cli

type HTTPEngine interface {
	HTTP() (*http.Client, string, error)
}

type Options struct {
	// Engine returns the engine to build with; cmd is the build command
	// (its flags, and its parents', are parsed). Nil: dial the -H/--host
	// flag of the command or a parent, else $WCTR_HOST, else DefaultHost.
	Engine func(cmd *cobra.Command) (driver.Engine, error)
	// Cache is the step cache. Nil: a file under the user cache directory,
	// or a cache for this build only where there is none (a browser).
	Cache builder.Cache
	// Stdin is read for "-" (default os.Stdin).
	Stdin io.Reader
	// Limits bound the context (default buildcontext.DefaultLimits).
	Limits buildcontext.Limits
}