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package docker |
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import (
"fmt"
"io/ioutil"
"os"
"path"
"path/filepath"
"time"
)
type Graph struct {
Root string
}
|
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func NewGraph(root string) (*Graph, error) { |
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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) { |
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// FIXME: return nil when the image doesn't exist, instead of an error |
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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)
} |
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img.graph = graph |
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return img, nil
}
|
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func (graph *Graph) Create(layerData Archive, container *Container, comment string) (*Image, error) { |
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img := &Image{
Id: GenerateId(),
Comment: comment,
Created: time.Now(),
} |
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if container != nil {
img.Parent = container.Image |
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img.Container = container.Id
img.ContainerConfig = *container.Config |
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} |
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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) { |
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tmp, err := NewGraph(path.Join(graph.Root, ":tmp:")) |
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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) { |
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return NewGraph(path.Join(graph.Root, ":garbage:")) |
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}
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)
}
|
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func (graph *Graph) Map() (map[string]*Image, error) {
// FIXME: this should replace All()
all, err := graph.All()
if err != nil {
return nil, err
}
images := make(map[string]*Image, len(all))
for _, image := range all {
images[image.Id] = image
}
return images, nil
}
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func (graph *Graph) All() ([]*Image, error) { |
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var images []*Image
err := graph.WalkAll(func(image *Image) {
images = append(images, image)
})
return images, err
}
func (graph *Graph) WalkAll(handler func(*Image)) error { |
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files, err := ioutil.ReadDir(graph.Root)
if err != nil { |
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return err |
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}
for _, st := range files {
if img, err := graph.Get(st.Name()); err != nil {
// Skip image
continue |
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} else if handler != nil {
handler(img)
}
}
return nil
}
func (graph *Graph) ByParent() (map[string][]*Image, error) {
byParent := make(map[string][]*Image)
err := graph.WalkAll(func(image *Image) {
image, err := graph.Get(image.Parent)
if err != nil {
return
}
if children, exists := byParent[image.Parent]; exists {
byParent[image.Parent] = []*Image{image} |
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} else { |
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byParent[image.Parent] = append(children, image) |
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} |
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})
return byParent, err
}
func (graph *Graph) Heads() (map[string]*Image, error) {
heads := make(map[string]*Image)
byParent, err := graph.ByParent()
if err != nil {
return nil, err |
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} |
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err = graph.WalkAll(func(image *Image) {
// If it's not in the byParent lookup table, then
// it's not a parent -> so it's a head!
if _, exists := byParent[image.Id]; !exists {
heads[image.Id] = image
}
})
return heads, err |
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}
func (graph *Graph) imageRoot(id string) string {
return path.Join(graph.Root, id)
} |