Read config.yml to struct in golang

config.yml

login: "hello"
password: "world"
host: "localhost"
port: "8080"

go.mod

module auth-tests

go 1.15

require github.com/spf13/viper v1.9.0

main.go

package main

import (
	"fmt"
	"github.com/spf13/viper"
	"log"
	"strconv"
)

type Configuration struct {
	Login string `yml:"login"`
	Password string `yml:"password"`
	Host string `yml:"host"`
	Port int `yml:"port"`
}

const (
	filename = "config"
	configDir = "."
)

var (
	config *Configuration
)

func readConfiguration() *Configuration {
	log.Println("read `" + filename + "`")

	viper.SetConfigName(filename)
	viper.AddConfigPath(configDir)

	err := viper.ReadInConfig()
	if err != nil {
		panic(fmt.Errorf("Fatal error config file: %w \n", err))
	}

	config := &Configuration{}
	err = viper.Unmarshal(config)
	if err != nil {
		log.Printf("unable to decode into config struct, %v\n", err)
	}

	return config
}

func init() {
	config = readConfiguration()
}

func main() {
	log.Println("login: " + config.Login)
	log.Println("password: " + config.Password)
	log.Println("host: " + config.Host)
	log.Println("port: " + strconv.Itoa(config.Port))
}