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moby--moby/graph/export.go
Aaron Lehmann d4836cd7ec Documentation improvements and code cleanups for graph package
Expand the godoc documentation for the graph package.

Centralize DefaultTag in the graphs/tag package instead of defining it
twice.

Remove some unnecessary "config" structs that are only used to pass
a few parameters to a function.

Simplify the GetParentsSize function - there's no reason for it to take
an accumulator argument.

Unexport some functions that aren't needed outside the package.

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>
2015-07-30 14:27:10 -07:00

161 lines
4 KiB
Go

package graph
import (
"encoding/json"
"io"
"io/ioutil"
"os"
"path/filepath"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/parsers"
"github.com/docker/docker/registry"
)
// ImageExport exports list of images to a output stream specified in the
// config. The exported images are archived into a tar when written to the
// output stream. All images with the given tag and all versions containing the
// same tag are exported. names is the set of tags to export, and outStream
// is the writer which the images are written to.
func (s *TagStore) ImageExport(names []string, outStream io.Writer) error {
// get image json
tempdir, err := ioutil.TempDir("", "docker-export-")
if err != nil {
return err
}
defer os.RemoveAll(tempdir)
rootRepoMap := map[string]Repository{}
addKey := func(name string, tag string, id string) {
logrus.Debugf("add key [%s:%s]", name, tag)
if repo, ok := rootRepoMap[name]; !ok {
rootRepoMap[name] = Repository{tag: id}
} else {
repo[tag] = id
}
}
for _, name := range names {
name = registry.NormalizeLocalName(name)
logrus.Debugf("Serializing %s", name)
rootRepo := s.Repositories[name]
if rootRepo != nil {
// this is a base repo name, like 'busybox'
for tag, id := range rootRepo {
addKey(name, tag, id)
if err := s.exportImage(id, tempdir); err != nil {
return err
}
}
} else {
img, err := s.LookupImage(name)
if err != nil {
return err
}
if img != nil {
// This is a named image like 'busybox:latest'
repoName, repoTag := parsers.ParseRepositoryTag(name)
// check this length, because a lookup of a truncated has will not have a tag
// and will not need to be added to this map
if len(repoTag) > 0 {
addKey(repoName, repoTag, img.ID)
}
if err := s.exportImage(img.ID, tempdir); err != nil {
return err
}
} else {
// this must be an ID that didn't get looked up just right?
if err := s.exportImage(name, tempdir); err != nil {
return err
}
}
}
logrus.Debugf("End Serializing %s", name)
}
// write repositories, if there is something to write
if len(rootRepoMap) > 0 {
f, err := os.OpenFile(filepath.Join(tempdir, "repositories"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
f.Close()
return err
}
if err := json.NewEncoder(f).Encode(rootRepoMap); err != nil {
return err
}
if err := f.Close(); err != nil {
return err
}
} else {
logrus.Debugf("There were no repositories to write")
}
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
}
logrus.Debugf("End export image")
return nil
}
// FIXME: this should be a top-level function, not a class method
func (s *TagStore) exportImage(name, tempdir string) error {
for n := name; n != ""; {
// temporary directory
tmpImageDir := filepath.Join(tempdir, n)
if err := os.Mkdir(tmpImageDir, os.FileMode(0755)); err != nil {
if os.IsExist(err) {
return nil
}
return err
}
var version = "1.0"
var versionBuf = []byte(version)
if err := ioutil.WriteFile(filepath.Join(tmpImageDir, "VERSION"), versionBuf, os.FileMode(0644)); err != nil {
return err
}
// serialize json
json, err := os.Create(filepath.Join(tmpImageDir, "json"))
if err != nil {
return err
}
imageInspectRaw, err := s.lookupRaw(n)
if err != nil {
return err
}
written, err := json.Write(imageInspectRaw)
if err != nil {
return err
}
if written != len(imageInspectRaw) {
logrus.Warnf("%d byes should have been written instead %d have been written", written, len(imageInspectRaw))
}
// serialize filesystem
fsTar, err := os.Create(filepath.Join(tmpImageDir, "layer.tar"))
if err != nil {
return err
}
if err := s.ImageTarLayer(n, fsTar); err != nil {
return err
}
// find parent
img, err := s.LookupImage(n)
if err != nil {
return err
}
n = img.Parent
}
return nil
}