python实操

2021-06-15

2021-06-12

本文字数: 632 阅读时长: 3 分钟

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基础命令

pip isntall kazoo
服务器搭建zookeeper集群
python实操zookeeper1
python实操zookeeper2

import sys
from kazoo.client import KazooClient, KazooState
import logging

logging.basicConfig(
    level=logging.DEBUG,
    stream=sys.stdout,
    format='%(asctime)s %(pathname)s %(funcName)s%(lineno)d %(levelname)s: %(message)s')

zk = KazooClient(
    hosts='10.167.218.158:2181',
    timeout=10.0,
    logger=logging
)
# 开始心跳
zk.start()

# 获取根节点数据和状态
data, stat = zk.get('/')
print("data:", data)
print("stat:", stat)

# 获取子节点
children = zk.get_children("/")
print(children)

# 创建子节点
# zk.create('/sanguo/shuguo', b'caoChao', ephemeral=False)
if not zk.exists('/sanguo/weiguo'):
    zk.create('/sanguo/weiguo', b'caoChao', ephemeral=False)


children = zk.get_children("/sanguo")
print(children)
data, stat = zk.get('/sanguo/weiguo')
print("data:", data)
print("stat:", stat)


def monitor(event):
    print(type(event))
    print(event)
    print(zk.get_children('/sanguo'))


import time

children = zk.get_children('/sanguo', watch=monitor)
print(children)

node = zk.create('/b')
print(node, 'aaaaaaaaaaaaaaaaaaaaa')
print(zk.exists('/sanguo'), 'fafafafafaa')

zookeeper实现分布式锁

import time
import sys
from kazoo.client import KazooClient
import logging

class ZkLock:
    def __init__(self, root='/Lock', node=None):
        self.lock = False
        self.root = root
        self.node = node
        logging.basicConfig(
            level=logging.DEBUG,
            stream=sys.stdout,
            format='%(asctime)s %(pathname)s %(funcName)s%(lineno)d %(levelname)s: %(message)s')
        self.zk = KazooClient(
            hosts='10.167.218.158:2181',
            timeout=10.0,
            logger=logging
        )
        self.zk.start()

    def acquire(self):
        if not self.zk.exists(self.root):
            self.zk.create(self.root)
        if not self.node:
            self.node = self.zk.create(self.root+'/lock', ephemeral=True, sequence=True)
        nodes = self.zk.get_children(self.root)
        if nodes[0] == self.node:
            print('Acquire lock successfully')
            self.lock = True
        else:
            print('Acquire lock failed start watching')

            @self.zk.ChildrenWatch(self.root)
            def watch_func(data):
                print("Data is %s and node is %s and root.is %s" % (data, self.node, self.root))
                print(self.node, self.root + '/' + data[-1], self.node == self.root + '/' + data[-1])
                if self.node == self.root + '/' + data[-1]:
                    self.lock = True

    def release(self):
        self.zk.stop()


if __name__ == '__main__':
    t = ZkLock()
    while not t.lock:
        t.acquire()
    print('执行获取锁后的操作')
    time.sleep(10)
    print('执行操作结束释放锁')
    t.release()

优点:ZK可以不需要关心锁超时时间，实现起来有现成的第三方包，比较方便，并且支持读写锁，
ZK获取锁会按照加锁的顺序，所以其是公平锁。对于高可用利用ZK集群进行保证。
缺点:ZK需要额外维护，增加维护成本，性能和Mysql相差不大，依然比较差。并且需要开发人员了解ZK是什么。

bigdatazookeeper

基础命令

zookeeper实现分布式锁