Python 消息队列snakemq总结
最近学习消息总线zeromq，在网上搜了python实现的消息总线模块，意外发现有个消息队列snakemq，于是拿来研究一下，感觉还是很不错的，入手简单使用也简单（比ice强多了），就是资料太少了，只能自己抠。
一、关于snakemq的官方介绍
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()
6symmetrical -- 单个TCP连接可用于双工通讯
7多数据库支持 -- SQLite、MongoDB……
8brokerless - 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 -*-
#*********************************************************#
# @@FileName: callbacks.py
# @@Author:
Shelwinnee<[email protected]>
# @@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类（snakemqConnector.py）：
# -*- coding:utf-8 -*-
#*********************************************************#
# @@FileName: snakemqConnector.py
# @@Author:
Shelwinnee<[email protected]>
# @@Create Date: 2016-04-14 22:24:14
# @@Modify Date: 2016-04-14 22:24:34
# @@Description: file operation base
class,sub class should implement saveByDocument and loadByDocument
# 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类（snakemqListener.py）：
# -*- coding:utf-8 -*-
#*********************************************************#
# @@FileName: snakemqListener.py
# @@Author:
Shelwinnee<[email protected]>
# @@Create Date: 2016-04-14 22:24:14
# @@Modify Date: 2016-04-14 22:24:34
# @@Description: file operation base
class,sub class should implement saveByDocument and loadByDocument
# 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)
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...")
四、测试结果
应该与其它消息类组件对比后出结论。应付一个小项目绝对杠杠滴。