service

type Config struct {
	Name, DisplayName, Description string

	UserName  string   // Run as username.
	Arguments []string // Run with arguments.

	DependsOn        []string // Other services that this depends on.
	WorkingDirectory string   // Service working directory.
	ChRoot           string
	UserService      bool // Install as a current user service.

	// System specific parameters.
	KV KeyValue
}

type Controller interface {
	// Starts this service on the system.
	Start() error

	// Stops this service on the system.
	Stop() error
}

type Installer interface {
	// Installs this service on the system.  May return an
	// error if this service is already installed.
	Install() error

	// Removes this service from the system.  May return an
	// error if this service is not already installed.
	Remove() error
}

type KeyValue map[string]interface{}

type Logger interface {
	// Basic log functions in the context of the service.
	Error(format string, a ...interface{}) error
	Warning(format string, a ...interface{}) error
	Info(format string, a ...interface{}) error
}

type Runner interface {
	// Call quickly after initial entry point.  Does not return until
	// service is ready to stop.  onStart is called when the service is
	// starting, returning an error will fail to start the service.
	// If an error is returned from onStop, the service will still stop.
	// An error passed from onStart or onStop will be returned as
	// an error from Run.
	// Both callbacks should return quickly and not block.
	Run(onStart, onStop func() error) error
}

type Service interface {
	Installer
	Controller
	Runner
	Logger
	String() string
}