show progress

README.md

@@ -119,7 +119,8 @@ the self-deploy check).
   and rejected if they later change, same as normal SSH behavior.
 - Because every run re-hashes the whole destination, a re-sync costs a
   full read of both sides even when little changed — the win is in the
-  bytes transferred, not the bytes read.
+  bytes transferred, not the bytes read. That read shows on the status
+  line as a `scanning destination` phase before `syncing` begins.
 - `agent` is an internal subcommand spawned automatically by `sync`; it's
   not meant to be run by hand, though it will work standalone for
   debugging.

agent.go

@@ -75,16 +75,27 @@ func runControlAgent() error {
 	}
 }
 
-// readHashFrame reads one frameHashTable off fr and expands it.
-func readHashFrame(fr *FrameReader) ([][32]byte, error) {
-	typ, payload, err := fr.ReadFrame()
-	if err != nil {
-		return nil, fmt.Errorf("read hash table: %w", err)
+// readHashFrame reads frames off fr until the hash table arrives, relaying
+// any "scan" progress frames the sink sends while it hashes the destination
+// onward to the manager via out.
+func readHashFrame(fr *FrameReader, out *FrameWriter) ([][32]byte, error) {
+	for {
+		typ, payload, err := fr.ReadFrame()
+		if err != nil {
+			return nil, fmt.Errorf("read hash table: %w", err)
+		}
+		switch typ {
+		case frameHashTable:
+			return unflattenHashes(payload)
+		case frameCtrlJSON:
+			var m CtrlMsg
+			if json.Unmarshal(payload, &m) == nil && m.Type == msgProgress {
+				_ = out.WriteJSON(m)
+			}
+		default:
+			return nil, fmt.Errorf("expected hash table frame, got type %d", typ)
+		}
 	}
-	if typ != frameHashTable {
-		return nil, fmt.Errorf("expected hash table frame, got type %d", typ)
-	}
-	return unflattenHashes(payload)
 }
 
 func handleStat(out *FrameWriter, m CtrlMsg) {
@@ -174,7 +185,7 @@ func runPushDriver(req CtrlMsg, out *FrameWriter) {
 	// Handshake succeeded: we're committed to push for this run. The sink
 	// now sends the current per-block hashes of the destination it just
 	// read; the source loop compares against those to decide what to send.
-	hashes, err := readHashFrame(fr)
+	hashes, err := readHashFrame(fr, out)
 	if err != nil {
 		_ = cmd.Process.Kill()
 		_ = cmd.Wait()
@@ -422,7 +433,7 @@ func runPullDriver(req CtrlMsg, out *FrameWriter) {
 	}
 	defer dstFile.Close()
 
-	hashes, err := hashFileBlocks(dstFile, req.Size, req.BlockSize)
+	hashes, err := hashFileBlocks(dstFile, req.Size, req.BlockSize, scanProgressEmitter(out))
 	if err != nil {
 		_ = cmd.Process.Kill()
 		_ = cmd.Wait()
@@ -480,7 +491,7 @@ func runSinkRole(path string, size, blockSize int64) error {
 		return err
 	}
 
-	hashes, err := hashFileBlocks(f, size, blockSize)
+	hashes, err := hashFileBlocks(f, size, blockSize, scanProgressEmitter(out))
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "sink: hash %s: %v\n", path, err)
 		return err

ctrlmsg.go

@@ -40,10 +40,11 @@ type CtrlMsg struct {
 	Message string `json:"message,omitempty"`
 
 	// progress
-	Copied      int64 `json:"copied,omitempty"`
-	Skipped     int64 `json:"skipped,omitempty"`
-	TotalBlocks int64 `json:"totalBlocks,omitempty"`
-	BytesCopied int64 `json:"bytesCopied,omitempty"`
+	Phase       string `json:"phase,omitempty"` // "scan" while hashing the destination; empty during transfer
+	Copied      int64  `json:"copied,omitempty"`
+	Skipped     int64  `json:"skipped,omitempty"`
+	TotalBlocks int64  `json:"totalBlocks,omitempty"`
+	BytesCopied int64  `json:"bytesCopied,omitempty"`
 
 	// log
 	Level string `json:"level,omitempty"`

manager.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"os"
 	"strings"
+	"time"
 )
 
 const defaultBlockSize = 4 * 1024 * 1024
@@ -85,7 +86,8 @@ func runSync(cfg SyncConfig) error {
 
 	blockCount := (targetSize + cfg.BlockSize - 1) / cfg.BlockSize
 
-	cb := transferCallbacks{onProgress: func(m CtrlMsg) { printProgress(m) }}
+	pp := newProgressPrinter(cfg.BlockSize)
+	cb := transferCallbacks{onProgress: pp.print}
 
 	bothLocal := srcSpec.IsLocal() && dstSpec.IsLocal()
 	srcHost, srcUser := resolveConnectHost(srcSpec, &cfg)
@@ -107,6 +109,7 @@ func runSync(cfg SyncConfig) error {
 		return err
 	}
 	if !ok {
+		pp.finish()
 		fmt.Fprintf(os.Stderr, "push not possible (%s); trying pull %s <- %s ...\n", reason, dstSpec, srcSpec)
 		pullReq := CtrlMsg{
 			Path: dstSpec.Path, Size: targetSize, BlockSize: cfg.BlockSize,
@@ -126,7 +129,7 @@ func runSync(cfg SyncConfig) error {
 		}
 	}
 
