Config Setup

Dokumentasi setup konfigurasi aplikasi.

Overview

Package config mengelola konfigurasi aplikasi menggunakan Viper untuk membaca environment variables dari file .env.

Configuration Struct

type Configuration struct {
    Server   ServerConfiguration
    Database DatabaseConfiguration
    BaseURL  string
}

SetupConfig

Membaca dan parse file .env.

func SetupConfig() error

Implementation

func SetupConfig() error {
    var configuration *Configuration

    viper.SetConfigFile(".env")
    if err := viper.ReadInConfig(); err != nil {
        logger.Errorf("Error to reading config file, %s", err)
        return err
    }

    err := viper.Unmarshal(&configuration)
    if err != nil {
        logger.Errorf("error to decode, %v", err)
        return err
    }

    return nil
}

Usage

Initialize Config

func main() {
    // Setup configuration first
    if err := config.SetupConfig(); err != nil {
        log.Fatal("Failed to load configuration")
    }
    
    // Now you can use viper to get config values
    appEnv := viper.GetString("APP_ENV")
    serverPort := viper.GetString("SERVER_PORT")
    
    // ...
}

Accessing Config Values

Gunakan Viper untuk mengakses nilai konfigurasi:

// String
appEnv := viper.GetString("APP_ENV")
serverHost := viper.GetString("SERVER_HOST")

// Integer
serverPort := viper.GetInt("SERVER_PORT")

// Boolean
debugMode := viper.GetBool("DEBUG")
dbLogMode := viper.GetBool("DB_LOG_MODE")

// With Default
port := viper.GetString("SERVER_PORT")
if port == "" {
    port = "8000"
}

File .env

Format

# Comments start with #
KEY=value
KEY_WITH_SPACES="value with spaces"

Example

# Application
APP_ENV=development
DEBUG=true

# Server
SERVER_HOST=0.0.0.0
SERVER_PORT=8000

# Database Master
MASTER_DB_HOST=localhost
MASTER_DB_PORT=5432
MASTER_DB_NAME=sisappra
MASTER_DB_USER=postgres
MASTER_DB_PASSWORD=secret
MASTER_SSL_MODE=disable

# Services
SERVER_API_GATEWAY=http://localhost:8000
SERVER_SERVICE_MASTER_DATA=http://localhost:8001

Error Handling

if err := config.SetupConfig(); err != nil {
    if _, ok := err.(viper.ConfigFileNotFoundError); ok {
        log.Fatal(".env file not found. Please create one from .env.example")
    }
    log.Fatalf("Failed to read config: %v", err)
}

Best Practices

1. Never commit .env - Tambahkan ke .gitignore

   .env
   .env.local
   .env.*.local

2. Provide .env.example - Template tanpa nilai sensitif

   APP_ENV=development
   SERVER_PORT=8000
   MASTER_DB_PASSWORD=your_password_here

3. Validate Required Config

   func validateConfig() error {
       required := []string{
           "MASTER_DB_HOST",
           "MASTER_DB_USER",
           "MASTER_DB_PASSWORD",
       }
       
       for _, key := range required {
           if viper.GetString(key) == "" {
               return fmt.Errorf("required config %s is missing", key)
           }
       }
       return nil
   }

4. Use Defaults

   viper.SetDefault("SERVER_HOST", "0.0.0.0")
   viper.SetDefault("SERVER_PORT", "8000")
   viper.SetDefault("APP_ENV", "development")

Configuration Hierarchy

Viper mendukung multiple config sources dengan prioritas:

1. Explicit Set - viper.Set("key", "value")
2. Flags - Command line flags
3. Environment Variables - OS environment
4. Config File - .env file
5. Key/Value Store - Consul, etcd
6. Defaults - viper.SetDefault()

Environment-Specific Config

func LoadEnvConfig() {
    env := os.Getenv("APP_ENV")
    
    switch env {
    case "production":
        viper.SetConfigFile(".env.production")
    case "staging":
        viper.SetConfigFile(".env.staging")
    default:
        viper.SetConfigFile(".env")
    }
    
    viper.ReadInConfig()
}