python implementation of twitter snowflake

snowflake.py

#!/usr/bin/env python3
import time
from uuid import getnode as get_mac
from sqlalchemy import create_engine
import flask 

"""
基于twitter的雪花算法生成不重复,且具有自增的流水号
该算法参考 https://github.com/twitter/snowflake
"""
app = flask.Flask(__name__)
@app.route('/',methods=['GET','POST'])
def index():
    sn = SnowFlake()
    return str(sn.nextId())

class SnowFlake:

    def __init__(self, dataCenterId=1,  machineId=None):
        """
        dataCenterId  #数据中心
        machineId     #机器标识
        """
        # 数据初始化
        # 起始的时间戳
        self.START_STMP = 1480166465631

        # #每一部分占用的位数
        
        self.SEQUENCE_BIT = 6 #序列号占用的位数
        self.MACHINE_BIT = 5   #机器标识占用的位数
        self.DATACENTER_BIT = 5#数据中心占用的位数

        #每一部分的最大值

        self.MAX_DATACENTER_NUM = -1 ^ (-1 << self.DATACENTER_BIT)   # 31
        self.MAX_MACHINE_NUM = -1 ^ (-1 << self.MACHINE_BIT)         # 31
        self.MAX_SEQUENCE = -1 ^ (-1 << self.SEQUENCE_BIT)           # 63

        
        #每一部分向左的位移
        
        self.MACHINE_LEFT = self.SEQUENCE_BIT
        self.DATACENTER_LEFT = self.SEQUENCE_BIT + self.MACHINE_BIT
        self.TIMESTMP_LEFT = self.DATACENTER_LEFT + self.DATACENTER_BIT

        #上一次时间戳
        self.lastStmp = -1 
        # 序列号
        self.sequence = 0 
        self.maxDataCenterId = -1 ^ (-1 << self.MACHINE_BIT)
        self.maxWorkerId = -1 ^ (-1 << self.DATACENTER_BIT)
        if not machineId:
            # 获得默认的machineID
            machineId = self.getMachineId()
        
        if (dataCenterId > self.MAX_DATACENTER_NUM or  dataCenterId < 0):
            print("dataCenterId can't be greater than MAX_DATACENTER_NUM or less than 0")
            return False
        
        if (machineId > self.MAX_MACHINE_NUM or machineId < 0):
            print("machineId can't be greater than MAX_MACHINE_NUM or less than 0")
            return False

        self.dataCenterId = dataCenterId
        self.machineId = machineId
    
    #产生下一个ID
    def nextId(self):
        currStmp = self.getNewstmp()
        if (currStmp < self.lastStmp):
            print("Clock moved backwards.  Refusing to generate id")
            return False
        
        if (currStmp == self.lastStmp):
            #相同毫秒内，序列号自增
            self.sequence = (self.sequence + 1) & self.MAX_SEQUENCE
            #同一毫秒的序列数已经达到最大
            if (self.sequence == 0):
                currStmp = self.getNextMill()
        else:
            #不同毫秒内，序列号置为0
            self.sequence = 0
    
        self.lastStmp = currStmp
        #时间戳部分 |  #数据中心部分 |  #机器标识部分  |  #序列号部分
        return (currStmp - self.START_STMP) << self.TIMESTMP_LEFT | self.dataCenterId << self.DATACENTER_LEFT | self.machineId << self.MACHINE_LEFT  | self.sequence                            
    

    def getNextMill(self):
        mill = self.getNewstmp()
        while (mill <= self.lastStmp):
            mill = self.getNewstmp()
        
        return mill
    

    def getNewstmp(self):
        return int(time.time() * 1000)
    

   
    def getMaxWorkerId(self,dataCenterId,maxWorkerId):
        mpid = []
        mpid.append(dataCenterId)
        mpid.append('mxname')
        return (mpid.toString().hashCode() & 0xffff) % (maxWorkerId + 1)
    
    # 根据机器所在的Mac地址计算除MachineID，保证不重复
    def getMachineId(self):
        mac = get_mac()
        mid = (0x000000FF & (mac // 10) | (0x0000FF00 & ( (mac // 100) << 8))) >> 6
        return mid 
    

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=9090)