Revert "Remove support for exporting ViewData (#188)" (#191)

* Revert "Remove support for exporting ViewData (#188)"

This reverts commit 4b7f306.

* Deprecate ExportView

* Keep the changes in equivalence_test and example

Author: songy23

example_test.go

@@ -34,6 +34,11 @@ func Example_defaults() {
 		log.Fatal(err)
 	}
 
+	// Export to Stackdriver Monitoring.
+	if err = exporter.StartMetricsExporter(); err != nil {
+		log.Fatal(err)
+	}
+
 	// Subscribe views to see stats in Stackdriver Monitoring.
 	if err := view.Register(
 		ochttp.ClientLatencyView,
@@ -73,7 +78,7 @@ func Example_gKE() {
 		zone = "unknown"
 	}
 
-	_, err = stackdriver.NewExporter(stackdriver.Options{
+	exporter, err := stackdriver.NewExporter(stackdriver.Options{
 		ProjectID: "google-project-id",
 		// Set a MonitoredResource that represents a GKE container.
 		Resource: &monitoredres.MonitoredResource{
@@ -100,4 +105,9 @@ func Example_gKE() {
 	if err != nil {
 		log.Fatal(err)
 	}
+
+	// Register so that views are exported.
+	if err = exporter.StartMetricsExporter(); err != nil {
+		log.Fatal(err)
+	}
 }

stackdriver.go

@@ -341,6 +341,13 @@ func NewExporter(o Options) (*Exporter, error) {
 	}, nil
 }
 
+// ExportView exports to the Stackdriver Monitoring if view data
+// has one or more rows.
+// Deprecated: use ExportMetrics and StartMetricsExporter instead.
+func (e *Exporter) ExportView(vd *view.Data) {
+	e.statsExporter.ExportView(vd)
+}
+
 // ExportMetricsProto exports OpenCensus Metrics Proto to Stackdriver Monitoring synchronously,
 // without de-duping or adding proto metrics to the bundler.
 func (e *Exporter) ExportMetricsProto(ctx context.Context, node *commonpb.Node, rsc *resourcepb.Resource, metrics []*metricspb.Metric) error {

stackdriver_test.go

@@ -25,6 +25,7 @@ import (
 
 	"contrib.go.opencensus.io/exporter/stackdriver/internal/testpb"
 	"go.opencensus.io/plugin/ochttp"
+	"go.opencensus.io/stats/view"
 	"go.opencensus.io/trace"
 	"golang.org/x/net/context/ctxhttp"
 )
@@ -47,6 +48,8 @@ func TestExport(t *testing.T) {
 
 	trace.RegisterExporter(exporter)
 	defer trace.UnregisterExporter(exporter)
+	view.RegisterExporter(exporter)
+	defer view.UnregisterExporter(exporter)
 
 	trace.ApplyConfig(trace.Config{DefaultSampler: trace.AlwaysSample()})
 
@@ -110,6 +113,8 @@ func TestGRPC(t *testing.T) {
 
 	trace.RegisterExporter(exporter)
 	defer trace.UnregisterExporter(exporter)
+	view.RegisterExporter(exporter)
+	defer view.UnregisterExporter(exporter)
 
 	trace.ApplyConfig(trace.Config{DefaultSampler: trace.AlwaysSample()})