go code can read and write chunk manifest

21 files changed, 511 insertions, 112 deletions

diff --git a/weed/filer2/filechunk_manifest.go b/weed/filer2/filechunk_manifest.go
new file mode 100644
index 000000000..92b114853
--- /dev/null
+++ b/weed/filer2/filechunk_manifest.go
@@ -0,0 +1,136 @@
+package filer2
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"math"
+
+	"github.com/golang/protobuf/proto"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/util"
+)
+
+func HasChunkManifest(chunks []*filer_pb.FileChunk) bool {
+	for _, chunk := range chunks {
+		if chunk.IsChunkManifest {
+			return true
+		}
+	}
+	return false
+}
+
+func ResolveChunkManifest(lookupFileIdFn LookupFileIdFunctionType, chunks []*filer_pb.FileChunk) (dataChunks, manifestChunks []*filer_pb.FileChunk, manefestResolveErr error) {
+	// TODO maybe parallel this
+	for _, chunk := range chunks {
+		if !chunk.IsChunkManifest {
+			dataChunks = append(dataChunks, chunk)
+			continue
+		}
+
+		// IsChunkManifest
+		data, err := fetchChunk(lookupFileIdFn, chunk.FileId, chunk.CipherKey, chunk.IsCompressed)
+		if err != nil {
+			return chunks, nil, fmt.Errorf("fail to read manifest %s: %v", chunk.FileId, err)
+		}
+		m := &filer_pb.FileChunkManifest{}
+		if err := proto.Unmarshal(data, m); err != nil {
+			return chunks, nil, fmt.Errorf("fail to unmarshal manifest %s: %v", chunk.FileId, err)
+		}
+		manifestChunks = append(manifestChunks, chunk)
+		// recursive
+		dchunks, mchunks, subErr := ResolveChunkManifest(lookupFileIdFn, m.Chunks)
+		if subErr != nil {
+			return chunks, nil, subErr
+		}
+		dataChunks = append(dataChunks, dchunks...)
+		manifestChunks = append(manifestChunks, mchunks...)
+	}
+	return
+}
+
+func fetchChunk(lookupFileIdFn LookupFileIdFunctionType, fileId string, cipherKey []byte, isGzipped bool) ([]byte, error) {
+	urlString, err := lookupFileIdFn(fileId)
+	if err != nil {
+		glog.V(1).Infof("operation LookupFileId %s failed, err: %v", fileId, err)
+		return nil, err
+	}
+	var buffer bytes.Buffer
+	err = util.ReadUrlAsStream(urlString, cipherKey, isGzipped, true, 0, 0, func(data []byte) {
+		buffer.Write(data)
+	})
+	if err != nil {
+		glog.V(0).Infof("read %s failed, err: %v", fileId, err)
+		return nil, err
+	}
+
+	return buffer.Bytes(), nil
+}
+
+func MaybeManifestize(saveFunc SaveDataAsChunkFunctionType, dataChunks []*filer_pb.FileChunk) (chunks []*filer_pb.FileChunk, err error) {
+	return doMaybeManifestize(saveFunc, dataChunks, 10000, mergeIntoManifest)
+}
+
+func doMaybeManifestize(saveFunc SaveDataAsChunkFunctionType, inputChunks []*filer_pb.FileChunk, mergeFactor int, mergefn func(saveFunc SaveDataAsChunkFunctionType, dataChunks []*filer_pb.FileChunk) (manifestChunk *filer_pb.FileChunk, err error)) (chunks []*filer_pb.FileChunk, err error) {
+
+	var dataChunks []*filer_pb.FileChunk
+	for _, chunk := range inputChunks {
+		if !chunk.IsChunkManifest {
+			dataChunks = append(dataChunks, chunk)
+		} else {
+			chunks = append(chunks, chunk)
+		}
+	}
+
+	manifestBatch := mergeFactor
+	remaining := len(dataChunks)
+	for i := 0; i+manifestBatch <= len(dataChunks); i += manifestBatch {
+		chunk, err := mergefn(saveFunc, dataChunks[i:i+manifestBatch])
+		if err != nil {
+			return dataChunks, err
+		}
+		chunks = append(chunks, chunk)
+		remaining -= manifestBatch
+	}
+	// remaining
+	for i := len(dataChunks) - remaining; i < len(dataChunks); i++ {
+		chunks = append(chunks, dataChunks[i])
+	}
+	return
+}
+
+func mergeIntoManifest(saveFunc SaveDataAsChunkFunctionType, dataChunks []*filer_pb.FileChunk) (manifestChunk *filer_pb.FileChunk, err error) {
+
+	// create and serialize the manifest
+	data, serErr := proto.Marshal(&filer_pb.FileChunkManifest{
+		Chunks: dataChunks,
+	})
+	if serErr != nil {
+		return nil, fmt.Errorf("serializing manifest: %v", serErr)
+	}
+
+	minOffset, maxOffset := int64(math.MaxInt64), int64(math.MinInt64)
+	for k := 0; k < len(dataChunks); k++ {
+		chunk := dataChunks[k]
+		if minOffset > int64(chunk.Offset) {
+			minOffset = chunk.Offset
+		}
+		if maxOffset < int64(chunk.Size)+chunk.Offset {
+			maxOffset = int64(chunk.Size) + chunk.Offset
+		}
+	}
+
+	manifestChunk, _, _, err = saveFunc(bytes.NewReader(data), "", 0)
+	if err != nil {
+		return nil, err
+	}
+	manifestChunk.IsChunkManifest = true
+	manifestChunk.Offset = minOffset
+	manifestChunk.Size = uint64(maxOffset - minOffset)
+
+	return
+}
+
+type SaveDataAsChunkFunctionType func(reader io.Reader, name string, offset int64) (chunk *filer_pb.FileChunk, collection, replication string, err error)
diff --git a/weed/filer2/filechunk_manifest_test.go b/weed/filer2/filechunk_manifest_test.go
new file mode 100644
index 000000000..2b0862d07
--- /dev/null
+++ b/weed/filer2/filechunk_manifest_test.go
@@ -0,0 +1,113 @@
+package filer2
+
+import (
+	"bytes"
+	"math"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+)
+
+func TestDoMaybeManifestize(t *testing.T) {
+	var manifestTests = []struct {
+		inputs   []*filer_pb.FileChunk
+		expected []*filer_pb.FileChunk
+	}{
+		{
+			inputs: []*filer_pb.FileChunk{
+				{FileId: "1", IsChunkManifest: false},
+				{FileId: "2", IsChunkManifest: false},
+				{FileId: "3", IsChunkManifest: false},
+				{FileId: "4", IsChunkManifest: false},
+			},
+			expected: []*filer_pb.FileChunk{
+				{FileId: "12", IsChunkManifest: true},
+				{FileId: "34", IsChunkManifest: true},
+			},
+		},
+		{
+			inputs: []*filer_pb.FileChunk{
+				{FileId: "1", IsChunkManifest: true},
+				{FileId: "2", IsChunkManifest: false},
+				{FileId: "3", IsChunkManifest: false},
+				{FileId: "4", IsChunkManifest: false},
+			},
+			expected: []*filer_pb.FileChunk{
+				{FileId: "1", IsChunkManifest: true},
+				{FileId: "23", IsChunkManifest: true},
+				{FileId: "4", IsChunkManifest: false},
+			},
+		},
+		{
+			inputs: []*filer_pb.FileChunk{
+				{FileId: "1", IsChunkManifest: false},
+				{FileId: "2", IsChunkManifest: true},
+				{FileId: "3", IsChunkManifest: false},
+				{FileId: "4", IsChunkManifest: false},
+			},
+			expected: []*filer_pb.FileChunk{
+				{FileId: "2", IsChunkManifest: true},
+				{FileId: "13", IsChunkManifest: true},
+				{FileId: "4", IsChunkManifest: false},
+			},
+		},
+		{
+			inputs: []*filer_pb.FileChunk{
+				{FileId: "1", IsChunkManifest: true},
+				{FileId: "2", IsChunkManifest: true},
+				{FileId: "3", IsChunkManifest: false},
+				{FileId: "4", IsChunkManifest: false},
+			},
+			expected: []*filer_pb.FileChunk{
+				{FileId: "1", IsChunkManifest: true},
+				{FileId: "2", IsChunkManifest: true},
+				{FileId: "34", IsChunkManifest: true},
+			},
+		},
+	}
+
+	for i, mtest := range manifestTests {
+		println("test", i)
+		actual, _ := doMaybeManifestize(nil, mtest.inputs, 2, mockMerge)
+		assertEqualChunks(t, mtest.expected, actual)
+	}
+
+}
+
+func assertEqualChunks(t *testing.T, expected, actual []*filer_pb.FileChunk) {
+	assert.Equal(t, len(expected), len(actual))
+	for i := 0; i < len(actual); i++ {
+		assertEqualChunk(t, actual[i], expected[i])
+	}
+}
+func assertEqualChunk(t *testing.T, expected, actual *filer_pb.FileChunk) {
+	assert.Equal(t, expected.FileId, actual.FileId)
+	assert.Equal(t, expected.IsChunkManifest, actual.IsChunkManifest)
+}
+
+func mockMerge(saveFunc SaveDataAsChunkFunctionType, dataChunks []*filer_pb.FileChunk) (manifestChunk *filer_pb.FileChunk, err error) {
+
+	var buf bytes.Buffer
+	minOffset, maxOffset := int64(math.MaxInt64), int64(math.MinInt64)
+	for k := 0; k < len(dataChunks); k++ {
+		chunk := dataChunks[k]
+		buf.WriteString(chunk.FileId)
+		if minOffset > int64(chunk.Offset) {
+			minOffset = chunk.Offset
+		}
+		if maxOffset < int64(chunk.Size)+chunk.Offset {
+			maxOffset = int64(chunk.Size) + chunk.Offset
+		}
+	}
+
+	manifestChunk = &filer_pb.FileChunk{
+		FileId: buf.String(),
+	}
+	manifestChunk.IsChunkManifest = true
+	manifestChunk.Offset = minOffset
+	manifestChunk.Size = uint64(maxOffset - minOffset)
+
+	return
+}
diff --git a/weed/filer2/filechunks.go b/weed/filer2/filechunks.go
index 6832d0f31..ea7772b4a 100644
--- a/weed/filer2/filechunks.go
+++ b/weed/filer2/filechunks.go
@@ -46,9 +46,9 @@ func ETagChunks(chunks []*filer_pb.FileChunk) (etag string) {
 	return fmt.Sprintf("%x", h.Sum32())
 }
 
