README
¶
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.
Installation
As a library
go get github.com/joho/godotenv
or if you want to use it as a bin command
go >= 1.17
go install github.com/joho/godotenv/cmd/godotenv@latest
go < 1.17
go get github.com/joho/godotenv/cmd/godotenv
Usage
Add your application configuration to your .env file in the root of your project:
S3_BUCKET=YOURS3BUCKET
SECRET_KEY=YOURSECRETKEYGOESHERE
Then in your Go app you can do something like
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
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
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)
# 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
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)
Contributing
Contributions are welcome, but with some caveats.
This library has been declared feature complete (see #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 and Node.js' 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
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Added some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request
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.
Documentation
¶
Overview ¶
Package godotenv is a go port of the ruby dotenv library (https://github.com/bkeepers/dotenv)
Examples/readme can be found on the GitHub page at https://github.com/joho/godotenv
The TL;DR is that you make a .env file that looks something like
SOME_ENV_VAR=somevalue
and then in your go code you can call
godotenv.Load()
and all the env vars declared in .env will be available through os.Getenv("SOME_ENV_VAR")
Index ¶
- func Exec(filenames []string, cmd string, cmdArgs []string, overload bool) error
- func Load(filenames ...string) (err error)
- func Marshal(envMap map[string]string) (string, error)
- func Overload(filenames ...string) (err error)
- func Parse(r io.Reader) (map[string]string, error)
- func Read(filenames ...string) (envMap map[string]string, err error)
- func Unmarshal(str string) (envMap map[string]string, err error)
- func UnmarshalBytes(src []byte) (map[string]string, error)
- func Write(envMap map[string]string, filename string) error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Exec ¶
Exec loads env vars from the specified filenames (empty map falls back to default) then executes the cmd specified.
Simply hooks up os.Stdin/err/out to the command and calls Run().
If you want more fine grained control over your command it's recommended that you use `Load()`, `Overload()` or `Read()` and the `os/exec` package yourself.
func Load ¶
Load will read your env file(s) and load them into ENV for this process.
Call this function as close as possible to the start of your program (ideally in main).
If you call Load without any args it will default to loading .env in the current path.
You can otherwise tell it which files to load (there can be more than one) like:
godotenv.Load("fileone", "filetwo")
It's important to note that it WILL NOT OVERRIDE an env variable that already exists - consider the .env file to set dev vars or sensible defaults.
func Marshal ¶
Marshal outputs the given environment as a dotenv-formatted environment file. Each line is in the format: KEY="VALUE" where VALUE is backslash-escaped.
func Overload ¶
Overload will read your env file(s) and load them into ENV for this process.
Call this function as close as possible to the start of your program (ideally in main).
If you call Overload without any args it will default to loading .env in the current path.
You can otherwise tell it which files to load (there can be more than one) like:
godotenv.Overload("fileone", "filetwo")
It's important to note this WILL OVERRIDE an env variable that already exists - consider the .env file to forcefully set all vars.
func Read ¶
Read all env (with same file loading semantics as Load) but return values as a map rather than automatically writing values into env
func UnmarshalBytes ¶ added in v1.5.0
UnmarshalBytes parses env file from byte slice of chars, returning a map of keys and values.
Types ¶
This section is empty.
Source Files
Directories