README
¶
env 
A KISS way to deal with environment variables in Go.
Why
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.
Example
A very basic example (check the examples folder):
package main
import (
"fmt"
"time"
"github.com/caarlos0/env"
)
type config struct {
Home string `env:"HOME"`
Port int `env:"PORT" envDefault:"3000"`
IsProduction bool `env:"PRODUCTION"`
Hosts []string `env:"HOSTS" envSeparator:":"`
Duration time.Duration `env:"DURATION"`
}
func main() {
cfg := config{}
err := env.Parse(&cfg)
if err != nil {
fmt.Printf("%+v\n", err)
}
fmt.Printf("%+v\n", cfg)
}
You can run it like this:
$ PRODUCTION=true HOSTS="host1:host2:host3" DURATION=1s go run examples/first.go
{Home:/your/home Port:3000 IsProduction:true Hosts:[host1 host2 host3] Duration:1s}
Supported types and defaults
The library has support for the following types:
stringintuintint64boolfloat32float64[]string[]int[]bool[]float32[]float64
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 strings, false for bools
and 0 for ints.
By default, slice types will split the environment value on ,; you can change this behavior by setting the envSeparator tag.
Required fields
The env tag option required (e.g., env:"tagKey,required") can be added
to ensure that some environment variable is set. In the example above,
an error is returned if the config struct is changed to:
type config struct {
Home string `env:"HOME"`
Port int `env:"PORT" envDefault:"3000"`
IsProduction bool `env:"PRODUCTION"`
Hosts []string `env:"HOSTS" envSeparator:":"`
SecretKey string `env:"SECRET_KEY,required"`
}
Documentation
¶
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
var ( // ErrNotAStructPtr is returned if you pass something that is not a pointer to a // Struct to Parse ErrNotAStructPtr = errors.New("Expected a pointer to a Struct") // ErrUnsupportedType if the struct field type is not supported by env ErrUnsupportedType = errors.New("Type is not supported") // ErrUnsupportedSliceType if the slice element type is not supported by env ErrUnsupportedSliceType = errors.New("Unsupported slice type") )
Functions ¶
func Parse ¶
func Parse(v interface{}) error
Parse parses a struct containing `env` tags and loads its values from environment variables.
Example ¶
package main
import (
"fmt"
"os"
"github.com/caarlos0/env"
)
func main() {
type config struct {
Home string `env:"HOME"`
Port int `env:"PORT" envDefault:"3000"`
IsProduction bool `env:"PRODUCTION"`
}
os.Setenv("HOME", "/tmp/fakehome")
cfg := config{}
env.Parse(&cfg)
fmt.Println(cfg)
}
Output: {/tmp/fakehome 3000 false}
Types ¶
This section is empty.
Source Files
Directories