-func CompactFileChunks(chunks []*filer_pb.FileChunk) (compacted, garbage []*filer_pb.FileChunk) {
+func CompactFileChunks(lookupFileIdFn LookupFileIdFunctionType, chunks []*filer_pb.FileChunk) (compacted, garbage []*filer_pb.FileChunk) {
 
-	visibles := NonOverlappingVisibleIntervals(chunks)
+	visibles, _ := NonOverlappingVisibleIntervals(lookupFileIdFn, chunks)
 
 	fileIds := make(map[string]bool)
 	for _, interval := range visibles {
@@ -65,7 +65,23 @@ func CompactFileChunks(chunks []*filer_pb.FileChunk) (compacted, garbage []*file
 	return
 }
 
-func MinusChunks(as, bs []*filer_pb.FileChunk) (delta []*filer_pb.FileChunk) {
+func MinusChunks(lookupFileIdFn LookupFileIdFunctionType, as, bs []*filer_pb.FileChunk) (delta []*filer_pb.FileChunk, err error) {
+
+	aData, aMeta, aErr := ResolveChunkManifest(lookupFileIdFn, as)
+	if aErr != nil {
+		return nil, aErr
+	}
+	bData, bMeta, bErr := ResolveChunkManifest(lookupFileIdFn, bs)
+	if bErr != nil {
+		return nil, bErr
+	}
+
+	delta = append(delta, DoMinusChunks(aData, bData)...)
+	delta = append(delta, DoMinusChunks(aMeta, bMeta)...)
+	return
+}
+
+func DoMinusChunks(as, bs []*filer_pb.FileChunk) (delta []*filer_pb.FileChunk) {
 
 	fileIds := make(map[string]bool)
 	for _, interval := range bs {
@@ -94,9 +110,9 @@ func (cv *ChunkView) IsFullChunk() bool {
 	return cv.Size == cv.ChunkSize
 }
 
