README
¶
CCache 一个LRU缓存，专注于支持高并发
CCache 是一个用 Go 语言编写的 LRU 缓存，专注于支持高并发。
通过以下方式减少对列表的锁竞争：
- 引入一个窗口来限制项目被提升的频率
- 使用缓冲通道来为单个工作者排队处理提升操作
- 在同一个工作者线程中进行垃圾回收
除非另有说明，所有方法都是线程安全的。
配置
基础配置
导入并创建一个 Cache 实例：
import (
"github.com/darkit/ccache"
)
// 创建一个存储字符串值的缓存
var cache = ccache.New(ccache.Configure[string]())
Configure 提供了链式 API：
// 创建一个存储整数值的缓存
var cache = ccache.New(ccache.Configure[int]().MaxSize(1000).ItemsToPrune(100))
配置选项
最可能需要调整的配置选项是：
MaxSize(int)- 缓存中存储的最大项目数（默认：10000）GetsPerPromote(int)- 在提升一个项目之前被获取的次数（默认：3）ItemsToPrune(int)- 当达到MaxSize时要清理的项目数量（默认：1000）
改变缓存内部结构的配置，通常不需要调整：
Buckets- ccache 对其内部映射进行分片以提供更高的并发性（默认：16）PromoteBuffer(int)- 用于队列提升操作的缓冲区大小（默认：1024）DeleteBuffer(int)- 用于队列删除操作的缓冲区大小（默认：1024）
基本操作
Get
获取缓存中的值：
item := cache.Get("user:4")
if item == nil {
//处理空值情况
} else {
user := item.Value()
}
返回的 *Item 提供了几个方法：
Value() T- 缓存的值Expired() bool- 项目是否已过期TTL() time.Duration- 项目过期前的持续时间Expires() time.Time- 项目将要过期的时间
Set
设置缓存值：
cache.Set("user:4", user, time.Minute * 10)
Delete
删除缓存值：
cache.Delete("user:4")
Has
检查键是否存在：
value, exists := cache.Has("user:4")
if exists {
// 使用 value
} else {
// 处理不存在的情况
}
高级操作
Fetch
智能获取或设置缓存值：
item, err := cache.Fetch("user:4", time.Minute * 10, func() (*User, error) {
// 缓存未命中时执行
user, err := db.GetUser(4)
if err != nil {
return nil, err
}
return user, nil
})
GetMulti/SetMulti
批量操作：
// 批量获取
items := cache.GetMulti([]string{"user:1", "user:2", "user:3"})
// 批量设置
items := map[string]string{
"user:1": "value1",
"user:2": "value2",
}
cache.SetMulti(items, time.Minute*10)
PushSlice/PushMap
向切片、Map类型的缓存追加值：
// 设置初始切片
cache.Set("numbers", []int{1, 2, 3}, time.Minute)
// 追加新的值
err := cache.PushSlice("numbers", []int{4}, time.Minute)
if err != nil {
// 处理错误
}
// 设置初始切片
cache.Set("map_numbers", map[string]int{"a": 1, "b": 2}, time.Minute)
// 追加新的值
err := cache.PushMap("map_numbers", map[string]int{"c": 3, "d": 4}, time.Minute)
if err != nil {
// 处理错误
}
Extend/Touch
更新缓存项的过期时间。两个方法的主要区别在于是否影响缓存项在 LRU 链表中的位置：
// 使用 Extend - 仅更新过期时间，不改变缓存项在 LRU 中的位置
success := cache.Extend("user:4", time.Minute * 10)
// 使用 Touch - 更新过期时间，同时将缓存项移动到 LRU 链表前端
success := cache.Touch("user:4", time.Minute * 10)
选择建议：
- 使用
Extend：当只需要延长过期时间，不需要改变访问频率时 - 使用
Touch：当需要同时更新过期时间和访问状态时
注意：两个方法都返回 bool 值表示操作是否成功（键是否存在）。
Replace
更新值但保持TTL：
cache.Replace("user:4", user)
SetIfNotExists/SetIfNotExistsWithFunc
两种方式设置不存在的键值：
// 方式1：直接设置值
cache.SetIfNotExists("key", "value", time.Minute)
// 方式2：通过函数生成值（延迟计算）
item := cache.SetIfNotExistsWithFunc("key", func() string {
// 只在键不存在时才会执行
return expensiveOperation()
}, time.Minute)
两者的区别：
SetIfNotExists：直接传入值，简单直观SetIfNotExistsWithFunc：- 传入函数来生成值
- 只在键不存在时才会执行函数
- 适合值的计算成本较高的场景
- 返回设置的缓存项
注意：SetIfNotExistsWithFunc 在并发场景下更高效，因为它避免了不必要的值计算。
Inc/Dec
数值增减：
newVal, err := cache.Inc("counter", 1)
if err != nil {
// 处理错误
}
newVal, err = cache.Dec("counter", 1)
if err != nil {
// 处理错误
}
监控和管理
GetDropped
获取被驱逐的键数量：
dropped := cache.GetDropped()
Stop
停止缓存的后台工作进程：
cache.Stop()
特殊功能
追踪模式
CCache 支持特殊的追踪模式，主要用于与代码中需要维护数据长期引用的其他部分配合使用。
使用 Track() 配置追踪模式：
cache = ccache.New(ccache.Configure[int]().Track())
通过 TrackingGet 获取的项目在调用 Release 之前不会被清除：
item := cache.TrackingGet("user:4")
user := item.Value() // 如果缓存中没有 "user:4"，将返回 nil
