README
¶
go-memorycache
In-memory cache with expiration and eviction.
Description
A thread-safe in-memory cache implementation.
Memory is an expensive resource, so an implementation of clearing obsolete records is provided, as well as an implementation of expelling records when the specified limit is reached.
Set CleanupInterval to enable obsolete records clearing.
Set LimitEntries to enable records expelling when count limit is reached.
Obsolete records are evicted first, then record are expelled by durability and FIFO method.
Special thanks to ks-troyan.
Install
go get github.com/a-projects/go-memorycache@latest
Usage
import (
"fmt"
"time"
"github.com/a-projects/go-memorycache"
)
func main() {
// create cache instance
cache := memorycache.New(memorycache.MemoryCacheOptions{
// periodic records clearing, every 15 min
// if not set, then it does not start
CleanupInterval: time.Minute * 15,
// cache entries limit, recods
// if not set, then unlimited
LimitEntries: 65_536,
// file used to restore data from disc when app is restarted
// if not set, it does not restore
FileName: "cache.bin",
})
// retrieve an item from cache by key "foo"
res, ok := cache.Get("foo")
// if item with given key are not found
// reasons:
// - entry was never stored in cache
// - entry was stored, but expired
// - entry was stored, but was removed from cache
// - entry was stored, but was expelled
if !ok {
// retrieving item from external sources
res = "bar"
// add entry to cache as a key value pair
cache.Set("foo", res, memorycache.MemoryCacheEntryOptions{
// set lifetime
// if not set, then not stored
Lifetime: time.Minute * 5,
// set expellence resistence
// if not set, then Normal
Durability: memorycache.Normal,
})
}
// cast result and print to console
fmt.Printf(res.(string))
// close cache instance, all chache data will be writen to FileName file
cache.Close()
}
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type MemoryCache ¶
type MemoryCache struct {
// contains filtered or unexported fields
}
MemoryCache cache
func New ¶
func New(options MemoryCacheOptions) (memorycache *MemoryCache)
New construct and load cache data from file if set FileName
func (*MemoryCache) Close ¶
func (m *MemoryCache) Close()
Close destruct and save cache data in file if set FileName
func (*MemoryCache) Count ¶
func (m *MemoryCache) Count() (count int)
Count provide count entries in cache
func (*MemoryCache) Get ¶
func (m *MemoryCache) Get(key string) (value interface{}, ok bool)
Get provide entry value by key
func (*MemoryCache) Set ¶
func (m *MemoryCache) Set(key string, value interface{}, options MemoryCacheEntryOptions)
Set add entry or update value by key
type MemoryCacheEntryDurability ¶
type MemoryCacheEntryDurability int
MemoryCacheEntryDurability resistance to evicting entries from cache when limit is reached
const ( Weak MemoryCacheEntryDurability = -1 // lowest resistance, evicted first Normal MemoryCacheEntryDurability = 0 // evicted if there are no records with priority Weak Strong MemoryCacheEntryDurability = 1 // evicted if there are no records with priority Normal )
type MemoryCacheEntryOptions ¶
type MemoryCacheEntryOptions struct {
// Lifetime entry lifetime, if not set, then 0
Lifetime time.Duration
// Durability eviction resistance, if not set, then Normal
Durability MemoryCacheEntryDurability
}
MemoryCacheEntryOptions
type MemoryCacheOptions ¶
type MemoryCacheOptions struct {
// CleanupInterval interval for clearing cache from obsolete entries, if not set, then it does not start
CleanupInterval time.Duration
// LimitEntries limit of entries in cache, upon reaching which eviction begins, if not set, then unlimited
LimitEntries int
// FileName file to restore cache when application is restarted, if not set, it does not restore
FileName string
}
MemoryCacheOptions cache options
Source Files