chore(ux): optimize progress bar (#1349)

Signed-off-by: Billy Zha <[email protected]>

cmd/oras/internal/display/status/progress/manager.go

@@ -27,7 +27,8 @@ import (
 const (
 	// BufferSize is the size of the status channel buffer.
 	BufferSize       = 1
-	bufFlushDuration = 200 * time.Millisecond
+	framePerSecond   = 5
+	bufFlushDuration = time.Second / framePerSecond
 )
 
 var errManagerStopped = errors.New("progress output manager has already been stopped")

cmd/oras/internal/display/status/progress/speed.go

@@ -0,0 +1,61 @@
+/*
+Copyright The ORAS 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 progress
+
+import "time"
+
+type speedPoint struct {
+	time   time.Time
+	offset int64
+}
+
+type speedWindow struct {
+	point []speedPoint
+	next  int
+	size  int
+}
+
+// newSpeedWindow creates a new speed window with a given capacity.
+func newSpeedWindow(capacity int) *speedWindow {
+	return &speedWindow{
+		point: make([]speedPoint, capacity),
+	}
+}
+
+// Add adds a done workload to the window.
+func (w *speedWindow) Add(time time.Time, offset int64) {
+	if w.size != len(w.point) {
+		w.size++
+	}
+	w.point[w.next] = speedPoint{
+		time:   time,
+		offset: offset,
+	}
+	w.next = (w.next + 1) % len(w.point)
+}
+
+// Mean returns the mean speed of the window with unit of byte per second.
+func (w *speedWindow) Mean() float64 {
+	if w.size < 2 {
+		// no speed diplayed for first read
+		return 0
+	}
+
+	begin := (w.next - w.size + len(w.point)) % len(w.point)
+	end := (begin - 1 + w.size) % w.size
+
+	return float64(w.point[end].offset-w.point[begin].offset) / w.point[end].time.Sub(w.point[begin].time).Seconds()
+}

cmd/oras/internal/display/status/progress/speed_test.go

@@ -0,0 +1,49 @@
+/*
+Copyright The ORAS 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 progress
+
+import (
+	"testing"
+	"time"
+)
+
+func Test_speedWindow(t *testing.T) {
+	w := newSpeedWindow(3)
+	if s := w.Mean(); s != 0 {
+		t.Errorf("expected 0, got %f", s)
+	}
+
+	now := time.Now()
+	w.Add(now, 100)
+	if s := w.Mean(); s != 0 {
+		t.Errorf("expected 0, got %f", s)
+	}
+
+	w.Add(now.Add(1*time.Second), 200)
+	if s := w.Mean(); s != 100 {
+		t.Errorf("expected 100, got %f", s)
+	}
+
+	w.Add(now.Add(4*time.Second), 900)
+	if s := w.Mean(); s != 200 {
+		t.Errorf("expected 200, got %f", s)
+	}
+
+	w.Add(now.Add(5*time.Second), 1400)
+	if s := w.Mean(); s != 300 {
+		t.Errorf("expected 300, got %f", s)
+	}
+}

cmd/oras/internal/display/status/progress/status.go

@@ -43,13 +43,12 @@ var (
 
 // status is used as message to update progress view.
 type status struct {
-	done           bool // done is true when the end time is set
-	prompt         string
-	descriptor     ocispec.Descriptor
-	offset         int64
-	total          humanize.Bytes
-	lastOffset     int64
-	lastRenderTime time.Time
+	done        bool // done is true when the end time is set
+	prompt      string
+	descriptor  ocispec.Descriptor
+	offset      int64
+	total       humanize.Bytes
+	speedWindow *speedWindow
 
 	startTime time.Time
 	endTime   time.Time
@@ -60,14 +59,14 @@ type status struct {
 // newStatus generates a base empty status.
 func newStatus() *status {
 	return &status{
-		offset:         -1,
-		total:          humanize.ToBytes(0),
-		lastRenderTime: time.Now(),
+		offset:      -1,
+		total:       humanize.ToBytes(0),
+		speedWindow: newSpeedWindow(framePerSecond),
 	}
 }
 
-// NewStatus generates a status.
-func NewStatus(prompt string, descriptor ocispec.Descriptor, offset int64) *status {
+// NewStatusMessage generates a status for messaging.
+func NewStatusMessage(prompt string, descriptor ocispec.Descriptor, offset int64) *status {
 	return &status{
 		prompt:     prompt,
 		descriptor: descriptor,
@@ -159,20 +158,12 @@ func (s *status) String(width int) (string, string) {
 // calculateSpeed calculates the speed of the progress and update last status.
 // caller must hold the lock.
 func (s *status) calculateSpeed() humanize.Bytes {
-	now := time.Now()
-	if s.lastRenderTime.IsZero() {
-		s.lastRenderTime = s.startTime
+	if s.offset < 0 {
+		// not started
+		return humanize.ToBytes(0)
 	}
-	secondsTaken := now.Sub(s.lastRenderTime).Seconds()
-	if secondsTaken == 0 {
-		secondsTaken = bufFlushDuration.Seconds()
-	}
-	bytes := float64(s.offset - s.lastOffset)
-
-	s.lastOffset = s.offset
-	s.lastRenderTime = now
-
-	return humanize.ToBytes(int64(bytes / secondsTaken))
+	s.speedWindow.Add(time.Now(), s.offset)
+	return humanize.ToBytes(int64(s.speedWindow.Mean()))
 }
 
 // durationString returns a viewable TTY string of the status with duration.
@@ -216,6 +207,7 @@ func (s *status) Update(n *status) {
 	}
 	if !n.startTime.IsZero() {
 		s.startTime = n.startTime
+		s.speedWindow.Add(s.startTime, 0)
 	}
 	if !n.endTime.IsZero() {
 		s.endTime = n.endTime

cmd/oras/internal/display/status/progress/status_test.go

@@ -140,3 +140,12 @@ func Test_status_durationString(t *testing.T) {
 		t.Errorf("status.durationString() = %v, want %v", d, want)
 	}
 }
+
+func Test_status_calculateSpeed_negative(t *testing.T) {
+	s := &status{
+		offset: -1,
+	}
+	if s.calculateSpeed() != humanize.ToBytes(0) {
+		t.Errorf("status.calculateSpeed() = %v, want 0", s.calculateSpeed())
+	}
+}

cmd/oras/internal/display/status/track/reader.go

@@ -66,7 +66,7 @@ func (r *reader) StopManager() {
 
 // Done sends message to mark the tracked progress as complete.
 func (r *reader) Done() {
-	r.status <- progress.NewStatus(r.donePrompt, r.descriptor, r.descriptor.Size)
+	r.status <- progress.NewStatusMessage(r.donePrompt, r.descriptor, r.descriptor.Size)
 	r.status <- progress.EndTiming()
 }
 
@@ -95,7 +95,7 @@ func (r *reader) Read(p []byte) (int, error) {
 	}
 	for {
 		select {
-		case r.status <- progress.NewStatus(r.actionPrompt, r.descriptor, r.offset):
+		case r.status <- progress.NewStatusMessage(r.actionPrompt, r.descriptor, r.offset):
 			// purge the channel until successfully pushed
 			return n, err
 		case <-r.status:

cmd/oras/internal/display/status/track/target.go

@@ -115,7 +115,7 @@ func (t *graphTarget) Prompt(desc ocispec.Descriptor, prompt string) error {
 		return err
 	}
 	defer close(status)
-	status <- progress.NewStatus(prompt, desc, desc.Size)
+	status <- progress.NewStatusMessage(prompt, desc, desc.Size)
 	status <- progress.EndTiming()
 	return nil
 }