item.Release() // 即使 item.Value() 返回 nil 也可以调用
追踪模式的主要优势：
Release通常在代码的其他地方延迟调用- 可以使用
TrackingSet设置需要追踪的值 - 有助于确保系统返回一致的数据
- 适合其他代码部分也持有对象引用的场景
分层缓存（LayeredCache）
LayeredCache 提供了通过主键和次键来存储和检索值的能力。它特别适合需要管理数据多个变体的场景，如 HTTP 缓存。
主要特点：
- 支持主键和次键的组合
- 可以针对特定键或主键下所有值进行删除
- 使用与主缓存相同的配置
- 支持可选的追踪功能
使用示例：
cache := ccache.Layered(ccache.Configure[string]())
// 设置不同格式的数据
cache.Set("/users/goku", "type:json", "{value_to_cache}", time.Minute * 5)
cache.Set("/users/goku", "type:xml", "<value_to_cache>", time.Minute * 5)
// 获取特定格式
json := cache.Get("/users/goku", "type:json")
xml := cache.Get("/users/goku", "type:xml")
// 删除操作
cache.Delete("/users/goku", "type:json") // 删除特定格式
cache.DeleteAll("/users/goku") // 删除所有格式
二级缓存（SecondaryCache）
当使用 LayeredCache 时，有时需要频繁操作某个主键下的缓存条目。SecondaryCache 提供了这种便利性：
cache := ccache.Layered(ccache.Configure[string]())
sCache := cache.GetOrCreateSecondaryCache("/users/goku")
sCache.Set("type:json", "{value_to_cache}", time.Minute * 5)
特点：
- 与普通
Cache的操作方式相同 Get操作不返回 nil，而是返回空缓存- 简化了对特定主键数据的操作
大小控制
缓存项目的大小管理：
- 默认每个项目大小为 1
- 如果值实现了
Size() int64方法，将使用该方法返回的大小 - 每个缓存条目有约 350 字节的额外开销（不计入大小限制）
示例：
- 配置
MaxSize(10000)可存储 10000 个默认大小的项目 - 对于实现了
Size() int64的项目，实际存储数量 = MaxSize/项目大小
许可证
MIT License - 查看 LICENSE 文件了解详情。
Documentation
¶
Overview ¶
An LRU cached aimed at high concurrency
An LRU cached aimed at high concurrency
Index ¶
- type Cache
- func (c Cache) Clear()
- func (c *Cache[T]) Dec(key string, delta int64) (int64, error)
- func (c *Cache[T]) Delete(key string) bool
- func (c *Cache[T]) DeleteFunc(matches func(key string, item *Item[T]) bool) int
- func (c *Cache[T]) DeletePrefix(prefix string) int
- func (c *Cache[T]) Extend(key string, duration time.Duration) bool
- func (c *Cache[T]) Fetch(key string, duration time.Duration, fetch func() (T, error)) (*Item[T], error)
- func (c *Cache[T]) ForEachFunc(matches func(key string, item *Item[T]) bool)
- func (c Cache) GC()
- func (c *Cache[T]) Get(key string) *Item[T]
- func (c Cache) GetDropped() int
- func (c *Cache[T]) GetMulti(keys []string) map[string]*Item[T]
- func (c Cache) GetSize() int64
- func (c *Cache[T]) GetWithoutPromote(key string) *Item[T]
- func (c *Cache[T]) Has(key string) (T, bool)
- func (c *Cache[T]) Inc(key string, delta int64) (int64, error)
- func (c *Cache[T]) ItemCount() int
- func (c *Cache[T]) Pull(key string) *Item[T]
- func (c *Cache[T]) PushMap(key string, values T, duration time.Duration) error
- func (c *Cache[T]) PushSlice(key string, values T, duration time.Duration) error
- func (c *Cache[T]) Replace(key string, value T) bool
- func (c *Cache[T]) Set(key string, value T, duration time.Duration)
- func (c *Cache[T]) SetIfNotExists(key string, value T, duration time.Duration)
- func (c *Cache[T]) SetIfNotExistsWithFunc(key string, f func() T, duration time.Duration) *Item[T]
- func (c Cache) SetMaxSize(size int64)
- func (c *Cache[T]) SetMulti(items map[string]T, duration time.Duration)
- func (c Cache) Stop()
- func (c Cache) SyncUpdates()
- func (c *Cache[T]) Touch(key string, duration time.Duration) bool
- func (c *Cache[T]) TrackingGet(key string) TrackedItem[T]
- func (c *Cache[T]) TrackingSet(key string, value T, duration time.Duration) TrackedItem[T]
