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-rw-r--r--libpod/image/image.go67
1 files changed, 67 insertions, 0 deletions
diff --git a/libpod/image/image.go b/libpod/image/image.go
index 72f07dad1..c5939e055 100644
--- a/libpod/image/image.go
+++ b/libpod/image/image.go
@@ -1212,3 +1212,70 @@ func (i *Image) newImageEvent(status events.Status) {
logrus.Infof("unable to write event to %s", i.imageruntime.EventsLogFilePath)
}
}
+
+// LayerInfo keeps information of single layer
+type LayerInfo struct {
+ // Layer ID
+ ID string
+ // Parent ID of current layer.
+ ParentID string
+ // ChildID of current layer.
+ // there can be multiple children in case of fork
+ ChildID []string
+ // RepoTag will have image repo names, if layer is top layer of image
+ RepoTags []string
+ // Size stores Uncompressed size of layer.
+ Size int64
+}
+
+// GetLayersMapWithImageInfo returns map of image-layers, with associated information like RepoTags, parent and list of child layers.
+func GetLayersMapWithImageInfo(imageruntime *Runtime) (map[string]*LayerInfo, error) {
+
+ // Memory allocated to store map of layers with key LayerID.
+ // Map will build dependency chain with ParentID and ChildID(s)
+ layerInfoMap := make(map[string]*LayerInfo)
+
+ // scan all layers & fill size and parent id for each layer in layerInfoMap
+ layers, err := imageruntime.store.Layers()
+ if err != nil {
+ return nil, err
+ }
+ for _, layer := range layers {
+ _, ok := layerInfoMap[layer.ID]
+ if !ok {
+ layerInfoMap[layer.ID] = &LayerInfo{
+ ID: layer.ID,
+ Size: layer.UncompressedSize,
+ ParentID: layer.Parent,
+ }
+ } else {
+ return nil, fmt.Errorf("detected multiple layers with the same ID %q", layer.ID)
+ }
+ }
+
+ // scan all layers & add all childs for each layers to layerInfo
+ for _, layer := range layers {
+ _, ok := layerInfoMap[layer.ID]
+ if ok {
+ if layer.Parent != "" {
+ layerInfoMap[layer.Parent].ChildID = append(layerInfoMap[layer.Parent].ChildID, layer.ID)
+ }
+ } else {
+ return nil, fmt.Errorf("lookup error: layer-id %s, not found", layer.ID)
+ }
+ }
+
+ // Add the Repo Tags to Top layer of each image.
+ imgs, err := imageruntime.store.Images()
+ if err != nil {
+ return nil, err
+ }
+ for _, img := range imgs {
+ e, ok := layerInfoMap[img.TopLayer]
+ if !ok {
+ return nil, fmt.Errorf("top-layer for image %s not found local store", img.ID)
+ }
+ e.RepoTags = append(e.RepoTags, img.Names...)
+ }
+ return layerInfoMap, nil
+}