在 Python 中使用 Redis 连接池的正确方法
Correct Way of using Redis Connection Pool in Python
两个不同的模块foo.py
和bar.py
应该如何从Redis连接池获取连接?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。
Q1:在我的示例中,两个模块是否从同一连接池获取连接?
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?
Q3:延迟加载conn
实例变量真的有用吗?
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())
还是这样更好?
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())
A1:是的,他们用的是同一个连接池
A2:这不是一个好的做法。因为您无法控制此实例的初始化。另一种方法是使用单例。
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(metaclass=Singleton):
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)
那么RedisClient
就是一个单例class。无论你调用多少次client = RedisClient()
,你都会得到相同的对象。
所以你可以像这样使用它:
from RedisClient import RedisClient
client = RedisClient()
species = 'lion'
key = 'zoo:{0}'.format(species)
data = client.conn.hmget(key, 'age', 'weight')
print(data)
而您第一次调用 client = RedisClient()
将实际初始化此实例。
或者您可能希望根据不同的参数获取不同的实例:
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]
两个不同的模块foo.py
和bar.py
应该如何从Redis连接池获取连接?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。
Q1:在我的示例中,两个模块是否从同一连接池获取连接?
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?
Q3:延迟加载conn
实例变量真的有用吗?
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())
还是这样更好?
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())
A1:是的,他们用的是同一个连接池
A2:这不是一个好的做法。因为您无法控制此实例的初始化。另一种方法是使用单例。
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(metaclass=Singleton):
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)
那么RedisClient
就是一个单例class。无论你调用多少次client = RedisClient()
,你都会得到相同的对象。
所以你可以像这样使用它:
from RedisClient import RedisClient
client = RedisClient()
species = 'lion'
key = 'zoo:{0}'.format(species)
data = client.conn.hmget(key, 'age', 'weight')
print(data)
而您第一次调用 client = RedisClient()
将实际初始化此实例。
或者您可能希望根据不同的参数获取不同的实例:
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]