- type Configuration
- func (c *Configuration[T]) Buckets(count uint32) *Configuration[T]
- func (c *Configuration[T]) DeleteBuffer(size uint32) *Configuration[T]
- func (c *Configuration[T]) GetsPerPromote(count int32) *Configuration[T]
- func (c *Configuration[T]) ItemsToPrune(count uint32) *Configuration[T]
- func (c *Configuration[T]) MaxSize(max int64) *Configuration[T]
- func (c *Configuration[T]) OnDelete(callback func(item *Item[T])) *Configuration[T]
- func (c *Configuration[T]) PromoteBuffer(size uint32) *Configuration[T]
- func (c *Configuration[T]) Track() *Configuration[T]
- type Item
- type LayeredCache
- func (c LayeredCache) Clear()
- func (c *LayeredCache[T]) Delete(primary, secondary string) bool
- func (c *LayeredCache[T]) DeleteAll(primary string) bool
- func (c *LayeredCache[T]) DeleteFunc(primary string, matches func(key string, item *Item[T]) bool) int
- func (c *LayeredCache[T]) DeletePrefix(primary, prefix string) int
- func (c *LayeredCache[T]) Fetch(primary, secondary string, duration time.Duration, fetch func() (T, error)) (*Item[T], error)
- func (c *LayeredCache[T]) ForEachFunc(primary string, matches func(key string, item *Item[T]) bool)
- func (c LayeredCache) GC()
- func (c *LayeredCache[T]) Get(primary, secondary string) *Item[T]
- func (c LayeredCache) GetDropped() int
- func (c *LayeredCache[T]) GetOrCreateSecondaryCache(primary string) *SecondaryCache[T]
- func (c LayeredCache) GetSize() int64
- func (c *LayeredCache[T]) GetWithoutPromote(primary, secondary string) *Item[T]
- func (c *LayeredCache[T]) Has(primary, secondary string) (bool, T)
- func (c *LayeredCache[T]) ItemCount() int
- func (c *LayeredCache[T]) Replace(primary, secondary string, value T) bool
- func (c *LayeredCache[T]) Set(primary, secondary string, value T, duration time.Duration)
- func (c LayeredCache) SetMaxSize(size int64)
- func (c LayeredCache) Stop()
- func (c LayeredCache) SyncUpdates()
- func (c *LayeredCache[T]) TrackingGet(primary, secondary string) TrackedItem[T]
- func (c *LayeredCache[T]) TrackingSet(primary, secondary string, value T, duration time.Duration) TrackedItem[T]
- type List
- type SecondaryCache
- func (s *SecondaryCache[T]) Delete(secondary string) bool
- func (s *SecondaryCache[T]) Fetch(secondary string, duration time.Duration, fetch func() (T, error)) (*Item[T], error)
- func (s *SecondaryCache[T]) Get(secondary string) *Item[T]
- func (s *SecondaryCache[T]) Has(secondary string) (bool, T)
- func (s *SecondaryCache[T]) Replace(secondary string, value T) bool
- func (s *SecondaryCache[T]) Set(secondary string, value T, duration time.Duration) *Item[T]
- func (c *SecondaryCache[T]) TrackingGet(secondary string) TrackedItem[T]
- type Sized
- type TrackedItem
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Cache ¶
type Cache[T any] struct { *Configuration[T] // contains filtered or unexported fields }
func New ¶
func New[T any](config *Configuration[T]) *Cache[T]
Create a new cache with the specified configuration See ccache.Configure() for creating a configuration
func (*Cache[T]) Dec ¶
Dec decreases the value of key by delta. Returns error if value is not integer
