Hook

实现方式

Overview

hooked 通过匿名包含 zapcore.Core 实例，直接满足 zapcore.Core 接口。通过覆盖特定方法，实现 hook 方法写日志的功能。

结构与注册

hooked 定义

type hooked struct {
    Core // 匿名包含，直接实现接口方法的继承
    funcs []func(Entry) error
}

hook 注册

func RegisterHooks(core Core, hooks ...func(Entry) error) Core {
    funcs := append([]func(Entry) error{}, hooks...) // 直接创建 hook 切片，并追加
    return &hooked{
        Core:  core,
        funcs: funcs,
    }
}

复写关键方法

With

func (h *hooked) With(fields []Field) Core {
    return &hooked{
        Core:  h.Core.With(fields), // 代理
        funcs: h.funcs,
    }
}

Check

func (h *hooked) Check(ent Entry, ce *CheckedEntry) *CheckedEntry {
    // Let the wrapped Core decide whether to log this message or not. This
    // also gives the downstream a chance to register itself directly with the
    // CheckedEntry.
    if downstream := h.Core.Check(ent, ce); downstream != nil {
        return downstream.AddCore(ent, h)
    }
    return ce
}

Write

func (h *hooked) Write(ent Entry, _ []Field) error {
    // Since our downstream had a chance to register itself directly with the
    // CheckedMessage, we don't need to call it here.
    var err error
    for i := range h.funcs {
        err = multierr.Append(err, h.funcs[i](ent))
    }
    return err
}