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moby--moby/image/tarexport/save.go
Tonis Tiigi eeb2d4c1ad Clean up reference type switches
Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
2015-12-16 11:58:53 -08:00

300 lines
6.6 KiB
Go

package tarexport
import (
"encoding/json"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"time"
"github.com/docker/distribution/digest"
"github.com/docker/docker/image"
"github.com/docker/docker/image/v1"
"github.com/docker/docker/layer"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/reference"
)
type imageDescriptor struct {
refs []reference.NamedTagged
layers []string
}
type saveSession struct {
*tarexporter
outDir string
images map[image.ID]*imageDescriptor
savedLayers map[string]struct{}
}
func (l *tarexporter) Save(names []string, outStream io.Writer) error {
images, err := l.parseNames(names)
if err != nil {
return err
}
return (&saveSession{tarexporter: l, images: images}).save(outStream)
}
func (l *tarexporter) parseNames(names []string) (map[image.ID]*imageDescriptor, error) {
imgDescr := make(map[image.ID]*imageDescriptor)
addAssoc := func(id image.ID, ref reference.Named) {
if _, ok := imgDescr[id]; !ok {
imgDescr[id] = &imageDescriptor{}
}
if ref != nil {
var tagged reference.NamedTagged
if _, ok := ref.(reference.Canonical); ok {
return
}
var ok bool
if tagged, ok = ref.(reference.NamedTagged); !ok {
var err error
if tagged, err = reference.WithTag(ref, reference.DefaultTag); err != nil {
return
}
}
for _, t := range imgDescr[id].refs {
if tagged.String() == t.String() {
return
}
}
imgDescr[id].refs = append(imgDescr[id].refs, tagged)
}
}
for _, name := range names {
ref, err := reference.ParseNamed(name)
if err != nil {
return nil, err
}
if ref.Name() == string(digest.Canonical) {
imgID, err := l.is.Search(name)
if err != nil {
return nil, err
}
addAssoc(imgID, nil)
continue
}
if reference.IsNameOnly(ref) {
assocs := l.rs.ReferencesByName(ref)
for _, assoc := range assocs {
addAssoc(assoc.ImageID, assoc.Ref)
}
if len(assocs) == 0 {
imgID, err := l.is.Search(name)
if err != nil {
return nil, err
}
addAssoc(imgID, nil)
}
continue
}
var imgID image.ID
if imgID, err = l.rs.Get(ref); err != nil {
return nil, err
}
addAssoc(imgID, ref)
}
return imgDescr, nil
}
func (s *saveSession) save(outStream io.Writer) error {
s.savedLayers = make(map[string]struct{})
// get image json
tempDir, err := ioutil.TempDir("", "docker-export-")
if err != nil {
return err
}
defer os.RemoveAll(tempDir)
s.outDir = tempDir
reposLegacy := make(map[string]map[string]string)
var manifest []manifestItem
for id, imageDescr := range s.images {
if err = s.saveImage(id); err != nil {
return err
}
var repoTags []string
var layers []string
for _, ref := range imageDescr.refs {
if _, ok := reposLegacy[ref.Name()]; !ok {
reposLegacy[ref.Name()] = make(map[string]string)
}
reposLegacy[ref.Name()][ref.Tag()] = imageDescr.layers[len(imageDescr.layers)-1]
repoTags = append(repoTags, ref.String())
}
for _, l := range imageDescr.layers {
layers = append(layers, filepath.Join(l, legacyLayerFileName))
}
manifest = append(manifest, manifestItem{
Config: digest.Digest(id).Hex() + ".json",
RepoTags: repoTags,
Layers: layers,
})
}
if len(reposLegacy) > 0 {
reposFile := filepath.Join(tempDir, legacyRepositoriesFileName)
f, err := os.OpenFile(reposFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
f.Close()
return err
}
if err := json.NewEncoder(f).Encode(reposLegacy); err != nil {
return err
}
if err := f.Close(); err != nil {
return err
}
if err := os.Chtimes(reposFile, time.Unix(0, 0), time.Unix(0, 0)); err != nil {
return err
}
}
manifestFileName := filepath.Join(tempDir, manifestFileName)
f, err := os.OpenFile(manifestFileName, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
f.Close()
return err
}
if err := json.NewEncoder(f).Encode(manifest); err != nil {
return err
}
if err := f.Close(); err != nil {
return err
}
if err := os.Chtimes(manifestFileName, time.Unix(0, 0), time.Unix(0, 0)); err != nil {
return err
}
fs, err := archive.Tar(tempDir, archive.Uncompressed)
if err != nil {
return err
}
defer fs.Close()
if _, err := io.Copy(outStream, fs); err != nil {
return err
}
return nil
}
func (s *saveSession) saveImage(id image.ID) error {
img, err := s.is.Get(id)
if err != nil {
return err
}
if len(img.RootFS.DiffIDs) == 0 {
return fmt.Errorf("empty export - not implemented")
}
var parent digest.Digest
var layers []string
for i := range img.RootFS.DiffIDs {
v1Img := image.V1Image{}
if i == len(img.RootFS.DiffIDs)-1 {
v1Img = img.V1Image
}
rootFS := *img.RootFS
rootFS.DiffIDs = rootFS.DiffIDs[:i+1]
v1ID, err := v1.CreateID(v1Img, rootFS.ChainID(), parent)
if err != nil {
return err
}
v1Img.ID = v1ID.Hex()
if parent != "" {
v1Img.Parent = parent.Hex()
}
if err := s.saveLayer(rootFS.ChainID(), v1Img, img.Created); err != nil {
return err
}
layers = append(layers, v1Img.ID)
parent = v1ID
}
configFile := filepath.Join(s.outDir, digest.Digest(id).Hex()+".json")
if err := ioutil.WriteFile(configFile, img.RawJSON(), 0644); err != nil {
return err
}
if err := os.Chtimes(configFile, img.Created, img.Created); err != nil {
return err
}
s.images[id].layers = layers
return nil
}
func (s *saveSession) saveLayer(id layer.ChainID, legacyImg image.V1Image, createdTime time.Time) error {
if _, exists := s.savedLayers[legacyImg.ID]; exists {
return nil
}
outDir := filepath.Join(s.outDir, legacyImg.ID)
if err := os.Mkdir(outDir, 0755); err != nil {
return err
}
// todo: why is this version file here?
if err := ioutil.WriteFile(filepath.Join(outDir, legacyVersionFileName), []byte("1.0"), 0644); err != nil {
return err
}
imageConfig, err := json.Marshal(legacyImg)
if err != nil {
return err
}
if err := ioutil.WriteFile(filepath.Join(outDir, legacyConfigFileName), imageConfig, 0644); err != nil {
return err
}
// serialize filesystem
tarFile, err := os.Create(filepath.Join(outDir, legacyLayerFileName))
if err != nil {
return err
}
defer tarFile.Close()
l, err := s.ls.Get(id)
if err != nil {
return err
}
defer layer.ReleaseAndLog(s.ls, l)
arch, err := l.TarStream()
if err != nil {
return err
}
defer arch.Close()
if _, err := io.Copy(tarFile, arch); err != nil {
return err
}
for _, fname := range []string{"", legacyVersionFileName, legacyConfigFileName, legacyLayerFileName} {
// todo: maybe save layer created timestamp?
if err := os.Chtimes(filepath.Join(outDir, fname), createdTime, createdTime); err != nil {
return err
}
}
s.savedLayers[legacyImg.ID] = struct{}{}
return nil
}