-func ViewFromChunks(chunks []*filer_pb.FileChunk, offset int64, size int64) (views []*ChunkView) {
+func ViewFromChunks(lookupFileIdFn LookupFileIdFunctionType, chunks []*filer_pb.FileChunk, offset int64, size int64) (views []*ChunkView) {
 
-	visibles := NonOverlappingVisibleIntervals(chunks)
+	visibles, _ := NonOverlappingVisibleIntervals(lookupFileIdFn, chunks)
 
 	return ViewFromVisibleIntervals(visibles, offset, size)
 
@@ -190,7 +206,11 @@ func MergeIntoVisibles(visibles, newVisibles []VisibleInterval, chunk *filer_pb.
 	return newVisibles
 }
 
-func NonOverlappingVisibleIntervals(chunks []*filer_pb.FileChunk) (visibles []VisibleInterval) {
+// NonOverlappingVisibleIntervals translates the file chunk into VisibleInterval in memory
+// If the file chunk content is a chunk manifest
+func NonOverlappingVisibleIntervals(lookupFileIdFn LookupFileIdFunctionType, chunks []*filer_pb.FileChunk) (visibles []VisibleInterval, err error) {
+
+	chunks, _, err = ResolveChunkManifest(lookupFileIdFn, chunks)
 
 	sort.Slice(chunks, func(i, j int) bool {
 		return chunks[i].Mtime < chunks[j].Mtime
diff --git a/weed/filer2/filechunks_test.go b/weed/filer2/filechunks_test.go
index 7b1133b85..bfee59198 100644
--- a/weed/filer2/filechunks_test.go
+++ b/weed/filer2/filechunks_test.go
@@ -16,7 +16,7 @@ func TestCompactFileChunks(t *testing.T) {
 		{Offset: 110, Size: 200, FileId: "jkl", Mtime: 300},
 	}
 
-	compacted, garbage := CompactFileChunks(chunks)
+	compacted, garbage := CompactFileChunks(nil, chunks)
 
 	if len(compacted) != 3 {
 		t.Fatalf("unexpected compacted: %d", len(compacted))
@@ -49,7 +49,7 @@ func TestCompactFileChunks2(t *testing.T) {
 		})
 	}
 
-	compacted, garbage := CompactFileChunks(chunks)
+	compacted, garbage := CompactFileChunks(nil, chunks)
 
 	if len(compacted) != 4 {
 		t.Fatalf("unexpected compacted: %d", len(compacted))
@@ -186,7 +186,7 @@ func TestIntervalMerging(t *testing.T) {
 
 	for i, testcase := range testcases {
 		log.Printf("++++++++++ merged test case %d ++++++++++++++++++++", i)
-		intervals := NonOverlappingVisibleIntervals(testcase.Chunks)
+		intervals, _ := NonOverlappingVisibleIntervals(nil, testcase.Chunks)
 		for x, interval := range intervals {
 			log.Printf("test case %d, interval %d, start=%d, stop=%d, fileId=%s",
 				i, x, interval.start, interval.stop, interval.fileId)
@@ -371,7 +371,7 @@ func TestChunksReading(t *testing.T) {
 
 	for i, testcase := range testcases {
 		log.Printf("++++++++++ read test case %d ++++++++++++++++++++", i)
-		chunks := ViewFromChunks(testcase.Chunks, testcase.Offset, testcase.Size)
+		chunks := ViewFromChunks(nil, testcase.Chunks, testcase.Offset, testcase.Size)
 		for x, chunk := range chunks {
 			log.Printf("read case %d, chunk %d, offset=%d, size=%d, fileId=%s",
 				i, x, chunk.Offset, chunk.Size, chunk.FileId)
@@ -415,6 +415,6 @@ func BenchmarkCompactFileChunks(b *testing.B) {
 	}
 
 	for n := 0; n < b.N; n++ {
-		CompactFileChunks(chunks)
+		CompactFileChunks(nil, chunks)
 	}
 }
diff --git a/weed/filer2/reader_at.go b/weed/filer2/reader_at.go
index 11a80443f..568d94267 100644
--- a/weed/filer2/reader_at.go
+++ b/weed/filer2/reader_at.go
@@ -1,7 +1,6 @@
 package filer2
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -9,7 +8,6 @@ import (
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
-	"github.com/chrislusf/seaweedfs/weed/util"
 	"github.com/chrislusf/seaweedfs/weed/util/chunk_cache"
 	"github.com/chrislusf/seaweedfs/weed/wdclient"
 )
@@ -144,19 +142,6 @@ func (c *ChunkReadAt) fetchChunkData(chunkView *ChunkView) (data []byte, err err
 
 func (c *ChunkReadAt) doFetchFullChunkData(fileId string, cipherKey []byte, isGzipped bool) ([]byte, error) {
 
-	urlString, err := c.lookupFileId(fileId)
-	if err != nil {
-		glog.V(1).Infof("operation LookupFileId %s failed, err: %v", fileId, err)
-		return nil, err
-	}
-	var buffer bytes.Buffer
-	err = util.ReadUrlAsStream(urlString, cipherKey, isGzipped, true, 0, 0, func(data []byte) {
-		buffer.Write(data)
-	})
-	if err != nil {
-		glog.V(0).Infof("read %s failed, err: %v", fileId, err)
-		return nil, err
-	}
+	return fetchChunk(c.lookupFileId, fileId, cipherKey, isGzipped)
 
-	return buffer.Bytes(), nil
 }
diff --git a/weed/filer2/stream.go b/weed/filer2/stream.go
index 033a8dd13..c7df007ec 100644
--- a/weed/filer2/stream.go
+++ b/weed/filer2/stream.go
@@ -2,6 +2,7 @@ package filer2
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"math"
 	"strings"
@@ -14,7 +15,8 @@ import (
 
 func StreamContent(masterClient *wdclient.MasterClient, w io.Writer, chunks []*filer_pb.FileChunk, offset int64, size int64) error {
 
-	chunkViews := ViewFromChunks(chunks, offset, size)
+	fmt.Printf("start to stream content for chunks: %+v\n", chunks)
+	chunkViews := ViewFromChunks(masterClient.LookupFileId, chunks, offset, size)
 
 	fileId2Url := make(map[string]string)
 
