func (fetcher *DockerRepositoryFetcher) fetchFromEndpoint(endpoint string, imgID string, token []string) error {
history, err := fetcher.registry.GetRemoteHistory(imgID, endpoint, token)
if err != nil {
return err
}
for i := len(history) - 1; i >= 0; i-- {
id := history[i]
if fetcher.graph.Exists(id) {
log.Println("already exists:", id)
continue
}
imgJSON, _, err := fetcher.registry.GetRemoteImageJSON(id, endpoint, token)
if err != nil {
return err
}
img, err := image.NewImgJSON(imgJSON)
if err != nil {
return err
}
layer, err := fetcher.registry.GetRemoteImageLayer(img.ID, endpoint, token)
if err != nil {
return err
}
defer layer.Close()
log.Println("downloading layer:", id)
err = fetcher.graph.Register(imgJSON, layer, img)
if err != nil {
return err
}
}
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
}