5 files changed, 41 insertions, 44 deletions

diff --git a/vendor/go.opencensus.io/stats/view/collector.go b/vendor/go.opencensus.io/stats/view/collector.go
index 863a5b6..250395d 100644
--- a/vendor/go.opencensus.io/stats/view/collector.go
+++ b/vendor/go.opencensus.io/stats/view/collector.go
@@ -40,11 +40,12 @@ func (c *collector) addSample(s string, v float64) {
 	aggregator.addSample(v)
 }
 
+// collectRows returns a snapshot of the collected Row values.
 func (c *collector) collectedRows(keys []tag.Key) []*Row {
-	var rows []*Row
+	rows := make([]*Row, 0, len(c.signatures))
 	for sig, aggregator := range c.signatures {
 		tags := decodeTags([]byte(sig), keys)
-		row := &Row{tags, aggregator}
+		row := &Row{Tags: tags, Data: aggregator.clone()}
 		rows = append(rows, row)
 	}
 	return rows
diff --git a/vendor/go.opencensus.io/stats/view/export.go b/vendor/go.opencensus.io/stats/view/export.go
index ffd0d1a..7cb5971 100644
--- a/vendor/go.opencensus.io/stats/view/export.go
+++ b/vendor/go.opencensus.io/stats/view/export.go
@@ -27,6 +27,9 @@ var (
 // Exporter takes a significant amount of time to
 // process a Data, that work should be done on another goroutine.
 //
+// It is safe to assume that ExportView will not be called concurrently from
+// multiple goroutines.
+//
 // The Data should not be modified.
 type Exporter interface {
 	ExportView(viewData *Data)
diff --git a/vendor/go.opencensus.io/stats/view/view.go b/vendor/go.opencensus.io/stats/view/view.go
index 87bf5d4..22323e2 100644
--- a/vendor/go.opencensus.io/stats/view/view.go
+++ b/vendor/go.opencensus.io/stats/view/view.go
@@ -29,7 +29,7 @@ import (
 )
 
 // View allows users to aggregate the recorded stats.Measurements.
-// Views need to be passed to the Subscribe function to be before data will be
+// Views need to be passed to the Register function to be before data will be
 // collected and sent to Exporters.
 type View struct {
 	Name        string // Name of View. Must be unique. If unset, will default to the name of the Measure.
@@ -71,10 +71,10 @@ func (v *View) same(other *View) bool {
 // defaults for Name and Description and sorting the TagKeys
 func (v *View) canonicalize() error {
 	if v.Measure == nil {
-		return fmt.Errorf("cannot subscribe view %q: measure not set", v.Name)
+		return fmt.Errorf("cannot register view %q: measure not set", v.Name)
 	}
 	if v.Aggregation == nil {
-		return fmt.Errorf("cannot subscribe view %q: aggregation not set", v.Name)
+		return fmt.Errorf("cannot register view %q: aggregation not set", v.Name)
 	}
 	if v.Name == "" {
 		v.Name = v.Measure.Name()
diff --git a/vendor/go.opencensus.io/stats/view/worker.go b/vendor/go.opencensus.io/stats/view/worker.go
index ba9d7fc..fef7bf5 100644
--- a/vendor/go.opencensus.io/stats/view/worker.go
+++ b/vendor/go.opencensus.io/stats/view/worker.go
@@ -49,8 +49,8 @@ var defaultWorker *worker
 
 var defaultReportingDuration = 10 * time.Second
 
-// Find returns a subscribed view associated with this name.
-// If no subscribed view is found, nil is returned.
+// Find returns a registered view associated with this name.
+// If no registered view is found, nil is returned.
 func Find(name string) (v *View) {
 	req := &getViewByNameReq{
 		name: name,
@@ -62,7 +62,7 @@ func Find(name string) (v *View) {
 }
 
