@@ -87,7 +87,7 @@ const (

 	jsonFileName      = "json"

 	layersizeFileName = "layersize"

 	digestFileName    = "checksum"

-	tardataFileName   = "tar-data.json.gz"

+	tarDataFileName   = "tar-data.json.gz"

 )

 var (

@@ -6,14 +6,18 @@ import (

 	"compress/gzip"

 	"encoding/json"

 	"fmt"

+	"io"

 	"os"

 	"path/filepath"

 	"strings"

 	"syscall"

+	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/pkg/archive"

 	"github.com/docker/docker/pkg/system"

+	"github.com/vbatts/tar-split/tar/asm"

+	"github.com/vbatts/tar-split/tar/storage"

 )

 // setupInitLayer populates a directory with mountpoints suitable

@@ -92,14 +96,14 @@ func (graph *Graph) storeImage(img *image.Image, layerData archive.ArchiveReader

 	// Store the layer. If layerData is not nil, unpack it into the new layer

 	if layerData != nil {

 		// this is saving the tar-split metadata

-		mf, err := os.OpenFile(filepath.Join(root, tardataFileName), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))

+		mf, err := os.OpenFile(filepath.Join(root, tarDataFileName), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))

 		if err != nil {

 			return err

 		}

 		defer mf.Close()

 		mfz := gzip.NewWriter(mf)

 		defer mfz.Close()

-		metaPacker := storage.NewJSONPacker(mf)

+		metaPacker := storage.NewJSONPacker(mfz)

 		inflatedLayerData, err := archive.DecompressStream(layerData)

 		if err != nil {

@@ -134,6 +138,49 @@ func (graph *Graph) storeImage(img *image.Image, layerData archive.ArchiveReader

 // TarLayer returns a tar archive of the image's filesystem layer.

 func (graph *Graph) TarLayer(img *image.Image) (arch archive.Archive, err error) {

-	// TODO(vbatts) let's reassemble!

-	return graph.driver.Diff(img.ID, img.Parent)

+	root := graph.imageRoot(img.ID)

+	mFileName := filepath.Join(root, tarDataFileName)

+	mf, err := os.Open(mFileName)

+	if err != nil {

+		if !os.IsNotExist(err) {

+			logrus.Errorf("failed to open %q: %s", mFileName, err)

+		}

+		logrus.Debugf("[graph] TarLayer with traditional differ: %s", img.ID)

+		return graph.driver.Diff(img.ID, img.Parent)

+	}

+	pR, pW := io.Pipe()

+	// this will need to be in a goroutine, as we are returning the stream of a

+	// tar archive, but can not close the metadata reader early (when this

+	// function returns)...

+	go func() {

+		defer mf.Close()

+		// let's reassemble!

+		logrus.Debugf("[graph] TarLayer with reassembly: %s", img.ID)

+		mfz, err := gzip.NewReader(mf)

+		if err != nil {

+			pW.CloseWithError(fmt.Errorf("[graph] error with %s:  %s", mFileName, err))

+			return

+		}

+		defer mfz.Close()

+

+		// get our relative path to the container

+		fsLayer, err := graph.driver.Get(img.ID, "")

+		if err != nil {

+			pW.CloseWithError(err)

+			return

+		}

+		defer graph.driver.Put(img.ID)

+

+		metaUnpacker := storage.NewJSONUnpacker(mfz)

+		fileGetter := storage.NewPathFileGetter(fsLayer)

+		logrus.Debugf("[graph] %s is at %q", img.ID, fsLayer)

+		ots := asm.NewOutputTarStream(fileGetter, metaUnpacker)

+		defer ots.Close()

+		if _, err := io.Copy(pW, ots); err != nil {

+			pW.CloseWithError(err)

+			return

+		}

+		pW.Close()

+	}()

+	return pR, nil

 }

@@ -6,6 +6,7 @@ import (

 	"compress/gzip"

 	"encoding/json"

 	"fmt"

+	"io"

 	"os"

 	"path/filepath"

@@ -13,6 +14,8 @@ import (

 	"github.com/docker/docker/daemon/graphdriver/windows"

 	"github.com/docker/docker/image"

 	"github.com/docker/docker/pkg/archive"

+	"github.com/vbatts/tar-split/tar/asm"

+	"github.com/vbatts/tar-split/tar/storage"

 )

 // setupInitLayer populates a directory with mountpoints suitable

@@ -118,14 +121,14 @@ func (graph *Graph) storeImage(img *image.Image, layerData archive.ArchiveReader

 		// Store the layer. If layerData is not nil, unpack it into the new layer

 		if layerData != nil {

 			// this is saving the tar-split metadata

-			mf, err := os.OpenFile(filepath.Join(root, tardataFileName), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))

+			mf, err := os.OpenFile(filepath.Join(root, tarDataFileName), os.O_CREATE|os.O_WRONLY|os.O_TRUNC, os.FileMode(0600))

 			if err != nil {

 				return err

 			}

 			defer mf.Close()

 			mfz := gzip.NewWriter(mf)

 			defer mfz.Close()

-			metaPacker := storage.NewJSONPacker(mf)

+			metaPacker := storage.NewJSONPacker(mfz)

 			inflatedLayerData, err := archive.DecompressStream(layerData)

 			if err != nil {

@@ -180,7 +183,50 @@ func (graph *Graph) TarLayer(img *image.Image) (arch archive.Archive, err error)

 		// We keep this functionality here so that we can still work with the VFS

 		// driver during development. VFS is not supported (and just will not work)

 		// for Windows containers.

-		// TODO(vbatts) let's reassemble!

-		return graph.driver.Diff(img.ID, img.Parent)

+		root := graph.imageRoot(img.ID)

+		mFileName := filepath.Join(root, tarDataFileName)

+		mf, err := os.Open(mFileName)

+		if err != nil {

+			if !os.IsNotExist(err) {

+				logrus.Errorf("failed to open %q: %s", mFileName, err)

+			}

+			logrus.Debugf("[graph] TarLayer with traditional differ: %s", img.ID)

+			return graph.driver.Diff(img.ID, img.Parent)

+		}

+		pR, pW := io.Pipe()

+		// this will need to be in a goroutine, as we are returning the stream of a

+		// tar archive, but can not close the metadata reader early (when this

+		// function returns)...

+		go func() {

+			defer mf.Close()

+			// let's reassemble!

+			logrus.Debugf("[graph] TarLayer with reassembly: %s", img.ID)

+			mfz, err := gzip.NewReader(mf)

+			if err != nil {

+				pW.CloseWithError(fmt.Errorf("[graph] error with %s:  %s", mFileName, err))

+				return

+			}

+			defer mfz.Close()

+

+			// get our relative path to the container

+			fsLayer, err := graph.driver.Get(img.ID, "")

+			if err != nil {

+				pW.CloseWithError(err)

+				return

+			}

+			defer graph.driver.Put(img.ID)

+

+			metaUnpacker := storage.NewJSONUnpacker(mfz)

+			fileGetter := storage.NewPathFileGetter(fsLayer)

+			logrus.Debugf("[graph] %s is at %q", img.ID, fsLayer)

+			ots := asm.NewOutputTarStream(fileGetter, metaUnpacker)

+			defer ots.Close()

+			if _, err := io.Copy(pW, ots); err != nil {

+				pW.CloseWithError(err)

+				return

+			}

+			pW.Close()

+		}()

+		return pR, nil

 	}

 }