架构师训练营 -- 第五周作业

import hashlib
import random
import numpy as np


# 获取到经过MD5加密的字符串并返回
def md5_encode(str):
    str = str.encode('utf-8')
    m = hashlib.md5()
    m.update(str)
    return m.hexdigest()


class NodeInfo(object):
    def __init__(self, hash_key, node, virtual_node):
        self.hash_key = hash_key
        self.node = node
        self.virtual_node = virtual_node


class ConsistencyHash(object):
    def __init__(self):
        self.nodes = []
        self.key_nodes = []
        # 每个节点虚拟出多少节点
        self.virtual_node_num = 185

    @staticmethod
    def get_hash_key(key):
        md5 = md5_encode(key)
        # 将md5值当成16进制解析，转成10进制，除进2的32次方，计算hash值
        return int(md5, 16) % (2 ** 32)

    # 获取某个key值对应的node
    def get_node(self, str):
        hash_key = self.get_hash_key(str)
        for i, val in enumerate(self.key_nodes):
            if hash_key < val.hash_key:
                return val.node
        return self.key_nodes[-1].node

    # 添加服务器
    def add_node(self, node):
        self.nodes.append(node)
        for num in range(0, self.virtual_node_num):
            virtual_node = node + '#' + str(num)
            virtual_node_key = self.get_hash_key(virtual_node)
            node_info = NodeInfo(virtual_node_key, node, virtual_node)
            self.key_nodes.append(node_info)

        # 按hash key 从小到大排序
        self.key_nodes.sort(key=lambda n: n.hash_key)


# 生成随机字符串
def random_str(slen=10):
    seed = "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!@#$%^&*()_+=-"
    sa = []
    for i in range(slen):
        sa.append(random.choice(seed))
    return ''.join(sa)


if __name__ == '__main__':
    consistency_hash = ConsistencyHash()
    nodes = [
        "192.168.1.1",
        "192.168.1.2",
        "192.168.1.3",
        "192.168.1.4",
        "192.168.1.5",
        "192.168.1.6",
        "192.168.1.7",
        "192.168.1.8",
        "192.168.1.9",
        "192.168.1.10",
    ]
    map_node_count = {}
    for node in nodes:
        consistency_hash.add_node(node)
        map_node_count[node] = 0

    for i in range(0, 1000000):
        slen = random.randint(1, 50)
        str = random_str(slen)
        node = consistency_hash.get_node(str)
        map_node_count[node] += 1
    print(map_node_count)
    print(np.std(list(map_node_count.values()), ddof=1))