make progress output optional

cmd/cachectl/main.go

@@ -19,7 +19,7 @@ import (
 )
 
 var (
-	version string
+	progress bool
 )
 
 const gib = 1024 * 1024 * 1024
@@ -72,9 +72,13 @@ remove file (uses `+srcKey+`):
 
   rm file:///mnt/nfs /buzz.txt
 
+options
+  -p  show copy progress
+
 `)
 		os.Exit(1)
 	}
+	flag.BoolVar(&progress, "p", false, "show copy progress")
 	flag.Parse()
 
 	args := flag.Args()
@@ -180,18 +184,24 @@ func cp(args []string) (err error) {
 		return
 	}
 	defer df.Close()
-	fi, err := sf.Stat()
+	if progress {
-	if err != nil {
+		fi, err := sf.Stat()
-		return
+		if err != nil {
+			return err
+		}
+		r := &progressReader{
+			f:    sf,
+			done: make(chan struct{}),
+			size: fi.Size(),
+		}
+		go r.Progress()
+		_, err = io.Copy(df, r)
+		close(r.done)
+		r.Print()
+		fmt.Println()
+	} else {
+		_, err = io.Copy(df, sf)
 	}
-	r := &progressReader{
-		f:    sf,
-		done: make(chan struct{}),
-		size: fi.Size(),
-	}
-	go r.PrintProgress()
-	_, err = io.Copy(df, r)
-	close(r.done)
 	return
 }
 
@@ -214,19 +224,21 @@ func (p *progressReader) ReadAt(b []byte, off int64) (n int, err error) {
 	return
 }
 
-func (p *progressReader) PrintProgress() {
+func (p *progressReader) Print() {
+	n := atomic.LoadInt64(&p.n)
+	percent := int(math.Round(float64(n) / float64(p.size) * 100))
+	fmt.Printf("progress: %d / %d %d%%\r", n, p.size, percent)
+}
+
+func (p *progressReader) Progress() {
 	for {
 		select {
 		case <-p.done:
-			fmt.Println()
 			return
 		case <-time.After(time.Millisecond * 500):
 		}
-		n := atomic.LoadInt64(&p.n)
+		p.Print()
-		percent := int(math.Round(float64(n) / float64(p.size) * 100))
-		fmt.Printf("progress: %d / %d %d%%\r", n, p.size, percent)
 	}
-	return
 }
 
 func rm(args []string) (err error) {