From 69c2e8ce7e2a83639471242f898b84c820da0d3a Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Thu, 4 Aug 2016 19:42:40 +0200
Subject: [PATCH] Add first version of the `prune` command

---
 src/cmds/restic/cmd_prune.go | 199 +++++++++++++++++++++++++++++++++++
 1 file changed, 199 insertions(+)
 create mode 100644 src/cmds/restic/cmd_prune.go

diff --git a/src/cmds/restic/cmd_prune.go b/src/cmds/restic/cmd_prune.go
new file mode 100644
index 000000000..f0c87fb84
--- /dev/null
+++ b/src/cmds/restic/cmd_prune.go
@@ -0,0 +1,199 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"restic"
+	"restic/backend"
+	"restic/debug"
+	"restic/list"
+	"restic/pack"
+	"restic/repository"
+	"restic/worker"
+	"time"
+
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+// CmdPrune implements the 'prune' command.
+type CmdPrune struct {
+	global *GlobalOptions
+}
+
+func init() {
+	_, err := parser.AddCommand("prune",
+		"removes content from a repository",
+		"The prune command removes rendundant and unneeded data from the repository",
+		&CmdPrune{global: &globalOpts})
+	if err != nil {
+		panic(err)
+	}
+}
+
+// newProgressMax returns a progress that counts blobs.
+func newProgressMax(show bool, max uint64, description string) *restic.Progress {
+	if !show {
+		return nil
+	}
+
+	p := restic.NewProgress(time.Second)
+
+	p.OnUpdate = func(s restic.Stat, d time.Duration, ticker bool) {
+		status := fmt.Sprintf("[%s] %s  %d / %d %s",
+			formatDuration(d),
+			formatPercent(s.Blobs, max),
+			s.Blobs, max, description)
+
+		w, _, err := terminal.GetSize(int(os.Stdout.Fd()))
+		if err == nil {
+			if len(status) > w {
+				max := w - len(status) - 4
+				status = status[:max] + "... "
+			}
+		}
+
+		fmt.Printf("\x1b[2K%s\r", status)
+	}
+
+	p.OnDone = func(s restic.Stat, d time.Duration, ticker bool) {
+		p.OnUpdate(s, d, false)
+		fmt.Printf("\n")
+	}
+
+	return p
+}
+
+// Execute runs the 'prune' command.
+func (cmd CmdPrune) Execute(args []string) error {
+	repo, err := cmd.global.OpenRepository()
+	if err != nil {
+		return err
+	}
+
+	lock, err := lockRepoExclusive(repo)
+	defer unlockRepo(lock)
+	if err != nil {
+		return err
+	}
+
+	err = repo.LoadIndex()
+	if err != nil {
+		return err
+	}
+
+	done := make(chan struct{})
+	defer close(done)
+
+	cmd.global.Verbosef("loading list of files from the repo\n")
+
+	var stats struct {
+		blobs     int
+		packs     int
+		snapshots int
+	}
+
+	packs := make(map[backend.ID]pack.BlobSet)
+	for packID := range repo.List(backend.Data, done) {
+		debug.Log("CmdPrune.Execute", "found %v", packID.Str())
+		packs[packID] = pack.NewBlobSet()
+		stats.packs++
+	}
+
+	cmd.global.Verbosef("listing %v files\n", stats.packs)
+
+	blobCount := make(map[backend.ID]int)
+	duplicateBlobs := 0
+	duplicateBytes := 0
+	rewritePacks := backend.NewIDSet()
+
+	ch := make(chan worker.Job)
+	go list.AllPacks(repo, ch, done)
+
+	bar := newProgressMax(cmd.global.ShowProgress(), uint64(len(packs)), "files")
+	bar.Start()
+	for job := range ch {
+		packID := job.Data.(backend.ID)
+		if job.Error != nil {
+			cmd.global.Warnf("unable to list pack %v: %v\n", packID.Str(), job.Error)
+			continue
+		}
+
+		j := job.Result.(list.Result)
+
+		debug.Log("CmdPrune.Execute", "pack %v contains %d blobs", packID.Str(), len(j.Entries()))
+		for _, pb := range j.Entries() {
+			packs[packID].Insert(pack.Handle{ID: pb.ID, Type: pb.Type})
+			stats.blobs++
+			blobCount[pb.ID]++
+
+			if blobCount[pb.ID] > 1 {
+				duplicateBlobs++
+				duplicateBytes += int(pb.Length)
+			}
+		}
+		bar.Report(restic.Stat{Blobs: 1})
+	}
+	bar.Done()
+
+	cmd.global.Verbosef("processed %d blobs: %d duplicate blobs, %d duplicate bytes\n",
+		stats.blobs, duplicateBlobs, duplicateBytes)
+	cmd.global.Verbosef("load all snapshots\n")
+
+	snapshots, err := restic.LoadAllSnapshots(repo)
+	if err != nil {
+		return err
+	}
+
+	stats.snapshots = len(snapshots)
+
+	cmd.global.Verbosef("find data that is still in use for %d snapshots\n", stats.snapshots)
+
+	usedBlobs := pack.NewBlobSet()
+	seenBlobs := pack.NewBlobSet()
+
+	bar = newProgressMax(cmd.global.ShowProgress(), uint64(len(snapshots)), "snapshots")
+	bar.Start()
+	for _, sn := range snapshots {
+		debug.Log("CmdPrune.Execute", "process snapshot %v", sn.ID().Str())
+
+		err = restic.FindUsedBlobs(repo, *sn.Tree, usedBlobs, seenBlobs)
+		if err != nil {
+			return err
+		}
+
+		debug.Log("CmdPrune.Execute", "found %v blobs for snapshot %v", sn.ID().Str())
+		bar.Report(restic.Stat{Blobs: 1})
+	}
+	bar.Done()
+
+	cmd.global.Verbosef("found %d of %d data blobs still in use\n", len(usedBlobs), stats.blobs)
+
+	for packID, blobSet := range packs {
+		for h := range blobSet {
+			if !usedBlobs.Has(h) {
+				rewritePacks.Insert(packID)
+			}
+
+			if blobCount[h.ID] > 1 {
+				rewritePacks.Insert(packID)
+			}
+		}
+	}
+
+	cmd.global.Verbosef("will rewrite %d packs\n", len(rewritePacks))
+
+	err = repository.Repack(repo, rewritePacks, usedBlobs)
+	if err != nil {
+		return err
+	}
+
+	cmd.global.Verbosef("creating new index\n")
+
+	err = repository.RebuildIndex(repo)
+	if err != nil {
+		return err
+	}
+
+	cmd.global.Verbosef("done\n")
+	return nil
+}