架构师训练营 - 第五周作业

type Master struct {	keys      []int	          //存放虚拟节点的hash值	serverMap map[int]Server  //虚拟节点hash值对应的真实服务器	hasher    hash.Hash32     //hash计算器}
type Server struct {	Name        string        //节点名称	Performance int           //性能(生成多少个虚拟节点)}

func (m *Master) Add(servers ...Server) {	rand.Seed(time.Now().Unix())	for _, server := range servers {		for i := 0; i < server.Performance; i++ {			h := rand.Intn(1 << 32)			m.keys = append(m.keys, h)			m.serverMap[h] = server		}	}	sort.Ints(m.keys)}

func (m *Master) FindServer(key string) Server {	m.hasher.Write([]byte(key))	h := int(m.hasher.Sum32())	m.hasher.Reset()	l := 0	r := len(m.keys) - 1	for l < r {		i := (l + r) / 2		curr := m.keys[i]		if curr == h {			return m.serverMap[curr]		}		if curr > h {			r = i - 1		} else {			l = i + 1		}	}	i := (l + r) / 2	return m.serverMap[m.keys[i]]}

func main() {	master := Master{		keys:      []int{},		serverMap: make(map[int]Server),		hasher:    crc32.NewIEEE(),	}
	//第一轮测试	master.Add(		Server{Name: "node1", Performance: 150},		Server{Name: "node2", Performance: 150},		Server{Name: "node3", Performance: 150},		Server{Name: "node4", Performance: 150},		Server{Name: "node5", Performance: 150},		Server{Name: "node6", Performance: 150},		Server{Name: "node7", Performance: 150},		Server{Name: "node8", Performance: 150},		Server{Name: "node9", Performance: 150},		Server{Name: "node10", Performance: 150})	m := make(map[string]int)	// 两轮测试使用相同随机数种子，生成一样的测试数据，以排除随机带来的干扰  rand.Seed(100) 	for i := 0; i < 10000000; i++ {		server := master.FindServer(strconv.Itoa(rand.Int()))		m[server.Name]++	}	fmt.Println(m)
	//第二轮测试	master.Add(Server{Name: "node11", Performance: 300})	m = make(map[string]int)	rand.Seed(100)	for i := 0; i < 10000000; i++ {		server := master.FindServer(strconv.Itoa(rand.Int()))		m[server.Name]++	}	fmt.Println(m)}