Fang configuration loader

Inspired by spf13/viper, this is intended to be a minimalistic and opinionated configuration loader library.

Usage

Most basic example would be:

type Config struct {
	Name string
}

config := fang.New[Config].Load()

Which does nothing really.

A slightly more interesting example would be:

type Config struct {
	Name string
}

config := fang.New[Config].
    WithEnvironment(map[string]string {
        "NAME": "Name"
    }).
    Load()

This would load the NAME environment variable into config.Name. There is also a WithAutomaticEnv(prefix string) which automatically maps enviroment variables to fields in the struct. For example NAME gets bound to config.Name but USER__NAME would get bound to config.User.Name.

A typical example of how this library would be used looks like this:

func ConfigFromEnvironmentWithPrefix(envPrefix string) (Config, error) {
	loader := fang.New[Config]().
		WithDefault(DefaultConfig()).
		WithAutomaticEnv(envPrefix).
		WithConfigFile(fang.ConfigFileOptions{
			Paths: []string{"$HOME", "."},
			Names: []string{"config"},
			Type:  fang.ConfigFileTypeYaml,
		})

	return loader.Load()
}

This specifies default values, automatically maps environment variables to fields in the struct and also looks for a config.yaml file in either the user home or current directory for further configuration.