dockerfile

type Metadata struct {
	StageFroms     []string          // every image "FROM" instruction value (or the parent stage's FROM value in the case of a named stage)
	StageNames     []string          // the name of any named stage (in order)
	StageNameFroms map[string]string // map of stage names to FROM values (or the parent stage's FROM value in the case of a named stage), useful for resolving stage names to FROM values

	Froms []string // every "FROM" or "COPY --from=xxx" value (minus named and/or numbered stages in the case of "--from=")
}