Go binding configuration and command flag made easy✨✨

// single tag key
type MyConfig struct {
    Token string `json:token_json" xml:"token_xml" arg:"token" env:"token" environ:"TOKEN"`
}
// multiple tag keys
type MyConfig struct {
    Token string `json xml bson yaml toml arg env:"token" environ:"TOKEN"`
}

package main

import (
    "flag"
    "fmt"
    "os"

    "github.com/ii64/go-binder/binder"
    "github.com/pkg/errors"
)

type MyConfig struct {
    Token string `json xml bson yaml toml arg:"token,omitempty" env:"TOKEN" environ:"TOKEN"`
    Count int    `json xml bson yaml toml arg:"count,omitempty" env:"COUNT" usage:"this is the usage"`

    Ktes *int
    Sub  **struct {
        Hello    *string
        SubOfSub struct {
            InSub **bool
        }
        PtrOfSub *struct {
            YourName **string `json xml bson yaml toml bind:"your_name,omitempty" env:"COUNT" usage:"this is the usage"`
        }
    }
    Log struct {
        SubLog       int
        Directory    string
        Filename     string `json xml bson yaml toml arg:"filename" env:"FILENAME"`
        DedicatedArg string `json xml bson yaml toml argx:"dedicatedArg" env:"DEDICATED_ARG"`
    } `json xml bson yaml toml arg env bind:"log"`
}
var (
    configFile = os    env("CONFIG_FILE")
    Loaded     *MyConfig
)

func registerToBinder() {
    Loaded = &MyConfig{
        Token: "some default value",
        Count: 121,
    }
    binder.BindArgsConf(Loaded, "my")
}

func main() {
    var err error
    if configFile == "" {
        configFile = "config.json"
    }
    binder.LoadConfig = binder.LoadConfigJSON(configFile)
    binder.SaveConfig = binder.SaveConfigJSON(configFile)
    binder.SaveOnClose = true
    // register component to binder
    registerToBinder()
    // perform binding
    if err = binder.Init(); err != nil {
        if errors.Is(err, os.ErrNotExist) {
            if err = binder.Save(); err != nil {
                panic(err)
            }
        } else {
            panic(err)
        }
    }
    flag.Parse()
    // reflect back to component
    binder.In()
    defer binder.Close()

    // runtime
    fmt.Printf("%+#v\n", Loaded)
}