432 lines
9.6 KiB
Go
432 lines
9.6 KiB
Go
package rest
|
||
|
||
import (
|
||
"errors"
|
||
"fmt"
|
||
"log"
|
||
"sort"
|
||
"sync"
|
||
"time"
|
||
)
|
||
|
||
//缓存项
|
||
//主要借鉴了cache2go https://github.com/muesli/cache2go
|
||
type CacheItem struct {
|
||
sync.RWMutex //读写锁
|
||
//缓存键
|
||
key interface{}
|
||
//缓存值
|
||
data interface{}
|
||
// 缓存项的生命期
|
||
duration time.Duration
|
||
//创建时间
|
||
createTime time.Time
|
||
//最后访问时间
|
||
accessTime time.Time
|
||
//访问次数
|
||
count int64
|
||
// 在删除缓存项之前调用的回调函数
|
||
deleteCallback func(key interface{})
|
||
}
|
||
|
||
//新建一项缓存
|
||
func NewCacheItem(key interface{}, duration time.Duration, data interface{}) *CacheItem {
|
||
t := time.Now()
|
||
return &CacheItem{
|
||
key: key,
|
||
duration: duration,
|
||
createTime: t,
|
||
accessTime: t,
|
||
count: 0,
|
||
deleteCallback: nil,
|
||
data: data,
|
||
}
|
||
}
|
||
|
||
//手动获取一下，保持该项
|
||
func (item *CacheItem) KeepAlive() {
|
||
item.Lock()
|
||
defer item.Unlock()
|
||
item.accessTime = time.Now()
|
||
item.count++
|
||
}
|
||
|
||
//返回生命周期
|
||
func (item *CacheItem) Duration() time.Duration {
|
||
return item.duration
|
||
}
|
||
|
||
//返回访问时间。可能并发，加锁
|
||
func (item *CacheItem) AccessTime() time.Time {
|
||
item.RLock()
|
||
defer item.RUnlock()
|
||
return item.accessTime
|
||
}
|
||
|
||
//返回创建时间
|
||
func (item *CacheItem) CreateTime() time.Time {
|
||
return item.createTime
|
||
}
|
||
|
||
//返回访问时间。可能并发，加锁
|
||
func (item *CacheItem) Count() int64 {
|
||
item.RLock()
|
||
defer item.RUnlock()
|
||
return item.count
|
||
}
|
||
|
||
//返回key值
|
||
func (item *CacheItem) Key() interface{} {
|
||
return item.key
|
||
}
|
||
|
||
//返回数据
|
||
func (item *CacheItem) Data() interface{} {
|
||
return item.data
|
||
}
|
||
|
||
//设置回调函数
|
||
func (item *CacheItem) SetDeleteCallback(f func(interface{})) {
|
||
item.Lock()
|
||
defer item.Unlock()
|
||
item.deleteCallback = f
|
||
}
|
||
|
||
// 统一管理缓存项的表
|
||
type CacheTable struct {
|
||
sync.RWMutex
|
||
|
||
//缓存表名
|
||
name string
|
||
//所有缓存项
|
||
items map[interface{}]*CacheItem
|
||
// 触发缓存清理的定时器
|
||
cleanupTimer *time.Timer
|
||
// 缓存清理周期
|
||
cleanupInterval time.Duration
|
||
// 该缓存表的日志
|
||
logger *log.Logger
|
||
// 获取一个不存在的缓存项时的回调函数
|
||
loadData func(key interface{}, args ...interface{}) *CacheItem
|
||
// 向缓存表增加缓存项时的回调函数
|
||
addedCallback func(item *CacheItem)
|
||
// 从缓存表删除一个缓存项时的回调函数
|
||
deleteCallback func(item *CacheItem)
|
||
}
|
||
|
||
// 返回缓存中存储有多少项
|
||
func (table *CacheTable) Count() int {
|
||
table.RLock()
|
||
defer table.RUnlock()
|
||
return len(table.items)
|
||
}
|
||
|
||
// 遍历所有项
|
||
func (table *CacheTable) Foreach(trans func(key interface{}, item *CacheItem)) {
|
||
table.RLock()
|
||
defer table.RUnlock()
|
||
|
||
for k, v := range table.items {
|
||
trans(k, v)
|
||
}
|
||
}
|
||
|
||
// SetDataLoader配置一个数据加载的回调，当尝试去请求一个不存在的key的时候调用
|
||
func (table *CacheTable) SetDataLoader(f func(interface{}, ...interface{}) *CacheItem) {
|
||
table.Lock()
|
||
defer table.Unlock()
|
||
table.loadData = f
|
||
}
|
||
|
||
// 添加时的回调函数
|
||
func (table *CacheTable) SetAddedCallback(f func(*CacheItem)) {
|
||
table.Lock()
|
||
defer table.Unlock()
|
||
table.addedCallback = f
|
||
}
|
||
|
||
// 删除时的回调函数
|
||
func (table *CacheTable) SetDeleteCallback(f func(*CacheItem)) {
|
||
table.Lock()
|
||
defer table.Unlock()
|
||
table.deleteCallback = f
|
||
}
|
||
|
||
// 设置缓存表需要使用的log
|
||
func (table *CacheTable) SetLogger(logger *log.Logger) {
|
||
table.Lock()
|
||
defer table.Unlock()
|
||
table.logger = logger
|
||
}
|
||
|
||
//终结检查，被自调整的时间触发
|
||
func (table *CacheTable) checkExpire() {
|
||
table.Lock()
|
||
if table.cleanupTimer != nil {
|
||
table.cleanupTimer.Stop()
|
||
}
|
||
if table.cleanupInterval > 0 {
|
||
table.log("Expiration check triggered after", table.cleanupInterval, "for table", table.name)
|
||
} else {
|
||
table.log("Expiration check installed for table", table.name)
|
||
}
|
||
|
||
// 为了不抢占锁，采用临时的items.
