fanyang89 / go-generics-cache

A key:value store/cache library written in Go generics. LRU, LFU, FIFO, MRU, Clock support.

go-generics-cache

go-generics-cache is an in-memory key:value store/cache that is suitable for applications running on a single machine. This in-memory cache uses Go Generics which is introduced in 1.18.

• a thread-safe
• implemented with Go Generics
• TTL supported (with expiration times)
• Simple cache is like map[string]interface{}
  • See examples
• Cache replacement policies
  • Least recently used (LRU)
    • Discards the least recently used items first.
    • See examples
  • Least-frequently used (LFU)
    • Counts how often an item is needed. Those that are used least often are discarded first.
    • An O(1) algorithm for implementing the LFU cache eviction scheme
    • See examples
  • First in first out (FIFO)
    • Using this algorithm the cache behaves in the same way as a FIFO queue.
    • The cache evicts the blocks in the order they were added, without any regard to how often or how many times they were accessed before.
    • See examples
  • Most recently used (MRU)
    • In contrast to Least Recently Used (LRU), MRU discards the most recently used items first.
    • See examples
  • Clock
    • Clock is a more efficient version of FIFO than Second-chance cache algorithm.
    • See examples

Requirements

Go 1.18 or later.

Install

$ go get github.com/Code-Hex/go-generics-cache

Usage

See also examples or go playground

package main

import (
	"context"
	"fmt"
	"time"

	cache "github.com/Code-Hex/go-generics-cache"
)

func main() {
	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// use simple cache algorithm without options.
	c := cache.NewContext[string, int](ctx)
	c.Set("a", 1)
	gota, aok := c.Get("a")
	gotb, bok := c.Get("b")
	fmt.Println(gota, aok) // 1 true
	fmt.Println(gotb, bok) // 0 false

	// Create a cache for Number constraint. key as string, value as int.
	nc := cache.NewNumber[string, int]()
	nc.Set("age", 26, cache.WithExpiration(time.Hour))

	incremented := nc.Increment("age", 1)
	fmt.Println(incremented) // 27

	decremented := nc.Decrement("age", 1)
	fmt.Println(decremented) // 26
}

Articles

• English: Some tips and bothers for Go 1.18 Generics
• Japanese: Go 1.18 の Generics を使ったキャッシュライブラリを作った時に見つけた tips と微妙な点