ahmedkamalio / go-cli

Golang CLI app library.

Package cli implements command line apps library.

Usage

A basic example of go-cli usage is as follows

package main

import (
	"fmt"

	"github.com/amedmoore/go-cli"
)

// Greeting command to print greeting message.
type Greeting struct {
	Name     string `cli:"name"`
	Help     string `cli:"help"`
	Username string `cli:"option" optName:"name" optAlias:"n" optHelp:"Username to say hi to"`
}

// Run executes the command's logic.
func (g *Greeting) Run(_ *cli.App) {
	fmt.Printf("Hello, %s!\n", g.Username)
}

func main() {
	// create a new app instance
	app := cli.NewApp()
	// register greeting command
	app.Register(&Greeting{Name:  "greeting", Help:  "Say hi!"})
	// run the app
	app.Run()
}

App

App is the main structure of your cli application.

An app instance will always have two commands registered by default help and version commands.

version command will print the name, version, and build time of your application.

help command will print help message for the app or a specific command, given the example above, help command can be used in two forms.

1. $ myapp help that will print the following message

   $ myapp help
   Usage: myapp [command] [options...]
   
   Commands:
     help        print app or command help message
     version     print version and build time
     greeting    Say hi!

2. $ myapp greeting help that will print the following message

   $ myapp greeting help
   Usage: myapp greeting [options...]
   
   Say hi!
   
   Options:
     --name, --n    Username to say hi to

Command

A command struct can be any Go struct that has at least these requirements:

1. A string field that has cli:"name" tag representing the command name.
2. A string field that has cli:"help" tag representing the command description.
3. A function Run(app *cli.App) that will be executed at runtime.

A command can have an optional alias tag, i.e.

type Command struct {
    Alias string `cli:"alias"` // field name will not make a difference
}

A command can have any number of option fields identified by the cli:"option" tag, see example above.

An option (command option field) must have at least optName:"[OPTION_NAME]", and optHelp:"[OPTION_HELP]" tags.

An option can have an optional alias tag, i.e.

type Command struct {
    MyOption string `cli:"option" optName:"myOption" optAlias:"myOptionAlias" optHelp:"Option with alias name"`
}

License

This package is licensed under the MIT License feel free to use it as you want!