kubernetes/vendor/github.com/sirupsen/logrus/hooks.go

type Hook …

type LevelHooks …

// Add a hook to an instance of logger. This is called with
// `log.Hooks.Add(new(MyHook))` where `MyHook` implements the `Hook` interface.
func (hooks LevelHooks) Add(hook Hook) { … }

// Fire all the hooks for the passed level. Used by `entry.log` to fire
// appropriate hooks for a log entry.
func (hooks LevelHooks) Fire(level Level, entry *Entry) error { … }