|
||
items := table.items
|
||
table.Unlock()
|
||
|
||
//为了定时器更准确，我们需要在每一个循环中更新‘now’，不确定是否是有效率的。
|
||
now := time.Now()
|
||
smallestDuration := 0 * time.Second
|
||
for key, item := range items {
|
||
// 取出我们需要的东西，为了不抢占锁
|
||
item.RLock()
|
||
duration := item.duration
|
||
accessTime := item.accessTime
|
||
item.RUnlock()
|
||
|
||
// 0永久有效
|
||
if duration == 0 {
|
||
continue
|
||
}
|
||
if now.Sub(accessTime) >= duration {
|
||
//缓存项已经过期
|
||
_, e := table.Delete(key)
|
||
if e != nil {
|
||
table.log("删除缓存项时出错 ", e.Error())
|
||
}
|
||
} else {
|
||
//查找最靠近结束生命周期的项目
|
||
if smallestDuration == 0 || duration-now.Sub(accessTime) < smallestDuration {
|
||
smallestDuration = duration - now.Sub(accessTime)
|
||
}
|
||
}
|
||
}
|
||
|
||
// 为下次清理设置间隔，自触发机制
|
||
table.Lock()
|
||
table.cleanupInterval = smallestDuration
|
||
if smallestDuration > 0 {
|
||
table.cleanupTimer = time.AfterFunc(smallestDuration, func() {
|
||
go table.checkExpire()
|
||
})
|
||
}
|
||
table.Unlock()
|
||
}
|
||
|
||
// 添加缓存项
|
||
func (table *CacheTable) Add(key interface{}, duration time.Duration, data interface{}) *CacheItem {
|
||
item := NewCacheItem(key, duration, data)
|
||
|
||
// 将缓存项放入表中
|
||
table.Lock()
|
||
table.log("Adding item with key", key, "and lifespan of", duration, "to table", table.name)
|
||
table.items[key] = item
|
||
|
||
// 取出需要的东西，释放锁
|
||
expDur := table.cleanupInterval
|
||
addedItem := table.addedCallback
|
||
table.Unlock()
|
||
|
||
// 有回调函数便执行回调
|
||
if addedItem != nil {
|
||
addedItem(item)
|
||
}
|
||
|
||
// 如果我们没有设置任何心跳检查定时器或者找一个即将迫近的项目
|
||
if duration > 0 && (expDur == 0 || duration < expDur) {
|
||
table.checkExpire()
|
||
}
|
||
|
||
return item
|
||
}
|
||
|
||
// 从缓存中删除项
|
||
func (table *CacheTable) Delete(key interface{}) (*CacheItem, error) {
|
||
table.RLock()
|
||
r, ok := table.items[key]
|
||
if !ok {
|
||
table.RUnlock()
|
||
return nil, errors.New(fmt.Sprintf("没有找到%s对应的记录", key))
|
||
}
|
||
|
||
// 取出要用到的东西，释放锁
|
||
deleteCallback := table.deleteCallback
|
||
table.RUnlock()
|
||
|
||
// 调用删除回调函数
|
||
if deleteCallback != nil {
|
||
deleteCallback(r)
|
||
}
|
||
|
||
r.RLock()
|
||
defer r.RUnlock()
|
||
if r.deleteCallback != nil {
|
||
r.deleteCallback(key)
|
||
}
|
||
|
||
table.Lock()
|
||
defer table.Unlock()
|
||
table.log("Deleting item with key", key, "created on", r.createTime, "and hit", r.count, "times from table", table.name)
|
||
delete(table.items, key)
|
||
|
||
return r, nil
|
||
}
|
||
|
||
//单纯的检查某个键是否存在
|
||
func (table *CacheTable) Exists(key interface{}) bool {
|
||
table.RLock()
|
||
defer table.RUnlock()
|
||
_, ok := table.items[key]
|
||
|
||
return ok
|
||
}
|
||
|
||
//如果存在，返回false. 如果不存在,就去添加一个键，并且返回true
|
||
func (table *CacheTable) NotFoundAdd(key interface{}, lifeSpan time.Duration, data interface{}) bool {
|
||
table.Lock()
|
||
|
||
if _, ok := table.items[key]; ok {
|
||
table.Unlock()
|
||
return false
|
||
}
|
||
|
||
item := NewCacheItem(key, lifeSpan, data)
|
||
table.log("Adding item with key", key, "and lifespan of", lifeSpan, "to table", table.name)
