package command import ( "fmt" "os" "os/signal" "syscall" "github.com/mitchellh/cli" ) // Factory is a function that returns a new instance of a CLI-sub command. type Factory func(cli.Ui) (cli.Command, error) // Register adds a new CLI sub-command to the registry. func Register(name string, fn Factory) { if registry == nil { registry = make(map[string]Factory) } if registry[name] != nil { panic(fmt.Errorf("Command %q is already registered", name)) } registry[name] = fn } // Map returns a realized mapping of available CLI commands in a format that // the CLI class can consume. This should be called after all registration is // complete. func Map(ui cli.Ui) map[string]cli.CommandFactory { m := make(map[string]cli.CommandFactory) for name, fn := range registry { thisFn := fn m[name] = func() (cli.Command, error) { return thisFn(ui) } } return m } // registry has an entry for each available CLI sub-command, indexed by sub // command name. This should be populated at package init() time via Register(). var registry map[string]Factory // MakeShutdownCh returns a channel that can be used for shutdown notifications // for commands. This channel will send a message for every interrupt or SIGTERM // received. func MakeShutdownCh() <-chan struct{} { resultCh := make(chan struct{}) signalCh := make(chan os.Signal, 4) signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM) go func() { for { <-signalCh resultCh <- struct{}{} } }() return resultCh }