Navigation Menu

Skip to content

📝 Go configuration manage(load,get,set,export). support JSON, YAML, TOML, Properties, INI, HCL, ENV and Flags. Multi file load, data override merge, parse ENV var. Go应用配置加载管理,支持多种格式,多文件加载,远程文件加载,支持数据合并,解析环境变量名



Repository files navigation


GitHub go.mod Go version Codacy Badge Build Status Actions Status Coverage Status Go Report Card Go Reference

config - Simple, full-featured Go application configuration management tool library.



  • Support multi format: JSON(default), JSON5, INI, Properties, YAML, TOML, HCL, ENV, Flags
    • JSON content support comments. will auto clear comments
    • Other drivers are used on demand, not used will not be loaded into the application.
      • Possibility to add custom driver for your specific format
  • Support multi-file and multi-data loading
  • Support for loading configuration from system ENV
  • Support for loading configuration data from remote URLs
  • Support for setting configuration data from command line(flags)
  • Support listen and fire events on config data changed.
    • allow events: set.value,,,,
  • Support data overlay and merge, automatically load by key when loading multiple copies of data
  • Support for binding all or part of the configuration data to the structure
    • Support init default value by struct tag default:"def_value"
    • Support init default value from ENV default:"${APP_ENV | dev}"
  • Support get sub value by key-path, like map.key arr.2
  • Support parse ENV name and allow with default value. like envKey: ${SHELL|/bin/bash} -> envKey: /bin/zsh
  • Generic API: Get Int Uint Int64 Float String Bool Ints IntMap Strings StringMap ...
  • Complete unit test(code coverage > 95%)

Only use INI

If you just want to use INI for simple config management, recommended use gookit/ini

Load dotenv file

On gookit/ini: Provide a sub-package dotenv that supports importing data from files (eg .env) to ENV

go get



go get


Here using the yaml format as an example(testdata/yml_other.yml):

name: app2
debug: false
baseKey: value2
shell: ${SHELL}
envKey1: ${NotExist|defValue}

    key: val2
    key2: val20

    - val1
    - val21

Load data

examples code please see _examples/yaml.go:

package main

import (

// go run ./examples/yaml.go
func main() {
	// config.ParseEnv: will parse env var in string value. eg: shell: ${SHELL}

	// add driver for support yaml content

	err := config.LoadFiles("testdata/yml_base.yml")
	if err != nil {

	// load more files
	err = config.LoadFiles("testdata/yml_other.yml")
	// can also load multi at once
	// err := config.LoadFiles("testdata/yml_base.yml", "testdata/yml_other.yml")
	if err != nil {

	// fmt.Printf("config data: \n %#v\n", config.Data())

Usage tips:

  • More extra options can be added using WithOptions(). For example: ParseEnv, ParseDefault
  • You can use AddDriver() to add the required format driver (json is loaded by default, no need to add)
  • The configuration data can then be loaded using LoadFiles() LoadStrings() etc.
    • You can pass in multiple files or call multiple times
    • Data loaded multiple times will be automatically merged by key

Bind Structure

Note: The default binding mapping tag of a structure is mapstructure, which can be changed by setting the decoder's option options.DecoderConfig.TagName

type User struct {
    Age  int  `mapstructure:"age"`
    Key  string `mapstructure:"key"`
    UserName  string `mapstructure:"user_name"`
    Tags []int  `mapstructure:"tags"`

user := User{}
err = config.BindStruct("user", &user)

fmt.Println(user.UserName) // inhere

Change struct tag name

config.WithOptions(func(opt *Options) {
    options.DecoderConfig.TagName = "config"

// use custom tag name.
type User struct {
  Age  int  `config:"age"`
  Key  string `config:"key"`
  UserName  string `config:"user_name"`
  Tags []int  `config:"tags"`

user := User{}
err = config.Decode(&user)

Can bind all config data to a struct:

