# 体现"高内聚、低耦合"思想的模块结构
api/configs/
├── feature/        # 功能特性配置 - 业务逻辑配置
├── middleware/     # 中间件配置 - 基础设施配置
├── deploy/         # 部署配置 - 环境相关配置
├── enterprise/     # 企业版配置 - 商业化扩展
└── remote_sources/ # 远程配置源 - 配置管理扩展

# 体现"类型安全"和"自文档化"思想
class DatabaseConfig(BaseSettings):
    DB_HOST: str = Field(
        description="数据库服务器地址",
        default="localhost",
    )
    
    @computed_field
    def SQLALCHEMY_DATABASE_URI(self) -> str:
        """动态计算属性 - 避免配置冗余"""
        return f"postgresql://{self.DB_USERNAME}:{self.DB_PASSWORD}@{self.DB_HOST}:{self.DB_PORT}/{self.DB_DATABASE}"

# 体现"策略模式"和"责任链模式"思想
class DifyConfig(BaseSettings):
    @classmethod
    def settings_customise_sources(cls, ...):
        return (
            init_settings,                    # 1. 程序参数
            env_settings,                     # 2. 环境变量
            RemoteSettingsSourceFactory(...), # 3. 远程配置中心
            dotenv_settings,                  # 4. .env 文件
            file_secret_settings,             # 5. 密钥文件
        )

# 体现"工厂模式"和"接口隔离"思想
class RemoteSettingsSourceFactory:
    def __call__(self) -> dict[str, Any]:
        remote_source_name = self.current_state.get("REMOTE_SETTINGS_SOURCE_NAME")
        
        # 工厂方法模式 - 根据配置动态创建配置源
        match remote_source_name:
            case RemoteSettingsSourceName.APOLLO:
                remote_source = ApolloSettingsSource(self.current_state)
            case RemoteSettingsSourceName.NACOS:
                remote_source = NacosSettingsSource(self.current_state)
            case _:
                return {}
        
        return self._load_from_remote_source(remote_source)

# 体现"面向接口编程"思想
class RemoteSettingsSource(ABC):
    @abstractmethod
    def get_field_value(self, field: FieldInfo, field_name: str) -> tuple[Any, str, bool]:
        """获取配置字段值的统一接口"""
        pass
    
    def prepare_field_value(self, field_name: str, field: FieldInfo, value: Any, value_is_complex: bool) -> Any:
        """配置值预处理的模板方法"""
        return value

# 体现"基础设施即代码"思想
apiVersion: v1
kind: ConfigMap
metadata:
  name: dify-config
data:
  # 环境隔离配置
  DEPLOY_ENV: "PRODUCTION"
  # 服务发现配置
  DB_HOST: "postgres-service.database.svc.cluster.local"
  # 远程配置中心
  REMOTE_SETTINGS_SOURCE_NAME: "apollo"
  APOLLO_CONFIG_URL: "http://apollo-config:8080"

# 体现"安全第一"思想
apiVersion: v1
kind: Secret
metadata:
  name: dify-secrets
type: Opaque
data:
  db-password: <base64-encoded>
  api-keys: <base64-encoded>

# 在二次开发中的实际应用
class EnterpriseConfig(BaseSettings):
    # 企业级功能开关
    ENTERPRISE_SSO_ENABLED: bool = Field(default=False, description="企业SSO集成")
    ENTERPRISE_AUDIT_ENABLED: bool = Field(default=True, description="操作审计")
    
    # 自定义业务配置
    CUSTOM_WORKFLOW_LIMIT: int = Field(default=100, description="自定义工作流限制")
    CUSTOM_MODEL_PROVIDERS: list[str] = Field(default_factory=list, description="自定义模型提供商")

# Apollo配置热更新实现
class ApolloClient:
    def _start_hot_update(self):
        """启动配置热更新 - 体现"实时响应"思想"""
        self._long_poll_thread = threading.Thread(target=self._long_poll)
        self._long_poll_thread.daemon = True
        self._long_poll_thread.start()
    
    def _handle_config_change(self, notifications):
        """配置变更处理 - 体现"事件驱动"思想"""
        for notification in notifications:
            self._reload_config(notification.get("namespaceName"))