@@ -50,14 +52,14 @@ func ReadAll(masterClient *wdclient.MasterClient, chunks []*filer_pb.FileChunk)
 
 	buffer := bytes.Buffer{}
 
-	chunkViews := ViewFromChunks(chunks, 0, math.MaxInt32)
-
-	lookupFileId := func(fileId string) (targetUrl string, err error) {
+	lookupFileIdFn := func(fileId string) (targetUrl string, err error) {
 		return masterClient.LookupFileId(fileId)
 	}
 
+	chunkViews := ViewFromChunks(lookupFileIdFn, chunks, 0, math.MaxInt64)
+
 	for _, chunkView := range chunkViews {
-		urlString, err := lookupFileId(chunkView.FileId)
+		urlString, err := lookupFileIdFn(chunkView.FileId)
 		if err != nil {
 			glog.V(1).Infof("operation LookupFileId %s failed, err: %v", chunkView.FileId, err)
 			return nil, err
@@ -88,23 +90,27 @@ var _ = io.ReadSeeker(&ChunkStreamReader{})
 
 func NewChunkStreamReaderFromFiler(masterClient *wdclient.MasterClient, chunks []*filer_pb.FileChunk) *ChunkStreamReader {
 
-	chunkViews := ViewFromChunks(chunks, 0, math.MaxInt32)
+	lookupFileIdFn := func(fileId string) (targetUrl string, err error) {
+		return masterClient.LookupFileId(fileId)
+	}
+
+	chunkViews := ViewFromChunks(lookupFileIdFn, chunks, 0, math.MaxInt64)
 
 	return &ChunkStreamReader{
-		chunkViews: chunkViews,
-		lookupFileId: func(fileId string) (targetUrl string, err error) {
-			return masterClient.LookupFileId(fileId)
-		},
+		chunkViews:   chunkViews,
+		lookupFileId: lookupFileIdFn,
 	}
 }
 
 func NewChunkStreamReader(filerClient filer_pb.FilerClient, chunks []*filer_pb.FileChunk) *ChunkStreamReader {
 
-	chunkViews := ViewFromChunks(chunks, 0, math.MaxInt32)
+	lookupFileIdFn := LookupFn(filerClient)
+
+	chunkViews := ViewFromChunks(lookupFileIdFn, chunks, 0, math.MaxInt64)
 
 	return &ChunkStreamReader{
 		chunkViews:   chunkViews,
-		lookupFileId: LookupFn(filerClient),
+		lookupFileId: lookupFileIdFn,
 	}
 }
 
diff --git a/weed/filesys/dirty_page.go b/weed/filesys/dirty_page.go
index 45224b3e7..46d20e466 100644
--- a/weed/filesys/dirty_page.go
+++ b/weed/filesys/dirty_page.go
@@ -2,16 +2,12 @@ package filesys
 
 import (
 	"bytes"
-	"context"
-	"fmt"
 	"io"
 	"sync"
 	"time"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
-	"github.com/chrislusf/seaweedfs/weed/operation"
 	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
-	"github.com/chrislusf/seaweedfs/weed/security"
 )
 
 type ContinuousDirtyPages struct {
@@ -141,53 +137,15 @@ func (pages *ContinuousDirtyPages) saveExistingLargestPageToStorage() (chunk *fi
 
 func (pages *ContinuousDirtyPages) saveToStorage(reader io.Reader, offset int64, size int64) (*filer_pb.FileChunk, error) {
 
-	var fileId, host string
-	var auth security.EncodedJwt
-
 	dir, _ := pages.f.fullpath().DirAndName()
 
-	if err := pages.f.wfs.WithFilerClient(func(client filer_pb.SeaweedFilerClient) error {
-
-		request := &filer_pb.AssignVolumeRequest{
-			Count:       1,
-			Replication: pages.f.wfs.option.Replication,
-			Collection:  pages.f.wfs.option.Collection,
-			TtlSec:      pages.f.wfs.option.TtlSec,
-			DataCenter:  pages.f.wfs.option.DataCenter,
-			ParentPath:  dir,
-		}
-
-		resp, err := client.AssignVolume(context.Background(), request)
-		if err != nil {
-			glog.V(0).Infof("assign volume failure %v: %v", request, err)
-			return err
-		}
-		if resp.Error != "" {
-			return fmt.Errorf("assign volume failure %v: %v", request, resp.Error)
-		}
-
-		fileId, host, auth = resp.FileId, resp.Url, security.EncodedJwt(resp.Auth)
-		host = pages.f.wfs.AdjustedUrl(host)
-		pages.collection, pages.replication = resp.Collection, resp.Replication
-
-		return nil
-	}); err != nil {
-		return nil, fmt.Errorf("filerGrpcAddress assign volume: %v", err)
-	}
-
-	fileUrl := fmt.Sprintf("http://%s/%s", host, fileId)
-	uploadResult, err, data := operation.Upload(fileUrl, pages.f.Name, pages.f.wfs.option.Cipher, reader, false, "", nil, auth)
+	chunk, collection, replication, err := pages.f.wfs.saveDataAsChunk(dir)(reader, pages.f.Name, offset)
 	if err != nil {
-		glog.V(0).Infof("upload data %v to %s: %v", pages.f.Name, fileUrl, err)
-		return nil, fmt.Errorf("upload data: %v", err)
-	}
-	if uploadResult.Error != "" {
-		glog.V(0).Infof("upload failure %v to %s: %v", pages.f.Name, fileUrl, err)
-		return nil, fmt.Errorf("upload result: %v", uploadResult.Error)
+		return nil, err
 	}
-	pages.f.wfs.chunkCache.SetChunk(fileId, data)
+	pages.collection, pages.replication = collection, replication
 
-	return uploadResult.ToPbFileChunk(fileId, offset), nil
+	return chunk, nil
 
 }
 
diff --git a/weed/filesys/file.go b/weed/filesys/file.go
index 4a6bc9a8a..dcda93522 100644
--- a/weed/filesys/file.go
+++ b/weed/filesys/file.go
@@ -253,7 +253,7 @@ func (file *File) addChunks(chunks []*filer_pb.FileChunk) {
 
 func (file *File) setEntry(entry *filer_pb.Entry) {
 	file.entry = entry
-	file.entryViewCache = filer2.NonOverlappingVisibleIntervals(file.entry.Chunks)
+	file.entryViewCache, _ = filer2.NonOverlappingVisibleIntervals(filer2.LookupFn(file.wfs), file.entry.Chunks)
 	file.reader = nil
 }
 
diff --git a/weed/filesys/filehandle.go b/weed/filesys/filehandle.go
index 9b9df916c..31fd08f97 100644
--- a/weed/filesys/filehandle.go
+++ b/weed/filesys/filehandle.go
@@ -88,8 +88,12 @@ func (fh *FileHandle) readFromChunks(buff []byte, offset int64) (int64, error) {
 		return 0, nil
 	}
 
