Question

两个不同的模块foo.py和bar.py如何从Redis连接池获得连接？换句话说，我们应该如何构建应用程序？

我认为目标是为所有模块提供一个连接池，以便从中获取连接。

Q1：在我的示例中，两个模块是否从同一个连接池获得连接？

Q2：在RedisClient.py中创建RedisClient实例是否可以，然后将实例导入其他2个模块？或者有更好的方法吗？

问题3： conn实例变量的延迟加载实际上有用吗？

RedisClient.py

import redis

class RedisClient(object):

    def __init__(self):
        self.pool = redis.ConnectionPool(host = HOST, port = PORT, password = PASSWORD)

    @property
    def conn(self):
        if not hasattr(self, '_conn'):
            self.getConnection()
        return self._conn

    def getConnection(self):
        self._conn = redis.Redis(connection_pool = self.pool)

redisClient = RedisClient()

foo.py

from RedisClient import redisClient

species = 'lion'
key = 'zoo:{0}'.format(species)
data = redisClient.conn.hmget(key, 'age', 'weight')
print(data)

bar.py

from RedisClient import redisClient

print(redisClient.conn.ping())

或者这样更好吗？

RedisClient.py

import redis

class RedisClient(object):

    def __init__(self):
        self.pool = redis.ConnectionPool(host = HOST, port = PORT, password = PASSWORD)

    def getConnection(self):
        return redis.Redis(connection_pool = self.pool)

redisClient = RedisClient()

foo.py

from RedisClient import redisClient

species = 'lion'
key = 'zoo:{0}'.format(species)
data = redisClient.getConnection().hmget(key, 'age', 'weight')
print(data)

bar.py

from RedisClient import redisClient

print(redisClient.getConnection().ping())

Answer 1

A1：是的，他们使用相同的连接池。

A2：这不是一个好习惯。因为您无法控制此实例的初始化。替代方案可以是使用单身人士。

import redis


class Singleton(type):
    """
    An metaclass for singleton purpose. Every singleton class should inherit from this class by 'metaclass=Singleton'.
    """
    _instances = {}

    def __call__(cls, *args, **kwargs):
        if cls not in cls._instances:
            cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls]


class RedisClient(object):

    def __init__(self):
        self.pool = redis.ConnectionPool(host = HOST, port = PORT, password = PASSWORD)

    @property
    def conn(self):
        if not hasattr(self, '_conn'):
            self.getConnection()
        return self._conn

    def getConnection(self):
        self._conn = redis.Redis(connection_pool = self.pool)

然后RedisClient将成为单身人士类。无论您拨打client = RedisClient()多少次，都会获得相同的对象。

所以你可以像：

一样使用它

from RedisClient import RedisClient

client = RedisClient()
species = 'lion'
key = 'zoo:{0}'.format(species)
data = client.conn.hmget(key, 'age', 'weight')
print(data)

第一次调用client = RedisClient()时，实际上会初始化此实例。

或者您可能希望根据不同的参数获得不同的实例：

class Singleton(type):
    """
    An metaclass for singleton purpose. Every singleton class should inherit from this class by 'metaclass=Singleton'.
    """
    _instances = {}

    def __call__(cls, *args, **kwargs):
        key = (args, tuple(sorted(kwargs.items())))
        if cls not in cls._instances:
            cls._instances[cls] = {}
        if key not in cls._instances[cls]:
            cls._instances[cls][key] = super(Singleton, cls).__call__(*args, **kwargs)
        return cls._instances[cls][key]

在Python中使用Redis连接池的正确方法

1 个答案: