env

Documentation

Overview

Package env 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/env

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

env.Load()

and all the env vars declared in .env will be available through os.Getenv("SOME_ENV_VAR")

Index

• Variables
• func Exec(filenames []string, cmd string, cmdArgs []string) error
• func Load(filenames ...string) (err error)
• func Marshal(envMap map[string]string) (string, error)
• func Overload(filenames ...string) (err error)
• func Parse(v interface{}, opts ...Options) error
• func ParseDotenv(r io.Reader) (envMap map[string]string, err error)
• func ParseWithFuncs(v interface{}, funcMap map[reflect.Type]ParserFunc, opts ...Options) error
• func Read(filenames ...string) (envMap map[string]string, err error)
• func Unmarshal(str string) (envMap map[string]string, err error)
• func Write(envMap map[string]string, filename string) error
• type Options
• type ParserFunc

Examples

• Parse
• ParseWithFuncs

Variables

var (
	// ErrNotAStructPtr is returned if you pass something that is not a pointer to a
	// Struct to Parse
	ErrNotAStructPtr = errors.New("env: expected a pointer to a Struct")
)

nolint: gochecknoglobals

Functions

func Exec

func Exec(filenames []string, cmd string, cmdArgs []string) error

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()` or `Read()` and the `os/exec` package yourself.

func Load

func Load(filenames ...string) (err error)

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

env.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

func Marshal(envMap map[string]string) (string, error)

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

func Overload(filenames ...string) (err error)

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

env.Overload("fileone", "filetwo")

It's important to note this WILL OVERRIDE an env variable that already exists - consider the .env file to forcefilly set all vars.

func Parse

func Parse(v interface{}, opts ...Options) error

Parse parses a struct containing `env` tags and loads its values from environment variables.

Example

type inner struct {
	Foo string `env:"FOO" envDefault:"foobar"`
}
type config struct {
	Home         string `env:"HOME,required"`
	Port         int    `env:"PORT" envDefault:"3000"`
	IsProduction bool   `env:"PRODUCTION"`
	Inner        inner
}
os.Setenv("HOME", "/tmp/fakehome")
var cfg config
if err := Parse(&cfg); err != nil {
	fmt.Println("failed:", err)
}
fmt.Printf("%+v", cfg)

Output:

{Home:/tmp/fakehome Port:3000 IsProduction:false Inner:{Foo:foobar}}

func ParseDotenv

func ParseDotenv(r io.Reader) (envMap map[string]string, err error)

ParseDotenv reads an env file from io.Reader, returning a map of keys and values.

func ParseWithFuncs

func ParseWithFuncs(v interface{}, funcMap map[reflect.Type]ParserFunc, opts ...Options) error

ParseWithFuncs is the same as `Parse` except it also allows the user to pass in custom parsers.

Example

type thing struct {
	desc string
}

type conf struct {
	Thing thing `env:"THING"`
}

os.Setenv("THING", "my thing")

var c = conf{}

err := ParseWithFuncs(&c, map[reflect.Type]ParserFunc{
	reflect.TypeOf(thing{}): func(v string) (interface{}, error) {
		return thing{desc: v}, nil
	},
})
if err != nil {
	fmt.Println(err)
}
fmt.Println(c.Thing.desc)

Output:

my thing

func Read

func Read(filenames ...string) (envMap map[string]string, err error)

Read all env (with same file loading semantics as Load) but return values as a map rather than automatically writing values into env

func Unmarshal

func Unmarshal(str string) (envMap map[string]string, err error)

Unmarshal reads an env file from a string, returning a map of keys and values.

func Write

func Write(envMap map[string]string, filename string) error

Write serializes the given environment and writes it to a file

Types

type Options

type Options struct {
	// Environment keys and values that will be accessible for the service.
	Environment map[string]string
	// TagName specifies another tagname to use rather than the default env.
	TagName string
	// contains filtered or unexported fields
}

Options for the parser.

type ParserFunc

type ParserFunc func(v string) (interface{}, error)

ParserFunc defines the signature of a function that can be used within `CustomParsers`