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package graph
import (
"io"
"github.com/dotcloud/docker/engine"
"github.com/dotcloud/docker/image"
"github.com/dotcloud/docker/utils"
)
func (s *TagStore) Install(eng *engine.Engine) error {
eng.Register("image_set", s.CmdSet)
eng.Register("image_tag", s.CmdTag)
eng.Register("image_get", s.CmdGet)
eng.Register("image_inspect", s.CmdLookup)
eng.Register("image_tarlayer", s.CmdTarLayer)
return nil
}
// CmdSet stores a new image in the graph.
// Images are stored in the graph using 4 elements:
// - A user-defined ID
// - A collection of metadata describing the image
// - A directory tree stored as a tar archive (also called the "layer")
// - A reference to a "parent" ID on top of which the layer should be applied
//
// NOTE: even though the parent ID is only useful in relation to the layer and how
// to apply it (ie you could represent the full directory tree as 'parent_layer + layer',
// it is treated as a top-level property of the image. This is an artifact of early
// design and should probably be cleaned up in the future to simplify the design.
//
// Syntax: image_set ID
// Input:
// - Layer content must be streamed in tar format on stdin. An empty input is
// valid and represents a nil layer.
//
// - Image metadata must be passed in the command environment.
// 'json': a json-encoded object with all image metadata.
// It will be stored as-is, without any encoding/decoding artifacts.
// That is a requirement of the current registry client implementation,
// because a re-encoded json might invalidate the image checksum at
// the next upload, even with functionaly identical content.
func (s *TagStore) CmdSet(job *engine.Job) engine.Status {
if len(job.Args) != 1 {
return job.Errorf("usage: %s NAME", job.Name)
}
var (
imgJSON = []byte(job.Getenv("json"))
layer = job.Stdin
)
if len(imgJSON) == 0 {
return job.Errorf("mandatory key 'json' is not set")
}
// We have to pass an *image.Image object, even though it will be completely
// ignored in favor of the redundant json data.
// FIXME: the current prototype of Graph.Register is stupid and redundant.
img, err := image.NewImgJSON(imgJSON)
if err != nil {
return job.Error(err)
}
if err := s.graph.Register(imgJSON, layer, img); err != nil {
return job.Error(err)
}
return engine.StatusOK
}
// CmdTag assigns a new name and tag to an existing image. If the tag already exists,
// it is changed and the image previously referenced by the tag loses that reference.
// This may cause the old image to be garbage-collected if its reference count reaches zero.
//
// Syntax: image_tag NEWNAME OLDNAME
// Example: image_tag shykes/myapp:latest shykes/myapp:1.42.0
func (s *TagStore) CmdTag(job *engine.Job) engine.Status {
if len(job.Args) != 2 {
return job.Errorf("usage: %s NEWNAME OLDNAME", job.Name)
}
var (
newName = job.Args[0]
oldName = job.Args[1]
)
newRepo, newTag := utils.ParseRepositoryTag(newName)
// FIXME: Set should either parse both old and new name, or neither.
// the current prototype is inconsistent.
if err := s.Set(newRepo, newTag, oldName, true); err != nil {
return job.Error(err)
}
return engine.StatusOK
}
// CmdGet returns information about an image.
// If the image doesn't exist, an empty object is returned, to allow
// checking for an image's existence.
func (s *TagStore) CmdGet(job *engine.Job) engine.Status {
if len(job.Args) != 1 {
return job.Errorf("usage: %s NAME", job.Name)
}
name := job.Args[0]
res := &engine.Env{}
img, err := s.LookupImage(name)
// Note: if the image doesn't exist, LookupImage returns
// nil, nil.
if err != nil {
return job.Error(err)
}
if img != nil {
// We don't directly expose all fields of the Image objects,
// to maintain a clean public API which we can maintain over
// time even if the underlying structure changes.
// We should have done this with the Image object to begin with...
// but we didn't, so now we're doing it here.
//
// Fields that we're probably better off not including:
// - Config/ContainerConfig. Those structs have the same sprawl problem,
// so we shouldn't include them wholesale either.
// - Comment: initially created to fulfill the "every image is a git commit"
// metaphor, in practice people either ignore it or use it as a
// generic description field which it isn't. On deprecation shortlist.
res.SetAuto("Created", img.Created)
res.Set("Author", img.Author)
res.Set("Os", img.OS)
res.Set("Architecture", img.Architecture)
res.Set("DockerVersion", img.DockerVersion)
res.Set("Id", img.ID)
res.Set("Parent", img.Parent)
}
res.WriteTo(job.Stdout)
return engine.StatusOK
}
// CmdLookup return an image encoded in JSON
func (s *TagStore) CmdLookup(job *engine.Job) engine.Status {
if len(job.Args) != 1 {
return job.Errorf("usage: %s NAME", job.Name)
}
name := job.Args[0]
if image, err := s.LookupImage(name); err == nil && image != nil {
if job.GetenvBool("raw") {
b, err := image.RawJson()
if err != nil {
return job.Error(err)
}
job.Stdout.Write(b)
return engine.StatusOK
}
out := &engine.Env{}
out.Set("Id", image.ID)
out.Set("Parent", image.Parent)
out.Set("Comment", image.Comment)
out.SetAuto("Created", image.Created)
out.Set("Container", image.Container)
out.SetJson("ContainerConfig", image.ContainerConfig)
out.Set("DockerVersion", image.DockerVersion)
out.Set("Author", image.Author)
out.SetJson("Config", image.Config)
out.Set("Architecture", image.Architecture)
out.Set("Os", image.OS)
out.SetInt64("Size", image.Size)
if _, err = out.WriteTo(job.Stdout); err != nil {
return job.Error(err)
}
return engine.StatusOK
}
return job.Errorf("No such image: %s", name)
}
// CmdTarLayer return the tarLayer of the image
func (s *TagStore) CmdTarLayer(job *engine.Job) engine.Status {
if len(job.Args) != 1 {
return job.Errorf("usage: %s NAME", job.Name)
}
name := job.Args[0]
if image, err := s.LookupImage(name); err == nil && image != nil {
fs, err := image.TarLayer()
if err != nil {
return job.Error(err)
}
defer fs.Close()
if written, err := io.Copy(job.Stdout, fs); err != nil {
return job.Error(err)
} else {
utils.Debugf("rendered layer for %s of [%d] size", image.ID, written)
}
return engine.StatusOK
}
return job.Errorf("No such image: %s", name)
}
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