You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: Config.go
    path of file: ./repos/learning/golang/practice/go-crontab/gopath/src/github.com/owenliang/crontab/worker
    
    the code of the file until where you have to start completion: package worker

import (
	"io/ioutil"
	"encoding/json"
)

// 程序配置
type Config struct {
	EtcdEndpoints []string `json:"etcdEndpoints"`
	EtcdDialTimeout int `json:"etcdDialTimeout"`
	MongodbUri string `json:"mongodbUri"`
	MongodbConnectTimeout int `js
    
func InitConfig(filename string) (err error) {
	var (
		content []byte
		conf Config
	)

	// 1, 把配置文件读进来
	if content, err = ioutil.ReadFile(filename); err != nil {
		return
	}

	// 2, 做JSON反序列化
	if err = json.Unmarshal(content, &conf); err != nil {
		return
	}

	// 3, 赋值单例
	G_config = &conf

	return
}