+	var chunkResolveErr error
 	if fh.f.entryViewCache == nil {
-		fh.f.entryViewCache = filer2.NonOverlappingVisibleIntervals(fh.f.entry.Chunks)
+		fh.f.entryViewCache, chunkResolveErr = filer2.NonOverlappingVisibleIntervals(filer2.LookupFn(fh.f.wfs), fh.f.entry.Chunks)
+		if chunkResolveErr != nil {
+			return 0, fmt.Errorf("fail to resolve chunk manifest: %v", chunkResolveErr)
+		}
 		fh.f.reader = nil
 	}
 
@@ -206,7 +210,12 @@ func (fh *FileHandle) Flush(ctx context.Context, req *fuse.FlushRequest) error {
 			glog.V(3).Infof("%s chunks %d: %v [%d,%d)", fh.f.fullpath(), i, chunk.FileId, chunk.Offset, chunk.Offset+int64(chunk.Size))
 		}
 
-		chunks, garbages := filer2.CompactFileChunks(fh.f.entry.Chunks)
+		chunks, garbages := filer2.CompactFileChunks(filer2.LookupFn(fh.f.wfs), fh.f.entry.Chunks)
+		chunks, manifestErr := filer2.MaybeManifestize(fh.f.wfs.saveDataAsChunk(fh.f.dir.FullPath()), chunks)
+		if manifestErr != nil {
+			// not good, but should be ok
+			glog.V(0).Infof("MaybeManifestize: %v", manifestErr)
+		}
 		fh.f.entry.Chunks = chunks
 		// fh.f.entryViewCache = nil
 
diff --git a/weed/filesys/wfs_write.go b/weed/filesys/wfs_write.go
new file mode 100644
index 000000000..786d0b42a
--- /dev/null
+++ b/weed/filesys/wfs_write.go
@@ -0,0 +1,66 @@
+package filesys
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"github.com/chrislusf/seaweedfs/weed/filer2"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/operation"
+	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/chrislusf/seaweedfs/weed/security"
+)
+
+func (wfs *WFS) saveDataAsChunk(dir string) filer2.SaveDataAsChunkFunctionType {
+
+	return func(reader io.Reader, filename string, offset int64) (chunk *filer_pb.FileChunk, collection, replication string, err error) {
+		var fileId, host string
+		var auth security.EncodedJwt
+
+		if err := wfs.WithFilerClient(func(client filer_pb.SeaweedFilerClient) error {
+
+			request := &filer_pb.AssignVolumeRequest{
+				Count:       1,
+				Replication: wfs.option.Replication,
+				Collection:  wfs.option.Collection,
+				TtlSec:      wfs.option.TtlSec,
+				DataCenter:  wfs.option.DataCenter,
+				ParentPath:  dir,
+			}
+
+			resp, err := client.AssignVolume(context.Background(), request)
+			if err != nil {
+				glog.V(0).Infof("assign volume failure %v: %v", request, err)
+				return err
+			}
+			if resp.Error != "" {
+				return fmt.Errorf("assign volume failure %v: %v", request, resp.Error)
+			}
+
+			fileId, host, auth = resp.FileId, resp.Url, security.EncodedJwt(resp.Auth)
+			host = wfs.AdjustedUrl(host)
+			collection, replication = resp.Collection, resp.Replication
+
+			return nil
+		}); err != nil {
+			return nil, "", "", fmt.Errorf("filerGrpcAddress assign volume: %v", err)
+		}
+
+		fileUrl := fmt.Sprintf("http://%s/%s", host, fileId)
+		uploadResult, err, data := operation.Upload(fileUrl, filename, wfs.option.Cipher, reader, false, "", nil, auth)
+		if err != nil {
+			glog.V(0).Infof("upload data %v to %s: %v", filename, fileUrl, err)
+			return nil, "", "", fmt.Errorf("upload data: %v", err)
+		}
+		if uploadResult.Error != "" {
+			glog.V(0).Infof("upload failure %v to %s: %v", filename, fileUrl, err)
+			return nil, "", "", fmt.Errorf("upload result: %v", uploadResult.Error)
+		}
+
+		wfs.chunkCache.SetChunk(fileId, data)
+
+		chunk = uploadResult.ToPbFileChunk(fileId, offset)
+		return chunk, "", "", nil
+	}
+}
diff --git a/weed/replication/sink/azuresink/azure_sink.go b/weed/replication/sink/azuresink/azure_sink.go
index aef97c06e..fa229de22 100644
--- a/weed/replication/sink/azuresink/azure_sink.go
+++ b/weed/replication/sink/azuresink/azure_sink.go
@@ -96,7 +96,7 @@ func (g *AzureSink) CreateEntry(key string, entry *filer_pb.Entry) error {
 	}
 
 	totalSize := filer2.TotalSize(entry.Chunks)
-	chunkViews := filer2.ViewFromChunks(entry.Chunks, 0, int64(totalSize))
+	chunkViews := filer2.ViewFromChunks(g.filerSource.LookupFileId, entry.Chunks, 0, int64(totalSize))
 
