progress: method to Log messages while tracking (fixes #195) (#197)

cmd/demo-progress/demo.go

@@ -12,8 +12,9 @@ import (
 
 var (
 	autoStop    = flag.Bool("auto-stop", false, "Auto-stop rendering?")
-	randomFail  = flag.Bool("rnd-fail", false, "Enable random failures")
 	numTrackers = flag.Int("num-trackers", 13, "Number of Trackers")
+	randomFail  = flag.Bool("rnd-fail", false, "Enable random failures in tracking")
+	randomLogs  = flag.Bool("rnd-logs", false, "Enable random logs in the middle of tracking")
 
 	messageColors = []text.Color{
 		text.FgRed,
@@ -133,7 +134,16 @@ func main() {
 	// wait for one or more trackers to become active (just blind-wait for a
 	// second) and then keep watching until Rendering is in progress
 	time.Sleep(time.Second)
+	messagesLogged := make(map[string]bool)
 	for pw.IsRenderInProgress() {
+		if *randomLogs && pw.LengthDone()%3 == 0 {
+			logMsg := text.Faint.Sprintf("[INFO] done with %d trackers", pw.LengthDone())
+			if !messagesLogged[logMsg] {
+				pw.Log(logMsg)
+				messagesLogged[logMsg] = true
+			}
+		}
+
 		// for manual-stop mode, stop when there are no more active trackers
 		if !*autoStop && pw.LengthActive() == 0 {
 			pw.Stop()

progress/progress.go

@@ -1,6 +1,7 @@
 package progress
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"sync"
@@ -28,6 +29,8 @@ type Progress struct {
 	hideTracker           bool
 	hideValue             bool
 	hidePercentage        bool
+	logsToRender          []string
+	logsToRenderMutex     sync.RWMutex
 	messageWidth          int
 	numTrackersExpected   int64
 	overallTracker        *Tracker
@@ -144,6 +147,17 @@ func (p *Progress) LengthInQueue() int {
 	return out
 }
 
+// Log appends a log to display above the active progress bars during the next
+// refresh.
+func (p *Progress) Log(msg string, a ...interface{}) {
+	if len(a) > 0 {
+		msg = fmt.Sprintf(msg, a...)
+	}
+	p.logsToRenderMutex.Lock()
+	p.logsToRender = append(p.logsToRender, msg)
+	p.logsToRenderMutex.Unlock()
+}
+
 // SetAutoStop toggles the auto-stop functionality. Auto-stop set to true would
 // mean that the Render() function will automatically stop once all currently
 // active Trackers reach their final states. When set to false, the client code

progress/progress_test.go

@@ -87,6 +87,14 @@ func TestProgress_LengthInQueue(t *testing.T) {
 	assert.Equal(t, 1, p.LengthInQueue())
 }
 
+func TestProgress_Log(t *testing.T) {
+	p := Progress{}
+	assert.Len(t, p.logsToRender, 0)
+
+	p.Log("testing log")
+	assert.Len(t, p.logsToRender, 1)
+}
+
 func TestProgress_SetAutoStop(t *testing.T) {
 	p := Progress{}
 	assert.False(t, p.autoStop)

progress/render.go

@@ -272,39 +272,54 @@ func (p *Progress) renderTrackers(lastRenderLength int) int {
 		p.moveCursorToTheTop(&out)
 	}
 
+	// render the trackers that are done, and then the ones that are active
+	p.renderTrackersDoneAndActive(&out)
+
+	// render the overall tracker
+	if p.showOverallTracker {
+		p.renderTracker(&out, p.overallTracker, renderHint{isOverallTracker: true})
+	}
+
+	// write the text to the output writer
+	_, _ = p.outputWriter.Write([]byte(out.String()))
+
+	// stop if auto stop is enabled and there are no more active trackers
+	if p.autoStop && p.LengthActive() == 0 {
+		p.done <- true
+	}
+
+	return out.Len()
+}
+
+func (p *Progress) renderTrackersDoneAndActive(out *strings.Builder) {
 	// find the currently "active" and "done" trackers
 	trackersActive, trackersDone := p.extractDoneAndActiveTrackers()
 
