flutter-config

Flavor Architecture

• Define three flavors: dev, staging, prod
• Use a single main.dart entry point for all flavors
• Pass flavor-specific configuration via --dart-define-from-file:

  flutter run --flavor dev --dart-define-from-file=config/dev.json
  flutter run --flavor staging --dart-define-from-file=config/staging.json
  flutter run --flavor prod --dart-define-from-file=config/prod.json
  

• NEVER create separate main_dev.dart, main_staging.dart, main_prod.dart entry points

Config JSON Structure

• Store per-flavor JSON config files in a config/ directory at project root:

  config/
  ├── dev.json
  ├── staging.json
  └── prod.json
  

• Example config/dev.json:

  {
    "FLAVOR": "dev",
    "BASE_URL": "https://api-dev.example.com",
    "APP_NAME": "MyApp Dev",
    "ENABLE_LOGGING": "true",
    "ENABLE_CRASHLYTICS": "false"
  }
  

• NEVER put secrets (API keys, signing credentials) in these JSON files: use CI-injected env vars or flutter_secure_storage
• Add config/*.json to .gitignore if they contain any environment-specific secrets; otherwise commit them for team convenience

Entry Point Pattern

// lib/main.dart
void main() {
  const flavor = String.fromEnvironment('FLAVOR', defaultValue: 'dev');
  AppConfig.init(flavor: Flavor.fromString(flavor));
  runApp(const App());
}

• Read all compile-time values via String.fromEnvironment('KEY') or bool.fromEnvironment('KEY')
• Use a sealed Flavor enum: sealed class Flavor { dev, staging, prod }
• AppConfig is a singleton holding flavor, base URL, feature flags, and Firebase config

Environment Configuration

• Store per-flavor config in a centralized AppConfig class:
  • baseUrl: API endpoint per environment
  • enableLogging: verbose logging for dev only
  • enableCrashlytics: disabled in dev
  • appName: display name per flavor (e.g., "MyApp Dev", "MyApp")
• All values come from the JSON file via --dart-define-from-file: NO hardcoded per-flavor logic in Dart code
• NEVER put secrets in the JSON config files: use flutter_secure_storage or CI-injected env vars