 	// Create a URL that references a to-be-created blob in your
 	// Azure Storage account's container.
diff --git a/weed/replication/sink/b2sink/b2_sink.go b/weed/replication/sink/b2sink/b2_sink.go
index 1e7d82ed4..bf8632827 100644
--- a/weed/replication/sink/b2sink/b2_sink.go
+++ b/weed/replication/sink/b2sink/b2_sink.go
@@ -85,7 +85,7 @@ func (g *B2Sink) CreateEntry(key string, entry *filer_pb.Entry) error {
 	}
 
 	totalSize := filer2.TotalSize(entry.Chunks)
-	chunkViews := filer2.ViewFromChunks(entry.Chunks, 0, int64(totalSize))
+	chunkViews := filer2.ViewFromChunks(g.filerSource.LookupFileId, entry.Chunks, 0, int64(totalSize))
 
 	bucket, err := g.client.Bucket(context.Background(), g.bucket)
 	if err != nil {
diff --git a/weed/replication/sink/filersink/filer_sink.go b/weed/replication/sink/filersink/filer_sink.go
index 50721a8f3..6429859b4 100644
--- a/weed/replication/sink/filersink/filer_sink.go
+++ b/weed/replication/sink/filersink/filer_sink.go
@@ -167,12 +167,15 @@ func (fs *FilerSink) UpdateEntry(key string, oldEntry *filer_pb.Entry, newParent
 		glog.V(0).Infof("already replicated %s", key)
 	} else {
 		// find out what changed
-		deletedChunks, newChunks := compareChunks(oldEntry, newEntry)
+		deletedChunks, newChunks, err := compareChunks(filer2.LookupFn(fs), oldEntry, newEntry)
+		if err != nil {
+			return true, fmt.Errorf("replicte %s compare chunks error: %v", key, err)
+		}
 
 		// delete the chunks that are deleted from the source
 		if deleteIncludeChunks {
 			// remove the deleted chunks. Actual data deletion happens in filer UpdateEntry FindUnusedFileChunks
-			existingEntry.Chunks = filer2.MinusChunks(existingEntry.Chunks, deletedChunks)
+			existingEntry.Chunks = filer2.DoMinusChunks(existingEntry.Chunks, deletedChunks)
 		}
 
 		// replicate the chunks that are new in the source
@@ -200,8 +203,21 @@ func (fs *FilerSink) UpdateEntry(key string, oldEntry *filer_pb.Entry, newParent
 	})
 
 }
-func compareChunks(oldEntry, newEntry *filer_pb.Entry) (deletedChunks, newChunks []*filer_pb.FileChunk) {
-	deletedChunks = filer2.MinusChunks(oldEntry.Chunks, newEntry.Chunks)
-	newChunks = filer2.MinusChunks(newEntry.Chunks, oldEntry.Chunks)
+func compareChunks(lookupFileIdFn filer2.LookupFileIdFunctionType, oldEntry, newEntry *filer_pb.Entry) (deletedChunks, newChunks []*filer_pb.FileChunk, err error) {
+	aData, aMeta, aErr := filer2.ResolveChunkManifest(lookupFileIdFn, oldEntry.Chunks)
+	if aErr != nil {
+		return nil, nil, aErr
+	}
+	bData, bMeta, bErr := filer2.ResolveChunkManifest(lookupFileIdFn, newEntry.Chunks)
+	if bErr != nil {
+		return nil, nil, bErr
+	}
+
+	deletedChunks = append(deletedChunks, filer2.DoMinusChunks(aData, bData)...)
+	deletedChunks = append(deletedChunks, filer2.DoMinusChunks(aMeta, bMeta)...)
+
+	newChunks = append(newChunks, filer2.DoMinusChunks(bData, aData)...)
+	newChunks = append(newChunks, filer2.DoMinusChunks(bMeta, aMeta)...)
+
 	return
 }
diff --git a/weed/replication/sink/gcssink/gcs_sink.go b/weed/replication/sink/gcssink/gcs_sink.go
index bb5a54272..4b58160db 100644
--- a/weed/replication/sink/gcssink/gcs_sink.go
+++ b/weed/replication/sink/gcssink/gcs_sink.go
@@ -90,7 +90,7 @@ func (g *GcsSink) CreateEntry(key string, entry *filer_pb.Entry) error {
 	}
 
 	totalSize := filer2.TotalSize(entry.Chunks)
-	chunkViews := filer2.ViewFromChunks(entry.Chunks, 0, int64(totalSize))
+	chunkViews := filer2.ViewFromChunks(g.filerSource.LookupFileId, entry.Chunks, 0, int64(totalSize))
 
 	wc := g.client.Bucket(g.bucket).Object(key).NewWriter(context.Background())
 
diff --git a/weed/replication/sink/s3sink/s3_sink.go b/weed/replication/sink/s3sink/s3_sink.go
index d7af105b8..625cf406c 100644
--- a/weed/replication/sink/s3sink/s3_sink.go
+++ b/weed/replication/sink/s3sink/s3_sink.go
@@ -108,7 +108,7 @@ func (s3sink *S3Sink) CreateEntry(key string, entry *filer_pb.Entry) error {
 	}
 
 	totalSize := filer2.TotalSize(entry.Chunks)
-	chunkViews := filer2.ViewFromChunks(entry.Chunks, 0, int64(totalSize))
+	chunkViews := filer2.ViewFromChunks(s3sink.filerSource.LookupFileId, entry.Chunks, 0, int64(totalSize))
 
 	parts := make([]*s3.CompletedPart, len(chunkViews))
 
diff --git a/weed/server/filer_grpc_server.go b/weed/server/filer_grpc_server.go
index 17e32731c..48e9253f0 100644
--- a/weed/server/filer_grpc_server.go
+++ b/weed/server/filer_grpc_server.go
@@ -14,6 +14,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/operation"
 	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
 	"github.com/chrislusf/seaweedfs/weed/pb/master_pb"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
@@ -137,13 +138,28 @@ func (fs *FilerServer) LookupVolume(ctx context.Context, req *filer_pb.LookupVol
 	return resp, nil
 }
 
