func GenerateAncestry(s storage.Storage, imageID, parentID string) (err error) {
logger.Debug("[GenerateAncestry] imageID=" + imageID + " parentID=" + parentID)
path := storage.ImageAncestryPath(imageID)
if parentID == "" {
return s.Put(path, []byte(`["`+imageID+`"]`))
}
var content []byte
if content, err = s.Get(storage.ImageAncestryPath(parentID)); err != nil {
return err
}
var ancestry []string
if err := json.Unmarshal(content, &ancestry); err != nil {
return err
}
ancestry = append([]string{imageID}, ancestry...)
if content, err = json.Marshal(&ancestry); err != nil {
return err
}
return s.Put(path, content)
}
func GenDiff(s storage.Storage, imageID string) {
// Comment from docker-registry 0.6.5
// get json describing file differences in layer
// Calculate the diff information for the files contained within
// the layer. Return a dictionary of lists grouped by whether they
// were deleted, changed or created in this layer.
// To determine what happened to a file in a layer we walk backwards
// through the ancestry until we see the file in an older layer. Based
// on whether the file was previously deleted or not we know whether
// the file was created or modified. If we do not find the file in an
// ancestor we know the file was just created.
// - File marked as deleted by union fs tar: DELETED
// - Ancestor contains non-deleted file: CHANGED
// - Ancestor contains deleted marked file: CREATED
// - No ancestor contains file: CREATED
diffJson, err := GetImageDiffCache(s, imageID)
if err == nil && diffJson != nil {
// cache hit, just return
logger.Debug("[GenDiff][" + imageID + "] already exists")
return
}
anPath := storage.ImageAncestryPath(imageID)
anContent, err := s.Get(anPath)
if err != nil {
// error fetching ancestry, just return
logger.Error("[GenDiff][" + imageID + "] error fetching ancestry: " + err.Error())
return
}
var ancestry []string
if err := json.Unmarshal(anContent, &ancestry); err != nil {
// json unmarshal fail, just return
logger.Error("[GenDiff][" + imageID + "] error unmarshalling ancestry json: " + err.Error())
return
}
// get map of file infos
infoMap, err := fileInfoMap(s, imageID)
if err != nil {
// error getting file info, just return
logger.Error("[GenDiff][" + imageID + "] error getting files info: " + err.Error())
return
}
deleted := map[string][]interface{}{}
changed := map[string][]interface{}{}
created := map[string][]interface{}{}
for _, anID := range ancestry {
anInfoMap, err := fileInfoMap(s, anID)
if err != nil {
// error getting file info, just return
logger.Error("[GenDiff][" + imageID + "] error getting ancestor " + anID + " files info: " + err.Error())
return
}
for fname, info := range infoMap {
isDeleted, isBool := (info[1]).(bool)
// if the file info is in a bad format (isDeleted is not a bool), we should just assume it is deleted.
// technically isBool should never be false.
if !isBool || isDeleted {
if !isBool {
logger.Error("[GenDiff][" + imageID + "] file info is in a bad format")
}
deleted[fname] = info
delete(infoMap, fname)
continue
}
anInfo := anInfoMap[fname]
if err != nil || anInfo == nil {
// doesn't exist, must be created. do nothing.
continue
}
isDeleted, isBool = anInfo[1].(bool)
if !isBool || isDeleted {
if !isBool {
logger.Error("[GenDiff][" + imageID + "] file info is in a bad format")
}
// deleted in ancestor, must be created now.
created[fname] = info
} else {
// not deleted in ancestor, must have just changed now.
changed[fname] = info
}
delete(infoMap, fname)
}
}
// dump all created stuff from infoMap
for fname, info := range infoMap {
created[fname] = info
}
diff := map[string]map[string][]interface{}{
"deleted": deleted,
"changed": changed,
"created": created,
}
if diffJson, err = json.Marshal(&diff); err != nil {
// json marshal fail. just return
logger.Error("[GenDiff][" + imageID + "] error marshalling new diff json: " + err.Error())
return
}
if err := SetImageDiffCache(s, imageID, diffJson); err != nil {
// json marshal fail. just return
logger.Error("[GenDiff][" + imageID + "] error setting new diff cache: " + err.Error())
return
}
}