cache

package module
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 Go to latest Published: Feb 20, 2021 License: MIT Imports: 11 Imported by: 0

README

go-cache

在 github.com/patrickmn/go-cache 的基础上进行了一些功能添加

    1. 可注册key删除时，执行后置函数
    1. 可注册cache flush时，执行的后置函数
    1. 添加指定时间间隔和指定时刻flush cache的功能 (为了服务长时间运行不出现oom)
    1. 将初始化方式改为option函数初始化方式
Installation

go get github.com/anyanlong/go-cache

Usage
import (
	"fmt"
	"github.com/anyanlong/go-cache"
	"time"
)

func main() {
	// 以下初始化效果为
	c := cache.NewCache(
            cache.WithDefaultExpiration(time.Minute), // key默认过期时间为1分钟
            cache.WithCleanupInterval(5*time.Minute), // key全局清理时间为5分钟
            cache.WithItemsInitInterval(5*time.Minute), // cache清空时间间隔为5分钟
            gocache.WithItemsInitTiming(int64(3*3600)), // cache清空时刻为每日凌晨3点
            cache.WithOnFlush(func(cacheSize int) { // 设置cache清空时 执行的函数
                log.WithField("cacheSize", cacheSize).Infoln("go - cache flush!!") 
            }),
            cache.WithOnEvicted(func(k string, v interface{}) { // 设置key被删除时 执行的函数
                log.WithField("k", k).WithField("v", v).Infoln("go - key deleted!!") 
            }),
    )

	// Set the value of the key "foo" to "bar", with the default expiration time
	c.Set("foo", "bar", cache.DefaultExpiration)

	// Set the value of the key "baz" to 42, with no expiration time
	// (the item won't be removed until it is re-set, or removed using
	// c.Delete("baz")
	c.Set("baz", 42, cache.NoExpiration)

	// Get the string associated with the key "foo" from the cache
	foo, found := c.Get("foo")
	if found {
		fmt.Println(foo)
	}

	// Since Go is statically typed, and cache values can be anything, type
	// assertion is needed when values are being passed to functions that don't
	// take arbitrary types, (i.e. interface{}). The simplest way to do this for
	// values which will only be used once--e.g. for passing to another
	// function--is:
	foo, found := c.Get("foo")
	if found {
		MyFunction(foo.(string))
	}

	// This gets tedious if the value is used several times in the same function.
	// You might do either of the following instead:
	if x, found := c.Get("foo"); found {
		foo := x.(string)
		// ...
	}
	// or
	var foo string
	if x, found := c.Get("foo"); found {
		foo = x.(string)
	}
	// ...
	// foo can then be passed around freely as a string

	// Want performance? Store pointers!
	c.Set("foo", &MyStruct, cache.DefaultExpiration)
	if x, found := c.Get("foo"); found {
		foo := x.(*MyStruct)
			// ...
	}
}
Reference

godoc or http://godoc.org/github.com/patrickmn/go-cache

Documentation

Index

Constants

View Source 
const (
	// For use with functions that take an expiration time.
	NoExpiration time.Duration = -1
	// For use with functions that take an expiration time. Equivalent to
	// passing in the same expiration duration as was given to New() or
	// NewFrom() when the cache was created (e.g. 5 minutes.)
	DefaultExpiration time.Duration = 0
)

Variables

This section is empty.

Functions

This section is empty.

Types

type Cache 

type Cache struct {
	// contains filtered or unexported fields
}

func NewCache 

func NewCache(opt ...FuncOpt) *Cache

func (Cache) Add 

func (c Cache) Add(k string, x interface{}, d time.Duration) error

Add an item to the cache only if an item doesn't already exist for the given key, or if the existing item has expired. Returns an error otherwise.

func (Cache) Decrement 

func (c Cache) Decrement(k string, n int64) error

Decrement an item of type int, int8, int16, int32, int64, uintptr, uint, uint8, uint32, or uint64, float32 or float64 by n. Returns an error if the item's value is not an integer, if it was not found, or if it is not possible to decrement it by n. To retrieve the decremented value, use one of the specialized methods, e.g. DecrementInt64.

func (Cache) DecrementFloat 

func (c Cache) DecrementFloat(k string, n float64) error

Decrement an item of type float32 or float64 by n. Returns an error if the item's value is not floating point, if it was not found, or if it is not possible to decrement it by n. Pass a negative number to decrement the value. To retrieve the decremented value, use one of the specialized methods, e.g. DecrementFloat64.

