The Twelve-Factor App Manifest promotes using environment variables as the only configuration approach. We follow and love this principle.

The .env files are just a genuine extension of env vars. The .env files simplify local debug, exposing variables to a Docker containers, and so on.

Godenv is a tiny package that reads those .env files.

We took inspiration from the godotenv repository. We aimed at creating a parser without using regular expressions but with a lexer/parser approach.

If you are curious about learning more about the approach, see the following links:

• https://en.wikipedia.org/wiki/Abstract_syntax_tree
• https://en.wikipedia.org/wiki/Lexical_analysis
• https://en.wikipedia.org/wiki/Parsing#Parser

go get github.com/headframe-io/godenv

Add a configuration to your .env file:

HTTP_ADDRESS=":8080"
LOG_LEVEL="info"

Then in the Go app read the file and parse its content:

package main

import (
	"fmt"
	"os"

	"github.com/headframe-io/godenv"
)

func main() {
	f, err := os.Open(".env")
	if err != nil {
		panic(err)
	}
	defer f.Close()

	vars, err := godenv.Parse(f)
	if err != nil {
		panic(err)
	}

	fmt.Println(vars)
}

godenv stands for go-dot-env. It is pronounced as goh denv, not as gahd env.

The complete specification can be found here: SPECIFICATION.md.