dotcloud/docker

package containerd

import (
    "context"

    containerdimages "github.com/containerd/containerd/images"
    "github.com/docker/docker/errdefs"
    "github.com/docker/docker/image"
    "github.com/opencontainers/go-digest"
    "github.com/pkg/errors"
)

// getImagesWithLabel returns all images that have the matching label key and value.
func (i *ImageService) getImagesWithLabel(ctx context.Context, labelKey string, labelValue string) ([]image.ID, error) {
    imgs, err := i.images.List(ctx, "labels."+labelKey+"=="+labelValue)
    if err != nil {
        return []image.ID{}, errdefs.System(errors.Wrap(err, "failed to list all images"))
    }

    var children []image.ID
    for _, img := range imgs {
        children = append(children, image.ID(img.Target.Digest))
    }

    return children, nil
}

// Children returns a slice of image IDs that are children of the `id` image
func (i *ImageService) Children(ctx context.Context, id image.ID) ([]image.ID, error) {
    return i.getImagesWithLabel(ctx, imageLabelClassicBuilderParent, string(id))
}

// parents returns a slice of image IDs that are parents of the `id` image
//
// Called from image_delete.go to prune dangling parents.
func (i *ImageService) parents(ctx context.Context, id image.ID) ([]containerdimages.Image, error) {
    targetImage, err := i.resolveImage(ctx, id.String())
    if err != nil {
        return nil, errors.Wrap(err, "failed to get child image")
    }

    var imgs []containerdimages.Image
    for {
        parent, ok := targetImage.Labels[imageLabelClassicBuilderParent]
        if !ok || parent == "" {
            break
        }

        parentDigest, err := digest.Parse(parent)
        if err != nil {
            return nil, err
        }
        img, err := i.resolveImage(ctx, parentDigest.String())
        if err != nil {
            return nil, err
        }
        imgs = append(imgs, img)
        targetImage = img
    }

    return imgs, nil
}