Read json file value in Go

I have a config file. I want to get specific value from that file. Here is my code :

package main

import (
	"fmt"
	"os"
	"encoding/json"
)

type Configuration struct {
	consumer_key   string
	consumer_secret   string
	access_token   string
	access_token_secret   string
	db_name   string
	db_user   string
	db_password   string
	secret_key   string
	fb_page   string
	fb_page_token   string
	domain   string
}

func main() {
	file, _ := os.Open("./config.json")
	decoder := json.NewDecoder(file)
	configuration := Configuration{}
    error_ := decoder.Decode(&configuration)
	 fmt.Println(configuration.domain)
}

config.json

{
  "consumer_key": "",
  "consumer_secret": "",
  "access_token": "",
  "access_token_secret": "",
  "db_name": "",
  "db_user": "",
  "db_password": "",
  "secret_key": "",
  "fb_page": "",
  "fb_page_token": "",
  "domain": "localhost:8000"
}

But the problem is it always print empty line, not the value localhost:8000 I am expecting.

You need to export Configuration.domain field so that json package can see it.

Rename the domain field to Domain:

type Configuration struct {
  Domain string
}

You can also specify json name explicitly if it differs from field name:

type Configuration struct {
  Domain string `json:"domain_name"`
}