cmd/tailscale/cli/file.go

@@ -32,6 +32,7 @@ import (
 	"tailscale.com/client/tailscale/apitype"
 	"tailscale.com/cmd/tailscale/cli/ffcomplete"
 	"tailscale.com/envknob"
+	"tailscale.com/ipn"
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/net/tsaddr"
 	"tailscale.com/tailcfg"
@@ -78,14 +79,16 @@ var fileCpCmd = &ffcli.Command{
 		fs.StringVar(&cpArgs.name, "name", "", "alternate filename to use, especially useful when <file> is \"-\" (stdin)")
 		fs.BoolVar(&cpArgs.verbose, "verbose", false, "verbose output")
 		fs.BoolVar(&cpArgs.targets, "targets", false, "list possible file cp targets")
+		fs.DurationVar(&cpArgs.updateInterval, "update-interval", 250*time.Millisecond, "how often to repaint the progress line; zero or negative disables progress display entirely")
 		return fs
 	})(),
 }
 
 var cpArgs struct {
-	name    string
-	verbose bool
-	targets bool
+	name           string
+	verbose        bool
+	targets        bool
+	updateInterval time.Duration
 }
 
 func runCp(ctx context.Context, args []string) error {
@@ -119,9 +122,6 @@ func runCp(ctx context.Context, args []string) error {
 	if err != nil {
 		return fmt.Errorf("can't send to %s: %v", target, err)
 	}
-	if isOffline {
-		fmt.Fprintf(Stderr, "# warning: %s is offline\n", target)
-	}
 
 	if len(files) > 1 {
 		if cpArgs.name != "" {
@@ -132,7 +132,51 @@ func runCp(ctx context.Context, args []string) error {
 		}
 	}
 
-	for _, fileArg := range files {
+	// outFiles tracks per-name push state, populated by a goroutine subscribed
+	// to the IPN bus. tailscaled's OutgoingFile.Sent is the bytes-pulled-toward-
+	// peerAPI signal; it stays at 0 until the peerAPI request body is actually
+	// being read, which is what we want both for the progress display and for
+	// disarming the offline warning. The CLI's local-side bytes counter would
+	// say "100% sent" the moment net/http buffers a small body into the local
+	// unix-socket conn to tailscaled, well before the peer has heard a thing.
+	type pushState struct {
+		sent      atomic.Int64
+		warnTimer *time.Timer // disarmed on first byte sent to peerAPI; nil after
+	}
+	var (
+		outMu    sync.Mutex
+		outFiles = map[string]*pushState{} // keyed by file name
+	)
+
+	busCtx, cancelBus := context.WithCancel(ctx)
+	defer cancelBus()
+	go watchOutgoingFiles(busCtx, stableID, func(name string, sent int64) {
+		outMu.Lock()
+		ps := outFiles[name]
+		outMu.Unlock()
+		if ps == nil {
+			return
+		}
+		// Only ever advance ps.sent forward. Bus updates can arrive late
+		// (after the success path below has already written contentLength
+		// to ps.sent for an instant final-100% paint), so we'd otherwise
+		// regress the count and the progress printer would compute a
+		// negative delta on its next tick.
+		for {
+			old := ps.sent.Load()
+			if sent <= old {
+				return
+			}
+			if ps.sent.CompareAndSwap(old, sent) {
+				if old == 0 && ps.warnTimer != nil {
+					ps.warnTimer.Stop()
+				}
+				return
+			}
+		}
+	})
+
+	for i, fileArg := range files {
 		var fileContents *countingReader
 		var name = cpArgs.name
 		var contentLength int64 = -1
@@ -175,16 +219,57 @@ func runCp(ctx context.Context, args []string) error {
 			log.Printf("sending %q to %v/%v/%v ...", name, target, ip, stableID)
 		}
 