func (*Cache[T]) Delete ¶
Remove the item from the cache, return true if the item was present, false otherwise.
func (*Cache[T]) DeleteFunc ¶
Deletes all items that the matches func evaluates to true.
func (*Cache[T]) DeletePrefix ¶
func (*Cache[T]) Extend ¶
Extend the value if it exists, does not set if it doesn't exists. Returns true if the expire time of the item an was extended, false otherwise.
func (*Cache[T]) Fetch ¶
func (c *Cache[T]) Fetch(key string, duration time.Duration, fetch func() (T, error)) (*Item[T], error)
Attempts to get the value from the cache and calles fetch on a miss (missing or stale item). If fetch returns an error, no value is cached and the error is returned back to the caller. Note that Fetch merely calls the public Get and Set functions. If you want a different Fetch behavior, such as thundering herd protection or returning expired items, implement it in your application.
func (*Cache[T]) ForEachFunc ¶
func (Cache) GC ¶
func (c Cache) GC()
Forces GC. There should be no reason to call this function, except from tests which require synchronous GC. This is a control command.
func (*Cache[T]) Get ¶
Get an item from the cache. Returns nil if the item wasn't found. This can return an expired item. Use item.Expired() to see if the item is expired and item.TTL() to see how long until the item expires (which will be negative for an already expired item).
func (Cache) GetDropped ¶
func (c Cache) GetDropped() int
Gets the number of items removed from the cache due to memory pressure since the last time GetDropped was called This is a control command.
func (Cache) GetSize ¶
func (c Cache) GetSize() int64
Gets the size of the cache. This is an O(1) call to make, but it is handled by the worker goroutine. It's meant to be called periodically for metrics, or from tests. This is a control command.
func (*Cache[T]) GetWithoutPromote ¶
Same as Get but does not promote the value. This essentially circumvents the "least recently used" aspect of this cache. To some degree, it's akin to a "peak"
func (*Cache[T]) Has ¶
Has checks if the key exists in cache and returns whether it exists along with its value Returns (zero value, false) if the key doesn't exist or is expired
func (*Cache[T]) Inc ¶
Inc increases the value of key by delta. Returns error if value is not integer
func (*Cache[T]) PushMap ¶
PushMap merges values into the map in cache Returns error if the value is not a map type
func (*Cache[T]) PushSlice ¶
PushSlice appends values to the slice in cache Returns error if the value is not a slice type
func (*Cache[T]) Replace ¶
Replace the value if it exists, does not set if it doesn't. Returns true if the item existed an was replaced, false otherwise. Replace does not reset item's TTL
func (*Cache[T]) SetIfNotExists ¶
SetIfNotExists set the value in the cache for the specified duration if not exists
func (*Cache[T]) SetIfNotExistsWithFunc ¶
SetIfNotExistsWithFunc set the value in the cache for the specified duration if not exists
func (Cache) SetMaxSize ¶
func (c Cache) SetMaxSize(size int64)
Sets a new max size. That can result in a GC being run if the new maxium size is smaller than the cached size This is a control command.