 	// sort and render the done trackers
 	for _, tracker := range trackersDone {
-		p.renderTracker(&out, tracker, renderHint{})
+		p.renderTracker(out, tracker, renderHint{})
 	}
 	p.trackersDoneMutex.Lock()
 	p.trackersDone = append(p.trackersDone, trackersDone...)
 	p.trackersDoneMutex.Unlock()
 
+	// render all the logs received and flush them out
+	p.logsToRenderMutex.Lock()
+	for _, log := range p.logsToRender {
+		out.WriteString(text.EraseLine.Sprint())
+		out.WriteString(log)
+		out.WriteRune('\n')
+	}
+	p.logsToRender = nil
+	p.logsToRenderMutex.Unlock()
+
 	// sort and render the active trackers
 	for _, tracker := range trackersActive {
-		p.renderTracker(&out, tracker, renderHint{})
+		p.renderTracker(out, tracker, renderHint{})
 	}
 	p.trackersActiveMutex.Lock()
 	p.trackersActive = trackersActive
 	p.trackersActiveMutex.Unlock()
-
-	// render the overall tracker
-	if p.showOverallTracker {
-		p.renderTracker(&out, p.overallTracker, renderHint{isOverallTracker: true})
-	}
-
-	// write the text to the output writer
-	_, _ = p.outputWriter.Write([]byte(out.String()))
-
-	// stop if auto stop is enabled and there are no more active trackers
-	if p.autoStop && p.LengthActive() == 0 {
-		p.done <- true
-	}
-
-	return out.Len()
 }
 
 func (p *Progress) renderTrackerStats(out *strings.Builder, t *Tracker, hint renderHint) {

progress/render_test.go

@@ -611,6 +611,9 @@ func TestProgress_RenderSomeTrackers_WithOverallTracker(t *testing.T) {
 	pw.ShowOverallTracker(true)
 	pw.Style().Options.TimeOverallPrecision = time.Millisecond
 	go trackSomething(pw, &Tracker{Message: "Calculating Total   # 1\r", Total: 1000, Units: UnitsDefault})
+	go func() {
+		pw.Log("some information about something that happened at %s", time.Now().Format(time.RFC3339))
+	}()
 	go trackSomething(pw, &Tracker{Message: "Downloading File\t# 2", Total: 1000, Units: UnitsBytes})
 	go trackSomething(pw, &Tracker{Message: "Transferring Amount # 3", Total: 1000, Units: UnitsCurrencyDollar})
 	renderAndWait(pw, false)
@@ -623,6 +626,7 @@ func TestProgress_RenderSomeTrackers_WithOverallTracker(t *testing.T) {
 		regexp.MustCompile(`\x1b\[KDownloading File    # 2 \.\.\. done! \[\d+\.\d+KB in [\d.]+ms]`),
 		regexp.MustCompile(`\x1b\[KTransferring Amount # 3 \.\.\. done! \[\$\d+\.\d+K in [\d.]+ms]`),
 		regexp.MustCompile(`\x1b\[K\[[.#]+] \[[\d.ms]+; ~ETA: [\d.ms]+`),
+		regexp.MustCompile(`some information about something that happened at \d\d\d\d`),
 	}
 	out := renderOutput.String()
 	for _, expectedOutPattern := range expectedOutPatterns {

progress/writer.go

@@ -15,6 +15,7 @@ type Writer interface {
 	LengthActive() int
 	LengthDone() int
 	LengthInQueue() int
+	Log(msg string, a ...interface{})
 	SetAutoStop(autoStop bool)
 	SetMessageWidth(width int)
 	SetNumTrackersExpected(numTrackers int)