Python的消息队列包SnakeMQ使用初探

638次阅读  |  发布于5年以前

一、关于snakemq的官方介绍
SnakeMQ的GitHub项目页:https://github.com/dsiroky/snakemq
1.纯python实现,跨平台

2.自动重连接

3.可靠发送--可配置的消息方式与消息超时方式

4.持久化/临时 两种队列

5.支持异步 -- poll()

6.symmetrical -- 单个TCP连接可用于双工通讯

7.多数据库支持 -- SQLite、MongoDB……

8.brokerless - 类似ZeroMQ的实现原理

9.扩展模块:RPC, bandwidth throttling

以上都是官话,需要自己验证,动手封装了一下,感觉萌萌哒。

二、几个主要问题说明

1.支持自动重连,不需要自己动手写心跳逻辑,你只需要关注发送和接收就行

2.支持数据持久化,如果开始持久化,在重连之后会自动发送数据。

3.数据的接收,snakemq通过提供回调实现,你只需要写个接收方法添加到回调列表里去。

4.数据的发送,在此发送的都是bytes类型(二进制),因此需要转换。我在程序中测试的都是文本字符串,使用str.encode('utf-8')转换成bytes,接收时再转换回来。

5.术语解释,Connector:类似于socket的TcpClient,Lisenter:类似于socket的TcpServer,每个connector或者listener都一个一个ident标识,发送和接收数据时就知道是谁的数据了。

6.使用sqlite持久化时,需要修改源码,sqlite3.connect(filename,check_same_thread = False),用于解决多线程访问sqlite的问题。(会不会死锁?)

7.启动持久化时,如果重新连上,则会自动发送,保证可靠。

8.为了封装的需要,数据接收以后,我通过callback方式传送出去。

三、代码

说明代码中使用了自定义的日志模块


    from common import nxlogger

    import snakemqlogger as logger

可替换成logging的。

回调类(callbacks.py):


    # -*- coding:utf-8 -*-

    '''synchronized callback'''

    class Callback(object):

      def __init__(self):

        self.callbacks = []



      def add(self, func):

        self.callbacks.append(func)



      def remove(self, func):

        self.callbacks.remove(func)



      def __call__(self, *args, **kwargs):

        for callback in self.callbacks:

          callback(*args, **kwargs)

Connector类(snakemqConnector.py):


    # -*- coding:utf-8 -*-

    import threading

    import snakemq

    import snakemq.link

    import snakemq.packeter

    import snakemq.messaging

    import snakemq.message

    from snakemq.storage.sqlite import SqliteQueuesStorage

    from snakemq.message import FLAG_PERSISTENT

    from common.callbacks import Callback



    from common import nxlogger

    import snakemqlogger as logger



    class SnakemqConnector(threading.Thread):

         def __init__(self, snakemqident = None, remoteIp = "localhost", remotePort = 9090, persistent = False):

             super(SnakemqConnector,self).__init__()

             self.messaging = None

             self.link = None

             self.snakemqident = snakemqident

             self.pktr = None

             self.remoteIp = remoteIp

             self.remotePort = remotePort

             self.persistent = persistent

             self.on_recv = Callback()

             self._initConnector()



         def run(self):

             logger.info("connector start...")



             if self.link != None:

                  self.link.loop()



             logger.info("connector end...")



         def terminate(self):

             logger.info("connetor terminating...")

             if self.link != None:

                  self.link.stop()

                  self.link.cleanup()

             logger.info("connetor terminated")



         def on_recv_message(self, conn, ident, message):

             try:

                  self.on_recv(ident, message.data.decode('utf-8'))#dispatch received data

             except Exception as e:

                  logger.error("connector recv:{0}".format(e))

                  print(e)



         '''send message to dest host named destIdent'''

         def sendMsg(self, destIdent, byteseq):

             msg = None

             if self.persistent:

                  msg = snakemq.message.Message(byteseq, ttl=60, flags=FLAG_PERSISTENT)

             else:

                  msg = snakemq.message.Message(byteseq, ttl=60)

             if self.messaging == None:

                  logger.error("connector:messaging is not initialized, send message failed")

                  return

             self.messaging.send_message(destIdent, msg)



         '''



         '''

         def _initConnector(self):

             try:

                  self.link = snakemq.link.Link()

                  self.link.add_connector((self.remoteIp, self.remotePort))



                  self.pktr = snakemq.packeter.Packeter(self.link)



                  if self.persistent:

                      storage = SqliteQueuesStorage("SnakemqStorage.db")

                      self.messaging = snakemq.messaging.Messaging(self.snakemqident, "", self.pktr, storage)

                  else:

                      self.messaging = snakemq.messaging.Messaging(self.snakemqident, "", self.pktr)



                  self.messaging.on_message_recv.add(self.on_recv_message)



             except Exception as e:

                  logger.error("connector:{0}".format(e))

             finally:

                  logger.info("connector[{0}] loop ended...".format(self.snakemqident))