func (Cache) Stop ¶
func (c Cache) Stop()
Sends a stop signal to the worker thread. The worker thread will shut down 5 seconds after the last message is received. The cache should not be used after Stop is called, but concurrently executing requests should properly finish executing. This is a control command.
func (Cache) SyncUpdates ¶
func (c Cache) SyncUpdates()
SyncUpdates waits until the cache has finished asynchronous state updates for any operations that were done by the current goroutine up to now.
For efficiency, the cache's implementation of LRU behavior is partly managed by a worker goroutine that updates its internal data structures asynchronously. This means that the cache's state in terms of (for instance) eviction of LRU items is only eventually consistent; there is no guarantee that it happens before a Get or Set call has returned. Most of the time application code will not care about this, but especially in a test scenario you may want to be able to know when the worker has caught up.
This applies only to cache methods that were previously called by the same goroutine that is now calling SyncUpdates. If other goroutines are using the cache at the same time, there is no way to know whether any of them still have pending state updates when SyncUpdates returns. This is a control command.
func (*Cache[T]) Touch ¶
Touch updates the expiry time of an existing item without changing its value
func (*Cache[T]) TrackingGet ¶
func (c *Cache[T]) TrackingGet(key string) TrackedItem[T]
Used when the cache was created with the Track() configuration option. Avoid otherwise
func (*Cache[T]) TrackingSet ¶
func (c *Cache[T]) TrackingSet(key string, value T, duration time.Duration) TrackedItem[T]
Used when the cache was created with the Track() configuration option. Sets the item, and returns a tracked reference to it.
type Configuration ¶
type Configuration[T any] struct { // contains filtered or unexported fields }
func Configure ¶
func Configure[T any]() *Configuration[T]
Creates a configuration object with sensible defaults Use this as the start of the fluent configuration: e.g.: ccache.New(ccache.Configure().MaxSize(10000))
func (*Configuration[T]) Buckets ¶
func (c *Configuration[T]) Buckets(count uint32) *Configuration[T]
Keys are hashed into % bucket count to provide greater concurrency (every set requires a write lock on the bucket). Must be a power of 2 (1, 2, 4, 8, 16, ...) [16]
func (*Configuration[T]) DeleteBuffer ¶
func (c *Configuration[T]) DeleteBuffer(size uint32) *Configuration[T]
The size of the queue for items which should be deleted. If the queue fills up, calls to Delete() will block
func (*Configuration[T]) GetsPerPromote ¶
func (c *Configuration[T]) GetsPerPromote(count int32) *Configuration[T]
Give a large cache with a high read / write ratio, it's usually unnecessary to promote an item on every Get. GetsPerPromote specifies the number of Gets a key must have before being promoted [3]
func (*Configuration[T]) ItemsToPrune ¶
func (c *Configuration[T]) ItemsToPrune(count uint32) *Configuration[T]
The number of items to prune when memory is low [500]
func (*Configuration[T]) MaxSize ¶
func (c *Configuration[T]) MaxSize(max int64) *Configuration[T]
The max size for the cache [5000]
func (*Configuration[T]) OnDelete ¶
func (c *Configuration[T]) OnDelete(callback func(item *Item[T])) *Configuration[T]
OnDelete allows setting a callback function to react to ideam deletion. This typically allows to do a cleanup of resources, such as calling a Close() on cached object that require some kind of tear-down.
func (*Configuration[T]) PromoteBuffer ¶
func (c *Configuration[T]) PromoteBuffer(size uint32) *Configuration[T]
The size of the queue for items which should be promoted. If the queue fills up, promotions are skipped [1024]
func (*Configuration[T]) Track ¶
func (c *Configuration[T]) Track() *Configuration[T]
By turning tracking on and using the cache's TrackingGet, the cache won't evict items which you haven't called Release() on. It's a simple reference counter.
