Envconfig: Parse the configuration from environment variables

'github.com/vrischmann/envconfig' allows you to read the configuraition from environment variables.

Step 1: Create a structure that can hold all the configuration values.

var conf struct {

         Admin struct {

                  UserName string `envconfig:"default=Krishna"`

                  PassWord string `envconfig:"default=admin123"`

         }

         BaseURL string `envconfig:"default=abc.com"`

}

As you see above struct, It is holding Admin details and BaseURL to connect to.  If the values are not presented in environment, it can take the default values provided in the struct.

Whenever you want to get the configurations from conf object, it checks for below keys in the environment.

BaseURL or baseurl

ADMIN_USERNAME, or admin_username

ADMIN_PASSWORD, or admin_password

Step 2: Set the Environment variables.

os.Setenv("ADMIN_USERNAME", "admin")

os.Setenv("ADMIN_PASSWORD", "password123")

if err := envconfig.Init(&conf); err != nil {

         fmt.Printf("err=%s\n", err)

}

Step 3: Now whenever you access the configuration values, you can get the values that are set in os environment, if no value set, then you will get the default value.

fmt.Println("User Name : ", conf.Admin.UserName)

fmt.Println("Password : ", conf.Admin.Password)

fmt.Println("Base URL", conf.BaseURL)

App.go

package main

import (
 "fmt"
 "os"

 "github.com/vrischmann/envconfig"
)

var conf struct {
 Admin struct {
  UserName string `envconfig:"default=Krishna"`
  Password string `envconfig:"default=admin123"`
 }

 BaseURL string `envconfig:"default=abc.com"`
}

func main() {
 os.Setenv("ADMIN_USERNAME", "admin")
 os.Setenv("ADMIN_PASSWORD", "password123")

 if err := envconfig.Init(&conf); err != nil {
  fmt.Printf("err=%s\n", err)
 }

 fmt.Println("User Name : ", conf.Admin.UserName)
 fmt.Println("Password : ", conf.Admin.Password)
 fmt.Println("Base URL", conf.BaseURL)

}

Output

User Name :  admin

Password :  password123

Base URL abc.com