+func (fs *FilerServer) lookupFileId(fileId string) (targetUrl string, err error) {
+	fid, err := needle.ParseFileIdFromString(fileId)
+	if err != nil {
+		return "", err
+	}
+	locations, found := fs.filer.MasterClient.GetLocations(uint32(fid.VolumeId))
+	if !found || len(locations) == 0 {
+		return "", fmt.Errorf("not found volume %d in %s", fid.VolumeId, fileId)
+	}
+	return fmt.Sprintf("http://%s/%s", locations[0].Url, fileId), nil
+}
+
 func (fs *FilerServer) CreateEntry(ctx context.Context, req *filer_pb.CreateEntryRequest) (resp *filer_pb.CreateEntryResponse, err error) {
 
 	glog.V(4).Infof("CreateEntry %v", req)
 
 	resp = &filer_pb.CreateEntryResponse{}
 
-	chunks, garbages := filer2.CompactFileChunks(req.Entry.Chunks)
+	chunks, garbage, err2 := fs.cleanupChunks(nil, req.Entry)
+	if err2 != nil {
+		return &filer_pb.CreateEntryResponse{}, fmt.Errorf("CreateEntry cleanupChunks %s %s: %v", req.Directory, req.Entry.Name, err2)
+	}
 
 	if req.Entry.Attributes == nil {
 		glog.V(3).Infof("CreateEntry %s: nil attributes", filepath.Join(req.Directory, req.Entry.Name))
@@ -158,7 +174,7 @@ func (fs *FilerServer) CreateEntry(ctx context.Context, req *filer_pb.CreateEntr
 	}, req.OExcl, req.IsFromOtherCluster)
 
 	if createErr == nil {
-		fs.filer.DeleteChunks(garbages)
+		fs.filer.DeleteChunks(garbage)
 	} else {
 		glog.V(3).Infof("CreateEntry %s: %v", filepath.Join(req.Directory, req.Entry.Name), createErr)
 		resp.Error = createErr.Error()
@@ -177,10 +193,10 @@ func (fs *FilerServer) UpdateEntry(ctx context.Context, req *filer_pb.UpdateEntr
 		return &filer_pb.UpdateEntryResponse{}, fmt.Errorf("not found %s: %v", fullpath, err)
 	}
 
-	// remove old chunks if not included in the new ones
-	unusedChunks := filer2.MinusChunks(entry.Chunks, req.Entry.Chunks)
-
-	chunks, garbages := filer2.CompactFileChunks(req.Entry.Chunks)
+	chunks, garbage, err2 := fs.cleanupChunks(entry, req.Entry)
+	if err2 != nil {
+		return &filer_pb.UpdateEntryResponse{}, fmt.Errorf("UpdateEntry cleanupChunks %s: %v", fullpath, err2)
+	}
 
 	newEntry := &filer2.Entry{
 		FullPath: util.JoinPath(req.Directory, req.Entry.Name),
@@ -214,8 +230,7 @@ func (fs *FilerServer) UpdateEntry(ctx context.Context, req *filer_pb.UpdateEntr
 	}
 
 	if err = fs.filer.UpdateEntry(ctx, entry, newEntry); err == nil {
-		fs.filer.DeleteChunks(unusedChunks)
-		fs.filer.DeleteChunks(garbages)
+		fs.filer.DeleteChunks(garbage)
 	} else {
 		glog.V(3).Infof("UpdateEntry %s: %v", filepath.Join(req.Directory, req.Entry.Name), err)
 	}
@@ -225,6 +240,37 @@ func (fs *FilerServer) UpdateEntry(ctx context.Context, req *filer_pb.UpdateEntr
 	return &filer_pb.UpdateEntryResponse{}, err
 }
 
+func (fs *FilerServer) cleanupChunks(existingEntry *filer2.Entry, newEntry *filer_pb.Entry) (chunks, garbage []*filer_pb.FileChunk, err error) {
+	chunks = newEntry.Chunks
+
+	// remove old chunks if not included in the new ones
+	if existingEntry != nil {
+		garbage, err = filer2.MinusChunks(fs.lookupFileId, existingEntry.Chunks, newEntry.Chunks)
+		if err != nil {
+			return chunks, nil, fmt.Errorf("MinusChunks: %v", err)
+		}
+	}
+
+	// files with manifest chunks are usually large and append only, skip calculating covered chunks
+	var coveredChunks []*filer_pb.FileChunk
+	if !filer2.HasChunkManifest(newEntry.Chunks) {
+		chunks, coveredChunks = filer2.CompactFileChunks(fs.lookupFileId, newEntry.Chunks)
+		garbage = append(garbage, coveredChunks...)
+	}
+
+	chunks, err = filer2.MaybeManifestize(fs.saveAsChunk(
+		newEntry.Attributes.Replication,
+		newEntry.Attributes.Collection,
+		"",
+		needle.SecondsToTTL(newEntry.Attributes.TtlSec),
+		false), chunks)
+	if err != nil {
+		// not good, but should be ok
+		glog.V(0).Infof("MaybeManifestize: %v", err)
+	}
+	return
+}
+
 func (fs *FilerServer) AppendToEntry(ctx context.Context, req *filer_pb.AppendToEntryRequest) (*filer_pb.AppendToEntryResponse, error) {
 
 	glog.V(4).Infof("AppendToEntry %v", req)
@@ -254,6 +300,17 @@ func (fs *FilerServer) AppendToEntry(ctx context.Context, req *filer_pb.AppendTo
 
 	entry.Chunks = append(entry.Chunks, req.Chunks...)
 
+	entry.Chunks, err = filer2.MaybeManifestize(fs.saveAsChunk(
+		entry.Replication,
+		entry.Collection,
+		"",
+		needle.SecondsToTTL(entry.TtlSec),
+		false), entry.Chunks)
+	if err != nil {
+		// not good, but should be ok
+		glog.V(0).Infof("MaybeManifestize: %v", err)
+	}
+
 	err = fs.filer.CreateEntry(context.Background(), entry, false, false)
 
 	return &filer_pb.AppendToEntryResponse{}, err
diff --git a/weed/server/filer_server_handlers_write.go b/weed/server/filer_server_handlers_write.go
index a642c502a..da66178ce 100644
--- a/weed/server/filer_server_handlers_write.go
+++ b/weed/server/filer_server_handlers_write.go
@@ -40,7 +40,7 @@ type FilerPostResult struct {
 	Url   string `json:"url,omitempty"`
 }
 