type Item ¶
type Item[T any] struct { // contains filtered or unexported fields }
func (*Item[T]) String ¶
String returns a string representation of the Item. This includes the default string representation of its Value(), as implemented by fmt.Sprintf with "%v", but the exact format of the string should not be relied on; it is provided only for debugging purposes, and because otherwise including an Item in a call to fmt.Printf or fmt.Sprintf expression could cause fields of the Item to be read in a non-thread-safe way.
type LayeredCache ¶
type LayeredCache[T any] struct { *Configuration[T] // contains filtered or unexported fields }
func Layered ¶
func Layered[T any](config *Configuration[T]) *LayeredCache[T]
See ccache.Configure() for creating a configuration
func (LayeredCache) Clear ¶
func (c LayeredCache) Clear()
Clears the cache This is a control command.
func (*LayeredCache[T]) Delete ¶
func (c *LayeredCache[T]) Delete(primary, secondary string) bool
Remove the item from the cache, return true if the item was present, false otherwise.
func (*LayeredCache[T]) DeleteAll ¶
func (c *LayeredCache[T]) DeleteAll(primary string) bool
Deletes all items that share the same primary key
func (*LayeredCache[T]) DeleteFunc ¶
func (c *LayeredCache[T]) DeleteFunc(primary string, matches func(key string, item *Item[T]) bool) int
Deletes all items that share the same primary key and where the matches func evaluates to true.
func (*LayeredCache[T]) DeletePrefix ¶
func (c *LayeredCache[T]) DeletePrefix(primary, prefix string) int
Deletes all items that share the same primary key and prefix.
func (*LayeredCache[T]) Fetch ¶
func (c *LayeredCache[T]) Fetch(primary, secondary string, duration time.Duration, fetch func() (T, error)) (*Item[T], error)
Attempts to get the value from the cache and calles fetch on a miss. If fetch returns an error, no value is cached and the error is returned back to the caller. Note that Fetch merely calls the public Get and Set functions. If you want a different Fetch behavior, such as thundering herd protection or returning expired items, implement it in your application.
func (*LayeredCache[T]) ForEachFunc ¶
func (c *LayeredCache[T]) ForEachFunc(primary string, matches func(key string, item *Item[T]) bool)
func (LayeredCache) GC ¶
func (c LayeredCache) GC()
Forces GC. There should be no reason to call this function, except from tests which require synchronous GC. This is a control command.
func (*LayeredCache[T]) Get ¶
func (c *LayeredCache[T]) Get(primary, secondary string) *Item[T]
Get an item from the cache. Returns nil if the item wasn't found. This can return an expired item. Use item.Expired() to see if the item is expired and item.TTL() to see how long until the item expires (which will be negative for an already expired item).
func (LayeredCache) GetDropped ¶
func (c LayeredCache) GetDropped() int
Gets the number of items removed from the cache due to memory pressure since the last time GetDropped was called This is a control command.
func (*LayeredCache[T]) GetOrCreateSecondaryCache ¶
func (c *LayeredCache[T]) GetOrCreateSecondaryCache(primary string) *SecondaryCache[T]
Get the secondary cache for a given primary key. This operation will never return nil. In the case where the primary key does not exist, a new, underlying, empty bucket will be created and returned.
func (LayeredCache) GetSize ¶
func (c LayeredCache) GetSize() int64
Gets the size of the cache. This is an O(1) call to make, but it is handled by the worker goroutine. It's meant to be called periodically for metrics, or from tests. This is a control command.