func (Cache) DecrementFloat32 

func (c Cache) DecrementFloat32(k string, n float32) (float32, error)

Decrement an item of type float32 by n. Returns an error if the item's value is not an float32, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementFloat64 

func (c Cache) DecrementFloat64(k string, n float64) (float64, error)

Decrement an item of type float64 by n. Returns an error if the item's value is not an float64, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt 

func (c Cache) DecrementInt(k string, n int) (int, error)

Decrement an item of type int by n. Returns an error if the item's value is not an int, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt16 

func (c Cache) DecrementInt16(k string, n int16) (int16, error)

Decrement an item of type int16 by n. Returns an error if the item's value is not an int16, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt32 

func (c Cache) DecrementInt32(k string, n int32) (int32, error)

Decrement an item of type int32 by n. Returns an error if the item's value is not an int32, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt64 

func (c Cache) DecrementInt64(k string, n int64) (int64, error)

Decrement an item of type int64 by n. Returns an error if the item's value is not an int64, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementInt8 

func (c Cache) DecrementInt8(k string, n int8) (int8, error)

Decrement an item of type int8 by n. Returns an error if the item's value is not an int8, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint 

func (c Cache) DecrementUint(k string, n uint) (uint, error)

Decrement an item of type uint by n. Returns an error if the item's value is not an uint, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint16 

func (c Cache) DecrementUint16(k string, n uint16) (uint16, error)

Decrement an item of type uint16 by n. Returns an error if the item's value is not an uint16, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint32 

func (c Cache) DecrementUint32(k string, n uint32) (uint32, error)

Decrement an item of type uint32 by n. Returns an error if the item's value is not an uint32, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint64 

func (c Cache) DecrementUint64(k string, n uint64) (uint64, error)

Decrement an item of type uint64 by n. Returns an error if the item's value is not an uint64, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUint8 

func (c Cache) DecrementUint8(k string, n uint8) (uint8, error)

Decrement an item of type uint8 by n. Returns an error if the item's value is not an uint8, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) DecrementUintptr 

func (c Cache) DecrementUintptr(k string, n uintptr) (uintptr, error)

Decrement an item of type uintptr by n. Returns an error if the item's value is not an uintptr, or if it was not found. If there is no error, the decremented value is returned.

func (Cache) Delete 

func (c Cache) Delete(k string)

Delete an item from the cache. Does nothing if the key is not in the cache.

func (Cache) DeleteExpired 

func (c Cache) DeleteExpired()

Delete all expired items from the cache.

func (Cache) Flush 

func (c Cache) Flush()

func (Cache) Get 

func (c Cache) Get(k string) (interface{}, bool)

Get an item from the cache. Returns the item or nil, and a bool indicating whether the key was found.

func (Cache) GetWithExpiration 

func (c Cache) GetWithExpiration(k string) (interface{}, time.Time, bool)

GetWithExpiration returns an item and its expiration time from the cache. It returns the item or nil, the expiration time if one is set (if the item never expires a zero value for time.Time is returned), and a bool indicating whether the key was found.

func (Cache) Increment 

func (c Cache) Increment(k string, n int64) error

Increment an item of type int, int8, int16, int32, int64, uintptr, uint, uint8, uint32, or uint64, float32 or float64 by n. Returns an error if the item's value is not an integer, if it was not found, or if it is not possible to increment it by n. To retrieve the incremented value, use one of the specialized methods, e.g. IncrementInt64.

func (Cache) IncrementFloat 

func (c Cache) IncrementFloat(k string, n float64) error

Increment an item of type float32 or float64 by n. Returns an error if the item's value is not floating point, if it was not found, or if it is not possible to increment it by n. Pass a negative number to decrement the value. To retrieve the incremented value, use one of the specialized methods, e.g. IncrementFloat64.

func (Cache) IncrementFloat32 

func (c Cache) IncrementFloat32(k string, n float32) (float32, error)

Increment an item of type float32 by n. Returns an error if the item's value is not an float32, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementFloat64 

func (c Cache) IncrementFloat64(k string, n float64) (float64, error)

Increment an item of type float64 by n. Returns an error if the item's value is not an float64, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt 

func (c Cache) IncrementInt(k string, n int) (int, error)

Increment an item of type int by n. Returns an error if the item's value is not an int, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt16 

func (c Cache) IncrementInt16(k string, n int16) (int16, error)

Increment an item of type int16 by n. Returns an error if the item's value is not an int16, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt32 

func (c Cache) IncrementInt32(k string, n int32) (int32, error)

