progress: add new Clear() method to the progressBar

This commit adds a new `Clear()` method on the progressBar so
that we can clear subprogress easily. This is useful when switching
from image building to image uploading, here we need a single
progress again.

bib/internal/progress/progress.go

@@ -8,6 +8,7 @@ import (
 	"os"
 	"os/exec"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/cheggaaa/pb/v3"
@@ -39,10 +40,6 @@ type ProgressBar interface {
 	// SetProgress sets the progress details at the given "level".
 	// Levels should start with "0" and increase as the nesting
 	// gets deeper.
-	//
-	// Note that reducing depth is currently not supported, once
-	// a sub-progress is added it cannot be removed/hidden
-	// (but if required it can be added, its a SMOP)
 	SetProgress(level int, msg string, done int, total int) error
 
 	// The high-level message that is displayed in a spinner
@@ -58,6 +55,10 @@ type ProgressBar interface {
 	// like "Starting module org.osbuild.selinux"
 	SetMessagef(fmt string, args ...interface{})
 
+	// Clear clears all the subprogress/pulse/messages. This is
+	// useful when there is a need to reduce the sublevels.
+	Clear()
+
 	// Start will start rendering the progress information
 	Start()
 
@@ -89,7 +90,8 @@ type terminalProgressBar struct {
 
 	shutdownCh chan bool
 
-	out io.Writer
+	outMu sync.Mutex
+	out   io.Writer
 }
 
 // NewTerminalProgressBar creates a new default pb3 based progressbar suitable for
@@ -149,7 +151,29 @@ func (b *terminalProgressBar) SetMessagef(msg string, args ...interface{}) {
 	b.msgPb.Set("msg", shorten(fmt.Sprintf(msg, args...)))
 }
 
+func (b *terminalProgressBar) Clear() {
+	// ensure anything pending is output
+	b.render()
+
+	b.outMu.Lock()
+	defer b.outMu.Unlock()
+
+	// pulseMsg line + subLevel lines + message line
+	linesToClear := len(b.subLevelPbs) + 2
+	for i := 0; i < linesToClear; i++ {
+		fmt.Fprintf(b.out, "%s\n", ERASE_LINE)
+	}
+	fmt.Fprint(b.out, cursorUp(linesToClear))
+
+	b.subLevelPbs = nil
+	b.SetPulseMsgf("")
+	b.SetMessagef("")
+}
+
 func (b *terminalProgressBar) render() {
+	b.outMu.Lock()
+	defer b.outMu.Unlock()
+
 	var renderedLines int
 	fmt.Fprintf(b.out, "%s%s\n", ERASE_LINE, b.spinnerPb.String())
 	renderedLines++
@@ -262,6 +286,9 @@ func (b *plainProgressBar) SetProgress(subLevel int, msg string, done int, total
 	return nil
 }
 
+func (b *plainProgressBar) Clear() {
+}
+
 type debugProgressBar struct {
 	w io.Writer
 }
@@ -300,6 +327,9 @@ func (b *debugProgressBar) SetProgress(subLevel int, msg string, done int, total
 	fmt.Fprintf(b.w, "\n")
 	return nil
 }
+func (b *debugProgressBar) Clear() {
+	fmt.Fprintf(b.w, "Clear progressbar\n")
+}
 
 // XXX: merge variant back into images/pkg/osbuild/osbuild-exec.go
 func RunOSBuild(pb ProgressBar, manifest []byte, store, outputDirectory string, exports, extraEnv []string) error {

bib/internal/progress/progress_test.go

@@ -58,6 +58,8 @@ func TestPlainProgress(t *testing.T) {
 	assert.Equal(t, "", buf.String())
 	pbar.Stop()
 	assert.Equal(t, "", buf.String())
+	pbar.Clear()
+	assert.Equal(t, "", buf.String())
 }
 
 func TestDebugProgress(t *testing.T) {
@@ -87,6 +89,10 @@ func TestDebugProgress(t *testing.T) {
 	pbar.Stop()
 	assert.Equal(t, "Stop progressbar\n", buf.String())
 	buf.Reset()
+
+	pbar.Clear()
+	assert.Equal(t, "Clear progressbar\n", buf.String())
+	buf.Reset()
 }
 
 func TestTermProgress(t *testing.T) {
@@ -102,12 +108,15 @@ func TestTermProgress(t *testing.T) {
 	pbar.SetMessagef("some-message")
 	err = pbar.SetProgress(0, "set-progress-msg", 0, 5)
 	assert.NoError(t, err)
+	pbar.Clear()
 	pbar.Stop()
 	assert.NoError(t, pbar.(*progress.TerminalProgressBar).Err())
 
 	assert.Contains(t, buf.String(), "[1 / 6] set-progress-msg")
 	assert.Contains(t, buf.String(), "[|] pulse-msg\n")
 	assert.Contains(t, buf.String(), "Message: some-message\n")
+	// check clear (clear 3 lines)
+	assert.Contains(t, buf.String(), "\x1b[2K\n\x1b[2K\n\x1b[2K\n")
 	// check shutdown
 	assert.Contains(t, buf.String(), progress.CURSOR_SHOW)
 }