Python与Redis的连接教程

今天在写zabbix storm job监控脚本的时候用到了python的redis模块，之前也有用过，但是没有过多的了解，今天看了下相关的api和源码,看到有ConnectionPool的实现，这里简单说下。
在ConnectionPool之前，如果需要连接redis，我都是用StrictRedis这个类，在源码中可以看到这个类的具体解释：
 
redis.StrictRedis Implementation of the Redis protocol.This abstract class provides a Python interface to all Redis commands and an
implementation of the Redis protocol.Connection and Pipeline derive from this, implementing how the commands are sent and received to the Redis server

使用的方法：
 

 r=redis.StrictRedis(host=xxxx, port=xxxx, db=xxxx) r.xxxx()

有了ConnectionPool这个类之后，可以使用如下方法
 

pool = redis.ConnectionPool(host=xxx, port=xxx, db=xxxx)r = redis.Redis(connection_pool=pool)

这里Redis是StrictRedis的子类
简单分析如下：
在StrictRedis类的__init__方法中，可以初始化connection_pool这个参数，其对应的是一个ConnectionPool的对象：
 

class StrictRedis(object):........  def __init__(self, host='localhost', port=6379,         db=0, password=None, socket_timeout=None,         socket_connect_timeout=None,         socket_keepalive=None, socket_keepalive_options=None,         connection_pool=None, unix_socket_path=None,         encoding='utf-8', encoding_errors='strict',         charset=None, errors=None,         decode_responses=False, retry_on_timeout=False,         ssl=False, ssl_keyfile=None, ssl_certfile=None,         ssl_cert_reqs=None, ssl_ca_certs=None):     if not connection_pool:       ..........       connection_pool = ConnectionPool(**kwargs)     self.connection_pool = connection_pool

在StrictRedis的实例执行具体的命令时会调用execute_command方法，这里可以看到具体实现是从连接池中获取一个具体的连接，然后执行命令，完成后释放连接：

  # COMMAND EXECUTION AND PROTOCOL PARSING  def execute_command(self, *args, **options):    "Execute a command and return a parsed response"    pool = self.connection_pool    command_name = args[0]    connection = pool.get_connection(command_name, **options) #调用ConnectionPool.get_connection方法获取一个连接    try:      connection.send_command(*args) #命令执行，这里为Connection.send_command      return self.parse_response(connection, command_name, **options)    except (ConnectionError, TimeoutError) as e:      connection.disconnect()      if not connection.retry_on_timeout and isinstance(e, TimeoutError):        raise      connection.send_command(*args)       return self.parse_response(connection, command_name, **options)    finally:      pool.release(connection) #调用ConnectionPool.release释放连接