Strongly typed config with tags
Reflection based config validation, for syntax amd examples refer validator
- Required fields
- Optional fields
- Enum fields
- Min, Max, email, phone etc
Setting defaults for fields not in the config files. for syntax amd examples refer creasty's defaults
Config Sources
- YAML files
- Environment Variables
- Environment Variables Expanding
- Command line flags
- Kubernetes ConfigMaps
- Merge multiple config sources, recursively with Mergo
- Detect Runtime Environment (test, development, production), auto merge overlay files
Dynamic Configuration Management (Hot Reconfiguration)
- Remote config push
- Externalized configuration
- Live component reloading / zero-downtime
- Observe Config [Changes](https://play.golang.org/p/41ygGZ-QaB https://gist.github.com/patrickmn/1549985)
Support embed config files in Go binaries via Go 1.16 embed

all struct fields must be public

type Item struct {
    Name int `yaml:"full_name,omitempty"`
    Age int  `yaml:",omitempty"` //  Removing Empty JSON Fields
    City string `yaml:",omitempty"`
    TLS      bool   `default:"true" yaml:",omitempty"` // Use default when Empty
    Password string `yaml:"-"` // Ignoring Private Fields
    Name     string `validate:"-"`
    Title    string `validate:"alphanum,required"`
    AuthorIP string `validate:"ipv4"`
    Email    string `validate:"email"`
}

Usage

package main

import (
	"fmt"
	"github.com/xmlking/confy"
)

var Config = struct {
	APPName string `default:"app name" yaml:",omitempty"`

	DB struct {
		Name     string
		User     string `default:"root" yaml:",omitempty"`
		Password string `required:"true" env:"DBPassword"`
		Port     uint   `default:"3306" yaml:",omitempty"`
	}

	Contacts []struct {
		Name  string
		Email string `required:"true"`
	}
}{}

func main() {
    confy.Load(&Config, "config.yml")
	fmt.Printf("config: %#v", Config)
}

With configuration file config.yml:

appname: test

db:
    name:     test
    user:     test
    password: test
    port:     1234

contacts:
- name: i test
  email: [email protected]

Debug Mode & Verbose Mode

Debug/Verbose mode is helpful when debuging your application, debug mode will let you know how confy loaded your configurations, like from which file, shell env, verbose mode will tell you even more, like those shell environments confy tried to load.

// Enable debug mode or set env `CONFY_DEBUG_MODE` to true when running your application
confy.DefaultConfy = confy.NewConfy(confy.WithFS(os.DirFS(dir)))
confy.Load(&Config, "config.yaml")

// Enable verbose mode or set env `CONFY_VERBOSE_MODE` to true when running your application
confy.New(confy.WithVerboseMode()).Load(&Config, "config.yaml")

// You can create custom confy once and reuse to load multiple different configs  
configor := confy.NewConfy(confy.WithVerboseMode(), confy.WithFS(os.DirFS(".")))
configor.Load(&Config2, "config2.yaml")
configor.Load(&Config3, "config3.yaml")

Load

Advanced Usage

Load mutiple configurations

// Earlier configurations have higher priority
confy.Load(&Config, "application.yml", "database.json")

Return error on unmatched keys

Return an error on finding keys in the config file that do not match any fields in the config struct. In the example below, an error will be returned if config.toml contains keys that do not match any fields in the ConfigStruct struct. If ErrorOnUnmatchedKeys is not set, it defaults to false.

Note that for json files, setting ErrorOnUnmatchedKeys to true will have an effect only if using go 1.10 or later.

err := confy.NewConfy(confy.WithErrorOnUnmatchedKeys(), confy.WithFS(os.DirFS("."))).Load(&ConfigStruct, "config.toml")

Load configuration by environment

Use CONFY_ENV to set environment, if CONFY_ENV not set, environment will be development by default, and it will be test when running tests with go test

// config.go
confy.Load(&Config, "config.json")

$ go run config.go
// Will load `config.json`, `config.development.json` if it exists
// `config.development.json` will overwrite `config.json`'s configuration
// You could use this to share same configuration across different environments

$ CONFY_ENV=production go run config.go
// Will load `config.json`, `config.production.json` if it exists
// `config.production.json` will overwrite `config.json`'s configuration

$ cd confy

$ go test ./...
// Will load `config.json`, `config.test.json` if it exists
// `config.test.json` will overwrite `config.json`'s configuration

$ CONFY_ENV=production go test ./...
// Will load `config.json`, `config.production.json` if it exists
// `config.production.json` will overwrite `config.json`'s configuration

// Set environment by config
confy.NewConfy(confy.WithEnvironment("production"), confy.WithFS(os.DirFS("."))).Load(&Config, "config.json")

Example Configuration

// config.go
confy.Load(&Config, "config.yml")

$ go run config.go
// Will load `config.example.yml` automatically if `config.yml` not found and print warning message

Load files Via Go 1.16 FileSystem
Load From Shell Environment

Environment variable names are structured like this:

[PREFIX][SEP][MY][SEP][FIELD][SEP][NAME]

Struct field names will be converted to UpperSnakeCase

$ CONFY_APP_NAME="hello world" CONFY_DB_NAME="hello world" go run config.go
// Load configuration from shell environment, it's name is {{prefix}}_FieldName

// You could overwrite the prefix with environment CONFY_ENV_PREFIX, for example:
$ CONFY_ENV_PREFIX="WEB" WEB_APP_NAME="hello world" WEB_DB_NAME="hello world" go run config.go

// Set prefix by config
confy.NewConfy(confy.WithEnvironmentVariablePrefix("WEB"), confy.WithFS(os.DirFS("."))).Load(&Config, "config.json")

Anonymous Struct

Add the anonymous:"true" tag to an anonymous, embedded struct to NOT include the struct name in the environment variable of any contained fields. For example:

type Details struct {
	Description string
}

type Config struct {
	Details `anonymous:"true"`
}

With the anonymous:"true" tag specified, the environment variable for the Description field is CONFY_DESCRIPTION. Without the anonymous:"true"tag specified, then environment variable would include the embedded struct name and be CONFY_DETAILS_DESCRIPTION.

With flags

func main() {
	config := flag.String("file", "config.yml", "configuration file")
	flag.StringVar(&Config.APPName, "name", "", "app name")
	flag.StringVar(&Config.DB.Name, "db-name", "", "database name")
	flag.StringVar(&Config.DB.User, "db-user", "root", "database user")
	flag.Parse()

	os.Setenv("CONFY_ENV_PREFIX", "-")
    confy.Load(&Config, *config)
	// confy.Load(&Config) // only load configurations from shell env & flag
}