-	fmt.Fprintln(os.Stderr)
+	pp.finish()
 	label := cfg.Job
 	if label == "" {
 		label = fmt.Sprintf("%s -> %s", srcSpec, dstSpec)
@@ -226,10 +229,84 @@ func confirmShrink(dstSpec Spec, oldSize, newSize int64) bool {
 	return line == "y" || line == "yes"
 }
 
-func printProgress(m CtrlMsg) {
+// progressPrinter renders a single rewriting status line on stderr for both
+// phases of a run: "scan" while a side hashes the destination, then the
+// block transfer itself (with a rolling copy rate).
+type progressPrinter struct {
+	blockSize  int64
+	start      time.Time
+	lastT      time.Time
+	lastCopied int64
+	rate       float64 // copied blocks/sec, smoothed
+	active     bool
+}
+
+func newProgressPrinter(blockSize int64) *progressPrinter {
+	now := time.Now()
+	return &progressPrinter{blockSize: blockSize, start: now, lastT: now}
+}
+
+func (p *progressPrinter) print(m CtrlMsg) {
+	p.active = true
+	if m.Phase == "scan" {
+		fmt.Fprintf(os.Stderr, "\r  scanning destination %s %s/%s blocks          ",
+			progressBar(m.Copied, m.TotalBlocks),
+			formatCount(m.Copied), formatCount(m.TotalBlocks))
+		return
+	}
+
+	done := m.Copied + m.Skipped
 	total := m.TotalBlocks
 	if total <= 0 {
-		total = m.Copied + m.Skipped
+		total = done
+	}
+
+	now := time.Now()
+	if dt := now.Sub(p.lastT).Seconds(); dt >= 0.4 {
+		inst := float64(m.Copied-p.lastCopied) / dt
+		if p.rate == 0 {
+			p.rate = inst
+		} else {
+			p.rate = 0.6*p.rate + 0.4*inst
+		}
+		p.lastT, p.lastCopied = now, m.Copied
+	}
+	mib := p.rate * float64(p.blockSize) / (1024 * 1024)
+
+	fmt.Fprintf(os.Stderr, "\r  syncing %s %s/%s  copied=%s skipped=%s  %6.1f MiB/s          ",
+		progressBar(done, total), formatCount(done), formatCount(total),
+		formatCount(m.Copied), formatCount(m.Skipped), mib)
+}
+
+// finish ends the current status line with a newline so following output
+// (and the shell prompt) starts clean.
+func (p *progressPrinter) finish() {
+	if p.active {
+		fmt.Fprintln(os.Stderr)
+		p.active = false
+	}
+}
+
+func progressBar(done, total int64) string {
+	const w = 22
+	pct := 0
+	if total > 0 {
+		pct = int(done * 100 / total)
+	}
+	if pct > 100 {
+		pct = 100
+	}
+	n := pct * w / 100
+	return fmt.Sprintf("[%s%s] %3d%%", strings.Repeat("=", n), strings.Repeat(" ", w-n), pct)
+}
+
+func formatCount(n int64) string {
+	switch {
+	case n >= 1_000_000:
+		return fmt.Sprintf("%.1fM", float64(n)/1e6)
+	case n >= 10_000:
+		return fmt.Sprintf("%.0fk", float64(n)/1e3)
+	default:
+		return fmt.Sprintf("%d", n)
 	}
-	fmt.Fprintf(os.Stderr, "\rblocks: %d/%d  copied=%d skipped=%d          ", m.Copied+m.Skipped, total, m.Copied, m.Skipped)
 }

syncside.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"time"
 )
 
 // readBlockAt reads exactly min(len(buf), totalSize-offset) bytes at offset,
@@ -30,21 +31,41 @@ func readBlockAt(f *os.File, buf []byte, offset, totalSize int64) (int, error) {
 // hashFileBlocks reads f in blockSize-byte blocks up to size and returns the
 // SHA-256 of each. This is how a destination fingerprints its *current*
 // content at the start of every sync — clonetool keeps no hash state of its
-// own between runs.
-func hashFileBlocks(f *os.File, size, blockSize int64) ([][32]byte, error) {
+// own between runs. onProgress, if non-nil, is called with (blocksHashed,
+// totalBlocks) before the first block and after each one.
+func hashFileBlocks(f *os.File, size, blockSize int64, onProgress func(done, total int64)) ([][32]byte, error) {
 	blockCount := (size + blockSize - 1) / blockSize
 	out := make([][32]byte, blockCount)
 	buf := make([]byte, blockSize)
+	if onProgress != nil {
+		onProgress(0, blockCount)
+	}
 	for i := int64(0); i < blockCount; i++ {
 		n, err := readBlockAt(f, buf, i*blockSize, size)
 		if err != nil {
 			return nil, fmt.Errorf("hash %s at block %d: %w", f.Name(), i, err)
 		}
 		out[i] = sha256.Sum256(buf[:n])
+		if onProgress != nil {
+			onProgress(i+1, blockCount)
+		}
 	}
 	return out, nil
 }
 
+// scanProgressEmitter returns an onProgress callback for hashFileBlocks that
+// forwards "scan" phase progress onto out, throttled to ~3/second.
+func scanProgressEmitter(out *FrameWriter) func(done, total int64) {
+	var last time.Time
+	return func(done, total int64) {
+		if done != 0 && done != total && time.Since(last) < 350*time.Millisecond {
+			return
+		}
+		last = time.Now()
+		_ = out.WriteJSON(CtrlMsg{Type: msgProgress, Phase: "scan", Copied: done, TotalBlocks: total})
+	}
+}
+
 // sourceLoopParams drives the single read -> hash -> compare -> maybe-send
 // pass over a source path. It is used both by the standalone
 // "source-stream" role (writing to its own stdout) and by a source control