rework size estimation & dry sends

- use control connection (gRPC)
- use uint64 everywhere => fixes https://github.com/zrepl/zrepl/issues/463
- [BREAK] bump protocol version

closes https://github.com/zrepl/zrepl/pull/518
fixes https://github.com/zrepl/zrepl/issues/463

client/status/viewmodel/bytecountbinary.go

@@ -2,14 +2,22 @@ package viewmodel
 
 import (
 	"fmt"
+	"math"
 )
 
+func ByteCountBinaryUint(b uint64) string {
+	if b > math.MaxInt64 {
+		panic(b)
+	}
+	return ByteCountBinary(int64(b))
+}
+
 func ByteCountBinary(b int64) string {
 	const unit = 1024
 	if b < unit {
 		return fmt.Sprintf("%d B", b)
 	}
-	div, exp := int64(unit), 0
+	div, exp := unit, 0
 	for n := b / unit; n >= unit; n /= unit {
 		div *= unit
 		exp++

client/status/viewmodel/bytesprogresshistory.go

@@ -4,7 +4,7 @@ import "time"
 
 type byteProgressMeasurement struct {
 	time time.Time
-	val  int64
+	val  uint64
 }
 
 type bytesProgressHistory struct {
@@ -13,7 +13,7 @@ type bytesProgressHistory struct {
 	lastChange  time.Time
 }
 
-func (p *bytesProgressHistory) Update(currentVal int64) (bytesPerSecondAvg int64, changeCount int) {
+func (p *bytesProgressHistory) Update(currentVal uint64) (bytesPerSecondAvg int64, changeCount int) {
 
 	if p.last == nil {
 		p.last = &byteProgressMeasurement{
@@ -33,7 +33,12 @@ func (p *bytesProgressHistory) Update(currentVal int64) (bytesPerSecondAvg int64
 		return 0, 0
 	}
 
-	deltaV := currentVal - p.last.val
+	var deltaV int64
+	if currentVal >= p.last.val {
+		deltaV = int64(currentVal - p.last.val)
+	} else {
+		deltaV = -int64(p.last.val - currentVal)
+	}
 	deltaT := time.Since(p.last.time)
 	rate := float64(deltaV) / deltaT.Seconds()
 

client/status/viewmodel/render.go

@@ -230,7 +230,7 @@ func printFilesystemStatus(t *stringbuilder.B, rep *report.FilesystemReport, act
 	status := fmt.Sprintf("%s (step %d/%d, %s/%s)%s",
 		strings.ToUpper(string(rep.State)),
 		rep.CurrentStep, len(rep.Steps),
-		ByteCountBinary(replicated), ByteCountBinary(expected),
+		ByteCountBinaryUint(replicated), ByteCountBinaryUint(expected),
 		sizeEstimationImpreciseNotice,
 	)
 
@@ -358,12 +358,12 @@ func renderReplicationReport(t *stringbuilder.B, rep *report.Report, history *by
 		rate, changeCount := history.Update(replicated)
 		eta := time.Duration(0)
 		if rate > 0 {
-			eta = time.Duration((expected-replicated)/rate) * time.Second
+			eta = time.Duration((float64(expected)-float64(replicated))/float64(rate)) * time.Second
 		}
 
 		t.Write("Progress: ")
 		t.DrawBar(50, replicated, expected, changeCount)
-		t.Write(fmt.Sprintf(" %s / %s @ %s/s", ByteCountBinary(replicated), ByteCountBinary(expected), ByteCountBinary(rate)))
+		t.Write(fmt.Sprintf(" %s / %s @ %s/s", ByteCountBinaryUint(replicated), ByteCountBinaryUint(expected), ByteCountBinary(rate)))
 		if eta != 0 {
 			t.Write(fmt.Sprintf(" (%s remaining)", humanizeDuration(eta)))
 		}

client/status/viewmodel/stringbuilder/stringbuilder.go

@@ -99,11 +99,11 @@ func RightPad(str string, length int, pad string) string {
 }
 
 // changeCount = 0 indicates stall / no progress
-func (w *B) DrawBar(length int, bytes, totalBytes int64, changeCount int) {
+func (w *B) DrawBar(length int, bytes, totalBytes uint64, changeCount int) {
 	const arrowPositions = `>\|/`
 	var completedLength int
 	if totalBytes > 0 {
-		completedLength = int(int64(length) * bytes / totalBytes)
+		completedLength = int(uint64(length) * bytes / totalBytes)
 		if completedLength > length {
 			completedLength = length
 		}