// can also
config.BindStruct("", &myConf)

config.MapOnExists like BindStruct,but map binding only if key exists

Direct read data

  • Get integer
age := config.Int("age")
fmt.Print(age) // 100
  • Get bool
val := config.Bool("debug")
fmt.Print(val) // true
  • Get string
name := config.String("name")
fmt.Print(name) // inhere
  • Get strings(slice)
arr1 := config.Strings("arr1")
fmt.Printf("%#v", arr1) // []string{"val1", "val21"}
  • Get string map
val := config.StringMap("map1")
fmt.Printf("%#v",val) // map[string]string{"key":"val2", "key2":"val20"}
  • Value contains ENV var
value := config.String("shell")
fmt.Print(value) // "/bin/zsh"
  • Get value by key path
// from array
value := config.String("arr1.0")
fmt.Print(value) // "val1"

// from map
value := config.String("map1.key")
fmt.Print(value) // "val2"
  • Setting new value
// set value
config.Set("name", "new name")
name = config.String("name")
fmt.Print(name) // "new name"

Load from flags

Support simple flags parameter parsing, loading

// flags like: --name inhere --env dev --age 99 --debug

// load flag info
keys := []string{"name", "env", "age:int" "debug:bool"}
err := config.LoadFlags(keys)

// read
config.String("name") // "inhere"
config.String("env") // "dev"
config.Int("age") // 99
config.Bool("debug") // true

Load from ENV

// os env: APP_NAME=config APP_DEBUG=true
// load ENV info
config.LoadOSEnvs(map[string]string{"APP_NAME": "app_name", "APP_DEBUG": "app_debug"})

// read
config.Bool("app_debug") // true
config.String("app_name") // "config"

New config instance

You can create custom config instance

// create new instance, will auto register JSON driver
myConf := config.New("my-conf")

// create empty instance
myConf := config.NewEmpty("my-conf")

// create and with some options
myConf := config.NewWithOptions("my-conf", config.ParseEnv, config.ReadOnly)

Listen config change

Now, you can add a hook func for listen config data change. then, you can do something like: write data to file

Add hook func on create config:

hookFn := func(event string, c *Config) {
    fmt.Println("fire the:", event)

c := NewWithOptions("test", config.WithHookFunc(hookFn))
// for global config

After that, when calling LoadXXX, Set, SetData, ClearData methods, it will output:

fire the:
fire the: set.value
fire the:
fire the:

Watch loaded config files

To listen for changes to loaded config files, and reload the config when it changes, you need to use the library. For usage, please refer to the example ./_example/watch_file.go

Also, you need to listen to the event:

config.WithOptions(config.WithHookFunc(func(event string, c *config.Config) {
    if event == config.OnReloadData {
        fmt.Println("config reloaded, you can do something ....")

When the configuration changes, you can do related things, for example: rebind the configuration to your struct.

Dump config data

Can use config.DumpTo() export the configuration data to the specified writer, such as: buffer,file

Dump to JSON file

buf := new(bytes.Buffer)

_, err := config.DumpTo(buf, config.JSON)
ioutil.WriteFile("my-config.json", buf.Bytes(), 0755)

Dump pretty JSON

You can set the default var JSONMarshalIndent or custom a new JSON driver.

config.JSONMarshalIndent = "    "

Dump to YAML file

_, err := config.DumpTo(buf, config.YAML)
ioutil.WriteFile("my-config.yaml", buf.Bytes(), 0755)

Available options

// Options config options
type Options struct {
	// parse env in string value. like: "${EnvName}" "${EnvName|default}"
	ParseEnv bool
    // ParseTime parses a duration string to time.Duration
    // eg: 10s, 2m
    ParseTime bool
	// config is readonly. default is False
	Readonly bool
	// enable config data cache. default is False
	EnableCache bool
	// parse key, allow find value by key path. default is True eg: 'key.sub' will find `map[key]sub`
	ParseKey bool
	// the delimiter char for split key path, if `FindByPath=true`. default is '.'
	Delimiter byte
	// default write format
	DumpFormat string
	// default input format
	ReadFormat string
	// DecoderConfig setting for binding data to struct
	DecoderConfig *mapstructure.DecoderConfig
	// HookFunc on data changed.
	HookFunc HookFunc
	// ParseDefault tag on binding data to struct. tag: default
	ParseDefault bool

