docker/docker

package images // import "github.com/docker/docker/daemon/images"

import (
    "context"
    "fmt"
    "time"

    "github.com/distribution/reference"
    "github.com/docker/docker/api/types/backend"
    "github.com/docker/docker/api/types/image"
    "github.com/docker/docker/layer"
)

// ImageHistory returns a slice of ImageHistory structures for the specified image
// name by walking the image lineage.
func (i *ImageService) ImageHistory(ctx context.Context, name string) ([]*image.HistoryResponseItem, error) {
    start := time.Now()
    img, err := i.GetImage(ctx, name, backend.GetImageOpts{})
    if err != nil {
        return nil, err
    }

    history := []*image.HistoryResponseItem{}

    layerCounter := 0
    rootFS := *img.RootFS
    rootFS.DiffIDs = nil

    for _, h := range img.History {
        var layerSize int64

        if !h.EmptyLayer {
            if len(img.RootFS.DiffIDs) <= layerCounter {
                return nil, fmt.Errorf("too many non-empty layers in History section")
            }
            rootFS.Append(img.RootFS.DiffIDs[layerCounter])
            l, err := i.layerStore.Get(rootFS.ChainID())
            if err != nil {
                return nil, err
            }
            layerSize = l.DiffSize()
            layer.ReleaseAndLog(i.layerStore, l)
            layerCounter++
        }

        var created int64
        if h.Created != nil {
            created = h.Created.Unix()
        }

        history = append([]*image.HistoryResponseItem{{
            ID:        "<missing>",
            Created:   created,
            CreatedBy: h.CreatedBy,
            Comment:   h.Comment,
            Size:      layerSize,
        }}, history...)
    }

    // Fill in image IDs and tags
    histImg := img
    id := img.ID()
    for _, h := range history {
        h.ID = id.String()

        var tags []string
        for _, r := range i.referenceStore.References(id.Digest()) {
            if _, ok := r.(reference.NamedTagged); ok {
                tags = append(tags, reference.FamiliarString(r))
            }
        }

        h.Tags = tags

        id = histImg.Parent
        if id == "" {
            break
        }
        histImg, err = i.GetImage(ctx, id.String(), backend.GetImageOpts{})
        if err != nil {
            break
        }
    }
    ImageActions.WithValues("history").UpdateSince(start)
    return history, nil
}