PeanutCache

The gRPC implementation of groupcache: A high performance, open source, using RPC framework that communicated with each cache node. Cache service can register to etcd, and each cache client can dicovery the service list by etcd.For more information see the groupcache, or geecache.

Prerequisites

• Golang 1.16 or later
• Etcd v3.4.0 or later
• gRPC-go v1.38.0 or later
• protobuf v1.26.0 or later

TodoList

欢迎大家Pull Request，可随时联系作者。

1. 将一致性哈希从Server抽象出来，作为单独的一个Proxy层。避免在每个节点自己做一致性哈希，这样存在哈希环不一致的情况。
2. 增加缓存持久化的能力。
3. 改进LRU cache，使其具备TTL的能力，以及改进锁的粒度，提高并发度。

Installation

With Go module support (Go 1.11+), simply add the following import

import "github.com/peanutzhen/peanutcache"

to your code, and then go [build|run|test] will automatically fetch the necessary dependencies.

Otherwise, to install the peanutcache package, run the following command:

$ go get -u github.com/peanutzhen/peanutcache

Usage

Here, give a example to use it example.go:

// example.go file
// 运行前，你需要在本地启动Etcd实例，作为服务中心。

package main

import (
	"fmt"
	"github.com/peanutzhen/peanutcache"
	"log"
	"sync"
)

func main() {
	// 模拟MySQL数据库 用于peanutcache从数据源获取值
	var mysql = map[string]string{
		"Tom":  "630",
		"Jack": "589",
		"Sam":  "567",
	}
	// 新建cache实例
	group := peanutcache.NewGroup("scores", 2<<10, peanutcache.RetrieverFunc(
		func(key string) ([]byte, error) {
			log.Println("[Mysql] search key", key)
			if v, ok := mysql[key]; ok {
				return []byte(v), nil
			}
			return nil, fmt.Errorf("%s not exist", key)
		}))
	// New一个服务实例
	var addr string = "localhost:9999"
	svr, err := peanutcache.NewServer(addr)
	if err != nil {
		log.Fatal(err)
	}
	// 设置同伴节点IP(包括自己)
  // todo: 这里的peer地址从etcd获取(服务发现)
	svr.SetPeers(addr)
	// 将服务与cache绑定 因为cache和server是解耦合的
	group.RegisterSvr(svr)
	log.Println("peanutcache is running at", addr)
	// 启动服务(注册服务至etcd/计算一致性哈希...)
	go func() {
		// Start将不会return 除非服务stop或者抛出error
		err = svr.Start()
		if err != nil {
			log.Fatal(err)
		}
	}()

	// 发出几个Get请求
	var wg sync.WaitGroup
	wg.Add(4)
	go GetTomScore(group, &wg)
	go GetTomScore(group, &wg)
	go GetTomScore(group, &wg)
	go GetTomScore(group, &wg)
	wg.Wait()
}

func GetTomScore(group *peanutcache.Group, wg *sync.WaitGroup) {
	defer wg.Done()
	log.Printf("get Tom...")
	view, err := group.Get("Tom")
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	fmt.Println(view.String())
}

Before go run, you should run etcd local directly(without any spcified parameter) and then execute go run example.go, you will get follows:

$ go run peanutcache_usage.go
2021/08/01 18:09:17 peanutcache is running at localhost:9999
2021/08/01 18:09:17 get Tom...
2021/08/01 18:09:17 get Tom...
2021/08/01 18:09:17 get Tom...
2021/08/01 18:09:17 get Tom...
2021/08/01 18:09:17 ooh! pick myself, I am localhost:9999
2021/08/01 18:09:17 [Mysql] search key Tom
630
630
630
630