Reading a JSON into a compliant struct

//______________________________________________________________________________

type Config struct {
    BBoltFile  string `json:"bbolt_file"`
    SqliteFile string `json:"sqlite_file"`
    BucketPath string `json:"bucket_path"`
    TableName  string `json:"table_name"`
    Fields     []Corr `json:"fields"`
}

//______________________________________________________________________________

type Corr struct {
    ReadName  string `json:"read"`
    WriteName string `json:"write"`
}

//______________________________________________________________________________

// Reads config.json and decode into AppConfig
func loadAppConfig(configFile string, appcfg *Config) {
    file, err := os.Open(configFile)
    defer file.Close()
    if err != nil {
        log.Fatalf("[loadConfig] File: %s Error: %s\n", configFile, err)
    }
    decoder := json.NewDecoder(file)
    err = decoder.Decode(&appcfg)
    if err != nil {
        fmt.Println("configuration's reading report: ", err.Error())
        os.Exit(-1)
    }

    fmt.Printf("%+v\n", appcfg)
}

/*

{
    "bbolt_file": "",
    "sqlite_file": "",
    "bucket_path": "",
    "table_name": "",
    "fields": [
        {
            "read": "",
            "write": ""
        },
        {
            "read": "",
            "write": ""
        },
        {
            "read": "",
            "write": ""
        },
        {
            "read": "",
            "write": ""
        },
        {
            "read": "",
            "write": ""
        },
        {
            "read": "",
            "write": ""
        },
        {
            "read": "",
            "write": ""
        }
    ]
}

*/