|
||
table.items[key] = item
|
||
|
||
// 取出需要的内容，释放锁
|
||
expDur := table.cleanupInterval
|
||
addedItem := table.addedCallback
|
||
table.Unlock()
|
||
|
||
// 添加回调函数
|
||
if addedItem != nil {
|
||
addedItem(item)
|
||
}
|
||
|
||
// 触发过期检查
|
||
if lifeSpan > 0 && (expDur == 0 || lifeSpan < expDur) {
|
||
table.checkExpire()
|
||
}
|
||
return true
|
||
}
|
||
|
||
//从缓存中返回一个被标记的并保持活性的值。你可以传附件的参数到DataLoader回调函数
|
||
func (table *CacheTable) Value(key interface{}, args ...interface{}) (*CacheItem, error) {
|
||
table.RLock()
|
||
r, ok := table.items[key]
|
||
loadData := table.loadData
|
||
table.RUnlock()
|
||
|
||
if ok {
|
||
// 更新访问次数和访问时间
|
||
r.KeepAlive()
|
||
return r, nil
|
||
}
|
||
|
||
// 有加载数据的方式，就通过loadData函数去加载进来
|
||
if loadData != nil {
|
||
item := loadData(key, args...)
|
||
if item != nil {
|
||
table.Add(key, item.duration, item.data)
|
||
return item, nil
|
||
}
|
||
|
||
return nil, errors.New("无法加载到缓存值")
|
||
}
|
||
|
||
return nil, errors.New(fmt.Sprintf("没有找到%s对应的记录", key))
|
||
}
|
||
|
||
// 删除缓存表中的所有项目
|
||
func (table *CacheTable) Flush() {
|
||
table.Lock()
|
||
defer table.Unlock()
|
||
|
||
table.log("Flushing table", table.name)
|
||
|
||
table.items = make(map[interface{}]*CacheItem)
|
||
table.cleanupInterval = 0
|
||
if table.cleanupTimer != nil {
|
||
table.cleanupTimer.Stop()
|
||
}
|
||
}
|
||
|
||
//辅助table中排序，统计的
|
||
type CacheItemPair struct {
|
||
Key interface{}
|
||
AccessCount int64
|
||
}
|
||
|
||
type CacheItemPairList []CacheItemPair
|
||
|
||
func (p CacheItemPairList) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
|
||
func (p CacheItemPairList) Len() int { return len(p) }
|
||
func (p CacheItemPairList) Less(i, j int) bool { return p[i].AccessCount > p[j].AccessCount }
|
||
|
||
// 返回缓存表中被访问最多的项目
|
||
func (table *CacheTable) MostAccessed(count int64) []*CacheItem {
|
||
table.RLock()
|
||
defer table.RUnlock()
|
||
|
||
p := make(CacheItemPairList, len(table.items))
|
||
i := 0
|
||
for k, v := range table.items {
|
||
p[i] = CacheItemPair{k, v.count}
|
||
i++
|
||
}
|
||
sort.Sort(p)
|
||
|
||
var r []*CacheItem
|
||
c := int64(0)
|
||
for _, v := range p {
|
||
if c >= count {
|
||
break
|
||
}
|
||
|
||
item, ok := table.items[v.Key]
|
||
if ok {
|
||
r = append(r, item)
|
||
}
|
||
c++
|
||
}
|
||
|
||
return r
|
||
}
|
||
|
||
// 打印日志
|
||
func (table *CacheTable) log(v ...interface{}) {
|
||
if table.logger == nil {
|
||
fmt.Println(v...)
|
||
return
|
||
}
|
||
|
||
table.logger.Println(v...)
|
||
}
|
||
|
||
var (
|
||
cacheTableMap = make(map[string]*CacheTable)
|
||
cacheTableMutex sync.RWMutex
|
||
)
|
||
|
||
//统一管理所有的缓存表，如果没有就返回一个新的。
|
||
func Cache(table string) *CacheTable {
|
||
cacheTableMutex.RLock()
|
||
t, ok := cacheTableMap[table]
|
||
cacheTableMutex.RUnlock()
|
||
|
||
if !ok {
|
||
t = &CacheTable{
|
||
name: table,
|
||
items: make(map[interface{}]*CacheItem),
|
||
}
|
||
|
||
cacheTableMutex.Lock()
|
||
cacheTableMap[table] = t
|
||
cacheTableMutex.Unlock()
|
||
}
|
||
|
||
return t
|
||
}
|