cmd: add --progress/-P flag to show progress

Fixes #2347
Fixes #1210

cmd/progress.go

@@ -0,0 +1,118 @@
+// Show the dynamic progress bar
+
+package cmd
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/ncw/rclone/fs"
+	"github.com/ncw/rclone/fs/accounting"
+	"github.com/ncw/rclone/fs/log"
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+const (
+	// interval between progress prints
+	defaultProgressInterval = 500 * time.Millisecond
+	// time format for logging
+	logTimeFormat = "2006-01-02 15:04:05"
+)
+
+// startProgress starts the progress bar printing
+//
+// It returns a channel which should be closed to stop the stats.
+func startProgress() chan struct{} {
+	stopStats := make(chan struct{})
+	oldLogPrint := fs.LogPrint
+	if !log.Redirected() {
+		// Intercept the log calls if not logging to file or syslog
+		fs.LogPrint = func(level fs.LogLevel, text string) {
+			printProgress(fmt.Sprintf("%s %-6s: %s", time.Now().Format(logTimeFormat), level, text))
+
+		}
+	}
+	go func() {
+		progressInterval := defaultProgressInterval
+		if ShowStats() {
+			progressInterval = *statsInterval
+		}
+		ticker := time.NewTicker(progressInterval)
+		for {
+			select {
+			case <-ticker.C:
+				printProgress("")
+			case <-stopStats:
+				ticker.Stop()
+				fs.LogPrint = oldLogPrint
+				fmt.Println("")
+				return
+			}
+		}
+	}()
+	return stopStats
+}
+
+// VT100 codes
+const (
+	eraseLine         = "\x1b[2K"
+	moveToStartOfLine = "\x1b[0G"
+	moveUp            = "\x1b[A"
+)
+
+// state for the progress printing
+var (
+	nlines     = 0 // number of lines in the previous stats block
+	progressMu sync.Mutex
+)
+
+// printProgress prings the progress with an optional log
+func printProgress(logMessage string) {
+	progressMu.Lock()
+	defer progressMu.Unlock()
+
+	var buf bytes.Buffer
+	w, h, err := terminal.GetSize(int(os.Stdout.Fd()))
+	if err != nil {
+		w, h = 80, 25
+	}
+	_ = h
+	stats := strings.TrimSpace(accounting.Stats.String())
+	logMessage = strings.TrimSpace(logMessage)
+
+	out := func(s string) {
+		buf.WriteString(s)
+	}
+
+	if logMessage != "" {
+		out("\n")
+		out(moveUp)
+	}
+	// Move to the start of the block we wrote erasing all the previous lines
+	for i := 0; i < nlines-1; i++ {
+		out(eraseLine)
+		out(moveUp)
+	}
+	out(eraseLine)
+	out(moveToStartOfLine)
+	if logMessage != "" {
+		out(eraseLine)
+		out(logMessage + "\n")
+	}
+	fixedLines := strings.Split(stats, "\n")
+	nlines = len(fixedLines)
+	for i, line := range fixedLines {
+		if len(line) > w {
+			line = line[:w]
+		}
+		out(line)
+		if i != nlines-1 {
+			out("\n")
+		}
+	}
+	os.Stdout.Write(buf.Bytes())
+}