From 58bec40d16265362fd4e41dbd652e6fba903794d Mon Sep 17 00:00:00 2001
From: John Starks <jostarks@microsoft.com>
Date: Thu, 18 Feb 2016 17:58:23 -0800
Subject: [PATCH] graphdriver: Replace DiffPath with DiffGetter
This allows a graph driver to provide a custom FileGetter for tar-split
to use. Windows will use this to provide a more efficient implementation
in a follow-up change.
Signed-off-by: John Starks <jostarks@microsoft.com>
---
daemon/graphdriver/aufs/aufs.go | 18 +++++++++++----
daemon/graphdriver/driver.go | 18 +++++++++++++++
daemon/graphdriver/windows/windows.go | 26 +++++++++++++++------
layer/layer_store.go | 33 +++++++++++++++------------
4 files changed, 69 insertions(+), 26 deletions(-)
diff --git a/daemon/graphdriver/aufs/aufs.go b/daemon/graphdriver/aufs/aufs.go
index 51054fa6ef..07dba9e0fe 100644
--- a/daemon/graphdriver/aufs/aufs.go
+++ b/daemon/graphdriver/aufs/aufs.go
@@ -34,6 +34,7 @@ import (
"syscall"
"github.com/Sirupsen/logrus"
+ "github.com/vbatts/tar-split/tar/storage"
"github.com/docker/docker/daemon/graphdriver"
"github.com/docker/docker/pkg/archive"
@@ -367,10 +368,19 @@ func (a *Driver) Diff(id, parent string) (archive.Archive, error) {
})
}
-// DiffPath returns path to the directory that contains files for the layer
-// differences. Used for direct access for tar-split.
-func (a *Driver) DiffPath(id string) (string, func() error, error) {
- return path.Join(a.rootPath(), "diff", id), func() error { return nil }, nil
+type fileGetNilCloser struct {
+ storage.FileGetter
+}
+
+func (f fileGetNilCloser) Close() error {
+ return nil
+}
+
+// DiffGetter returns a FileGetCloser that can read files from the directory that
+// contains files for the layer differences. Used for direct access for tar-split.
+func (a *Driver) DiffGetter(id string) (graphdriver.FileGetCloser, error) {
+ p := path.Join(a.rootPath(), "diff", id)
+ return fileGetNilCloser{storage.NewPathFileGetter(p)}, nil
}
func (a *Driver) applyDiff(id string, diff archive.Reader) error {
diff --git a/daemon/graphdriver/driver.go b/daemon/graphdriver/driver.go
index d9ab839c2e..abc400083d 100644
--- a/daemon/graphdriver/driver.go
+++ b/daemon/graphdriver/driver.go
@@ -8,6 +8,7 @@ import (
"strings"
"github.com/Sirupsen/logrus"
+ "github.com/vbatts/tar-split/tar/storage"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/idtools"
@@ -92,6 +93,23 @@ type Driver interface {
DiffSize(id, parent string) (size int64, err error)
}
+// DiffGetterDriver is the interface for layered file system drivers that
+// provide a specialized function for getting file contents for tar-split.
+type DiffGetterDriver interface {
+ Driver
+ // DiffGetter returns an interface to efficiently retrieve the contents
+ // of files in a layer.
+ DiffGetter(id string) (FileGetCloser, error)
+}
+
+// FileGetCloser extends the storage.FileGetter interface with a Close method
+// for cleaning up.
+type FileGetCloser interface {
+ storage.FileGetter
+ // Close cleans up any resources associated with the FileGetCloser.
+ Close() error
+}
+
func init() {
drivers = make(map[string]InitFunc)
}
diff --git a/daemon/graphdriver/windows/windows.go b/daemon/graphdriver/windows/windows.go
index 77f4f1b774..58af3e5e04 100644
--- a/daemon/graphdriver/windows/windows.go
+++ b/daemon/graphdriver/windows/windows.go
@@ -22,6 +22,7 @@ import (
"github.com/docker/docker/pkg/idtools"
"github.com/docker/docker/pkg/ioutils"
"github.com/docker/docker/pkg/random"
+ "github.com/vbatts/tar-split/tar/storage"
)
// init registers the windows graph drivers to the register.
