 +172,7 @@ func (axe *awsXRayExporter) ExportSpans(ctx context.Context, td data.TraceData)
 	if err != nil {
 		return err
 	}
-	return exportSpans(ctx, "aws-xray", exp, td)
+	return ocProtoSpansToOCSpanDataInstrumented(ctx, "aws-xray", exp, td)
 }
 
 func (axe *awsXRayExporter) getOrMakeExporterByServiceName(serviceName string) (*xray.Exporter, error) {

exporter/exporterparser/datadog.go

@@ -90,5 +90,5 @@ func (dde *datadogExporter) ExportSpans(ctx context.Context, td data.TraceData)
 	// TODO: Examine the Datadog exporter to see
 	// if trace.ExportSpan was constraining and if perhaps the
 	// upload can use the context and information from the Node.
-	return exportSpans(ctx, "datadog", dde.exporter, td)
+	return ocProtoSpansToOCSpanDataInstrumented(ctx, "datadog", dde.exporter, td)
 }

exporter/exporterparser/exparser.go

@@ -32,7 +32,32 @@ import (
 	tracetranslator "github.com/census-instrumentation/opencensus-service/translator/trace"
 )
 
-func exportSpans(ctx context.Context, exporterName string, te trace.Exporter, td data.TraceData) error {
+// ocProtoSpansToOCSpanDataInstrumented converts
+// OpenCensus Proto TraceData to OpenCensus-Go SpanData.
+// The "Instrumented" suffix serves to document that this
+// function is traced but also has stats for self-observability.
+//
+// This is a bootstrapping mechanism for us to re-use as many of
+// the OpenCensus-Go trace.SpanData exporters which were written
+// by various vendors and contributors. Eventually the goal is to
+// get those exporters converted to directly receive
+// OpenCensus Proto TraceData.
+func ocProtoSpansToOCSpanDataInstrumented(ctx context.Context, exporterName string, te trace.Exporter, td data.TraceData) (aerr error) {
+	ctx, span := trace.StartSpan(ctx,
+		"opencensus.service.exporter."+exporterName+".ExportTrace",
+		trace.WithSampler(trace.NeverSample()))
+
+	span.Annotate([]trace.Attribute{
+		trace.Int64Attribute("n_spans", int64(len(td.Spans))),
+	}, "")
+
+	defer func() {
+		if aerr != nil {
+			span.SetStatus(trace.Status{Code: trace.StatusCodeInternal, Message: aerr.Error()})
+		}
+		span.End()
+	}()
+
 	var errs []error
 	var goodSpans []*tracepb.Span
 	for _, span := range td.Spans {
@@ -45,9 +70,5 @@ func exportSpans(ctx context.Context, exporterName string, te trace.Exporter, td
 		}
 	}
 
-	// And finally record metrics on the number of exported spans.
-	nSpansCounter := internal.NewExportedSpansRecorder(exporterName)
-	nSpansCounter(ctx, td.Node, goodSpans)
-
 	return internal.CombineErrors(errs)
 }

exporter/exporterparser/honeycomb.go

@@ -63,5 +63,5 @@ type honeycombExporter struct {
 }
 
 func (hce *honeycombExporter) ExportSpans(ctx context.Context, td data.TraceData) error {
-	return exportSpans(ctx, "honeycomb", hce.exporter, td)
+	return ocProtoSpansToOCSpanDataInstrumented(ctx, "honeycomb", hce.exporter, td)
 }

exporter/exporterparser/jaeger.go

@@ -75,5 +75,5 @@ func (je *jaegerExporter) ExportSpans(ctx context.Context, td data.TraceData) er
 	// TODO: Examine "contrib.go.opencensus.io/exporter/jaeger" to see
 	// if trace.ExportSpan was constraining and if perhaps the Jaeger
 	// upload can use the context and information from the Node.
-	return exportSpans(ctx, "jaeger", je.exporter, td)
+	return ocProtoSpansToOCSpanDataInstrumented(ctx, "jaeger", je.exporter, td)
 }

exporter/exporterparser/kafka.go

@@ -69,5 +69,5 @@ func KafkaExportersFromViper(v *viper.Viper) (tes []exporter.TraceExporter, mes
 }
 
 func (kde *kafkaExporter) ExportSpans(ctx context.Context, td data.TraceData) error {
-	return exportSpans(ctx, "kafka", kde.exporter, td)
+	return ocProtoSpansToOCSpanDataInstrumented(ctx, "kafka", kde.exporter, td)
 }

exporter/exporterparser/stackdriver.go

@@ -105,7 +105,7 @@ func (sde *stackdriverExporter) ExportSpans(ctx context.Context, td data.TraceDa
 	// TODO: Examine "contrib.go.opencensus.io/exporter/stackdriver" to see
 	// if trace.ExportSpan was constraining and if perhaps the Stackdriver
 	// upload can use the context and information from the Node.
-	return exportSpans(ctx, "stackdriver", sde.exporter, td)
+	return ocProtoSpansToOCSpanDataInstrumented(ctx, "stackdriver", sde.exporter, td)
 }
 
 var _ exporter.MetricsExporter = (*stackdriverExporter)(nil)

exporter/exporterparser/zipkin.go

@@ -192,7 +192,18 @@ func (ze *zipkinExporter) stop() error {
 	return ze.reporter.Close()
 }
 
-func (ze *zipkinExporter) ExportSpans(ctx context.Context, td data.TraceData) error {
+func (ze *zipkinExporter) ExportSpans(ctx context.Context, td data.TraceData) (zerr error) {
+	ctx, span := trace.StartSpan(ctx,
+		"opencensus.service.exporter.zipkin.ExportTrace",
+		trace.WithSampler(trace.NeverSample()))
+
+	defer func() {
+		if zerr != nil {
+			span.SetStatus(trace.Status{Code: trace.StatusCodeInternal, Message: zerr.Error()})
+		}
+		span.End()
+	}()
+
 	goodSpans := make([]*tracepb.Span, 0, len(td.Spans))
 	for _, span := range td.Spans {
 		sd, err := tracetranslator.ProtoSpanToOCSpanData(span)