Documentation
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Index ¶
- Constants
- Variables
- type BigCache
- func (c *BigCache) Append(key string, entry []byte) error
- func (c *BigCache) Capacity() int
- func (c *BigCache) Close() error
- func (c *BigCache) Delete(key string) error
- func (c *BigCache) Get(key string) ([]byte, error)
- func (c *BigCache) GetWithInfo(key string) ([]byte, Response, error)
- func (c *BigCache) Iterator() *EntryInfoIterator
- func (c *BigCache) KeyMetadata(key string) Metadata
- func (c *BigCache) Len() int
- func (c *BigCache) Reset() error
- func (c *BigCache) ResetStats() error
- func (c *BigCache) Set(key string, entry []byte) error
- func (c *BigCache) Stats() Stats
- type Config
- type EntryInfo
- type EntryInfoIterator
- type Metadata
- type RemoveReason
- type Response
- type Stats
Constants ¶
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const ( // Expired 表示条目因过期而被移除 Expired = RemoveReason(1) // NoSpace 表示由于空间不足而移除条目 NoSpace = RemoveReason(2) // Deleted 表示条目被显式删除 Deleted = RemoveReason(3) )
定义移除原因的常量
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const ErrCannotRetrieveEntry = iteratorError("cannot retrieve entry from cache")
ErrCannotRetrieveEntry is reported when entry cannot be retrieved from underlying
View Source
const ErrInvalidIteratorState = iteratorError("iterator is in invalid state. Use SetNext() to move to next position")
ErrInvalidIteratorState is reported when iterator is in invalid state
Variables ¶
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var ( // ErrEntryNotFound is an error type struct which is returned when entry was not found for provided key ErrEntryNotFound = errors.New("entry not found") )
Functions ¶
This section is empty.
Types ¶
type BigCache ¶
type BigCache struct {
// contains filtered or unexported fields
}
BigCache 是一个快速、并发、可淘汰的缓存，用于存储大量条目而不会影响性能 它将条目保存在堆上但避免了GC对它们的影响。为了实现这一点，操作在字节数组上进行， 因此在大多数使用场景下，缓存前需要对条目进行(反)序列化。
func New ¶
New 初始化 BigCache 的新实例 参数:
ctx: 上下文，用于控制清理goroutine的生命周期 config: 缓存配置
返回值:
*BigCache: BigCache实例指针 error: 错误信息
func NewBigCache ¶
NewBigCache 创建 BigCache 实例的旧版本接口（向后兼容） 参数:
config: 缓存配置
返回值:
*BigCache: BigCache实例指针 error: 错误信息
func (*BigCache) Append ¶
Append 如果键存在则在键下追加条目，否则行为与 Set() 相同 使用 Append() 可以以锁优化的方式在同一个键下连接多个条目 参数:
key: 键 entry: 要追加的条目数据
返回值:
error: 错误信息
func (*BigCache) Close ¶
Close 用于在使用完缓存后发出关闭信号 这允许清理goroutine退出，并确保不保留对缓存的引用，从而允许GC回收条目缓存 返回值:
error: 错误信息
func (*BigCache) Get ¶
Get 根据键读取条目 当给定键不存在条目时返回 ErrEntryNotFound 错误 参数:
key: 要查找的键
返回值:
[]byte: 条目数据 error: 错误信息
func (*BigCache) GetWithInfo ¶
GetWithInfo 根据键读取条目并返回响应信息 当给定键不存在条目时返回 ErrEntryNotFound 错误 参数:
key: 要查找的键
返回值:
[]byte: 条目数据 Response: 响应信息 error: 错误信息
func (*BigCache) Iterator ¶
func (c *BigCache) Iterator() *EntryInfoIterator
Iterator 返回迭代器函数，用于遍历整个缓存中的 EntryInfo 返回值:
*EntryInfoIterator: 条目信息迭代器
type Config ¶
type Config struct {
// Number of cache shards, value must be a power of two
Shards int
// Time after which entry can be evicted
LifeWindow time.Duration
// Interval between removing expired entries (clean up).
