Zookeeper深入理解（三）kazoo接口

yum install python-pip

pip install kazoo

#!/usr/bin/env python
# _*_coding:utf-8_*_
import time

from kazoo.client import KazooClient

from kazoo.client import KazooState


def main():
	zk = KazooClient(hosts='127.0.0.1:2182')

	zk.start()

	@zk.add_listener
	def my_listener(state):

		if state == KazooState.LOST:

			print("LOST")

		elif state == KazooState.SUSPENDED:

			print("SUSPENDED")

		else:

			print("Connected")

	# Creating Nodes

	# Ensure a path, create if necessary

	zk.ensure_path("/my/favorite")

	# Create a node with data

	zk.create("/my/favorite/node", b"")

	zk.create("/my/favorite/node/a", b"A")

	# Reading Data

	# Determine if a node exists

	if zk.exists("/my/favorite"):
		print("/my/favorite is existed")

	@zk.ChildrenWatch("/my/favorite/node")
	def watch_children(children):

		print("Children are now: %s" % children)

	# Above function called immediately, and from then on

	@zk.DataWatch("/my/favorite/node")
	def watch_node(data, stat):

		print("Version: %s, data: %s" % (stat.version, data.decode("utf-8")))

	# Print the version of a node and its data

	data, stat = zk.get("/my/favorite/node")

	print("Version: %s, data: %s" % (stat.version, data.decode("utf-8")))

	# List the children

	children = zk.get_children("/my/favorite/node")

	print("There are %s children with names %s" % (len(children), children))

	# Updating Data

	zk.set("/my/favorite", b"some data")

	# Deleting Nodes

	zk.delete("/my/favorite/node/a")

	# Transactions

	transaction = zk.transaction()

	transaction.check('/my/favorite/node', version=-1)

	transaction.create('/my/favorite/node/b', b"B")

	results = transaction.commit()

	print ("Transaction results is %s" % results)

	zk.delete("/my/favorite/node/b")

	zk.delete("/my", recursive=True)

	time.sleep(2)

	zk.stop()


if __name__ == "__main__":

	try:

		main()

	except Exception, ex:

		print "Ocurred Exception: %s" % str(ex)

		quit()

Children are now: [u'a']

Version: 0, data: 

Version: 0, data: 

There are 1 children with names [u'a']

Children are now: []

Transaction results is [True, u'/my/favorite/node/b']

Children are now: [u'b']

Children are now: []

No handlers could be found for logger "kazoo.recipe.watchers"

LOST

import logging, os, time

from kazoo.client import KazooClient

from kazoo.client import KazooState

from kazoo.recipe.lock import Lock

 

class ZooKeeperLock():

    def __init__(self, hosts, id_str, lock_name, logger=None, timeout=1):

        self.hosts = hosts

        self.id_str = id_str

        self.zk_client = None

        self.timeout = timeout

        self.logger = logger

        self.name = lock_name

        self.lock_handle = None

        self.create_lock()

    def create_lock(self):

        try:

            self.zk_client = KazooClient(hosts=self.hosts, logger=self.logger, timeout=self.timeout)

            self.zk_client.start(timeout=self.timeout)

        except Exception, ex:

            self.init_ret = False

            self.err_str = "Create KazooClient failed! Exception: %s" % str(ex)

            logging.error(self.err_str)

            return

        try:

            lock_path = os.path.join("/", "locks", self.name)

            self.lock_handle = Lock(self.zk_client, lock_path)

        except Exception, ex:

            self.init_ret = False

            self.err_str = "Create lock failed! Exception: %s" % str(ex)

            logging.error(self.err_str)

            return

    def destroy_lock(self):

        #self.release()

        if self.zk_client != None:

            self.zk_client.stop()

            self.zk_client = None

    def acquire(self, blocking=True, timeout=None):

        if self.lock_handle == None:

            return None

        try:

            return self.lock_handle.acquire(blocking=blocking, timeout=timeout)

        except Exception, ex:

            self.err_str = "Acquire lock failed! Exception: %s" % str(ex)

            logging.error(self.err_str)

            return None

    def release(self):

        if self.lock_handle == None:

            return None

        return self.lock_handle.release()

    def __del__(self):

        self.destroy_lock()

 

def main():

    logger = logging.getLogger()

    logger.setLevel(logging.INFO)

    sh = logging.StreamHandler()

    formatter = logging.Formatter('%(asctime)s -%(module)s:%(filename)s-L%(lineno)d-%(levelname)s: %(message)s')

    sh.setFormatter(formatter)

    logger.addHandler(sh)

    zookeeper_hosts = "127.0.0.1:2182"

    lock_name = "test"

    lock = ZooKeeperLock(zookeeper_hosts, "myid is 1", lock_name, logger=logger)

    ret = lock.acquire()

    if not ret:

        logging.info("Can't get lock! Ret: %s", ret)

        return

    logging.info("Get lock! Do something! Sleep 10 secs!")

    for i in range(1, 11):

        time.sleep(1)

        print str(i)

    lock.release()

 

if __name__ == "__main__":

    try:

        main()

    except Exception, ex:

        print "Ocurred Exception: %s" % str(ex)

        quit()