Increment an item of type int32 by n. Returns an error if the item's value is not an int32, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt64 

func (c Cache) IncrementInt64(k string, n int64) (int64, error)

Increment an item of type int64 by n. Returns an error if the item's value is not an int64, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementInt8 

func (c Cache) IncrementInt8(k string, n int8) (int8, error)

Increment an item of type int8 by n. Returns an error if the item's value is not an int8, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint 

func (c Cache) IncrementUint(k string, n uint) (uint, error)

Increment an item of type uint by n. Returns an error if the item's value is not an uint, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint16 

func (c Cache) IncrementUint16(k string, n uint16) (uint16, error)

Increment an item of type uint16 by n. Returns an error if the item's value is not an uint16, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint32 

func (c Cache) IncrementUint32(k string, n uint32) (uint32, error)

Increment an item of type uint32 by n. Returns an error if the item's value is not an uint32, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint64 

func (c Cache) IncrementUint64(k string, n uint64) (uint64, error)

Increment an item of type uint64 by n. Returns an error if the item's value is not an uint64, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUint8 

func (c Cache) IncrementUint8(k string, n uint8) (uint8, error)

Increment an item of type uint8 by n. Returns an error if the item's value is not an uint8, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) IncrementUintptr 

func (c Cache) IncrementUintptr(k string, n uintptr) (uintptr, error)

Increment an item of type uintptr by n. Returns an error if the item's value is not an uintptr, or if it was not found. If there is no error, the incremented value is returned.

func (Cache) ItemCount 

func (c Cache) ItemCount() int

Returns the number of items in the cache. This may include items that have expired, but have not yet been cleaned up.

func (Cache) Items 

func (c Cache) Items() map[string]Item

Copies all unexpired items in the cache into a new map and returns it.

func (Cache) Load 

func (c Cache) Load(r io.Reader) error

Add (Gob-serialized) cache items from an io.Reader, excluding any items with keys that already exist (and haven't expired) in the current cache.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) LoadFile 

func (c Cache) LoadFile(fname string) error

Load and add cache items from the given filename, excluding any items with keys that already exist in the current cache.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) OnEvicted 

func (c Cache) OnEvicted(f func(string, interface{}))

Sets an (optional) function that is called with the key and value when an item is evicted from the cache. (Including when it is deleted manually, but not when it is overwritten.) Set to nil to disable.

func (Cache) Replace 

func (c Cache) Replace(k string, x interface{}, d time.Duration) error

Set a new value for the cache key only if it already exists, and the existing item hasn't expired. Returns an error otherwise.

func (Cache) Save 

func (c Cache) Save(w io.Writer) (err error)

Write the cache's items (using Gob) to an io.Writer.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) SaveFile 

func (c Cache) SaveFile(fname string) error

Save the cache's items to the given filename, creating the file if it doesn't exist, and overwriting it if it does.

NOTE: This method is deprecated in favor of c.Items() and NewFrom() (see the documentation for NewFrom().)

func (Cache) Set 

func (c Cache) Set(k string, x interface{}, d time.Duration)

Add an item to the cache, replacing any existing item. If the duration is 0 (DefaultExpiration), the cache's default expiration time is used. If it is -1 (NoExpiration), the item never expires.

func (Cache) SetDefault 

func (c Cache) SetDefault(k string, x interface{})

Add an item to the cache, replacing any existing item, using the default expiration.

type FuncOpt 

type FuncOpt func(c *cache)

func WithCleanupInterval 

func WithCleanupInterval(interval time.Duration) FuncOpt

设置key过期清理时间间隔

func WithDefaultExpiration 

func WithDefaultExpiration(interval time.Duration) FuncOpt

设置key默认过期时间

func WithItems 

func WithItems(items map[string]Item) FuncOpt

设置初始化map

func WithItemsInitInterval 

func WithItemsInitInterval(interval time.Duration) FuncOpt

设置map内存清理(全部初始化) 时间间隔

func WithItemsInitTiming 

func WithItemsInitTiming(timing int64) FuncOpt

设置map内存清理(全部初始化) 时刻的时间戳(一日中的某个时刻以秒为单位 0-86399)

func WithOnEvicted 

func WithOnEvicted(f func(string, interface{})) FuncOpt

设置删除map key时调用的函数

func WithOnFlush 

func WithOnFlush(f func(int)) FuncOpt

设置清空map时调用的函数

type Item 

type Item struct {
	Object     interface{}
	Expiration int64
}

func (Item) Expired 

func (item Item) Expired() bool

Returns true if the item has expired.

Source Files

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