Refactoring: new packages console, http, Progress is interface.

console/progress.go

@@ -0,0 +1,134 @@
+package console
+
+import (
+	"fmt"
+	"github.com/cheggaaa/pb"
+	"github.com/smira/aptly/aptly"
+)
+
+const (
+	codePrint = iota
+	codeProgress
+	codeHideProgress
+)
+
+type printTask struct {
+	code    int
+	message string
+}
+
+// Progress is a progress displaying subroutine, it allows to show download and other operations progress
+// mixed with progress bar
+type Progress struct {
+	stop     chan bool
+	stopped  chan bool
+	queue    chan printTask
+	bar      *pb.ProgressBar
+	barShown bool
+}
+
+// Check interface
+var (
+	_ aptly.Progress = (*Progress)(nil)
+)
+
+// NewProgress creates new progress instance
+func NewProgress() *Progress {
+	return &Progress{
+		stop:    make(chan bool),
+		stopped: make(chan bool),
+		queue:   make(chan printTask, 100),
+	}
+}
+
+// Start makes progress start its work
+func (p *Progress) Start() {
+	go p.worker()
+}
+
+// Shutdown shuts down progress display
+func (p *Progress) Shutdown() {
+	p.ShutdownBar()
+	p.stop <- true
+	<-p.stopped
+}
+
+// InitBar starts progressbar for count bytes or count items
+func (p *Progress) InitBar(count int64, isBytes bool) {
+	if p.bar != nil {
+		panic("bar already initialized")
+	}
+	if RunningOnTerminal() {
+		p.bar = pb.New(0)
+		p.bar.Total = count
+		p.bar.NotPrint = true
+		p.bar.Callback = func(out string) {
+			p.queue <- printTask{code: codeProgress, message: out}
+		}
+
+		if isBytes {
+			p.bar.SetUnits(pb.U_BYTES)
+			p.bar.ShowSpeed = true
+		}
+		p.bar.Start()
+	}
+}
+
+// ShutdownBar stops progress bar and hides it
+func (p *Progress) ShutdownBar() {
+	if p.bar == nil {
+		return
+	}
+	p.bar.Finish()
+	p.bar = nil
+	p.queue <- printTask{code: codeHideProgress}
+}
+
+// Write is implementation of io.Writer to support updating of progress bar
+func (p *Progress) Write(s []byte) (int, error) {
+	if p.bar != nil {
+		p.bar.Add(len(s))
+	}
+	return len(s), nil
+}
+
+// AddBar increments progress for progress bar
+func (p *Progress) AddBar(count int) {
+	if p.bar != nil {
+		p.bar.Add(count)
+	}
+}
+
+// Printf does printf but in safe manner: not overwriting progress bar
+func (p *Progress) Printf(msg string, a ...interface{}) {
+	p.queue <- printTask{code: codePrint, message: fmt.Sprintf(msg, a...)}
+}
+
+func (p *Progress) worker() {
+	for {
+		select {
+		case task := <-p.queue:
+			switch task.code {
+			case codePrint:
+				if p.barShown {
+					fmt.Print("\r\033[2K")
+					p.barShown = false
+				}
+				fmt.Print(task.message)
+			case codeProgress:
+				if p.bar != nil {
+					fmt.Print("\r" + task.message)
+					p.barShown = true
+				}
+			case codeHideProgress:
+				if p.barShown {
+					fmt.Print("\r\033[2K")
+					p.barShown = false
+				}
+			}
+		case <-p.stop:
+			p.stopped <- true
+			return
+		}
+	}
+}