A low dependency package for .env files (or just environment variables).
go get github.com/h-dav/envconfigCode:
package main
import (
"fmt"
"log"
"path/filepath"
"github.com/h-dav/envconfig"
)
// ExampleConfig is your config struct using `env` struct tags.
type ExampleConfig struct {
Example string `env:"EXAMPLE,required"`
AnotherValue string `env:"ANOTHER_VALUE"`
IntExample int `env:"INT_EXAMPLE"`
Int32Example int32 `env:"INT32_EXAMPLE"`
FloatExample float64 `env:"FLOAT_EXAMPLE"`
Service struct {
Port int64 `env:"PORT"`
Name string `env:"NAME,required"`
} `env:"prefix=HTTP_"`
ExampleEndpoint string `env:"EXAMPLE_ENDPOINT"`
DefaultValue string `env:"DEFAULT_VALUE,default=thevalue"`
}
func main() {
cfg := ExampleConfig{}
if err := envconfig.SetPopulate(filepath.Join("config", "example.env"), &cfg); err != nil {
log.Fatal(err)
}
fmt.Printf("Populated Config: %+v\n", cfg)
}.env file:
EXAMPLE=value
ANOTHER_VALUE=v0.0.0
INT_EXAMPLE=4
INT32_EXAMPLE=23
#COMMENTED_EXAMPLE=test
FLOAT_EXAMPLE=4.44
HTTP_PORT=9999
HTTP_NAME=example_name
DNS=example.com
EXAMPLE_ENDPOINT=https://${DNS}/v1
Output:
Populated Config: {Example:value AnotherValue:v0.0.0 IntExample:4 Int32Example:23 FloatExample:4.44 Service:{Port:9999 Name:example_name} ExampleEndpoint:https://example.com/v1 DefaultValue:thevalue}
Code:
...
if err := envconfig.SetVars(filepath.Join("examples", "example.env")); err != nil {
panic(err)
}
...Code:
...
type ExampleConfig struct {
Example string `env:"EXAMPLE,required"`
AnotherValue string `env:"ANOTHER_VALUE"`
IntExample int `env:"INT_EXAMPLE"`
Int32Example int32 `env:"INT32_EXAMPLE"`
FloatExample float64 `env:"FLOAT_EXAMPLE"`
Service struct {
Port int64 `env:"PORT"`
Name string `env:"NAME,required"`
} `env:"prefix=HTTP_"`
ExampleEndpoint string `env:"EXAMPLE_ENDPOINT"`
DefaultValue string `env:"DEFAULT_VALUE,default=thevalue"`
}
cfg := ExampleConfig{}
if err := envconfig.Populate(&cfg); err != nil {
panic(err)
}
...| Tag Option | Type | Example |
|---|---|---|
| default | assignment | env:"KEY,default=dval" |
| prefix | assignment | env:"prefix=pstruct_" |
| required | flag | env:"KEYNAME,required" |
- Int, Int32, Int64
- String
- Float64
