算法实现
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import time
import logging
from exceptions import InvalidSystemClock # 继承的Excpetion即可。
# 64 位 id 的划分,通常机器位和数据位各为 5 位
WORKER_ID_BITS = 5 # 机器位
DATACENTER_ID_BITS = 5 # 数据位
SEQUENCE_BITS = 12 # 循环位
# 最大取值计算,计算机中负数表示为他的补码
MAX_WORKER_ID = -1^(-1 << WORKER_ID_BITS) # 2**5 -1 =31
MAX_DATACENTER_ID = -1 ^(-1 << DATACENTER_ID_BITS)
# 移位偏移计算
WORKER_ID_SHIFT = SEQUENCE_BITS
DATACENTER_ID_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS
TIMESTAMP_LEFT_SHIFT = SEQUENCE_BITS + WORKER_ID_BITS + DATACENTER_ID_BITS
# X序号循环掩码
SEQUENCE_MASK = -1^(-1 << SEQUENCE_BITS)
# Twitter 元年时间戳
TWEPOCH = 1288834974657
logger = logging.getLogger('雪花算法')
class IdWorker(object):
'''
用于生成IDS.
'''
def __init__(self,datacenter_id,worker_id,sequence=0):
'''
初始化方法
:param datacenter_id:数据id
:param worker_id:机器id
:param sequence:序列码
'''
if worker_id > MAX_WORKER_ID or worker_id <0:
raise ValueError('worker_id 值越界')
if datacenter_id >MAX_DATACENTER_ID or datacenter_id < 0:
raise ValueError('datacenter_id 值越界')
self.worker_id = worker_id
self.datacenter_id = datacenter_id
self.sequence = sequence
self.last_timestamp = -1 # 上次计算的时间戳
def _gen_timestamp(self):
'''
生成整数时间戳。
:return:
'''
return int(time.time()*1000)
def get_id(self):
'''
获取新的ID.
:return:
'''
# 获取当前时间戳
timestamp = self._gen_timestamp()
# 时钟回拨的情况
if timestamp < self.last_timestamp:
logging.error('clock is moving backwards. Rejecting requests util {}'.format(self.last_timestamp))
raise InvalidSystemClock
if timestamp == self.last_timestamp:
# 同一毫秒的处理。
self.sequence = (self.sequence+1) & SEQUENCE_MASK
if self.sequence == 0:
timestamp =self._til_next_millis(self.last_timestamp)
else:
self.sequence = 0
self.last_timestamp =timestamp
new_id = (((timestamp - TWEPOCH) << TIMESTAMP_LEFT_SHIFT)|(self.datacenter_id << DATACENTER_ID_SHIFT)|(self.worker_id << WORKER_ID_SHIFT))|self.sequence
return new_id
def _til_next_millis(self,last_timestamp):
'''
等到下一毫秒。
:param last_timestamp:
:return:
'''
timestamp = self._gen_timestamp()
while timestamp <= last_timestamp:
timestamp = self._gen_timestamp()
return timestamp
if __name__ == '__main__':
worker = IdWorker(1,2,0)
print(worker.get_id())
第三方包的使用
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> pip install pysnowflake
启动服务：
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> snowflake_start_server --worker=1
编程程序，获取id：
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from snowflake import client
print(client.get_guid())
相关链接：
Python 实现雪花算法