@@ -47,6 +48,8 @@ type Driver struct {
active map[string]int
}
+var _ graphdriver.DiffGetterDriver = &Driver{}
+
// InitFilter returns a new Windows storage filter driver.
func InitFilter(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
logrus.Debugf("WindowsGraphDriver InitFilter at %s", home)
@@ -564,8 +567,20 @@ func (d *Driver) setLayerChain(id string, chain []string) error {
return nil
}
-// DiffPath returns a directory that contains files needed to construct layer diff.
-func (d *Driver) DiffPath(id string) (path string, release func() error, err error) {
+type fileGetDestroyCloser struct {
+ storage.FileGetter
+ d *Driver
+ folderName string
+}
+
+func (f *fileGetDestroyCloser) Close() error {
+ // TODO: activate layers and release here?
+ return hcsshim.DestroyLayer(f.d.info, f.folderName)
+}
+
+// DiffGetter returns a FileGetCloser that can read files from the directory that
+// contains files for the layer differences. Used for direct access for tar-split.
+func (d *Driver) DiffGetter(id string) (fg graphdriver.FileGetCloser, err error) {
id, err = d.resolveID(id)
if err != nil {
return
@@ -597,9 +612,6 @@ func (d *Driver) DiffPath(id string) (path string, release func() error, err err
return
}
- return tempFolder, func() error {
- // TODO: activate layers and release here?
- _, folderName := filepath.Split(tempFolder)
- return hcsshim.DestroyLayer(d.info, folderName)
- }, nil
+ _, folderName := filepath.Split(tempFolder)
+ return &fileGetDestroyCloser{storage.NewPathFileGetter(tempFolder), d, folderName}, nil
}
diff --git a/layer/layer_store.go b/layer/layer_store.go
index 229ba6a3a2..4b01ea0fc0 100644
--- a/layer/layer_store.go
+++ b/layer/layer_store.go
@@ -577,11 +577,7 @@ func (ls *layerStore) initMount(graphID, parent, mountLabel string, initFunc Mou
}
func (ls *layerStore) assembleTarTo(graphID string, metadata io.ReadCloser, size *int64, w io.Writer) error {
- type diffPathDriver interface {
- DiffPath(string) (string, func() error, error)
- }
-
- diffDriver, ok := ls.driver.(diffPathDriver)
+ diffDriver, ok := ls.driver.(graphdriver.DiffGetterDriver)
if !ok {
diffDriver = &naiveDiffPathDriver{ls.driver}
}
@@ -589,17 +585,16 @@ func (ls *layerStore) assembleTarTo(graphID string, metadata io.ReadCloser, size
defer metadata.Close()
// get our relative path to the container
- fsPath, releasePath, err := diffDriver.DiffPath(graphID)
+ fileGetCloser, err := diffDriver.DiffGetter(graphID)
if err != nil {
return err
}
- defer releasePath()
+ defer fileGetCloser.Close()
metaUnpacker := storage.NewJSONUnpacker(metadata)
upackerCounter := &unpackSizeCounter{metaUnpacker, size}
- fileGetter := storage.NewPathFileGetter(fsPath)
- logrus.Debugf("Assembling tar data for %s from %s", graphID, fsPath)
- return asm.WriteOutputTarStream(fileGetter, upackerCounter, w)
+ logrus.Debugf("Assembling tar data for %s", graphID)
+ return asm.WriteOutputTarStream(fileGetCloser, upackerCounter, w)
}
func (ls *layerStore) Cleanup() error {
@@ -618,12 +613,20 @@ type naiveDiffPathDriver struct {
graphdriver.Driver
}
-func (n *naiveDiffPathDriver) DiffPath(id string) (string, func() error, error) {
+type fileGetPutter struct {
+ storage.FileGetter
+ driver graphdriver.Driver
+ id string
+}
+
+func (w *fileGetPutter) Close() error {
+ return w.driver.Put(w.id)
+}
+
+func (n *naiveDiffPathDriver) DiffGetter(id string) (graphdriver.FileGetCloser, error) {
p, err := n.Driver.Get(id, "")
if err != nil {
- return "", nil, err
+ return nil, err
}
- return p, func() error {
- return n.Driver.Put(id)
- }, nil
+ return &fileGetPutter{storage.NewPathFileGetter(p), n.Driver, id}, nil
}