Finalize driver interfaces

aufs/aufs.go

@@ -2,6 +2,7 @@ package aufs
 
 import (
 	"fmt"
+	"github.com/dotcloud/docker/archive"
 	"github.com/dotcloud/docker/graphdriver"
 	"log"
 	"os"
@@ -14,6 +15,7 @@ func init() {
 }
 
 type AufsDriver struct {
+	root string
 }
 
 // New returns a new AUFS driver.
@@ -23,17 +25,54 @@ func Init(root string) (graphdriver.Driver, error) {
 	if err := exec.Command("modprobe", "aufs").Run(); err != nil {
 		return nil, err
 	}
-	return &AufsDriver{}, nil
+	return &AufsDriver{root}, nil
 }
 
-func (a *AufsDriver) Mount(img graphdriver.Image, root string) error {
-	layers, err := img.Layers()
+func (a *AufsDriver) OnCreate(dir graphdriver.Dir, layer archive.Archive) error {
+	tmp := path.Join(os.TempDir(), dir.ID())
+	if err := os.MkdirAll(tmp, 0755); err != nil {
+		return err
+	}
+	defer os.RemoveAll(tmp)
+
+	layerRoot := path.Join(a.root, dir.ID())
+	if err := os.MkdirAll(layerRoot, 0755); err != nil {
+		return err
+	}
+
+	if layer != nil {
+		if err := archive.Untar(layer, tmp); err != nil {
+			return err
+		}
+	}
+
+	if err := os.Rename(tmp, layerRoot); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (a *AufsDriver) OnRemove(dir graphdriver.Dir) error {
+	tmp := path.Join(os.TempDir(), dir.ID())
+
+	if err := os.MkdirAll(tmp, 0755); err != nil {
+		return err
+	}
+
+	if err := os.Rename(path.Join(a.root, dir.ID()), tmp); err != nil {
+		return err
+	}
+	return os.RemoveAll(tmp)
+}
+
+func (a *AufsDriver) OnMount(dir graphdriver.Dir, dest string) error {
+	layers, err := a.getLayers(dir)
 	if err != nil {
 		return err
 	}
 
-	target := path.Join(root, "rootfs")
-	rw := path.Join(root, "rw")
+	target := path.Join(dest, "rootfs")
+	rw := path.Join(dest, "rw")
 
 	// Create the target directories if they don't exist
 	if err := os.Mkdir(target, 0755); err != nil && !os.IsExist(err) {
@@ -48,8 +87,8 @@ func (a *AufsDriver) Mount(img graphdriver.Image, root string) error {
 	return nil
 }
 
-func (a *AufsDriver) Unmount(root string) error {
-	target := path.Join(root, "rootfs")
+func (a *AufsDriver) OnUnmount(dest string) error {
+	target := path.Join(dest, "rootfs")
 	if _, err := os.Stat(target); err != nil {
 		if os.IsNotExist(err) {
 			return nil
@@ -59,8 +98,32 @@ func (a *AufsDriver) Unmount(root string) error {
 	return Unmount(target)
 }
 
-func (a *AufsDriver) Mounted(root string) (bool, error) {
-	return Mounted(path.Join(root, "rootfs"))
+func (a *AufsDriver) Mounted(dest string) (bool, error) {
+	return Mounted(path.Join(dest, "rootfs"))
+}
+
+func (a *AufsDriver) Layer(dir graphdriver.Dir, dest string) (archive.Archive, error) {
+	return nil, fmt.Errorf("not implemented")
+}
+
+func (a *AufsDriver) Cleanup() error {
+	return nil
+}
+
+func (a *AufsDriver) getLayers(dir graphdriver.Dir) ([]string, error) {
+	var (
+		err     error
+		layers  = []string{}
+		current = dir
+	)
+
+	for current != nil {
+		layers = append(layers, current.Path())
+		if current, err = current.Parent(); err != nil {
+			return nil, err
+		}
+	}
+	return layers, nil
 }
 
 func (a *AufsDriver) aufsMount(ro []string, rw, target string) error {

graphdriver/driver.go

@@ -2,10 +2,30 @@ package graphdriver
 
 import (
 	"fmt"
+	"github.com/dotcloud/docker/archive"
 )
 
 type InitFunc func(root string) (Driver, error)
 
+type Dir interface {
+	ID() string
+	Path() string
+	Parent() (Dir, error)
+}
+
+type Driver interface {
+	OnCreate(dir Dir, layer archive.Archive) error
+	OnRemove(dir Dir) error
+
+	OnMount(dir Dir, dest string) error
+	OnUnmount(dest string) error
+	Mounted(dest string) (bool, error)
+
+	Layer(dir Dir, dest string) (archive.Archive, error)
+
+	Cleanup() error
+}
+
 var (
 	// All registred drivers
 	drivers map[string]InitFunc
@@ -49,18 +69,3 @@ func New(root string) (Driver, error) {
 	}
 	return nil, lastError
 }
-
-type Image interface {
-	Layers() ([]string, error)
-}
-
-type Driver interface {
-	//	Create(img *Image) error
-	//	Delete(img *Image) error
-	Mount(img Image, root string) error
-	Unmount(root string) error
-	Mounted(root string) (bool, error)
-	//	UnmountAll(img *Image) error
-	//	Changes(img *Image, dest string) ([]Change, error)
-	//	Layer(img *Image, dest string) (Archive, error)
-}

image.go

@@ -183,43 +183,6 @@ func (img *Image) History() ([]*Image, error) {
 	return parents, nil
 }
 
-// layers returns all the filesystem layers needed to mount an image
-// FIXME: @shykes refactor this function with the new error handling
-//        (I'll do it if I have time tonight, I focus on the rest)
-func (img *Image) Layers() ([]string, error) {
-	if img.graph == nil {
-
-		return nil, fmt.Errorf("Can't lookup dockerinit layer of unregistered image")
-	}
-	var list []string
-	var e error
-	if err := img.WalkHistory(
-		func(img *Image) (err error) {
-			if layer, err := img.layer(); err != nil {
-				e = err
-			} else if layer != "" {
-				list = append(list, layer)
-			}
-			return err
-		},
-	); err != nil {
-		return nil, err
-	} else if e != nil { // Did an error occur inside the handler?
-		return nil, e
-	}
-	if len(list) == 0 {
-		return nil, fmt.Errorf("No layer found for image %s\n", img.ID)
-	}
-
-	// Inject the dockerinit layer (empty place-holder for mount-binding dockerinit)
-	if dockerinitLayer, err := img.graph.getDockerInitLayer(); err != nil {
-		return nil, err
-	} else {
-		list = append([]string{dockerinitLayer}, list...)
-	}
-	return list, nil
-}
-
 func (img *Image) WalkHistory(handler func(*Image) error) (err error) {
 	currentImg := img
 	for currentImg != nil {