架构师训练营 0 期第五周

package main
import (
	"fmt"
	"hash/crc32"
	"math"
	"sort"
	"strconv"
	"sync"
)
type Hash func(key string) uint32
type Node struct {
	host string
	data map[int]int
}
func NewNode(h string) *Node {
	return &Node{
		host: h,
		data: make(map[int]int),
	}
}
func (n *Node) Set(k int, v int) {
	n.data[k] = v
}
func (n *Node) Count() int {
	return len(n.data)
}
func (n *Node) Print() {
	fmt.Printf("Node:%s,Count:%d\n", n.host, n.Count())
}
type Map struct {
	hash     Hash
	replicas int
	keys     []int
	hashMap  map[int]*Node
	Nodes    []*Node
	sync.RWMutex
}
func NewMap(replicas int) *Map {
	return &Map{
		hash: func(key string) uint32 {
			return crc32.ChecksumIEEE([]byte(key))
		},
		replicas: replicas,
		hashMap:  make(map[int]*Node),
	}
}
func (m *Map) AddNode(h string) {
	m.Lock()
	defer m.Unlock()
	rNode := NewNode(h)
	for i := 0; i < m.replicas; i++ {
		node := NewNode(h + strconv.Itoa(i))
		hash := int(m.hash(node.host))
		m.keys = append(m.keys, hash)
		m.hashMap[hash] = rNode
	}
	m.Nodes = append(m.Nodes, rNode)
	sort.Ints(m.keys)
}
func (m *Map) GetNode(k string) *Node {
	hash := int(m.hash(k))
	idx := sort.Search(len(m.keys), func(i int) bool {
		return m.keys[i] >= hash
	})
	return m.hashMap[m.keys[idx%len(m.keys)]]
}
func main() {
	m := NewMap(200)
	for i := 1; i <= 10; i++ {
		m.AddNode("server-" + strconv.Itoa(i))
	}
	for i := 1; i <= 1000000; i++ {
		m.GetNode(strconv.Itoa(i)).Set(i, i)
	}
	for i := range m.Nodes {
		m.Nodes[i].Print()
	}
	var variance float64
	for i := range m.Nodes {
		variance += math.Pow(float64(m.Nodes[i].Count())-100000, 2)
	}
	fmt.Println("σ:", math.Sqrt(variance/float64(10)))
}

Node:server-1,Count:101717
Node:server-2,Count:100221
Node:server-3,Count:104626
Node:server-4,Count:99440
Node:server-5,Count:112020
Node:server-6,Count:124128
Node:server-7,Count:97952
Node:server-8,Count:110756
Node:server-9,Count:88892
Node:server-10,Count:60248
σ: 16046.327299416524