+		// Register this file with the watcher and, for the first file only,
+		// arm a timer that warns the user if no bytes have flowed to peerAPI
+		// after a few seconds. The watcher disarms it on first byte; PushFile
+		// returning also disarms it (cleanup, below). We don't gate on the
+		// netmap's Online bit (which can lag reality), but we do use it to
+		// pick between two warning messages.
+		ps := &pushState{}
+		if i == 0 {
+			ps.warnTimer = time.AfterFunc(3*time.Second, func() {
+				// vtRestartLine clears whatever (possibly progress) was on
+				// the current line, then we print the warning + \n so the
+				// next progress redraw lands on a fresh line below.
+				const vtRestartLine = "\r\x1b[K"
+				if isOffline {
+					fmt.Fprintf(Stderr, "%s# warning: %s is reportedly offline; trying anyway\n", vtRestartLine, target)
+				} else {
+					fmt.Fprintf(Stderr, "%s# warning: %s is not replying; trying anyway\n", vtRestartLine, target)
+				}
+			})
+		}
+		outMu.Lock()
+		outFiles[name] = ps
+		outMu.Unlock()
+
 		var group sync.WaitGroup
 		ctxProgress, cancelProgress := context.WithCancel(ctx)
 		defer cancelProgress()
-		if isatty.IsTerminal(os.Stderr.Fd()) {
-			group.Go(func() { progressPrinter(ctxProgress, name, fileContents.n.Load, contentLength) })
+		if cpArgs.updateInterval > 0 && isatty.IsTerminal(os.Stderr.Fd()) {
+			group.Go(func() {
+				progressPrinter(ctxProgress, name, ps.sent.Load, contentLength, cpArgs.updateInterval)
+			})
 		}
 
 		err := localClient.PushFile(ctx, stableID, contentLength, name, fileContents)
+		if err == nil {
+			// PushFile can finish faster than the IPN bus delivers a final
+			// OutgoingFile update, leaving the progress display stuck at 0%.
+			// Synthesize a "fully done" count before stopping the printer so
+			// its final paint shows 100%. For stdin (contentLength == -1) we
+			// don't know the size, so fall back to the local read count.
+			if contentLength >= 0 {
+				ps.sent.Store(contentLength)
+			} else {
+				ps.sent.Store(fileContents.n.Load())
+			}
+		}
 		cancelProgress()
 		group.Wait() // wait for progress printer to stop before reporting the error
+		if ps.warnTimer != nil {
+			ps.warnTimer.Stop()
+		}
 		if err != nil {
 			return err
 		}
@@ -195,15 +280,71 @@ func runCp(ctx context.Context, args []string) error {
 	return nil
 }
 
-func progressPrinter(ctx context.Context, name string, contentCount func() int64, contentLength int64) {
+// watchOutgoingFiles subscribes to the IPN bus and invokes onUpdate once
+// per OutgoingFile event for files going to peer. It runs until ctx is
+// done (which runCp does on return) and is best-effort: if the bus
+// subscription fails for any reason, onUpdate simply isn't called and the
+// caller's progress display stays at 0 — exactly the right degradation,
+// since the warning timer will then fire on its normal 3-second deadline.
+func watchOutgoingFiles(ctx context.Context, peer tailcfg.StableNodeID, onUpdate func(name string, sent int64)) {
+	// NotifyPeerChanges asks the broadcaster to deliver incremental peer
+	// updates as small PeerChanges blobs in place of the full NetMap, which
+	// we don't read anyway. (See ipn/ipnlocal/local.go's notify-elision.)
+	w, err := localClient.WatchIPNBus(ctx, ipn.NotifyInitialOutgoingFiles|ipn.NotifyPeerChanges)
+	if err != nil {
+		return
+	}
+	defer w.Close()
+	for {
+		n, err := w.Next()
+		if err != nil {
+			return
+		}
+		for _, of := range n.OutgoingFiles {
+			if of.PeerID != peer {
+				continue
+			}
+			// tailscaled keeps Finished entries in its OutgoingFiles map
+			// across PushFile calls (see feature/taildrop/ext.go), so a
+			// re-send of the same filename will see both the old completed
+			// (Sent == DeclaredSize) entry and the new in-progress one.
+			// Without this filter the watcher's monotonic CAS would latch
+			// onto the old entry's max value and the new transfer would
+			// appear stuck at 100% from the first bus tick.
+			if of.Finished {
+				continue
+			}
+			onUpdate(of.Name, of.Sent)
+		}
+	}
+}
+
+// progressPrinter repaints a single-line transfer progress display every
+// interval. interval must be > 0; runCp's caller gates on the
+// --update-interval flag and skips invoking us when it's <= 0.
+//
+// It returns when ctx is done OR when it detects the transfer is stuck —
+// "stuck" being: contentCount has equalled contentLength with a near-zero
+// rate for >2 seconds. The stuck case prints a final newline so subsequent
+// output (e.g. an error from PushFile) lands on a fresh line below the
+// frozen progress line, instead of being painted over by it.
+func progressPrinter(ctx context.Context, name string, contentCount func() int64, contentLength int64, interval time.Duration) {
 	var rateValueFast, rateValueSlow tsrate.Value
-	rateValueFast.HalfLife = 1 * time.Second  // fast response for rate measurement
-	rateValueSlow.HalfLife = 10 * time.Second // slow response for ETA measurement
+	// tailscaled emits OutgoingFile.Sent updates at ~1 Hz, so most printer
+	// ticks see no delta. With too short a half-life the displayed rate
+	// roughly halves between updates and doubles back when one arrives,
+	// looking jumpy. 5s keeps the swing under ~15% while still settling
+	// within a few seconds of a real change.
+	rateValueFast.HalfLife = 5 * time.Second  // smoothed rate for display
+	rateValueSlow.HalfLife = 10 * time.Second // even slower, for ETA measurement
 	var prevContentCount int64
 	print := func() {
 		currContentCount := contentCount()
-		rateValueFast.Add(float64(currContentCount - prevContentCount))
-		rateValueSlow.Add(float64(currContentCount - prevContentCount))
+		// Clamp so a regression (which shouldn't happen, but tsrate.Value.Add
+		// panics on a negative count) can't take down the CLI.
+		delta := max(currContentCount-prevContentCount, 0)
+		rateValueFast.Add(float64(delta))
+		rateValueSlow.Add(float64(delta))
 		prevContentCount = currContentCount
 
