env

README

Go Env

This is a Go library that reads configuration from file (.env.tkl in the current working directoy by default) to update the given struct. The configuration is in Tickle configuration format. If the configuration file doesn't exist, the configuration is loaded from environment variables.

Interface

import (
    "codeberg.org/yuce/go-env"
)

type Config struct {
    APIKey string `env:"API_KEY"`
    ServerAddress string `env:"SERVER_ADDRESS"`
}

// load configuration from .env.tkl file if it exists, or environment variables
var cfg Config
if err := env.Load(&cfg); err != nil {
    panic(err)
}

// load configuration from the given path if it exists, or environment variables
var cfg Config
if err := env.LoadFromPath("sample.tkl", &cfg); err != nil {
    panic(err)
}

Behaviour

The configuration from the Tickle file is tried first. The default Tickle file is named .env.tkl, which is searched in the current working directory. If it doesn't exist, the configuration is loaded from environment variables. The name of the environment variable corresponding to a struct field is take from the struct field tagged env.

The following types are supported as field types in the target struct:

• string
• int, int16, int32, int64 and their unsigned variants
• float32, float64
• bool. false string is mapped to false, true string is mapped to true.

Examples

Given the following struct:

type ServerConfig struct {
    Host string `ms:"HOST"`
    Port int `ms:"PORT"`
    Enabled bool `ms:"ENABLED"`
}

Example 1

$PWD/.env.tkl exists, and has the following contents:

HOST: "yuce.me"
PORT: 8080
ENABLED: true

The Go code below:

var cfg ServerConfig
err := env.Load(&cfg)
// err == nil

Results with the following values in the cfg struct:

cfg.Host == "yuce.me"
cfg.Port == 8080
cfg.Enabled == true

Example 2

$PWD/.env.tkl doesn't exist, and the following environment variables are defined:

HOST="foo.bar"
PORT=1234
ENABLED=false

The Go code below:

var cfg ServerConfig
err := env.Load(&cfg)
// err == nil

Results with the following values in the cfg struct:

cfg.Host == "foo.bar"
cfg.Port == 1234
cfg.Enabled == false

Documentation

Index

• Variables
• func Load(dst any) error
• func LoadFromPath(path string, dst any) error

Variables

var (
	ErrNotAPointerToStruct = errors.New("destination must be a pointer to a struct")
)

Functions

func Load

func Load(dst any) error

Load loads configuration from the default .env.tkl file in the current working directory. If the file does not exist, it loads from environment variables.

func LoadFromPath

func LoadFromPath(path string, dst any) error

LoadFromPath loads configuration from the file at path. If the file does not exist, it loads from environment variables.