supply

type Apt interface {
	Setup() error
	HasKeys() bool
	HasRepos() bool
	AddKeys() error
	AddRepos() error
	Update() error
	DownloadAll() error
	InstallAll() error
	Clean() error
	HasClean() bool
}

type Stager interface {
	LinkDirectoryInDepDir(string, string) error
	DepDir() string
	CacheDir() string
}

type Supplier struct {
	Stager Stager
	Log    *libbuildpack.Logger
	Apt    Apt
}