python zeromq

659441806

　　python examples https://github.com/imatix/zguide/tree/master/examples/Python
　　
　　hwserver.py
  
   
     
Python代码       

     

• #      
  
• # Hello World server in Python      
  
• # Binds REP socket to tcp://*:5555      
  
• # Expects "Hello" from client, replies with "World"      
  
• #      
  
• import zmq      
  
• import time      
  
•       
  
• context = zmq.Context()      
  
• socket = context.socket(zmq.REP)      
  
• socket.bind("tcp://*:5555")      
  
•       
  
• while True:      
  
• # Wait for next request from client      
  
• message = socket.recv()      
  
• print "Received request: ", message      
  
•       
  
• # Do some 'work'      
  
• time.sleep (1) # Do some 'work'      
  
•       
  
• # Send reply back to client      
  
• socket.send("World")   
  

   #
#   Hello World server in Python
#   Binds REP socket to tcp://*:5555
#   Expects "Hello" from client, replies with "World"
#
import zmq
import time
context = zmq.Context()
socket = context.socket(zmq.REP)
socket.bind("tcp://*:5555")
while True:
#  Wait for next request from client
message = socket.recv()
print "Received request: ", message
#  Do some 'work'
time.sleep (1)        #   Do some 'work'
#  Send reply back to client
socket.send("World")
　　hwclient.py






Python代码

• #
  
• # Hello World client in Python
  
• # Connects REQ socket to tcp://localhost:5555
  
• # Sends "Hello" to server, expects "World" back
  
• #
  
• import zmq
  
• 
  
• context = zmq.Context()
  
• 
  
• # Socket to talk to server
  
• print "Connecting to hello world server..."
  
• socket = context.socket(zmq.REQ)
  
• socket.connect ("tcp://localhost:5555")
  
• 
  
• # Do 10 requests, waiting each time for a response
  
• for request in range (1,10):
  
• print "Sending request ", request,"..."
  
• socket.send ("Hello")
  
• 
  
• # Get the reply.
  
• message = socket.recv()
  
• print "Received reply ", request, "[", message, "]"
  

#
#   Hello World client in Python
#   Connects REQ socket to tcp://localhost:5555
#   Sends "Hello" to server, expects "World" back
#
import zmq
context = zmq.Context()
#  Socket to talk to server
print "Connecting to hello world server..."
socket = context.socket(zmq.REQ)
socket.connect ("tcp://localhost:5555")
#  Do 10 requests, waiting each time for a response
for request in range (1,10):
print "Sending request ", request,"..."
socket.send ("Hello")
#  Get the reply.
message = socket.recv()
print "Received reply ", request, "[", message, "]"

　　问题3：zeroMQ实现一个消息层？
　　答：
　　实现一个ZeroMQ消息层需要三个步骤：
　　1.选择传输协议
　　0MQ提供了4种不同的传输协议
　　INPROC an In-Process communication model
　　IPC an Inter-Process communication model
　　MULTICAST multicast via PGM, possibly encapsulated in UDP
　　TCP a network based transport
　　
　　2.建立基础
　　由于在网络中两个端点是相对动态的，很难有一个稳定的单一连接点。
　　如果是这种情况，可以使用由0MQ提供的转发设备。
　　转发设备可以绑定2个不同端口，并且转发消息从一个端点到另一个端点。
　　这样做的话，在网络中转发设备能够变成一个稳定的点，其它组件都可以去连接。
　　
　　0MQ提供了3种类型的设备
　　QUEUE, a forwarder for the request/response messaging pattern
　　FORWARDER, a forwarder for the publish/subscribe messaging pattern
　　STREAMER, a forwarder for the pipelined messaging pattern
　　
　　
　　3.选择通讯模式
　　0MQ支持4种模式
　　REQUEST/REPLY, bidirectional, load balanced and state based
　　PUBLISH/SUBSCRIBE, publish to multiple recipients at once
　　UPSTREAM / DOWNSTREAM, distribute data to nodes arranged in a pipeline
　　PAIR, communication exclusively between peers
　　
　　Req/Rep
　　均衡负载请求：
　　server 1






Python代码

• import zmq
  
• context = zmq.Context()
  
• socket = context.socket(zmq.REP)
  
• socket.bind("tcp://127.0.0.1:5000")
  
• 
  
• while True:
  
• msg = socket.recv()
  
• print "Got", msg
  
• socket.send(msg)
  

import zmq
context = zmq.Context()
socket = context.socket(zmq.REP)
socket.bind("tcp://127.0.0.1:5000")
while True:
msg = socket.recv()
print "Got", msg
socket.send(msg)

　　server 2






Python代码

• import zmq
  
• context = zmq.Context()
  
• socket = context.socket(zmq.REP)
  
• socket.bind("tcp://127.0.0.1:6000")
  
• 
  
• while True:
  
• msg = socket.recv()
  
• print "Got", msg
  
• socket.send(msg)
  

import zmq
context = zmq.Context()
socket = context.socket(zmq.REP)
socket.bind("tcp://127.0.0.1:6000")
while True:
msg = socket.recv()
print "Got", msg
socket.send(msg)
　　client






