Python的訊息佇列套件SnakeMQ使用

使用訊息佇列在資料的通訊中擁有許多優點,SnakeMQ是一個開源的用Python實現的跨平台MQ函式庫,well,Python的訊息佇列套件SnakeMQ使用初探,here we go:

#一、關於snakemq的官方介紹
SnakeMQ的GitHub專案頁：https://github.com/dsiroky/snakemq1.純python實現，跨平台

2.自動重連線

3.可靠地傳送--可設定的訊息方式與訊息逾時方式

4.持久化/暫時兩種佇列

5.支援非同步-- poll ()

6.symmetrical -- 單一TCP連線可用於雙工通訊

7.多資料庫支援-- SQLite、MongoDB…

8.brokerless - 類似ZeroMQ的實作原理

9.擴充模組：RPC, bandwidth throttling

以上都是官話，需要自己驗證，動手封裝了一下，感覺萌萌噠。

二、幾個主要問題說明

1.支援自動重連，不需要自己動手寫心跳邏輯，你只需要專注於發送和接收就行

2.支援資料持久化，如果開始持久化，在重連之後會自動發送資料。

3.資料的接收，snakemq透過提供回呼實現，你只需要寫個接收方法加入回呼列表裡去。

4.資料的傳送，在此發送的都是bytes類型（二進位），因此需要轉換。我在程式中測試的都是文字字串，使用str.encode(‘utf-8')轉換成bytes，接收時再轉換回來。

5.術語解釋，Connector：類似socket的TcpClient，Lisenter：類似socket的TcpServer，每個connector或listener都一個一個ident標識，發送和接收資料時就知道是誰的資料了。

6.使用sqlite持久化時，需要修改原始碼，sqlite3.connect(filename,check_same_thread = False)，用於解決多執行緒存取sqlite的問題。 （會不會死鎖？）

7.啟動持久化時，如果重新連上，則會自動發送，保證可靠。

8.為了封裝的需要，資料接收以後，我透過callback方式傳送出去。

三、程式碼

說明程式碼中使用了自訂的日誌模組

from common import nxlogger

import snakemqlogger as logger

可替換成logging的。

回呼類別（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類別（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類別（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)

測試程式碼connector（testSnakeConnector.py）：

讀取本地一個1M的文件，然後傳送給listener，然後listener傳回一個hello的訊息。

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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