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authorValentin Rothberg <rothberg@redhat.com>2019-11-12 13:37:09 -0500
committerValentin Rothberg <rothberg@redhat.com>2019-11-12 17:29:30 -0500
commitbf62f9a5cfb4319aa9b0f25b57b3f63e4b965672 (patch)
tree48b0d6feb12f5d0135b5362b5ce4a34d9095d313 /libpod
parentde32b89eff0928abdef9d85a420b65d8865e737e (diff)
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history: rewrite mappings
Rewrite the backend for displaying the history of an image to simplify the code and be closer to docker's behaviour. Instead of driving index-based heuristics, create a reverse mapping from top-layers to the corresponding image IDs and lookup the layers on-demand. Also use the uncompressed layer size to be closer to Docker's behaviour. Note that intermediate images from local builds are not considered for the ID lookups anymore. Fixes: #3359 Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
Diffstat (limited to 'libpod')
-rw-r--r--libpod/image/image.go130
1 files changed, 43 insertions, 87 deletions
diff --git a/libpod/image/image.go b/libpod/image/image.go
index c912ac2ca..75ac85311 100644
--- a/libpod/image/image.go
+++ b/libpod/image/image.go
@@ -765,109 +765,65 @@ func (i *Image) History(ctx context.Context) ([]*History, error) {
return nil, err
}
- // Use our layers list to find images that use any of them (or no
- // layer, since every base layer is derived from an empty layer) as its
- // topmost layer.
- interestingLayers := make(map[string]bool)
- var layer *storage.Layer
- if i.TopLayer() != "" {
- if layer, err = i.imageruntime.store.Layer(i.TopLayer()); err != nil {
- return nil, err
- }
+ // Build a mapping from top-layer to image ID.
+ images, err := i.imageruntime.GetImages()
+ if err != nil {
+ return nil, err
}
- interestingLayers[""] = true
- for layer != nil {
- interestingLayers[layer.ID] = true
- if layer.Parent == "" {
- break
+ topLayerMap := make(map[string]string)
+ for _, image := range images {
+ if _, exists := topLayerMap[image.TopLayer()]; !exists {
+ topLayerMap[image.TopLayer()] = image.ID()
}
- layer, err = i.imageruntime.store.Layer(layer.Parent)
+ }
+
+ var allHistory []*History
+ var layer *storage.Layer
+
+ // Check if we have an actual top layer to prevent lookup errors.
+ if i.TopLayer() != "" {
+ layer, err = i.imageruntime.store.Layer(i.TopLayer())
if err != nil {
return nil, err
}
}
- // Get the IDs of the images that share some of our layers. Hopefully
- // this step means that we'll be able to avoid reading the
- // configuration of every single image in local storage later on.
- images, err := i.imageruntime.GetImages()
- if err != nil {
- return nil, errors.Wrapf(err, "error getting images from store")
- }
- interestingImages := make([]*Image, 0, len(images))
- for i := range images {
- if interestingLayers[images[i].TopLayer()] {
- interestingImages = append(interestingImages, images[i])
- }
- }
+ // Iterate in reverse order over the history entries, and lookup the
+ // corresponding image ID, size and get the next later if needed.
+ numHistories := len(oci.History) - 1
+ for x := numHistories; x >= 0; x-- {
+ var size int64
- // Build a list of image IDs that correspond to our history entries.
- historyImages := make([]*Image, len(oci.History))
- if len(oci.History) > 0 {
- // The starting image shares its whole history with itself.
- historyImages[len(historyImages)-1] = i
- for i := range interestingImages {
- image, err := images[i].ociv1Image(ctx)
- if err != nil {
- return nil, errors.Wrapf(err, "error getting image configuration for image %q", images[i].ID())
+ id := "<missing>"
+ if x == numHistories {
+ id = i.ID()
+ } else if layer != nil {
+ if !oci.History[x].EmptyLayer {
+ size = layer.UncompressedSize
}
- // If the candidate has a longer history or no history
- // at all, then it doesn't share the portion of our
- // history that we're interested in matching with other
- // images.
- if len(image.History) == 0 || len(image.History) > len(historyImages) {
- continue
- }
- // If we don't include all of the layers that the
- // candidate image does (i.e., our rootfs didn't look
- // like its rootfs at any point), then it can't be part
- // of our history.
- if len(image.RootFS.DiffIDs) > len(oci.RootFS.DiffIDs) {
- continue
- }
- candidateLayersAreUsed := true
- for i := range image.RootFS.DiffIDs {
- if image.RootFS.DiffIDs[i] != oci.RootFS.DiffIDs[i] {
- candidateLayersAreUsed = false
- break
- }
- }
- if !candidateLayersAreUsed {
- continue
- }
- // If the candidate's entire history is an initial
- // portion of our history, then we're based on it,
- // either directly or indirectly.
- sharedHistory := historiesMatch(oci.History, image.History)
- if sharedHistory == len(image.History) {
- historyImages[sharedHistory-1] = images[i]
+ if imageID, exists := topLayerMap[layer.ID]; exists {
+ id = imageID
+ // Delete the entry to avoid reusing it for following history items.
+ delete(topLayerMap, layer.ID)
}
}
- }
- var (
- size int64
- sizeCount = 1
- allHistory []*History
- )
-
- for i := len(oci.History) - 1; i >= 0; i-- {
- imageID := "<missing>"
- if historyImages[i] != nil {
- imageID = historyImages[i].ID()
- }
- if !oci.History[i].EmptyLayer {
- size = img.LayerInfos()[len(img.LayerInfos())-sizeCount].Size
- sizeCount++
- }
allHistory = append(allHistory, &History{
- ID: imageID,
- Created: oci.History[i].Created,
- CreatedBy: oci.History[i].CreatedBy,
+ ID: id,
+ Created: oci.History[x].Created,
+ CreatedBy: oci.History[x].CreatedBy,
Size: size,
- Comment: oci.History[i].Comment,
+ Comment: oci.History[x].Comment,
})
+
+ if layer != nil && layer.Parent != "" && !oci.History[x].EmptyLayer {
+ layer, err = i.imageruntime.store.Layer(layer.Parent)
+ if err != nil {
+ return nil, err
+ }
+ }
}
+
return allHistory, nil
}