Python代码

• import zmq
  
• context = zmq.Context()
  
• socket = context.socket(zmq.REQ)
  
• socket.connect("tcp://127.0.0.1:5000")
  
• socket.connect("tcp://127.0.0.1:6000")
  
• 
  
• for i in range(10):
  
• msg = "msg %s" % i
  
• socket.send(msg)
  
• print "Sending", msg
  
• msg_in = socket.recv()
  

import zmq
context = zmq.Context()
socket = context.socket(zmq.REQ)
socket.connect("tcp://127.0.0.1:5000")
socket.connect("tcp://127.0.0.1:6000")
for i in range(10):
msg = "msg %s" % i
socket.send(msg)
print "Sending", msg
msg_in = socket.recv()

　　会发现client的请求会被均衡的分配给两个server
　　Example client output:

　　Sending msg 0
Sending msg 1
Sending msg 2
Sending msg 3
Sending msg 4
Sending msg 5
Sending msg 6
Sending msg 7
Sending msg 8
Sending msg 9

　　Example output server 1 at port 5000:

　　Got msg 0
Got msg 2
Got msg 4
Got msg 6
Got msg 8

　　Example output server 2 at port 6000:

　　Got msg 1
Got msg 3
Got msg 5
Got msg 7
Got msg 9

　　现在，如果我们要加入一个额外的server去管理我们的请求，我们将不得不修改我们的代码。
　　这是非常麻烦的，我们需要让每个client都知道有一个额外的server可以均衡请求。
　　为了解决这个问题，替代client直接去连接多个server的方式，client去连接转发设备，再由转发设备路由全部的消息给server。
　　
　　Pub/Sub
　　在pub/sub模式下组件是松耦合的。类似于广播电台。
　　一个广播server为现场足球赛






Python代码

• import zmq
  
• from random import choice
  
• context = zmq.Context()
  
• socket = context.socket(zmq.PUB)
  
• socket.bind("tcp://127.0.0.1:5000")
  
• 
  
• countries = ['netherlands','brazil','germany','portugal']
  
• events = ['yellow card', 'red card', 'goal', 'corner', 'foul']
  
• 
  
• while True:
  
• msg = choice( countries ) +" "+ choice( events )
  
• print "->",msg
  
• socket.send( msg )  
  

import zmq
from random import choice
context = zmq.Context()
socket = context.socket(zmq.PUB)
socket.bind("tcp://127.0.0.1:5000")
countries = ['netherlands','brazil','germany','portugal']
events = ['yellow card', 'red card', 'goal', 'corner', 'foul']
while True:
msg = choice( countries ) +" "+ choice( events )
print "->",msg
socket.send( msg )
　　输出
　　-> portugal corner
-> portugal yellow card
-> portugal goal
-> netherlands yellow card
-> germany yellow card
-> brazil yellow card
-> portugal goal
-> germany corner
…
　　
　　一个客户端去收听特定的消息






Python代码

• import zmq
  
• 
  
• context = zmq.Context()
  
• socket = context.socket(zmq.SUB)
  
• socket.connect("tcp://127.0.0.1:5000")
  
• socket.setsockopt(zmq.SUBSCRIBE, "netherlands")
  
• socket.setsockopt(zmq.SUBSCRIBE, "germany")
  
• 
  
• while True:
  
• print socket.recv()
  

import zmq
context = zmq.Context()
socket = context.socket(zmq.SUB)
socket.connect("tcp://127.0.0.1:5000")
socket.setsockopt(zmq.SUBSCRIBE, "netherlands")
socket.setsockopt(zmq.SUBSCRIBE, "germany")
while True:
print  socket.recv()
　　输出
　　netherlands red card
netherlands goal
netherlands red card
germany foul
netherlands yellow card
germany foul
netherlands goal
netherlands corner
germany foul
netherlands corner
…
　　
　　Pipelining
　　并发处理数据，其工作模式
　　一个工作者得到来自上游socket的消息，一旦处理完成后发送消息到下游。
　　
　　Paired socket
　　服务器监听某个端口，客户端连接到这个端口，消息可以双向流动。
　　server






Python代码

• import zmq
  
• context = zmq.Context()
  
• socket = context.socket(zmq.PAIR)
  
• socket.bind("tcp://127.0.0.1:5555")
  

import zmq
context = zmq.Context()
socket = context.socket(zmq.PAIR)
socket.bind("tcp://127.0.0.1:5555")

　　
　　client






Python代码

• import zmq
  
• context = zmq.Context()
  
• socket = context.socket(zmq.PAIR)
  
• socket.connect("tcp://127.0.0.1:5555")
  

import zmq
context = zmq.Context()
socket = context.socket(zmq.PAIR)
socket.connect("tcp://127.0.0.1:5555")

　　
　　ps:
　　推荐
　　http://www.zeromq.org/
　　http://nichol.as/zeromq-an-introduction