Implement Repack()

src/restic/repository/prune.go

@@ -1,8 +1,12 @@
 package repository
 
 import (
+	"fmt"
+	"os"
 	"restic/backend"
 	"restic/debug"
+	"restic/pack"
+	"restic/worker"
 )
 
 // Repack takes a list of packs together with a list of blobs contained in
@@ -10,5 +14,133 @@ import (
 // into a new pack. Afterwards, the packs are removed.
 func Repack(repo *Repository, packs, keepBlobs backend.IDSet) error {
 	debug.Log("Repack", "repacking %d packs while keeping %d blobs", len(packs), len(keepBlobs))
+
+	var buf []byte
+	for packID := range packs {
+		list, err := repo.ListPack(packID)
+		if err != nil {
+			return err
+		}
+
+		debug.Log("Repack", "processing pack %v, blobs: %v", packID.Str(), list)
+
+		for _, blob := range list {
+			buf, err = repo.LoadBlob(blob.Type, blob.ID, buf)
+			if err != nil {
+				return err
+			}
+			debug.Log("Repack", "  loaded blob %v", blob.ID.Str())
+
+			_, err = repo.SaveAndEncrypt(blob.Type, buf, &blob.ID)
+			if err != nil {
+				return err
+			}
+
+			debug.Log("Repack", "  saved blob %v", blob.ID.Str())
+		}
+	}
+
+	if err := repo.Flush(); err != nil {
+		return err
+	}
+
+	for packID := range packs {
+		err := repo.Backend().Remove(backend.Data, packID.String())
+		if err != nil {
+			debug.Log("Repack", "error removing pack %v: %v", packID.Str(), err)
+			return err
+		}
+		debug.Log("Repack", "removed pack %v", packID.Str())
+	}
+
+	return nil
+}
+
+const rebuildIndexWorkers = 10
+
+type loadBlobsResult struct {
+	packID  backend.ID
+	entries []pack.Blob
+}
+
+// loadBlobsFromAllPacks sends the contents of all packs to ch.
+func loadBlobsFromAllPacks(repo *Repository, ch chan<- worker.Job, done <-chan struct{}) {
+	f := func(job worker.Job, done <-chan struct{}) (interface{}, error) {
+		packID := job.Data.(backend.ID)
+		entries, err := repo.ListPack(packID)
+		return loadBlobsResult{
+			packID:  packID,
+			entries: entries,
+		}, err
+	}
+
+	jobCh := make(chan worker.Job)
+	wp := worker.New(rebuildIndexWorkers, f, jobCh, ch)
+
+	go func() {
+		for id := range repo.List(backend.Data, done) {
+			jobCh <- worker.Job{Data: id}
+		}
+		close(jobCh)
+	}()
+
+	wp.Wait()
+}
+
+// RebuildIndex lists all packs in the repo, writes a new index and removes all
+// old indexes. This operation should only be done with an exclusive lock in
+// place.
+func RebuildIndex(repo *Repository) error {
+	debug.Log("RebuildIndex", "start rebuilding index")
+
+	done := make(chan struct{})
+	defer close(done)
+
+	ch := make(chan worker.Job)
+	go loadBlobsFromAllPacks(repo, ch, done)
+
+	idx := NewIndex()
+	for job := range ch {
+		id := job.Data.(backend.ID)
+
+		if job.Error != nil {
+			fmt.Fprintf(os.Stderr, "error for pack %v: %v\n", id, job.Error)
+			continue
+		}
+
+		res := job.Result.(loadBlobsResult)
+
+		for _, entry := range res.entries {
+			pb := PackedBlob{
+				ID:     entry.ID,
+				Type:   entry.Type,
+				Length: entry.Length,
+				Offset: entry.Offset,
+				PackID: res.packID,
+			}
+			idx.Store(pb)
+		}
+	}
+
+	oldIndexes := backend.NewIDSet()
+	for id := range repo.List(backend.Index, done) {
+		idx.AddToSupersedes(id)
+		oldIndexes.Insert(id)
+	}
+
+	id, err := SaveIndex(repo, idx)
+	if err != nil {
+		debug.Log("RebuildIndex.RebuildIndex", "error saving index: %v", err)
+		return err
+	}
+	debug.Log("RebuildIndex.RebuildIndex", "new index saved as %v", id.Str())
+
+	for indexID := range oldIndexes {
+		err := repo.Backend().Remove(backend.Index, indexID.String())
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "unable to remove index %v: %v\n", indexID.Str(), err)
+		}
+	}
+
 	return nil
 }

src/restic/repository/prune_test.go

@@ -55,55 +55,6 @@ func createRandomBlobs(t *testing.T, repo *Repository, blobs int, pData float32)
 	}
 }
 
