function

type Buildpack struct {
	BuildpackImplementation BuildpackImplementation
}

type BuildpackImplementation interface {
	// Build is called during the build phase of the buildpack lifecycle.
	Build(build build.Build) (int, error)

	// Detect is called during the detect phase of the buildpack lifecycle.
	Detect(detect detect.Detect, metadata Metadata) (int, error)

	// Id returns the id of the function buildpack.
	Id() string
}

type Metadata struct {
	// Artifact is the path to the main function artifact. This may be a java jar file, an executable file, etc
	// May be autodetected or chosen by a collaborating buildpack
	Artifact string `toml:"artifact"`

	// Handler is a "finer grained" handler for the function within the artifact, if applicable.
	// This may be a classname, a function name, etc. May be autodetected or chosen by a collaborating
	// buildpack or function invoker.
	Handler string `toml:"handler"`

	// Override is an optional value provided by the user to force a given language for the function and
	// completely bypass the detection mechanism, if needed.
	Override string `toml:"override"`
}