1 files changed, 233 insertions, 0 deletions
diff --git a/vendor/go.opencensus.io/stats/view/worker.go b/vendor/go.opencensus.io/stats/view/worker.go
new file mode 100644
index 0000000..ba9d7fc
--- /dev/null
+++ b/vendor/go.opencensus.io/stats/view/worker.go
@@ -0,0 +1,233 @@
+// Copyright 2017, OpenCensus Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+package view
+
+import (
+	"fmt"
+	"time"
+
+	"go.opencensus.io/stats"
+	"go.opencensus.io/stats/internal"
+	"go.opencensus.io/tag"
+)
+
+func init() {
+	defaultWorker = newWorker()
+	go defaultWorker.start()
+	internal.DefaultRecorder = record
+}
+
+type measureRef struct {
+	measure string
+	views   map[*viewInternal]struct{}
+}
+
+type worker struct {
+	measures   map[string]*measureRef
+	views      map[string]*viewInternal
+	startTimes map[*viewInternal]time.Time
+
+	timer      *time.Ticker
+	c          chan command
+	quit, done chan bool
+}
+
+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.
+func Find(name string) (v *View) {
+	req := &getViewByNameReq{
+		name: name,
+		c:    make(chan *getViewByNameResp),
+	}
+	defaultWorker.c <- req
+	resp := <-req.c
+	return resp.v
+}
+
+// Register begins collecting data for the given views.
+// Once a view is subscribed, it reports data to the registered exporters.
+func Register(views ...*View) error {
+	for _, v := range views {
+		if err := v.canonicalize(); err != nil {
+			return err
+		}
+	}
+	req := &registerViewReq{
+		views: views,
+		err:   make(chan error),
+	}
+	defaultWorker.c <- req
+	return <-req.err
+}
+
+// Unregister the given views. Data will not longer be exported for these views
+// after Unregister returns.
+// It is not necessary to unregister from views you expect to collect for the
+// duration of your program execution.
+func Unregister(views ...*View) {
+	names := make([]string, len(views))
+	for i := range views {
+		names[i] = views[i].Name
+	}
+	req := &unregisterFromViewReq{
+		views: names,
+		done:  make(chan struct{}),
+	}
+	defaultWorker.c <- req
+	<-req.done
+}
+
+// RetrieveData gets a snapshot of the data collected for the the view registered
+// with the given name. It is intended for testing only.
+func RetrieveData(viewName string) ([]*Row, error) {
+	req := &retrieveDataReq{
+		now: time.Now(),
+		v:   viewName,
+		c:   make(chan *retrieveDataResp),
+	}
+	defaultWorker.c <- req
+	resp := <-req.c
+	return resp.rows, resp.err
+}
+
+func record(tags *tag.Map, ms interface{}) {
+	req := &recordReq{
+		tm: tags,
+		ms: ms.([]stats.Measurement),
+	}
+	defaultWorker.c <- req
+}
+
+// SetReportingPeriod sets the interval between reporting aggregated views in
+// the program. If duration is less than or
+// equal to zero, it enables the default behavior.
+func SetReportingPeriod(d time.Duration) {
+	// TODO(acetechnologist): ensure that the duration d is more than a certain
+	// value. e.g. 1s
+	req := &setReportingPeriodReq{
+		d: d,
+		c: make(chan bool),
+	}
+	defaultWorker.c <- req
+	<-req.c // don't return until the timer is set to the new duration.
+}
+
+func newWorker() *worker {
+	return &worker{
+		measures:   make(map[string]*measureRef),
+		views:      make(map[string]*viewInternal),
+		startTimes: make(map[*viewInternal]time.Time),
+		timer:      time.NewTicker(defaultReportingDuration),
+		c:          make(chan command, 1024),
+		quit:       make(chan bool),
+		done:       make(chan bool),
+	}
+}
+
+func (w *worker) start() {
+	for {
+		select {
+		case cmd := <-w.c:
+			cmd.handleCommand(w)
+		case <-w.timer.C:
+			w.reportUsage(time.Now())
+		case <-w.quit:
+			w.timer.Stop()
+			close(w.c)
+			w.done <- true
+			return
+		}
+	}
+}
+
+func (w *worker) stop() {
+	w.quit <- true
+	<-w.done
+}
+
+func (w *worker) getMeasureRef(name string) *measureRef {
+	if mr, ok := w.measures[name]; ok {
+		return mr
+	}
+	mr := &measureRef{
+		measure: name,
+		views:   make(map[*viewInternal]struct{}),
+	}
+	w.measures[name] = mr
+	return mr
+}
+
+func (w *worker) tryRegisterView(v *View) (*viewInternal, error) {
+	vi, err := newViewInternal(v)
+	if err != nil {
+		return nil, err
+	}
+	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)
+		}
+
+		// the view is already registered so there is nothing to do and the
+		// command is considered successful.
+		return x, nil
+	}
+	w.views[vi.view.Name] = vi
+	ref := w.getMeasureRef(vi.view.Measure.Name())
+	ref.views[vi] = struct{}{}
+	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 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,
+		})
+	}
+	return newRows
+}