-func (fs *FilerServer) assignNewFileInfo(w http.ResponseWriter, r *http.Request, replication, collection, dataCenter, ttlString string, fsync bool) (fileId, urlLocation string, auth security.EncodedJwt, err error) {
+func (fs *FilerServer) assignNewFileInfo(replication, collection, dataCenter, ttlString string, fsync bool) (fileId, urlLocation string, auth security.EncodedJwt, err error) {
 
 	stats.FilerRequestCounter.WithLabelValues("assign").Inc()
 	start := time.Now()
@@ -67,7 +67,6 @@ func (fs *FilerServer) assignNewFileInfo(w http.ResponseWriter, r *http.Request,
 	assignResult, ae := operation.Assign(fs.filer.GetMaster(), fs.grpcDialOption, ar, altRequest)
 	if ae != nil {
 		glog.Errorf("failing to assign a file id: %v", ae)
-		writeJsonError(w, r, http.StatusInternalServerError, ae)
 		err = ae
 		return
 	}
@@ -114,7 +113,7 @@ func (fs *FilerServer) PostHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	fileId, urlLocation, auth, err := fs.assignNewFileInfo(w, r, replication, collection, dataCenter, ttlString, fsync)
+	fileId, urlLocation, auth, err := fs.assignNewFileInfo(replication, collection, dataCenter, ttlString, fsync)
 
 	if err != nil || fileId == "" || urlLocation == "" {
 		glog.V(0).Infof("fail to allocate volume for %s, collection:%s, datacenter:%s", r.URL.Path, collection, dataCenter)
diff --git a/weed/server/filer_server_handlers_write_autochunk.go b/weed/server/filer_server_handlers_write_autochunk.go
index 29546542c..be0438efb 100644
--- a/weed/server/filer_server_handlers_write_autochunk.go
+++ b/weed/server/filer_server_handlers_write_autochunk.go
@@ -102,7 +102,7 @@ func (fs *FilerServer) doAutoChunk(ctx context.Context, w http.ResponseWriter, r
 		limitedReader := io.LimitReader(partReader, int64(chunkSize))
 
 		// assign one file id for one chunk
-		fileId, urlLocation, auth, assignErr := fs.assignNewFileInfo(w, r, replication, collection, dataCenter, ttlString, fsync)
+		fileId, urlLocation, auth, assignErr := fs.assignNewFileInfo(replication, collection, dataCenter, ttlString, fsync)
 		if assignErr != nil {
 			return nil, assignErr
 		}
@@ -132,6 +132,12 @@ func (fs *FilerServer) doAutoChunk(ctx context.Context, w http.ResponseWriter, r
 		}
 	}
 
+	fileChunks, replyerr = filer2.MaybeManifestize(fs.saveAsChunk(replication, collection, dataCenter, ttlString, fsync), fileChunks)
+	if replyerr != nil {
+		glog.V(0).Infof("manifestize %s: %v", r.RequestURI, replyerr)
+		return
+	}
+
 	path := r.URL.Path
 	if strings.HasSuffix(path, "/") {
 		if fileName != "" {
@@ -184,3 +190,23 @@ func (fs *FilerServer) doUpload(urlLocation string, w http.ResponseWriter, r *ht
 	uploadResult, err, _ := operation.Upload(urlLocation, fileName, fs.option.Cipher, limitedReader, false, contentType, pairMap, auth)
 	return uploadResult, err
 }
+
+func (fs *FilerServer) saveAsChunk(replication string, collection string, dataCenter string, ttlString string, fsync bool) filer2.SaveDataAsChunkFunctionType {
+
+	return func(reader io.Reader, name string, offset int64) (*filer_pb.FileChunk, string, string, error) {
+		// assign one file id for one chunk
+		fileId, urlLocation, auth, assignErr := fs.assignNewFileInfo(replication, collection, dataCenter, ttlString, fsync)
+		if assignErr != nil {
+			return nil, "", "", assignErr
+		}
+
+		// upload the chunk to the volume server
+		uploadResult, uploadErr, _ := operation.Upload(urlLocation, name, fs.option.Cipher, reader, false, "", nil, auth)
+		if uploadErr != nil {
+			return nil, "", "", uploadErr
+		}
+
+		return uploadResult.ToPbFileChunk(fileId, offset), collection, replication, nil
+	}
+}
+
diff --git a/weed/server/filer_server_handlers_write_cipher.go b/weed/server/filer_server_handlers_write_cipher.go
index 17f35838d..8413496b8 100644
--- a/weed/server/filer_server_handlers_write_cipher.go
+++ b/weed/server/filer_server_handlers_write_cipher.go
@@ -19,7 +19,7 @@ import (
 func (fs *FilerServer) encrypt(ctx context.Context, w http.ResponseWriter, r *http.Request,
 	replication string, collection string, dataCenter string, ttlSeconds int32, ttlString string, fsync bool) (filerResult *FilerPostResult, err error) {
 
-	fileId, urlLocation, auth, err := fs.assignNewFileInfo(w, r, replication, collection, dataCenter, ttlString, fsync)
+	fileId, urlLocation, auth, err := fs.assignNewFileInfo(replication, collection, dataCenter, ttlString, fsync)
 
 	if err != nil || fileId == "" || urlLocation == "" {
 		return nil, fmt.Errorf("fail to allocate volume for %s, collection:%s, datacenter:%s", r.URL.Path, collection, dataCenter)
diff --git a/weed/server/webdav_server.go b/weed/server/webdav_server.go
index e8bedd352..8655daf70 100644
--- a/weed/server/webdav_server.go
+++ b/weed/server/webdav_server.go
@@ -474,7 +474,7 @@ func (f *WebDavFile) Read(p []byte) (readSize int, err error) {
 		return 0, io.EOF
 	}
 	if f.entryViewCache == nil {
-		f.entryViewCache = filer2.NonOverlappingVisibleIntervals(f.entry.Chunks)
+		f.entryViewCache, _ = filer2.NonOverlappingVisibleIntervals(filer2.LookupFn(f.fs), f.entry.Chunks)
 		f.reader = nil
 	}
 	if f.reader == nil {
diff --git a/weed/storage/needle/volume_ttl.go b/weed/storage/needle/volume_ttl.go
index 179057876..26ce3b8fd 100644
--- a/weed/storage/needle/volume_ttl.go
+++ b/weed/storage/needle/volume_ttl.go
@@ -1,11 +1,12 @@
 package needle
 
 import (
+	"fmt"
 	"strconv"
 )
 
 const (
-	//stored unit types
+	// stored unit types
 	Empty byte = iota
 	Minute
 	Hour
@@ -139,3 +140,10 @@ func (t TTL) Minutes() uint32 {
 	}
 	return 0
 }
+
+func SecondsToTTL(seconds int32) string {
+	if seconds == 0 {
+		return ""
+	}
+	return fmt.Sprintf("%dm", seconds/60)
+}