Environment Variable Nested Pointer Struct Unpopulated

[justmumu]

Hi friends,

I have configuration struct like below,

type Config struct {
    Encryption *Encryption `mapstructure:"encryption" yaml:"encryption,omitempty" validate:"required"`
}

type Encryption struct {
    EncryptionKey string `mapstructure:"encryption_key" yaml:"encryption_key,omitempty" validate:"required,len=32"`
    PrivateKey    string `mapstructure:"private_key" yaml:"private_key,omitempty" validate:"required,base64"`
}

I configured my viper instance to read from env. To do that i wrote something like below,

vv := viper.New()
vv.AutomaticEnv()
vv.SetEnvPrefix("APP_NAME")
vv.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
vv.AllowEmptyEnv(false)

It works and fills keys in viper.
For example,

os.Setenv("APP_NAME_ENCRYPTION_ENCRYPTION_KEY", "ThisIsTheKey")
fmt.Println(vv.Get("encryption.encryption_key"))
// Output
ThisIsTheKey

OR

os.Setenv("APP_NAME_ENCRYPTION_PRIVATE_KEY", "ThisIsThePrivate")
fmt.Println(vv.Get("encryption.private_key"))
// Output
ThisIsThePrivate

But when i unmarshal to struct Encryption is nil. It is not populated.

config := &Config{}
if err := vv.Unmarshal(config); err != nil {
		return nil, err
}
fmt.Println(config.Encrption)
// Output
<nil>

Has anyone faced this issue?
Thank you.

[justmumu]

See my answer on related issue.