 // Register begins collecting data for the given views.
-// Once a view is subscribed, it reports data to the registered exporters.
+// Once a view is registered, it reports data to the registered exporters.
 func Register(views ...*View) error {
 	for _, v := range views {
 		if err := v.canonicalize(); err != nil {
@@ -181,7 +181,7 @@ func (w *worker) tryRegisterView(v *View) (*viewInternal, error) {
 	}
 	if x, ok := w.views[vi.view.Name]; ok {
 		if !x.view.same(vi.view) {
-			return nil, fmt.Errorf("cannot subscribe view %q; a different view with the same name is already subscribed", v.Name)
+			return nil, fmt.Errorf("cannot register view %q; a different view with the same name is already registered", v.Name)
 		}
 
 		// the view is already registered so there is nothing to do and the
@@ -194,40 +194,30 @@ func (w *worker) tryRegisterView(v *View) (*viewInternal, error) {
 	return vi, nil
 }
 
-func (w *worker) reportUsage(now time.Time) {
-	for _, v := range w.views {
-		if !v.isSubscribed() {
-			continue
-		}
-		rows := v.collectedRows()
-		_, ok := w.startTimes[v]
-		if !ok {
-			w.startTimes[v] = now
-		}
-		// Make sure collector is never going
-		// to mutate the exported data.
-		rows = deepCopyRowData(rows)
-		viewData := &Data{
-			View:  v.view,
-			Start: w.startTimes[v],
-			End:   time.Now(),
-			Rows:  rows,
-		}
-		exportersMu.Lock()
-		for e := range exporters {
-			e.ExportView(viewData)
-		}
-		exportersMu.Unlock()
+func (w *worker) reportView(v *viewInternal, now time.Time) {
+	if !v.isSubscribed() {
+		return
 	}
+	rows := v.collectedRows()
+	_, ok := w.startTimes[v]
+	if !ok {
+		w.startTimes[v] = now
+	}
+	viewData := &Data{
+		View:  v.view,
+		Start: w.startTimes[v],
+		End:   time.Now(),
+		Rows:  rows,
+	}
+	exportersMu.Lock()
+	for e := range exporters {
+		e.ExportView(viewData)
+	}
+	exportersMu.Unlock()
 }
 
-func deepCopyRowData(rows []*Row) []*Row {
-	newRows := make([]*Row, 0, len(rows))
-	for _, r := range rows {
-		newRows = append(newRows, &Row{
-			Data: r.Data.clone(),
-			Tags: r.Tags,
-		})
+func (w *worker) reportUsage(now time.Time) {
+	for _, v := range w.views {
+		w.reportView(v, now)
 	}
-	return newRows
 }
diff --git a/vendor/go.opencensus.io/stats/view/worker_commands.go b/vendor/go.opencensus.io/stats/view/worker_commands.go
index ef79ec3..06c3c54 100644
--- a/vendor/go.opencensus.io/stats/view/worker_commands.go
+++ b/vendor/go.opencensus.io/stats/view/worker_commands.go
@@ -73,7 +73,7 @@ func (cmd *registerViewReq) handleCommand(w *worker) {
 	}
 }
 
-// unregisterFromViewReq is the command to unsubscribe to a view. Has no
+// unregisterFromViewReq is the command to unregister to a view. Has no
 // impact on the data collection for client that are pulling data from the
 // library.
 type unregisterFromViewReq struct {
@@ -88,6 +88,9 @@ func (cmd *unregisterFromViewReq) handleCommand(w *worker) {
 			continue
 		}
 
+		// Report pending data for this view before removing it.
+		w.reportView(vi, time.Now())
+
 		vi.unsubscribe()
 		if !vi.isSubscribed() {
 			// this was the last subscription and view is not collecting anymore.
@@ -143,7 +146,7 @@ type recordReq struct {
 
 func (cmd *recordReq) handleCommand(w *worker) {
 	for _, m := range cmd.ms {
-		if (m == stats.Measurement{}) { // not subscribed
+		if (m == stats.Measurement{}) { // not registered
 			continue
 		}
 		ref := w.getMeasureRef(m.Measure().Name())
@@ -154,7 +157,7 @@ func (cmd *recordReq) handleCommand(w *worker) {
 }
 
 // setReportingPeriodReq is the command to modify the duration between
-// reporting the collected data to the subscribed clients.
+// reporting the collected data to the registered clients.
 type setReportingPeriodReq struct {
 	d time.Duration
 	c chan bool