• python codis集群客户端(二)


     在这一篇中我们实现了不通过zk来编写codis集群proxys的api,http://www.cnblogs.com/kangoroo/p/7481567.html

    如果codis集群暴露zk给你的话,那么就方便了,探活和故障摘除与恢复codis集群都给你搞定了,你只需要监听zookeeper中实例的状态就好了。

    下面看我的实现。

    1、CodisByZKPool.py

    这里通过zk读取并初始化pool_shards,简单说一下如何故障摘除和恢复

    1)我们监听zk中节点状态改变,当发现某个实例对应的节点状态变化了,比如DELETE了,那么我们认为这个实例挂了,我们就会重新_create_pool刷新shards列表,摘除故障实例。

    2)同样,当我们发现节点CREATE,就是新增了实例,或者实例从崩溃中恢复了,我们也会重新_create_pool刷新shards列表,新增实例。

    # -*- coding:utf-8 -*-
    import redis
    import logging
    from kazoo.client import KazooClient
    from Podis import Podis
    from PickUp import RandomPickUp, PickUp
    
    logger = logging.getLogger(__name__)
    
    
    class CodisByZKPool(object):
    
        def __init__(self, zk_config):
            self._pool_shards = []
            self.zk_config = zk_config
            self.zk = self._init_zk()
    
        def _init_zk(self):
            return KazooClient(hosts=self.zk_config.get('hosts'), timeout=self.zk_config.get('timeout'))
    
        def _create_pool(self):
            try:
                if not self.zk.connected:
                    self.zk.start()
                address_list = self.zk.get_children(self.zk_config.get('path'), watch=self._watch_codis_instances)
                for address in address_list:
                    host = address.split(':')[0]
                    port = address.split(':')[1]
                    self._pool_shards.append(
                        Podis(
                            redis.ConnectionPool(
                                host=host, port=port, db=0,
                                password=None,
                                max_connections=None
                            )
                        )
                    )
                if len(self._pool_shards) == 0:
                    raise Exception('create pool failure!')
            except Exception, ex:
                raise
            finally:
                self.zk.stop()
    
        def _watch_codis_instances(self, event):
            if event.type == "CREATED" and event.state == "CONNECTED":
                self._create_pool()
            elif event.type == "DELETED" and event.state == "CONNECTED":
                self._create_pool()
            elif event.type == "CHANGED" and event.state == "CONNECTED":
                self._create_pool()
            elif event.type == "CHILD" and event.state == "CONNECTED":
                self._create_pool()
            else:
                logger.error('failure: not cover this event - %s'.format(event.type))
    
        def get_connection(self, pick_up=None):
            if isinstance(pick_up, PickUp):
                codisPool = pick_up.pick_up(self._pool_shards)
            else:
                pick_up = RandomPickUp()
                codisPool = pick_up.pick_up(self._pool_shards)
            return codisPool
    
        def get_availables(self):
            return self._pool_shards

    2、负载均衡PickUp.py

    上一篇一样,这里就不多说了。

    # -*- coding:utf-8 -*-
    import abc
    import uuid
    import threading
    
    class PickUp(object):
    
        __metaclass__ = abc.ABCMeta
    
        @abc.abstractmethod
        def __init__(self):
            pass
    
        @abc.abstractmethod
        def pick_up(self, pool_list):
            return
    
    
    class RandomPickUp(PickUp):
        def __init__(self):
            PickUp.__init__(self)
    
        def pick_up(self, pool_list):
            pool_size = len(pool_list)
            index = abs(hash(uuid.uuid4())) % pool_size
            pool = pool_list[index]
            print "RandomPickUp, 拿到第", index, "个pool"
            return pool
    
    
    class RoundRobinPickUp(PickUp):
    
        def __init__(self):
            PickUp.__init__(self)
            self.index = 0
            self.round_robin_lock = threading.Lock()
    
        def pick_up(self, pool_list):
            with self.round_robin_lock:
                pool_size = len(pool_list)
                self.index += 1
                index = abs(self.index) % pool_size
                pool = pool_list[index]
                print "RoundRobinPickUp, 拿到第", index, "个pool"
                return pool

    3、配置文件

    这里就只用zk_config就可以了,我们认为在zk中已经有所有的codisproxy实例的address了。

    codis_config = {
        'addrs': '100.90.186.47:3000,100.90.187.33:3000'
    }
    
    zk_config = {
        'hosts': '10.93.21.21:2181,10.93.18.34:2181,10.93.18.35:2181',
        'timeout': 10,
        'path': '/codis/instances'
    }

