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moby--moby/graph/graph.go

143 lines
3 KiB
Go

package graph
import (
"fmt"
"io/ioutil"
"os"
"path"
"path/filepath"
"time"
)
type Graph struct {
Root string
}
func New(root string) (*Graph, error) {
abspath, err := filepath.Abs(root)
if err != nil {
return nil, err
}
// Create the root directory if it doesn't exists
if err := os.Mkdir(root, 0700); err != nil && !os.IsExist(err) {
return nil, err
}
return &Graph{
Root: abspath,
}, nil
}
func (graph *Graph) Exists(id string) bool {
if _, err := graph.Get(id); err != nil {
return false
}
return true
}
func (graph *Graph) Get(id string) (*Image, error) {
img, err := LoadImage(graph.imageRoot(id))
if err != nil {
return nil, err
}
if img.Id != id {
return nil, fmt.Errorf("Image stored at '%s' has wrong id '%s'", id, img.Id)
}
return img, nil
}
func (graph *Graph) Create(layerData Archive, parent, comment string) (*Image, error) {
img := &Image{
Id: GenerateId(),
Parent: parent,
Comment: comment,
Created: time.Now(),
}
if err := graph.Register(layerData, img); err != nil {
return nil, err
}
return img, nil
}
func (graph *Graph) Register(layerData Archive, img *Image) error {
if err := ValidateId(img.Id); err != nil {
return err
}
// (This is a convenience to save time. Race conditions are taken care of by os.Rename)
if graph.Exists(img.Id) {
return fmt.Errorf("Image %s already exists", img.Id)
}
tmp, err := graph.Mktemp(img.Id)
defer os.RemoveAll(tmp)
if err != nil {
return fmt.Errorf("Mktemp failed: %s", err)
}
if err := StoreImage(img, layerData, tmp); err != nil {
return err
}
// Commit
if err := os.Rename(tmp, graph.imageRoot(img.Id)); err != nil {
return err
}
img.graph = graph
return nil
}
func (graph *Graph) Mktemp(id string) (string, error) {
tmp, err := New(path.Join(graph.Root, ":tmp:"))
if err != nil {
return "", fmt.Errorf("Couldn't create temp: %s", err)
}
if tmp.Exists(id) {
return "", fmt.Errorf("Image %d already exists", id)
}
return tmp.imageRoot(id), nil
}
func (graph *Graph) Garbage() (*Graph, error) {
return New(path.Join(graph.Root, ":garbage:"))
}
func (graph *Graph) Delete(id string) error {
garbage, err := graph.Garbage()
if err != nil {
return err
}
return os.Rename(graph.imageRoot(id), garbage.imageRoot(id))
}
func (graph *Graph) Undelete(id string) error {
garbage, err := graph.Garbage()
if err != nil {
return err
}
return os.Rename(garbage.imageRoot(id), graph.imageRoot(id))
}
func (graph *Graph) GarbageCollect() error {
garbage, err := graph.Garbage()
if err != nil {
return err
}
return os.RemoveAll(garbage.Root)
}
func (graph *Graph) All() ([]*Image, error) {
files, err := ioutil.ReadDir(graph.Root)
if err != nil {
return nil, err
}
var images []*Image
for _, st := range files {
if img, err := graph.Get(st.Name()); err != nil {
// Skip image
continue
} else {
images = append(images, img)
}
}
return images, nil
}
func (graph *Graph) imageRoot(id string) string {
return path.Join(graph.Root, id)
}