Golang Code Examples

jsoncfgo - JSON File Reader

24 Jul 2014


This example demonstrates how you could use the jsoncfgo config file reader.

jsoncfgo Features

jsoncfgo can handle the following data types in the .json configuration file that it reads:

  • bool
  • int
  • int64
  • string
  • []string
  • []int64

You can also call the Validate function to validate attempts to read non-existent variables.

Golang Features

This golang code sample demonstrates the following go language features:

  • Simple printing using fmt package

Code Example

In this code example we demonstrate how to use jsoncfgo convenience functions to read a simple json-based configuration file.

package main

import (

func main() {

    cfg := jsoncfgo.Load("/Users/lex/dev/go/data/jsoncfgo/simple-config.json")

    host := cfg.String("host")
    fmt.Printf("host: %v\n", host)
    bogusHost := cfg.String("bogusHost", "default_host_name")
    fmt.Printf("host: %v\n\n", bogusHost)

    port := cfg.Int("port")
    fmt.Printf("port: %v\n", port)
    bogusPort := cfg.Int("bogusPort", 9000)
    fmt.Printf("bogusPort: %v\n\n", bogusPort)

    bigNumber := cfg.Int64("bignNumber")
    fmt.Printf("bigNumber: %v\n", bigNumber)
    bogusBigNumber := cfg.Int64("bogusBigNumber", 9000000000000000000)
    fmt.Printf("bogusBigNumber: %v\n\n", bogusBigNumber)

    active := cfg.Bool("active")
    fmt.Printf("active: %v\n", active)
    bogusFalseActive := cfg.Bool("bogusFalseActive", false)
    fmt.Printf("bogusFalseActive: %v\n", bogusFalseActive)
    bogusTrueActive := cfg.Bool("bogusTrueActive", true)
    fmt.Printf("bogusTrueActive: %v\n\n", bogusTrueActive)

    appList := cfg.List("appList")
    fmt.Printf("appList: %v\n", appList)
    bogusAppList := cfg.List("bogusAppList", []string{"app1", "app2", "app3"})
    fmt.Printf("bogusAppList: %v\n\n", bogusAppList)

    numbers := cfg.IntList("numbers")
    fmt.Printf("numbers: %v\n", numbers)
    bogusSettings := cfg.IntList("bogusSettings", []int64{1, 2, 3})
    fmt.Printf("bogusAppList: %v\n\n", bogusSettings)


You will need to change the configPath to point to a the configuration file on your computer.

Any read errors are handled for us; Errors are logged to standard out.

For a more detailed example of how to leverage the more advanced features of jsoncfgo, please see jsoncfgo - Advanced Usage

Install jsconfgo

Install the jsconfgo library as follows:

$ go get github.com/l3x/jsoncfgo



   "host": "localhost",
   "port": 9000,
   "active": true,
   "appList": ["myapp", "sharedapp"]


host: localhost
host: default_host_name

port: 5432
bogusPort: 9000

bigNumber: 999999999999999
bogusBigNumber: 9000000000000000000

active: true
bogusFalseActive: false
bogusTrueActive: true

appList: [myapp sharedapp]
bogusAppList: [app1 app2 app3]

Process finished with exit code 1


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