插件机制

Nirvana 的 Config 除了使用 Configurer 配置基本信息以外，还提供了插件机制。

插件接口：

  1. // ConfigInstaller is used to install config to service builder.
  2. type ConfigInstaller interface {
  3.     // Name is the external config name.
  4.     Name() string
  5.     // Install installs stuffs before server starting.
  6.     Install(builder service.Builder, config *Config) error
  7.     // Uninstall uninstalls stuffs after server terminating.
  8.     Uninstall(builder service.Builder, config *Config) error
  9. }

插件实现了这个接口之后，即可通过 nirvana 包提供的方法进行注册：

  1. func RegisterConfigInstaller(ci ConfigInstaller)

一般情况下，插件应该通过插件 package 的 init() 进行注册。然后提供相应的 Configurer 在 Nirvana 的 Config 中添加插件配置。

Plugin Framework

一个基本的插件框架如下：

  1. func init() {
  2.     // Register your config installer into nirvana.
  3.     nirvana.RegisterConfigInstaller(&pluginInstaller{})
  4. }
  6. // ExternalConfigName is the external config name for your plugin. Please ensure that the
  7. // name is unique and won't conflict with other plugins.
  8. const ExternalConfigName = "pluginName"
  10. type pluginInstaller struct{}
  12. // Name is the external config name.
  13. func (i *pluginInstaller) Name() string {
  14.     return ExternalConfigName
  15. }
  17. // Install installs config to builder. You can get plugin config from nirvana config. Then
  18. // install/initialize what you need.
  19. func (i *pluginInstaller) Install(builder service.Builder, cfg *nirvana.Config) error {...}
  21. // Uninstall uninstalls stuffs after server terminating.
  22. func (i *pluginInstaller) Uninstall(builder service.Builder, cfg *nirvana.Config) error {...)
  24. // ConfigA configures fieldA. Be careful, you should get/save plugin config into nirvana config
  25. // by `c.Config(ExternalConfigName)`/`c.Set(ExternalConfigName, cfg)` rather than a global
  26. // plugin config.
  27. func ConfigA(fieldA FieldType) nirvana.Configurer {...}
  29. // ConfigB configures fieldB.
  30. func ConfigB() nirvana.Configurer {...}
  32. // Disable returns a configurer to disable current plugin for a certain nirvana server.
  33. func Disable() nirvana.Configurer {
  34.     return func(c *nirvana.Config) error {
  35.         // Set to nil will delete plugin config from nirvana config.
  36.         c.Set(ExternalConfigName, nil)
  37.         return nil
  38.     }
  39. }