// Register imports a pre-existing image into the graph.
// FIXME: pass img as first argument
func (graph *Graph) Register(jsonData []byte, layerData archive.ArchiveReader, img *image.Image) (err error) {
defer func() {
// If any error occurs, remove the new dir from the driver.
// Don't check for errors since the dir might not have been created.
// FIXME: this leaves a possible race condition.
if err != nil {
graph.driver.Remove(img.ID)
}
}()
if err := utils.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)
}
// Ensure that the image root does not exist on the filesystem
// when it is not registered in the graph.
// This is common when you switch from one graph driver to another
if err := os.RemoveAll(graph.ImageRoot(img.ID)); err != nil && !os.IsNotExist(err) {
return err
}
// If the driver has this ID but the graph doesn't, remove it from the driver to start fresh.
// (the graph is the source of truth).
// Ignore errors, since we don't know if the driver correctly returns ErrNotExist.
// (FIXME: make that mandatory for drivers).
graph.driver.Remove(img.ID)
tmp, err := graph.Mktemp("")
defer os.RemoveAll(tmp)
if err != nil {
return fmt.Errorf("Mktemp failed: %s", err)
}
// Create root filesystem in the driver
if err := graph.driver.Create(img.ID, img.Parent); err != nil {
return fmt.Errorf("Driver %s failed to create image rootfs %s: %s", graph.driver, img.ID, err)
}
// Mount the root filesystem so we can apply the diff/layer
rootfs, err := graph.driver.Get(img.ID, "")
if err != nil {
return fmt.Errorf("Driver %s failed to get image rootfs %s: %s", graph.driver, img.ID, err)
}
defer graph.driver.Put(img.ID)
img.SetGraph(graph)
if err := image.StoreImage(img, jsonData, layerData, tmp, rootfs); err != nil {
return err
}
// Commit
if err := os.Rename(tmp, graph.ImageRoot(img.ID)); err != nil {
return err
}
graph.idIndex.Add(img.ID)
return nil
}
func (daemon *Daemon) checkImageDepth(img *image.Image) error {
// We add 2 layers to the depth because the container's rw and
// init layer add to the restriction
depth, err := img.Depth()
if err != nil {
return err
}
if depth+2 >= MaxImageDepth {
return fmt.Errorf("Cannot create container with more than %d parents", MaxImageDepth)
}
return nil
}