 		const vtRestartLine = "\r\x1b[K"
@@ -215,16 +356,23 @@ func progressPrinter(ctx context.Context, name string, contentCount func() int64
 		if contentLength >= 0 {
 			currContentCount = min(currContentCount, contentLength) // cap at 100%
 			ratioRemain := float64(currContentCount) / float64(contentLength)
-			bytesRemain := float64(contentLength - currContentCount)
-			secsRemain := bytesRemain / rateValueSlow.Rate()
-			secs := int(min(max(0, secsRemain), 99*60*60+59+60+59))
+			etaStr := "ETA -"
+			if rate := rateValueSlow.Rate(); rate > 0 {
+				bytesRemain := float64(contentLength - currContentCount)
+				secsRemain := bytesRemain / rate
+				secs := int(min(max(0, secsRemain), 99*60*60+59+60+59))
+				etaStr = fmt.Sprintf("ETA %02d:%02d:%02d", secs/60/60, (secs/60)%60, secs%60)
+			}
 			fmt.Fprintf(os.Stderr, "    %s    %s",
 				leftPad(fmt.Sprintf("%0.2f%%", 100.0*ratioRemain), len("100.00%")),
-				fmt.Sprintf("ETA %02d:%02d:%02d", secs/60/60, (secs/60)%60, secs%60))
+				etaStr)
 		}
 	}
 
-	tc := time.NewTicker(250 * time.Millisecond)
+	const stuckAfter = 2 * time.Second
+	var fullStartedAt time.Time // when we first observed currCount==contentLength with ~zero rate
+
+	tc := time.NewTicker(interval)
 	defer tc.Stop()
 	print()
 	for {
@@ -235,6 +383,24 @@ func progressPrinter(ctx context.Context, name string, contentCount func() int64
 			return
 		case <-tc.C:
 			print()
+			if contentLength < 0 {
+				continue
+			}
+			currCount := contentCount()
+			rate := rateValueFast.Rate()
+			if currCount >= contentLength && rate < 1 {
+				if fullStartedAt.IsZero() {
+					fullStartedAt = time.Now()
+				} else if time.Since(fullStartedAt) >= stuckAfter {
+					// Transfer is stuck at 100% with no movement. Stop
+					// repainting so we don't keep clobbering anything the
+					// rest of runCp prints (warnings, errors).
+					fmt.Fprintln(os.Stderr)
+					return
+				}
+			} else {
+				fullStartedAt = time.Time{}
+			}
 		}
 	}
 }
@@ -328,7 +494,10 @@ peerLoop:
 		return "", isOffline, errors.New("cannot send files: missing required Taildrop capability")
 
 	case ipnstate.TaildropTargetOffline:
-		return "", isOffline, errors.New("cannot send files: peer is offline")
+		// Don't gate on the server-reported Online bit (which lags reality
+		// and isn't always accurate). runCp probes reachability itself with
+		// TSMP pings.
+		return foundPeer.ID, isOffline, nil
 
 	case ipnstate.TaildropTargetNoPeerInfo:
 		return "", isOffline, errors.New("cannot send files: invalid or unrecognized peer")