# README

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 will be 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.

If Go 1.18 has not been released but you want to try this package, you can easily do so by using the gotip command.

$ go install golang.org/dl/gotip@latest
$ gotip download # latest commit
$ gotip version
go version devel go1.18-c2397905e0 Sat Nov 13 03:33:55 2021 +0000 darwin/arm64

Install

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

Usage

See also examples or gotipplay playground

package main

import (
	"fmt"
	"time"

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

func main() {
	// use simple cache algorithm without options.
	c := cache.New[string, int]()
	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
}