GoDotEnv

A Go (golang) port of the Ruby dotenv project (which loads env vars from a .env file).

From the original Library:

Storing configuration in the environment is one of the tenets of a twelve-factor app. Anything that is likely to change between deployment environments–such as resource handles for databases or credentials for external services–should be extracted from the code into environment variables.

But it is not always practical to set environment variables on development machines or continuous integration servers where multiple projects are run. Dotenv load variables from a .env file into ENV when the environment is bootstrapped.

It can be used as a library (for loading in env for your own daemons etc.) or as a bin command.

There is test coverage and CI for both linuxish and Windows environments, but I make no guarantees about the bin version working on Windows.

I am a comment and that is OK

SOME_VAR=someval FOO=BAR # comments at line end are OK too export BAR=BAZ


Or finally you can do YAML(ish) style

```yaml
FOO: bar
BAR: baz

as a final aside, if you don’t want godotenv munging your env you can just get a map back instead

var myEnv map[string]string
myEnv, err := godotenv.Read()

s3Bucket := myEnv["S3_BUCKET"]

… or from an io.Reader instead of a local file

reader := getRemoteFile()
myEnv, err := godotenv.Parse(reader)

… or from a string if you so desire

content := getRemoteFileContent()
myEnv, err := godotenv.Unmarshal(content)

Precedence & Conventions

Existing envs take precedence of envs that are loaded later.

The convention for managing multiple environments (i.e. development, test, production) is to create an env named {YOURAPP}_ENV and load envs in this order:

env := os.Getenv("FOO_ENV")
if "" == env {
  env = "development"
}

godotenv.Load(".env." + env + ".local")
if "test" != env {
  godotenv.Load(".env.local")
}
godotenv.Load(".env." + env)
godotenv.Load() // The Original .env

If you need to, you can also use godotenv.Overload() to defy this convention and overwrite existing envs instead of only supplanting them. Use with caution.

Command Mode

Assuming you’ve installed the command as above and you’ve got $GOPATH/bin in your $PATH

godotenv -f /some/path/to/.env some_command with some args

If you don’t specify -f it will fall back on the default of loading .env in PWD

By default, it won’t override existing environment variables; you can do that with the -o flag.

Writing Env Files

Godotenv can also write a map representing the environment to a correctly-formatted and escaped file

env, err := godotenv.Unmarshal("KEY=value")
err := godotenv.Write(env, "./.env")

… or to a string

env, err := godotenv.Unmarshal("KEY=value")
content, err := godotenv.Marshal(env)

Releases

Releases should follow Semver though the first couple of releases are v1 and v1.1.

Use annotated tags for all releases. Example git tag -a v1.2.1

Who?

The original library dotenv was written by Brandon Keepers, and this port was done by John Barton based off the tests/fixtures in the original library.

godotenv