A KISS way to deal with environment variables in Go.
At first, it was boring for me to write down an entire function just to
get some var
from the environment and default to another in case it's missing.
For that manner, I wrote a GetOr
function in the
go-idioms project.
Then, I got pissed about writing os.Getenv
, os.Setenv
, os.Unsetenv
...
it kind of make more sense to me write it as env.Get
, env.Set
, env.Unset
.
So I did.
Then I got a better idea: to use struct
tags to do all that work for me.
A very basic example (check the examples
folder):
package main
import (
"fmt"
"os"
"github.com/caarlos0/env"
)
type config struct {
Home string `env:"HOME"`
Port int `env:"PORT" envDefault:"3000"`
IsProduction bool `env:"PRODUCTION"`
}
func main() {
os.Setenv("HOME", "/tmp/fakehome")
cfg := config{}
env.Parse(&cfg)
fmt.Println(cfg)
}
You can run it like this:
$ PRODUCTION=true go run examples/first.go
{/tmp/fakehome 3000 true}
Currently we only support string
, bool
and int
.
If you set the envDefault
tag for something, this value will be used in the
case of absence of it in the environment. If you don't do that AND the
environment variable is also not set, the zero-value
of the type will be used: empty for string
s, false
for bool
s
and 0
for int
s.