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package lazyconfig

import "golazy.dev/lazyconfig"

Package lazyconfig fills configuration structs from environment variables.

Use Getenv with an application-owned struct: 

type Config struct {
	Port       int
	ListenAddr string `var:"LISTEN_ADDR" default:":3000"`
}

config, err := lazyconfig.Getenv[Config]()

Use MustGetenv when invalid environment values should fail during package initialization: 

var Config = lazyconfig.MustGetenv[Config]()

Options can adjust environment name matching. RemoveEnvNamePrefix adds unprefixed aliases for environment variables, which is useful when a struct models a namespaced environment convention: 

type OTELConfig struct {
	SDKDisabled bool
	ServiceName string
}

config := lazyconfig.MustGetenv[OTELConfig](
	lazyconfig.RemoveEnvNamePrefix("OTEL"),
)

Values are trimmed before parsing. String, numeric, bool, pointer scalar, and []string fields are supported; []string values split on commas or whitespace. Bool fields treat yes, true, and 1 as true; no, false, 0, and unknown values are false. Bool matching is case-insensitive.

Functions

func Getenv[T any]

Getenv fills a configuration struct from environment variables. 

func Getenv[T any](options ...Option) (T, error)

func MustGetenv[T any]

MustGetenv fills a configuration struct from environment variables and panics when the environment is invalid. 

func MustGetenv[T any](options ...Option) T

Types

type Option

Option changes how Getenv and MustGetenv read environment variables. 

type Option func(*loader)
func RemoveEnvNamePrefix

RemoveEnvNamePrefix makes environment variables with prefix available without that prefix. RemoveEnvNamePrefix("OTEL") lets field SDKDisabled match OTEL_SDK_DISABLED as SDK_DISABLED.

Existing unprefixed environment variables keep precedence over generated aliases. 

func RemoveEnvNamePrefix(prefix string) Option