243 lines
5.6 KiB
Go
243 lines
5.6 KiB
Go
package graph
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
"github.com/dotcloud/docker/future"
|
|
"io/ioutil"
|
|
"os"
|
|
"path"
|
|
"strings"
|
|
"time"
|
|
)
|
|
|
|
type Image struct {
|
|
Id string
|
|
Parent string
|
|
Comment string
|
|
Created time.Time
|
|
graph *Graph
|
|
}
|
|
|
|
func LoadImage(root string) (*Image, error) {
|
|
// Load the json data
|
|
jsonData, err := ioutil.ReadFile(jsonPath(root))
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
var img Image
|
|
if err := json.Unmarshal(jsonData, &img); err != nil {
|
|
return nil, err
|
|
}
|
|
if err := ValidateId(img.Id); err != nil {
|
|
return nil, err
|
|
}
|
|
// Check that the filesystem layer exists
|
|
if stat, err := os.Stat(layerPath(root)); err != nil {
|
|
if os.IsNotExist(err) {
|
|
return nil, fmt.Errorf("Couldn't load image %s: no filesystem layer", img.Id)
|
|
} else {
|
|
return nil, err
|
|
}
|
|
} else if !stat.IsDir() {
|
|
return nil, fmt.Errorf("Couldn't load image %s: %s is not a directory", img.Id, layerPath(root))
|
|
}
|
|
return &img, nil
|
|
}
|
|
|
|
func StoreImage(img *Image, layerData Archive, root string) error {
|
|
// Check that root doesn't already exist
|
|
if _, err := os.Stat(root); err == nil {
|
|
return fmt.Errorf("Image %s already exists", img.Id)
|
|
} else if !os.IsNotExist(err) {
|
|
return err
|
|
}
|
|
// Store the layer
|
|
layer := layerPath(root)
|
|
if err := os.MkdirAll(layer, 0700); err != nil {
|
|
return err
|
|
}
|
|
if err := Untar(layerData, layer); err != nil {
|
|
return err
|
|
}
|
|
// Store the json ball
|
|
jsonData, err := json.Marshal(img)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if err := ioutil.WriteFile(jsonPath(root), jsonData, 0600); err != nil {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func layerPath(root string) string {
|
|
return path.Join(root, "layer")
|
|
}
|
|
|
|
func jsonPath(root string) string {
|
|
return path.Join(root, "json")
|
|
}
|
|
|
|
func MountAUFS(ro []string, rw string, target string) error {
|
|
// FIXME: Now mount the layers
|
|
rwBranch := fmt.Sprintf("%v=rw", rw)
|
|
roBranches := ""
|
|
for _, layer := range ro {
|
|
roBranches += fmt.Sprintf("%v=ro:", layer)
|
|
}
|
|
branches := fmt.Sprintf("br:%v:%v", rwBranch, roBranches)
|
|
return mount("none", target, "aufs", 0, branches)
|
|
}
|
|
|
|
func (image *Image) Mount(root, rw string) error {
|
|
if mounted, err := Mounted(root); err != nil {
|
|
return err
|
|
} else if mounted {
|
|
return fmt.Errorf("%s is already mounted", root)
|
|
}
|
|
layers, err := image.layers()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
// Create the target directories if they don't exist
|
|
if err := os.Mkdir(root, 0755); err != nil && !os.IsExist(err) {
|
|
return err
|
|
}
|
|
if err := os.Mkdir(rw, 0755); err != nil && !os.IsExist(err) {
|
|
return err
|
|
}
|
|
// FIXME: @creack shouldn't we do this after going over changes?
|
|
if err := MountAUFS(layers, rw, root); err != nil {
|
|
return err
|
|
}
|
|
// FIXME: Create tests for deletion
|
|
// FIXME: move this part to change.go
|
|
// Retrieve the changeset from the parent and apply it to the container
|
|
// - Retrieve the changes
|
|
changes, err := Changes(layers, layers[0])
|
|
if err != nil {
|
|
return err
|
|
}
|
|
// Iterate on changes
|
|
for _, c := range changes {
|
|
// If there is a delete
|
|
if c.Kind == ChangeDelete {
|
|
// Make sure the directory exists
|
|
file_path, file_name := path.Dir(c.Path), path.Base(c.Path)
|
|
if err := os.MkdirAll(path.Join(rw, file_path), 0755); err != nil {
|
|
return err
|
|
}
|
|
// And create the whiteout (we just need to create empty file, discard the return)
|
|
if _, err := os.Create(path.Join(path.Join(rw, file_path),
|
|
".wh."+path.Base(file_name))); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (image *Image) Changes(rw string) ([]Change, error) {
|
|
layers, err := image.layers()
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return Changes(layers, rw)
|
|
}
|
|
|
|
func ValidateId(id string) error {
|
|
if id == "" {
|
|
return fmt.Errorf("Image id can't be empty")
|
|
}
|
|
if strings.Contains(id, ":") {
|
|
return fmt.Errorf("Invalid character in image id: ':'")
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func GenerateId() string {
|
|
future.Seed()
|
|
return future.RandomId()
|
|
}
|
|
|
|
// Image includes convenience proxy functions to its graph
|
|
// These functions will return an error if the image is not registered
|
|
// (ie. if image.graph == nil)
|
|
|
|
func (img *Image) History() ([]*Image, error) {
|
|
var parents []*Image
|
|
if err := img.WalkHistory(
|
|
func(img *Image) {
|
|
parents = append(parents, img)
|
|
},
|
|
); err != nil {
|
|
return nil, err
|
|
}
|
|
return parents, nil
|
|
}
|
|
|
|
// layers returns all the filesystem layers needed to mount an image
|
|
func (img *Image) layers() ([]string, error) {
|
|
var list []string
|
|
var e error
|
|
if err := img.WalkHistory(
|
|
func(img *Image) {
|
|
if layer, err := img.layer(); err != nil {
|
|
e = err
|
|
} else if layer != "" {
|
|
list = append(list, layer)
|
|
}
|
|
},
|
|
); 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)
|
|
}
|
|
return list, nil
|
|
}
|
|
|
|
func (img *Image) WalkHistory(handler func(*Image)) error {
|
|
var err error
|
|
currentImg := img
|
|
for currentImg != nil {
|
|
if handler != nil {
|
|
handler(currentImg)
|
|
}
|
|
currentImg, err = currentImg.GetParent()
|
|
if err != nil {
|
|
return fmt.Errorf("Error while getting parent image: %v", err)
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (img *Image) GetParent() (*Image, error) {
|
|
if img.Parent == "" {
|
|
return nil, nil
|
|
}
|
|
if img.graph == nil {
|
|
return nil, fmt.Errorf("Can't lookup parent of unregistered image")
|
|
}
|
|
return img.graph.Get(img.Parent)
|
|
}
|
|
|
|
func (img *Image) root() (string, error) {
|
|
if img.graph == nil {
|
|
return "", fmt.Errorf("Can't lookup root of unregistered image")
|
|
}
|
|
return img.graph.imageRoot(img.Id), nil
|
|
}
|
|
|
|
// Return the path of an image's layer
|
|
func (img *Image) layer() (string, error) {
|
|
root, err := img.root()
|
|
if err != nil {
|
|
return "", err
|
|
}
|
|
return layerPath(root), nil
|
|
}
|