go-commando

README

go-commando

The go-commando module provides tools and testing utilities for creating and testing modular types that encapsulate distinct program flow. Inspired by the separation of concerns design principal.

Basic Usage

The Command Interface

type Command interface {
	// Get the command's identifier.
	GetID() string

	// Get the command's usage string.
	GetUsage() string

	// Initializes the command before it's run.
	Initialize()

	// Run the command using the provided arguments and return any errors.
	Run(args []string) error
}

A Sample Flag-Based Command

type HelloCommand struct {
	command.FlagCommandBase
}

func NewHelloCommand() *HelloCommand {
	return &HelloCommand{
		FlagCommandBase: command.NewFlagCommandBase("hello", "prints \"Hello {name}\" to the console"),
	}
}

func (cmd HelloCommand) Run(args []string) error {
	name := cmd.Flags.String("name", "World", "name to use when saying hello")
	cmd.Flags.Parse(args)

	if *name == "" {
		return fmt.Errorf("name cannot be empty")
	}

	fmt.Printf("Hello %s!\n", *name)
	return nil
}

Sample main Function

func main() {
	ls := flag.Bool("ls", false, "list all commands")
	flag.Parse()

	runner := command.NewRunner(
		sample.NewHelloCommand(),
	)

	if *ls || len(os.Args) < 2 {
		runner.ListCommands()
		return
	}

	if err := runner.RunCommand(os.Args[1], os.Args[2:]); err != nil {
		fmt.Printf("%s %s\n", style.BoldError.Sprint("ERROR:"), err.Error())
	}
}