Examples for set options:

config.WithOptions(func(opt *Options) {

Options: Parse default

Support parse default value by struct tag default

// add option: config.ParseDefault
c := config.New("test").WithOptions(config.ParseDefault)

// only set name
    "name": "inhere",

// age load from default tag
type User struct {
    Age  int `default:"30"`
    Name string
    Tags []int

user := &User{}


&config_test.User {
  Age: int(30),
  Name: string("inhere"), #len=6
  Tags: []int [ #len=0

API Methods Refer

Load Config

  • LoadOSEnvs(nameToKeyMap map[string]string) Load data from os ENV
  • LoadData(dataSource ...any) (err error) Load from struts or maps
  • LoadFlags(keys []string) (err error) Load from CLI flags
  • LoadExists(sourceFiles ...string) (err error)
  • LoadFiles(sourceFiles ...string) (err error)
  • LoadFromDir(dirPath, format string) (err error) Load custom format files from the given directory, the file name will be used as the key
  • LoadRemote(format, url string) (err error)
  • LoadSources(format string, src []byte, more ...[]byte) (err error)
  • LoadStrings(format string, str string, more ...string) (err error)
  • LoadFilesByFormat(format string, sourceFiles ...string) (err error)
  • LoadExistsByFormat(format string, sourceFiles ...string) error

Getting Values

  • Bool(key string, defVal ...bool) bool
  • Int(key string, defVal int
  • Uint(key string, defVal ...uint) uint
  • Int64(key string, defVal ...int64) int64
  • Ints(key string) (arr []int)
  • IntMap(key string) (mp map[string]int)
  • Float(key string, defVal ...float64) float64
  • String(key string, defVal ...string) string
  • Strings(key string) (arr []string)
  • SubDataMap(key string) maputi.Data
  • StringMap(key string) (mp map[string]string)
  • Get(key string, findByPath ...bool) (value any)

Mapping data to struct:

  • Decode(dst any) error
  • BindStruct(key string, dst any) error
  • MapOnExists(key string, dst any) error

Setting Values

  • Set(key string, val any, setByPath ...bool) (err error)

Useful Methods

  • Getenv(name string, defVal ...string) (val string)
  • AddDriver(driver Driver)
  • Data() map[string]any
  • SetData(data map[string]any) set data to override the Config.Data
  • Exists(key string, findByPath ...bool) bool
  • DumpTo(out io.Writer, format string) (n int64, err error)

Run Tests

go test -cover
// contains all sub-folder
go test -cover ./...

Projects using config

Check out these projects, which use :

Gookit packages

  • gookit/ini Go config management, use INI files
  • gookit/rux Simple and fast request router for golang HTTP
  • gookit/gcli build CLI application, tool library, running CLI commands
  • gookit/event Lightweight event manager and dispatcher implements by Go
  • gookit/cache Generic cache use and cache manager for golang. support File, Memory, Redis, Memcached.
  • gookit/config Go config management. support JSON, YAML, TOML, INI, HCL, ENV and Flags
  • gookit/color A command-line color library with true color support, universal API methods and Windows support
  • gookit/filter Provide filtering, sanitizing, and conversion of golang data
  • gookit/validate Use for data validation and filtering. support Map, Struct, Form data
  • gookit/goutil Some utils for the Go: string, array/slice, map, format, cli, env, filesystem, test and more
  • More, please see

See also




📝 Go configuration manage(load,get,set,export). support JSON, YAML, TOML, Properties, INI, HCL, ENV and Flags. Multi file load, data override merge, parse ENV var. Go应用配置加载管理,支持多种格式,多文件加载,远程文件加载,支持数据合并,解析环境变量名








No packages published