cflag - wraps and extends Go flag build pertty CLI command

cflag - wraps and extends Go flag build pertty CLI command

Use Go flag

Go flag is a package built into Go, and it is very easy to build a command application using the flag package.

package main

import (
    "flag"
    "os"

    "github.com/gookit/goutil/cliutil"
    "github.com/gookit/goutil/dump"
)

var opts1 = struct {
    age  int
    name string
    str1 string
    lOpt string
}{}

// go run ./_example/rawflag.go
// go run ./cflag/_example/rawflag.go -h
func main() {
    c := flag.NewFlagSet("mycmd", flag.ContinueOnError)

    c.IntVar(&opts1.age, "age", 0, "this is a int option")
    c.StringVar(&opts1.name, "name", "", "this is a string option and required")
    c.StringVar(&opts1.str1, "str1", "def-val", "this is a string option with default value")
    c.StringVar(&opts1.lOpt, "long-opt", "", "this is a string option with shorts")

    err := c.Parse(os.Args[1:])
    if err != nil {
        if err != flag.ErrHelp {
            cliutil.Errorln("Error:", err.Error())
        }
        return
    }

    // after parse, do something
    handleFunc1()
}

func handleFunc1() {
    cliutil.Infoln("after parse, do something")

    dump.P(opts1)
}

Show help

go run ./cflag/_example/rawflag.go -h

Some problems

It’s a package built into Go, and it’s very simple to use. But there are some problems:

• Adding short options to options is not supported
• Does not support parsing subsequent parameter information
• Can’t check if option is empty
• Rendering help information is very rudimentary

Use cflag

cflag - Wraps and extends go flag.FlagSet to build simple command line applications

• As easy as Go flag to use
• Supports auto-rendering of pretty help messages
• Allows adding short options to flag options, and multiples
• Allows binding named parameters
• Allows setting arguments or options as required
• Allows setting validators for arguments or options

Install

go get github.com/gookit/goutil/cflag

Usage example

cflag has the same binding option information as Go flag. At the same time, some additional information has been added, such as version, description, etc.

package main

import (
	"os"

	"github.com/gookit/goutil/cflag"
	"github.com/gookit/goutil/cliutil"
)

var opts = struct {
	age  int
	name string
	str1 string
	lOpt string
	bol  bool
}{}

// go run ./_example/cmd.go
// go run ./cflag/_example/cmd.go -h
// go run ./cflag/_example/cmd.go --name inhere -a 12 --lo val ab cd
func main() {
	c := cflag.New(func(c *cflag.CFlags) {
		c.Desc = "this is a demo command"
		c.Version = "0.5.1"
	})
	c.IntVar(&opts.age, "age", 0, "this is a int option;;a")
	c.StringVar(&opts.name, "name", "", "this is a string option and required;true")
	c.StringVar(&opts.str1, "str1", "def-val", "this is a string option with default value;;s")
	c.StringVar(&opts.lOpt, "long-opt", "", "this is a string option with shorts;;lo")

    // highlight-start
	c.AddArg("arg1", "this is arg1", true, nil)
	c.AddArg("arg2", "this is arg2", true, nil)
    // highlight-end

	// add handle func
	c.Func = handleFunc

	c.MustParse(os.Args[1:])
}

func handleFunc(c *cflag.CFlags) error {
	cliutil.Magentaln("hello, this is command:", c.Name())
	cliutil.Infoln("after parse, do something ...")

	cliutil.Yellowln("option values:")
	cliutil.Infoln("opts.age =", opts.age)
	cliutil.Infoln("opts.name =", opts.name)
	cliutil.Infoln("opts.str1 =", opts.str1)
	cliutil.Infoln("opts.lOpt =", opts.lOpt)

    // highlight-start
	cliutil.Yellowln("argument values:")
	cliutil.Infoln("arg1 =", c.Arg("arg1").String())
	cliutil.Infoln("arg2 =", c.Arg("arg2").String())
    // highlight-end

	cliutil.Infoln("\nremain args =", c.RemainArgs())

	return nil
}

Set required and shortcuts

Option can be set as required(required), and supports setting short option name.

TIPs: Implement required and shorts by extending usage that parses options

usage format

• Defatul: desc
• Foramt 1: desc;required
• Foramt 2: desc;required;shorts
• required: A boolean string. Mark option is required
  • True: true,on,yes
  • False: false,off,no,''
• shorts: Shortcut names for options, multiple values are allowed, separated by commas ,

Examples:

    // set option 'name' is required
	c.StringVar(&opts.name, "name", "", "this is a string option and required;true")
    // set option 'str1' shorts: s
	c.StringVar(&opts.str1, "str1", "def-val", "this is a string option with default value;;s")

Binding and get arguments

Binding arguments

	c.AddArg("arg1", "this is arg1", true, nil)
	c.AddArg("arg2", "this is arg2", true, nil)

Get arguments by name

	cliutil.Infoln("arg1 =", c.Arg("arg1").String())
	cliutil.Infoln("arg2 =", c.Arg("arg2").Int())

Show help

go run ./cflag/_example/cmd.go -h

Output:

Run command

go run ./cflag/_example/cmd.go --name inhere -a 12 --lo val ab cd
go run ./cflag/_example/cmd.go --name inhere -a 12 --lo val ab cd de fg

Output:

required check

go run ./cflag/_example/cmd.go -a 22
go run ./cflag/_example/cmd.go --name inhere

Output:

GitHub

• gookit/goutil/cflag