Python 消息隊列snakemq總結
最近學習消息總線zeromq，在網上搜了python實現的消息總線模塊，意外發現有個消息隊列snakemq，於是拿來研究一下，感覺還是很不錯的，入手簡單使用也簡單（比ice強多了），就是資料太少了，只能自己摳。
一、關於snakemq的官方介紹
1純python實現，跨平台
2自動重連接
3可靠發送--可配置的消息方式與消息超時方式
4持久化/臨時 兩種隊列
5支持異步 -- poll()
6symmetrical -- 單個TCP連接可用於雙工通訊
7多數據庫支持 -- SQLite、MongoDB……
8brokerless - 類似ZeroMQ的實現原理
9擴展模塊：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支持自動重連，不需要自己動手寫心跳邏輯，你只需要關注發送和接收就行
2支持數據持久化，如果開始持久化，在重連之后會自動發送數據。
3數據的接收，snakemq通過提供回調實現，你只需要寫個接收方法添加到回調列表里去。
4數據的發送，在此發送的都是bytes類型（二進制），因此需要轉換。我在程序中測試的都是文本字符串，使用str.encode(‘utf-8’)轉換成bytes，接收時再轉換回來。
5術語解釋，Connector：類似於socket的TcpClient，Lisenter：類似於socket的TcpServer，每個connector或者listener都一個一個ident標識，發送和接收數據時就知道是誰的數據了。
6使用sqlite持久化時，需要修改源碼，sqlite3.connect(filename,check_same_thread = False)，用於解決多線程訪問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，數據接收以后，我通過callback方式傳送出去。
三、代碼
說明代碼中使用了自定義的日志模塊
from common import nxlogger
import snakemqlogger as logger
可替換成logging的。
回調類（callbacks.py）：
# -*- coding:utf-8 -*-
#*********************************************************#
# @@FileName: callbacks.py
# @@Author: Shelwinnee<Shelwinnee@163.com>
# @@Create Date: 2016-04-14 22:24:14
# @@Modify Date: 2016-04-14 22:24:34
# @@Description: simple synchronized callbacks helper
#*********************************************************#
'''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（snakemqConnector.py）：
# -*- coding:utf-8 -*-
#*********************************************************#
# @@FileName: snakemqConnector.py
# @@Author: Shelwinnee<Shelwinnee@163.com>
# @@Create Date: 2016-04-14 22:24:14
# @@Modify Date: 2016-04-14 22:24:34
# @@Description:
# note:if message persistent is necessary, please make sure you know the following instruction meaning,
# 'sqlite object created in a thread can only be used in that same thread'
# this problem's solution: modify the connection method of sqlite3, open file ('snakemq\storage\sqlite.py') ,and modify the following code:
# self.conn = sqlite3.connect(filename,check_same_thread = False)
#*********************************************************#
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（snakemqListener.py）：
# -*- coding:utf-8 -*-
#*********************************************************#
# @@FileName: snakemqListener.py
# @@Author: Shelwinnee<Shelwinnee@163.com>
# @@Create Date: 2016-04-14 22:24:14
# @@Modify Date: 2016-04-14 22:24:34
# @@Description:
# note:if message persistent is necessary, please make sure you know the following instruction meaning,
# 'sqlite object created in a thread can only be used in that same thread'
# this problem's solution: modify the connection method of sqlite3, open file ('snakemq\storage\sqlite.py') ,and modify the following code:
# self.conn = sqlite3.connect(filename,check_same_thread = False)
#*********************************************************#
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)
測試代碼connector（testSnakeConnector.py）：
讀取本地一個1M的文件，然后發送給listener，然后listener發回一個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()
測試代碼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...")
四、測試結果
應該與其它消息類組件對比后出結論。應付一個小項目絕對杠杠滴。