/goargs

Opinionated argument parser for go

Primary LanguageGoMIT LicenseMIT

goargs

Use command-line arguments as easy as:

var args struct {
	Host string `goargs:"short:h"`
	User string
}
goargs.Bind(&args)
goargs.Parse()

fmt.Printf("Host: %s\n", args.Host)
See full file 
package main

import (
	"fmt"
	"os"

	"github.com/PKeidel/goargs"
)

var args struct {
	Host string `goargs:"short:h"`
	User string
}

func main() {
	goargs.Bind(&args)
	goargs.Parse()

	fmt.Printf("Host: %s\n", args.Host)
	fmt.Printf("User: %s\n", args.User)

	fmt.Println("To rerun, run:", os.Args[0], goargs.String())
}

Now you can run your program for example with: program --user PKeidel -h host01

strcase.ToKebab is applied to all "long" names. So a value like UserName will become --user-name as an arg.

Tags

There are a few tags to set/overrite the long form, short form and the required flag per field. long defaults to the field name in lowercase.

var args struct {
	Host string `goargs:"long:host,short:h,required"`
	User string
}

String()

goargs.String() returns a command-line variant of the current values. This can be usefull if the values are combined from different inputs but you want to rerun your program with the exact same arguments.

fmt.Println("To rerun, run:", os.Args[0], goargs.String())
// To rerun, run: program --host host01

Sources

goargs will search for the values in your os.Args, os.Environ and in the future in config files (json, yaml).

The order in which values overrite eachother can be configured with goargs.DefaultSourceOrder and defaults to: SourceFile, SourceEnv, SourceArgs with args overriding all other values.

Without structs

You can also register single values. For example:

var host string

func main() {
	goargs.WithString("host", &host)
	goargs.Parse()

	fmt.Printf("Host: %s\n", host)
}

To set for example the Required flag, you need to use the reference returned from the With* functions:

argHost := goargs.WithStringS("host", "h", &host)
argHost.Required = true
goargs.Parse()

Roadmap

[x] Support strings
[x] Support ints
[x] Support flags (bool)
[x] Support require flag
[x] Support os.Args parsing
[x] Support env parsing
[ ] Support multi flag to allow arrays like `--host host01 host02`
[ ] Support config file parsing
[ ] Detect undefined args
[ ] Detect wrong types
[x] Support externally changed values
[ ] Support values with spaces, quotes, ...
[ ] Print useage