Listener类(snakemqListener.py):


    # -*- coding:utf-8 -*-

    import threading

    import snakemq

    import snakemq.link

    import snakemq.packeter

    import snakemq.messaging

    import snakemq.message

    from common import nxlogger

    import snakemqlogger as logger

    from common.callbacks import Callback

    class SnakemqListener(threading.Thread):

         def __init__(self, snakemqident = None, ip = "localhost", port = 9090, persistent = False):

             super(SnakemqListener,self).__init__()

             self.messaging = None

             self.link = None

             self.pktr = None

             self.snakemqident = snakemqident

             self.ip = ip;

             self.port = port

             self.connectors = {}

             self.on_recv = Callback()

             self.persistent = persistent

             self._initlistener()



         '''

         thread run

         '''

         def run(self):

             logger.info("listener start...")



             if self.link != None:

                  self.link.loop()



             logger.info("listener end...")



         '''

         terminate snakemq listener thread

         '''

         def terminate(self):

             logger.info("listener terminating...")

             if self.link != None:

                  self.link.stop()

                  self.link.cleanup()

             logger.info("listener terminated")



         '''

         receive message from host named ident

         '''

         def on_recv_message(self, conn, ident, message):

             try:

                  self.on_recv(ident, message.data.decode('utf-8'))#dispatch received data

                  self.sendMsg('bob','hello,{0}'.format(ident).encode('utf-8'))

             except Exception as e:

                  logger.error("listener recv:{0}".format(e))

                  print(e)



         def on_drop_message(self, ident, message):

             print("message dropped", ident, message)

             logger.debug("listener:message dropped,ident:{0},message:{1}".format(ident, message))



         '''client connect'''

         def on_connect(self, ident):

             logger.debug("listener:{0} connected".format(ident))

             self.connectors[ident] = ident

             self.sendMsg(ident, "hello".encode('utf-8'))



         '''client disconnect'''

         def on_disconnect(self, ident):

             logger.debug("listener:{0} disconnected".format(ident))

             if ident in self.connectors:

                  self.connectors.pop(ident)



         '''

         listen start loop

         '''

         def _initlistener(self):

             try:

                  self.link = snakemq.link.Link()

                  self.link.add_listener((self.ip, self.port))



                  self.pktr = snakemq.packeter.Packeter(self.link)

                  self.pktr.on_connect.add(self.on_connect)

                  self.pktr.on_disconnect.add(self.on_disconnect)



                  if self.persistent:

                      storage = SqliteQueuesStorage("SnakemqStorage.db")

                      self.messaging = snakemq.messaging.Messaging(self.snakemqident, "", self.pktr, storage)

                  else:

                      self.messaging = snakemq.messaging.Messaging(self.snakemqident, "", self.pktr)



                  self.messaging.on_message_recv.add(self.on_recv_message)

                  self.messaging.on_message_drop.add(self.on_drop_message)



             except Exception as e:

                  logger.error("listener:{0}".format(e))

             finally:

                  logger.info("listener:loop ended...")

         '''send message to dest host named destIdent'''

         def sendMsg(self, destIdent, byteseq):

             msg = None

             if self.persistent:

                  msg = snakemq.message.Message(byteseq, ttl=60, flags=FLAG_PERSISTENT)

             else:

                  msg = snakemq.message.Message(byteseq, ttl=60)

             if self.messaging == None:

                  logger.error("listener:messaging is not initialized, send message failed")

                  return

             self.messaging.send_message(destIdent, msg)

测试代码connector(testSnakeConnector.py):

读取本地一个1M的文件,然后发送给listener,然后listener发回一个hello的信息。


    from netComm.snakemq import snakemqConnector

    import time

    import sys

    import os

    def received(ident, data):

         print(data)



    if __name__ == "__main__":

         bob = snakemqConnector.SnakemqConnector('bob',"10.16.5.45",4002,True)

         bob.on_recv.add(received)

         bob.start()

         try:

             with open("testfile.txt",encoding='utf-8') as f:

                  txt = f.read()

                  for i in range(100):

                      bob.sendMsg("niess",txt.encode('utf-8'))

                      time.sleep(0.1)

         except Exception as e:

             print(e)

         time.sleep(5)

         bob.terminate()   



    测试代码listener(testSnakeListener.py):

    from netComm.snakemq import snakemqListener

    import time



    def received(ident, data):

         filename = "log/recFile{0}.txt".format(time.strftime('%S',time.localtime()))

         file = open(filename,'w')

         file.writelines(data)

         file.close()



    if __name__ == "__main__":

         niess = snakemqListener.SnakemqListener("niess","10.16.5.45",4002)

         niess.on_recv.add(received)

         niess.start()

         print("niess start...")

         time.sleep(60)

         niess.terminate()  

         print("niess end...")

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