-// redundancy returns the amount of duplicate data in the repo. It only looks
-// at all pack files.
-func redundancy(t *testing.T, repo *Repository) float32 {
-	done := make(chan struct{})
-	defer close(done)
-
-	type redEntry struct {
-		count int
-		size  int
-	}
-	red := make(map[backend.ID]redEntry)
-
-	for id := range repo.List(backend.Data, done) {
-		entries, err := repo.ListPack(id)
-		if err != nil {
-			t.Fatalf("error listing pack %v: %v", id.Str(), err)
-		}
-
-		for _, e := range entries {
-			updatedEntry := redEntry{
-				count: 1,
-				size:  int(e.Length),
-			}
-
-			if oldEntry, ok := red[e.ID]; ok {
-				updatedEntry.count += oldEntry.count
-
-				if updatedEntry.size != oldEntry.size {
-					t.Fatalf("sizes do not match: %v != %v", updatedEntry.size, oldEntry.size)
-				}
-			}
-
-			red[e.ID] = updatedEntry
-		}
-	}
-
-	totalBytes := 0
-	redundantBytes := 0
-	for _, v := range red {
-		totalBytes += v.count * v.size
-
-		if v.count > 1 {
-			redundantBytes += (v.count - 1) * v.size
-		}
-	}
-
-	return float32(redundantBytes) / float32(totalBytes)
-}
-
 // selectBlobs returns a list of random blobs from the repository with probability p.
 func selectBlobs(t *testing.T, repo *Repository, p float32) backend.IDSet {
 	done := make(chan struct{})
@@ -155,6 +106,32 @@ func findPacksForBlobs(t *testing.T, repo *Repository, blobs backend.IDSet) back
 	return packs
 }
 
+func repack(t *testing.T, repo *Repository, packs, blobs backend.IDSet) {
+	err := Repack(repo, packs, blobs)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func saveIndex(t *testing.T, repo *Repository) {
+	if err := repo.SaveIndex(); err != nil {
+		t.Fatalf("repo.SaveIndex() %v", err)
+	}
+}
+
+func rebuildIndex(t *testing.T, repo *Repository) {
+	if err := RebuildIndex(repo); err != nil {
+		t.Fatalf("error rebuilding index: %v", err)
+	}
+}
+
+func reloadIndex(t *testing.T, repo *Repository) {
+	repo.SetIndex(NewMasterIndex())
+	if err := repo.LoadIndex(); err != nil {
+		t.Fatalf("error loading new index: %v", err)
+	}
+}
+
 func TestRepack(t *testing.T) {
 	repo, cleanup := TestRepository(t)
 	defer cleanup()
@@ -164,10 +141,7 @@ func TestRepack(t *testing.T) {
 	packsBefore := listPacks(t, repo)
 
 	// Running repack on empty ID sets should not do anything at all.
-	err := Repack(repo, nil, nil)
-	if err != nil {
-		t.Fatal(err)
-	}
+	repack(t, repo, nil, nil)
 
 	packsAfter := listPacks(t, repo)
 
@@ -176,19 +150,14 @@ func TestRepack(t *testing.T) {
 			packsBefore, packsAfter)
 	}
 
-	if err := repo.SaveIndex(); err != nil {
-		t.Fatalf("repo.SaveIndex() %v", err)
-	}
+	saveIndex(t, repo)
 
 	blobs := selectBlobs(t, repo, 0.2)
-	t.Logf("selected %d blobs: %v", len(blobs), blobs)
-
 	packs := findPacksForBlobs(t, repo, blobs)
 
-	err = Repack(repo, packs, blobs)
-	if err != nil {
-		t.Fatalf("Repack() error %v", err)
-	}
+	repack(t, repo, packs, blobs)
+	rebuildIndex(t, repo)
+	reloadIndex(t, repo)
 
 	packsAfter = listPacks(t, repo)
 	for id := range packs {