aconfig

aconfig

Simple, useful and opinionated config loader.

Rationale

There are more than 2000 repositories on Github regarding configuration in Go. I was looking for a simple configuration loader that will automate a lot of things for me. Idea was to load config from 4 common places: defaults (in the code), config files, environment variables, command-line flags. This library works with all of them.

Features

• Simple API.
• Automates a lot of things.
• Opinionated.
• Supports different sources:
  • defaults in code
  • files (JSON, YAML, TOML)
  • environment variables
  • command-line flags
• Dependency-free (except file parsers)

Install

Go version 1.14+

go get github.com/cristalhq/aconfig

Example

type MyConfig struct {
	Port int `default:"1111"`
	Auth struct {
		User string `default:"def-user"`
		Pass string `default:"def-pass"`
	}
}

loader := aconfig.NewLoader(aconfig.LoaderConfig{
	// feel free to skip some steps :)
	// SkipDefaults: true,
	// SkipFile: true,
	// SkipEnv:  true,
	// SkipFlag: true,

	Files:       []string{"file.json", "ouch.yaml"},
	FlagPrefix:  "app",
	EnvPrefix:   "APP",
})

var cfg MyConfig
if err := loader.Load(&cfg); err != nil {
	panic(err)
}

// configuration fields will be loaded from (in order):
//
// 1. defaults set in structure tags (see structure defenition)
// 2. loaded from files `file.json` if not `ouch.yaml` will be used
// 3. from corresponding environment variables with prefix `APP`
// 4. and command-line flags if they are

Also see examples: this above

Documentation

See here: pkgo.dev.

License

MIT License.