beego源码解析之cache

Posted 2021-06-26 better_hui

目录

使用

cache顶级接口

register

实例化

---

 

cache目前支持memory、file、redis、memcache，这种引擎模式，下文基于memory引擎

使用

import (
    "github.com/astaxie/beego/cache"
)
bm, err := cache.NewCache("memory", `{"interval":60}`)
bm.Put("astaxie", 1, 10*time.Second)

 

cache顶级接口

type Cache interface {
   // get cached value by key.
   Get(key string) interface{}
   // GetMulti is a batch version of Get.
   GetMulti(keys []string) []interface{}
   // set cached value with key and expire time.
   Put(key string, val interface{}, timeout time.Duration) error
   // delete cached value by key.
   Delete(key string) error
   // increase cached int value by key, as a counter.
   Incr(key string) error
   // decrease cached int value by key, as a counter.
   Decr(key string) error
   // check if cached value exists or not.
   IsExist(key string) bool
   // clear all cache.
   ClearAll() error
   // start gc routine based on config string settings.
   StartAndGC(config string) error
}
​
//基于内存的cache实现
type MemoryCache struct {
    sync.RWMutex
    dur   time.Duration
    items map[string]*MemoryItem
    Every int // run an expiration check Every clock time
}

 

register

注册的方法，可以自定义缓存的实现。

//定义一个函数类型,自定义的缓存需要实现这样的函数 给注册函数
type Instance func() Cache
//缓存adapter集合
var adapters = make(map[string]Instance)
//缓存adapter注册
func Register(name string, adapter Instance) {
   if adapter == nil {
      panic("cache: Register adapter is nil")
   }
   if _, ok := adapters[name]; ok {
      panic("cache: Register called twice for adapter " + name)
   }
   adapters[name] = adapter
}

 

实例化

func NewCache(adapterName, config string) (adapter Cache, err error) {
   //根据类型获取转换器 , 这个转换器就是上文 type Instance func() Cache ，这个的具体实现，其返回一个cache
   instanceFunc, ok := adapters[adapterName]
   if !ok {
      err = fmt.Errorf("cache: unknown adapter name %q (forgot to import?)", adapterName)
      return
   }
   adapter = instanceFunc()
   //开启缓存和GC 
   err = adapter.StartAndGC(config)
   if err != nil {
      adapter = nil
   }
   return
}
​
func (bc *MemoryCache) StartAndGC(config string) error {
    var cf map[string]int
    json.Unmarshal([]byte(config), &cf)
    if _, ok := cf["interval"]; !ok {
        cf = make(map[string]int)
        cf["interval"] = DefaultEvery
    }
    dur := time.Duration(cf["interval"]) * time.Second
    bc.Every = cf["interval"]
    bc.dur = dur
    go bc.vaccuum()
    return nil
}
​