settings - Imperative settings management for Go

Key points

1. This module allows you to manage the application settings imperative way. Being not declarative is the whole point of this project. Imperative code allows you to be more flexible and to have more control over the settings.
2. Performance is not a concern. Settings are usually loaded only once at the beginning of the application runtime. That's why we can afford to do a lot of unnecessary work in exchange for more flexibility.

If you don't share my unhappiness with the declarative style of managing settings, you probably don't need this module.

Features

• Read configuration from YAML, env variables, and command line arguments, and combine them.
• No reflection and no struct tags, so you can parse into a single variable, unexported field of a struct or even a field of a struct declared in another Go module (which means, no more intermediate structures!), anything would work.
• Mark required settings.
• Set default values.

Examples

Direct usage on a struct from another module

import (
	"github.com/redis/go-redis/v9"
	"github.com/tomr-ninja/go-settings"
)

func setupRedis() *redis.Client {
	redisOptions := new(redis.Options)
	redisConfig := settings.NewParser(settings.WithEnvPrefix("REDIS"))
	redisConfig.Add(&redisOptions.Addr).Env("ADDR").Default("localhost:6379")
	redisConfig.MustParse()	

	return redis.NewClient(redisOptions)
}

Multiple settings sources

import "github.com/tomr-ninja/go-settings"

func main() {
    var config struct {
        Addr string
        Port int
    }

	// priority decreases from the left to the right
	settings.Add(&config.Addr).Flag("addr").Env("ADDR").Default("localhost")
	settings.Add(&config.Port).Env("PORT").Flag("port").Default(8080)
	settings.MustParse()

    fmt.Printf("Addr: %s, Port: %d\n", config.Addr, config.Port)
}