func (*LayeredCache[T]) GetWithoutPromote ¶
func (c *LayeredCache[T]) GetWithoutPromote(primary, secondary string) *Item[T]
Same as Get but does not promote the value. This essentially circumvents the "least recently used" aspect of this cache. To some degree, it's akin to a "peak"
func (*LayeredCache[T]) Has ¶
func (c *LayeredCache[T]) Has(primary, secondary string) (bool, T)
Has checks if the key exists in layered cache and returns whether it exists along with its value Returns (false, zero value) if the key doesn't exist or is expired
func (*LayeredCache[T]) ItemCount ¶
func (c *LayeredCache[T]) ItemCount() int
func (*LayeredCache[T]) Replace ¶
func (c *LayeredCache[T]) Replace(primary, secondary string, value T) bool
Replace the value if it exists, does not set if it doesn't. Returns true if the item existed an was replaced, false otherwise. Replace does not reset item's TTL nor does it alter its position in the LRU
func (*LayeredCache[T]) Set ¶
func (c *LayeredCache[T]) Set(primary, secondary string, value T, duration time.Duration)
Set the value in the cache for the specified duration
func (LayeredCache) SetMaxSize ¶
func (c LayeredCache) SetMaxSize(size int64)
Sets a new max size. That can result in a GC being run if the new maxium size is smaller than the cached size This is a control command.
func (LayeredCache) Stop ¶
func (c LayeredCache) Stop()
Sends a stop signal to the worker thread. The worker thread will shut down 5 seconds after the last message is received. The cache should not be used after Stop is called, but concurrently executing requests should properly finish executing. This is a control command.
func (LayeredCache) SyncUpdates ¶
func (c LayeredCache) SyncUpdates()
SyncUpdates waits until the cache has finished asynchronous state updates for any operations that were done by the current goroutine up to now.
For efficiency, the cache's implementation of LRU behavior is partly managed by a worker goroutine that updates its internal data structures asynchronously. This means that the cache's state in terms of (for instance) eviction of LRU items is only eventually consistent; there is no guarantee that it happens before a Get or Set call has returned. Most of the time application code will not care about this, but especially in a test scenario you may want to be able to know when the worker has caught up.
This applies only to cache methods that were previously called by the same goroutine that is now calling SyncUpdates. If other goroutines are using the cache at the same time, there is no way to know whether any of them still have pending state updates when SyncUpdates returns. This is a control command.
func (*LayeredCache[T]) TrackingGet ¶
func (c *LayeredCache[T]) TrackingGet(primary, secondary string) TrackedItem[T]
Used when the cache was created with the Track() configuration option. Avoid otherwise
func (*LayeredCache[T]) TrackingSet ¶
func (c *LayeredCache[T]) TrackingSet(primary, secondary string, value T, duration time.Duration) TrackedItem[T]
Set the value in the cache for the specified duration
type List ¶
func (*List[T]) MoveToFront ¶
type SecondaryCache ¶
type SecondaryCache[T any] struct { // contains filtered or unexported fields }
func (*SecondaryCache[T]) Delete ¶
func (s *SecondaryCache[T]) Delete(secondary string) bool
Delete a secondary key. The semantics are the same as for LayeredCache.Delete
func (*SecondaryCache[T]) Fetch ¶
func (s *SecondaryCache[T]) Fetch(secondary string, duration time.Duration, fetch func() (T, error)) (*Item[T], error)
Fetch or set a secondary key. The semantics are the same as for LayeredCache.Fetch
func (*SecondaryCache[T]) Get ¶
func (s *SecondaryCache[T]) Get(secondary string) *Item[T]
Get the secondary key. The semantics are the same as for LayeredCache.Get
func (*SecondaryCache[T]) Has ¶
func (s *SecondaryCache[T]) Has(secondary string) (bool, T)
Has checks if the secondary key exists and returns whether it exists along with its value Returns (false, zero value) if the key doesn't exist or is expired
func (*SecondaryCache[T]) Replace ¶
func (s *SecondaryCache[T]) Replace(secondary string, value T) bool
Replace a secondary key. The semantics are the same as for LayeredCache.Replace
func (*SecondaryCache[T]) Set ¶
func (s *SecondaryCache[T]) Set(secondary string, value T, duration time.Duration) *Item[T]
Set the secondary key to a value. The semantics are the same as for LayeredCache.Set
func (*SecondaryCache[T]) TrackingGet ¶
func (c *SecondaryCache[T]) TrackingGet(secondary string) TrackedItem[T]
Track a secondary key. The semantics are the same as for LayeredCache.TrackingGet
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