    4、链接类Podis.py

    # -*- coding:utf-8 -*-
    import redis
    import logging
    import traceback
    
    logger = logging.getLogger(__name__)
    
    
    def redis_getter(func):
        def wrapper(*args, **kwargs):
            try:
                result = func(*args, **kwargs)
                return result or None
            except Exception, ex:
                logger.error(traceback.format_exc())
                raise
        return wrapper
    
    
    def redis_setter(func):
        def wrapper(*args, **kwargs):
            try:
                func(*args, **kwargs)
                return True
            except Exception, ex:
                logger.error(traceback.format_exc())
                raise
        return wrapper
    
    
    class Podis(object):
    
        def __init__(self, pool):
            self._connection = redis.StrictRedis(connection_pool=pool)
    
        @redis_getter
        def ping(self):
            return self._connection.ping()
    
        @redis_getter
        def get(self, key):
            return self._connection.get(key)
    
        @redis_setter
        def set(self, key, value):
            self._connection.set(key, value)
    
        @redis_setter
        def lpush(self, key, *value):
            self._connection.lpush(key, *value)
    
        @redis_getter
        def lpop(self, key):
            return self._connection.lpop(key)
    
        @redis_getter
        def lrange(self, key, start, end):
            return self._connection.lrange(key, start, end)
    
        @redis_setter
        def sadd(self, key, *value):
            self._connection.sadd(key, *value)
    
        @redis_setter
        def srem(self, key, *value):
            self._connection.srem(key, *value)
    
        @redis_getter
        def zrange(self,key,start,end):
            return self._connection.zrange(key,start,end)
    
        @redis_getter
        def zrevrange(self,key,start,end):
            return self._connection.zrevrange(key,start,end,withscores=True)
    
        @redis_getter
        def zscore(self,key,*value):
            return self._connection.zscore(key,value)
    
        @redis_setter
        def zadd(self,key,score,*value):
            self._connection.zadd(key,score,value)
    
        @redis_getter
        def smembers(self, key):
            return self._connection.smembers(key)
    
        @redis_getter
        def hgetall(self, key):
            return self._connection.hgetall(key)
    
        @redis_getter
        def hget(self, key, name):
            return self._connection.hget(key, name)
    
        @redis_getter
        def hkeys(self, key):
            return self._connection.hkeys(key)
    
        @redis_setter
        def hset(self, key, name, value):
            self._connection.hset(key, name, value)
    
        @redis_setter
        def hmset(self, name, mapping):
            self._connection.hmset(name, mapping)
    
        @redis_setter
        def hdel(self, key, name):
            self._connection.hdel(key, name)
    
        @redis_setter
        def delete(self, *key):
            self._connection.delete(*key)
    
        # codis不支持
        @redis_getter
        def keys(self, pattern):
            return self._connection.keys(pattern)
    
        @redis_setter
        def expire(self, key, time):
            return self._connection.expire(key, time)
    
        @redis_getter
        def ttl(self, key):
            return self._connection.ttl(key)

    5、例子

    import sys
    sys.path.append('../')
    import time
    import threading
    from pycodis.CodisConfig import zk_config
    from pycodis.CodisByZKPool import CodisByZKPool
    from pycodis.PickUp import RoundRobinPickUp
    
    codis_pool1 = CodisByZKPool(zk_config)
    print '------1-------'
    pick_up1 = RoundRobinPickUp()
    print '------2-------'
    codis_pool2 = CodisByZKPool(zk_config)
    print '------3-------'
    pick_up2 = RoundRobinPickUp()
    print '------4-------'
    
    
    def func(i):
        for i in range(10):
            podis1 = codis_pool1.get_connection(pick_up=pick_up1)
            podis2 = codis_pool2.get_connection(pick_up=pick_up2)
            podis1.delete(i)
            podis2.delete(i)
            time.sleep(1)
    
    thread_list = []
    for i in range(100):
        thread_list.append(threading.Thread(target=func, args=[i]))
    
    for thread in thread_list:
        thread.setDaemon(True)
        thread.start()
    
    time.sleep(10)
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  • 原文地址:https://www.cnblogs.com/kangoroo/p/7485760.html
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