carrotCache

carrotCache 特性

• 使用 LRU 缓存策略，并添加 sync.Mutex 互斥锁，实现 LRU 缓存并发控制；
• 使用一致性哈希（consistent hashing）选择节点，实现负载均衡；
• 使用 singleflight 缓存过滤机制，防止缓存击穿；
• 支持多节点互备热数据，避免频繁通过网络从远程节点获取数据；
• 建立基于 HTTP 的通信机制，实现缓存节点间通信；
• 支持 Protobuf 优化节点间二进制通信，提高效率；

项目框架

Example

var db = map[string]string{
	"Tom":  "630",
	"Jack": "589",
	"Sam":  "567",
	"Lily": "589",
	"Pity":  "567",
}

func createGroup() *carrotcache.Group {
	return carrotcache.NewGroup("scores", 2<<10, carrotcache.GetterFunc(
		func(key string) ([]byte, error) {
			log.Println("[SlowDB] search key", key)
			if v, ok := db[key]; ok {
				return []byte(v), nil
			}
			return nil, fmt.Errorf("%s not exist", key)
		}))
}

func startCacheServer(addr string, addrs []string, cache *carrotcache.Group) {
	peers := h.NewHTTPPool(addr)
	peers.Set(addrs...)
	cache.RegisterPeers(peers)
	log.Println("carrotCache is running at", addr)
	log.Fatal(http.ListenAndServe(addr[7:], peers))
}

func startAPIServer(apiAddr string, cache *carrotcache.Group) {
	http.Handle("/api", http.HandlerFunc(
		func(w http.ResponseWriter, r *http.Request) {
			key := r.URL.Query().Get("key")
			view, err := cache.Get(key)
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
				return
			}
			w.Header().Set("Content-Type", "application/octet-stream")
			w.Write(view.ByteSlice())
		}))
	log.Println("fontend server is running at", apiAddr)
	log.Fatal(http.ListenAndServe(apiAddr[7:], nil))
}

func main() {
	var port int
	var api bool
	flag.IntVar(&port, "port", 8001, "carrotCache server port")
	flag.BoolVar(&api, "api", false, "Start a api server?")
	flag.Parse()

	apiAddr := "http://localhost:9999"
	addrMap := map[int]string{
		8051: "http://localhost:8001",
		8052: "http://localhost:8002",
		8053: "http://localhost:8003",
	}

	var addrs []string
	for _, v := range addrMap {
		addrs = append(addrs, v)
	}
	cache := createGroup()
	if api {
		go startAPIServer(apiAddr, cache)
	}
	startCacheServer(addrMap[port], addrs, cache)
}