# GoDotEnv  [](https://goreportcard.com/report/github.com/joho/godotenv)
A Go (golang) port of the Ruby [dotenv](https://github.com/bkeepers/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.
## Installation
As a library
```shell
go get github.com/joho/godotenv
```
or if you want to use it as a bin command
go >= 1.17
```shell
go install github.com/joho/godotenv/cmd/godotenv@latest
```
go < 1.17
```shell
go get github.com/joho/godotenv/cmd/godotenv
```
## Usage
Add your application configuration to your `.env` file in the root of your project:
```shell
S3_BUCKET=YOURS3BUCKET
SECRET_KEY=YOURSECRETKEYGOESHERE
```
Then in your Go app you can do something like
```go
package main
import (
"log"
"os"
"github.com/joho/godotenv"
)
func main() {
err := godotenv.Load()
if err != nil {
log.Fatal("Error loading .env file")
}
s3Bucket := os.Getenv("S3_BUCKET")
secretKey := os.Getenv("SECRET_KEY")
// now do something with s3 or whatever
}
```
If you're even lazier than that, you can just take advantage of the autoload package which will read in `.env` on import
```go
import _ "github.com/joho/godotenv/autoload"
```
While `.env` in the project root is the default, you don't have to be constrained, both examples below are 100% legit
```go
godotenv.Load("somerandomfile")
godotenv.Load("filenumberone.env", "filenumbertwo.env")
```
If you want to be really fancy with your env file you can do comments and exports (below is a valid env file)
```shell
# 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
```go
var myEnv map[string]string
myEnv, err := godotenv.Read()
s3Bucket := myEnv["S3_BUCKET"]
```
... or from an `io.Reader` instead of a local file
```go
reader := getRemoteFile()
myEnv, err := godotenv.Parse(reader)
```
... or from a `string` if you so desire
```go
content := getRemoteFileContent()
myEnv, err := godotenv.Unmarshal(content)
```
### Precedence & Conventions
Existing envs take precedence of envs that are loaded later.
The [convention](https://github.com/bkeepers/dotenv#what-other-env-files-can-i-use)
for managing multiple environments (i.e. development, test, production)
is to create an env named `{YOURAPP}_ENV` and load envs in this order:
```go
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
```go
env, err := godotenv.Unmarshal("KEY=value")
err := godotenv.Write(env, "./.env")
```
... or to a string
```go
env, err := godotenv.Unmarshal("KEY=value")
content, err := godotenv.Marshal(env)
```
## Contributing
Contributions are welcome, but with some caveats.
This library has been declared feature complete (see [#182](https://github.com/joho/godotenv/issues/182) for background) and will not be accepting issues or pull requests adding new functionality or breaking the library API.
Contributions would be gladly accepted that:
* bring this library's parsing into closer compatibility with the mainline dotenv implementations, in particular [Ruby's dotenv](https://github.com/bkeepers/dotenv) and [Node.js' dotenv](https://github.com/motdotla/dotenv)
* keep the library up to date with the go ecosystem (ie CI bumps, documentation changes, changes in the core libraries)
* bug fixes for use cases that pertain to the library's purpose of easing development of codebases deployed into twelve factor environments
*code changes without tests and references to peer dotenv implementations will not be accepted*
1. Fork it
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Added some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request
## Releases
Releases should follow [Semver](http://semver.org/) though the first couple of releases are `v1` and `v1.1`.
Use [annotated tags for all releases](https://github.com/joho/godotenv/issues/30). Example `git tag -a v1.2.1`
## Who?
The original library [dotenv](https://github.com/bkeepers/dotenv) was written by [Brandon Keepers](http://opensoul.org/), and this port was done by [John Barton](https://johnbarton.co/) based off the tests/fixtures in the original library.