// If set to <= 0 then no action is performed. Setting to < 1 second is counterproductive — bigcache has a one second resolution.
CleanWindow time.Duration
// Max number of entries in life window. Used only to calculate initial size for cache shards.
// When proper value is set then additional memory allocation does not occur.
MaxEntriesInWindow int
// Max size of entry in bytes. Used only to calculate initial size for cache shards.
MaxEntrySize int
// StatsEnabled if true calculate the number of times a cached resource was requested.
StatsEnabled bool
// Verbose mode prints information about new memory allocation
Verbose bool
// Hasher used to calculate hash values for cache keys.
Hasher hash2.Hasher `json:"-"`
// HardMaxCacheSize is a limit for BytesQueue size in MB.
// It can protect application from consuming all available memory on machine, therefore from running OOM Killer.
// Default value is 0 which means unlimited size. When the limit is higher than 0 and reached then
// the oldest entries are overridden for the new ones. The max memory consumption will be bigger than
// HardMaxCacheSize due to Shards' s additional memory. Every Shard consumes additional memory for map of keys
// and statistics (map[uint64]uint32) the size of this map is equal to number of entries in
// cache ~ 2×(64+32)×n bits + overhead or map itself.
HardMaxCacheSize int
// OnRemove is a callback fired when the oldest entry is removed because of its expiration time or no space left
// for the new entry, or because delete was called.
// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
// ignored if OnRemoveWithMetadata is specified.
OnRemove func(key string, entry []byte)
// OnRemoveWithMetadata is a callback fired when the oldest entry is removed because of its expiration time or no space left
// for the new entry, or because delete was called. A structure representing details about that specific entry.
// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
OnRemoveWithMetadata func(key string, entry []byte, keyMetadata Metadata)
// OnRemoveWithReason is a callback fired when the oldest entry is removed because of its expiration time or no space left
// for the new entry, or because delete was called. A constant representing the reason will be passed through.
// Default value is nil which means no callback and it prevents from unwrapping the oldest entry.
// Ignored if OnRemove is specified.
OnRemoveWithReason func(key string, entry []byte, reason RemoveReason)
// Logger is a logging interface and used in combination with `Verbose`
// Defaults to `DefaultLogger()`
Logger *zap.Logger
// contains filtered or unexported fields
}
Config for BigCache
func DefaultConfig ¶
DefaultConfig initializes config with default values. When load for BigCache can be predicted in advance then it is better to use custom config.
func (Config) OnRemoveFilterSet ¶
func (c Config) OnRemoveFilterSet(reasons ...RemoveReason) Config
OnRemoveFilterSet sets which remove reasons will trigger a call to OnRemoveWithReason. Filtering out reasons prevents bigcache from unwrapping them, which saves cpu.
type EntryInfo ¶
type EntryInfo struct {
// contains filtered or unexported fields
}
EntryInfo holds informations about entry in the cache
type EntryInfoIterator ¶
type EntryInfoIterator struct {
// contains filtered or unexported fields
}
EntryInfoIterator allows to iterate over entries in the cache
func (*EntryInfoIterator) SetNext ¶
func (it *EntryInfoIterator) SetNext() bool
SetNext moves to next element and returns true if it exists
func (*EntryInfoIterator) Value ¶
func (it *EntryInfoIterator) Value() (EntryInfo, error)
Value returns current value from the iterator
type Metadata ¶
type Metadata struct {
// RequestCount 记录该条目被请求的次数
RequestCount uint32
}
Metadata 包含特定缓存条目的信息
type Response ¶
type Response struct {
EntryStatus RemoveReason
}
Response will contain metadata about the entry for witch GetWithInfo(key) was called
type Stats ¶
type Stats struct {
// Hits is a number of successfully found keys
Hits int64 `json:"hits"`
// Misses is a number of not found keys
Misses int64 `json:"misses"`
// DelHits is a number of successfully deleted keys
DelHits int64 `json:"delete_hits"`
// DelMisses is a number of not deleted keys
DelMisses int64 `json:"delete_misses"`
// Collisions is a number of happened key-collisions
Collisions int64 `json:"collisions"`
}
Stats stores cache statistics
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