Wrong struct returned from separate package function

I develop application on my Ubuntu 18.04 with go.

I have config package. The idea is to use this package in another packages to get configurations. Package config has struct variable _Config. The idea that function GetConfig will return _Config, and when _Config not filled the function will firstly fill _Config from json file.

The config package looks like this:

package config

import (
	"fmt"
	"github.com/tkanos/gonfig"
)

type Config struct {
	DB struct{
		DBHost string
		DBPort uint
		DBUser string
		DBPassword string
		DBName string
	}
}

var _Config Config

func GetConfig() Config {
	if (Config{}) == _Config {
		_Config := Config{}
		err := gonfig.GetConf("/home/mike/go/src/project/config.json", &_Config)
		if err != nil{
			panic("Error when parsing config")
		}
		fmt.Println(_Config.DB)
	}
	return _Config
}

And the result of Println is:

{127.0.0.1 3306 user Password project}

The code of main package looks like:

package main

import (
	"fmt"
	"project/config"
	_ "github.com/jinzhu/gorm/dialects/mysql"
	_ "project/config"
	"syscall"
	"unsafe"
)

func main() {
	_config := config.GetConfig()
	fmt.Println(_config)
}

And the result of Println is:

{{ 0   }}

The json file looks like:

{
  "DB": {
    "DBHost": "127.0.0.1",
    "DBPort": 3306,
    "DBUser": "user",
    "DBPassword": "Password",
    "DBName": "project"
  }
}

So why is that? Why I can't get correct config in main package? The problem I think that I have wrong imagination about how Go works in such situation.

Please clarify this moment for me, and is it good approach for config in application ? If not, what is good pattern? The idea is to have one access and one responsible package for config which I can use everywhere

You have a line in GetConfig() function -
_Config := Config{}.

Here, you are declaring a new variable _Config in local scope and shadowing the global variable. Remove this line and try again. Due to shadowing, global variable is not populated with config from json.