ZeroMQ is a library for building distributed applications that provides patterns for request-reply, publish-subscribe, and pipelining between clients and services. It demonstrates using these patterns to build a hello world server and client, stock ticker publisher and subscriber, and parallel task processing pipeline. ZeroMQ supports multiple transport types and languages.

1. Build your next project -
Super fast, distributed
and infinitely scalable.
Using ZeroMQ

2. Web Framework Tutorial
Application
Client
(Browser)

3. Real World

4. Queues
• Apache ActiveMQ
• RabbitMQ
• StormMQ
• Redis
…

5. ZeroMQ
0MQ
ØMQ

6. Basic Patterns
• Request/Reply
• Publish/Subscribe
• Pipelining
• Paired Sockets

7. Request - Reply

8. Hello World Server
import zmq
context = zmq.Context()
print "Starting hello world server..."
socket = context.socket(zmq.REP)
socket.bind("tcp://*:5555")
while True:
message = socket.recv()
print "Got: ", message
# Send the reply.
socket.send ("World")

9. Hello World Client
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 req_no in range (10):
socket.send ("Hello")
# Get the reply.
message = socket.recv()
print "Received reply ", req_no, "[", message, "]"

10. Hello World Client 2
import sys
import time
import zmq
context = zmq.Context()
print "Connecting to hello world server..."
socket = context.socket(zmq.REQ)
socket.connect ("tcp://localhost:5555")
while True:
socket.send(sys.argv[2])
# Get the reply.
message = socket.recv()
print "Received reply ", "[", message, "]"
time.sleep(float(sys.argv[1]))

11. Publish - Subscribe

12. Stock Ticker Server
import zmq
import time
import random
context = zmq.Context()
socket = context.socket(zmq.PUB)
socket.bind("tcp://*:5556")
scrips = ['AAPL', 'GOOG', 'MSFT', 'AMZN']
while True:
scrip = random.choice(scrips)
price = random.randrange(20,700)
msg = "%s: %d" % (scrip, price)
print msg
socket.send(msg)
time.sleep(0.5)

13. Stock Ticker Client
import sys
import zmq
context = zmq.Context()
socket = context.socket(zmq.SUB)
print "Collecting updates from stock server..."
socket.connect ("tcp://localhost:5556”)
scrip_filter = sys.argv[1:] if len(sys.argv) > 1 else ["AAPL"]
for scrip in scrip_filter:
socket.setsockopt(zmq.SUBSCRIBE, scrip)
while True:
string = socket.recv()
stock, price = string.split()
print "%s: %s" %(stock, price)

14. Parallel Pipeline

15. import antigravity

16. XKCD Task Ventilator
import sys
import zmq
context = zmq.Context()
sender = context.socket(zmq.PUSH)
sender.bind("tcp://*:5557")
print "Press Enter when the workers are ready: "
_ = raw_input()
print "Sending tasks to workers..."
base_url = 'http://xkcd.com/'
urls = [base_url + str(i) for i in xrange(1, int(sys.argv[1]))]
for url in urls:
sender.send(url)

17. XKCD Task Worker
import json
import zmq
import requests
from lxml import etree
def get_title(url):
"""Given a XKCD url, retrieve the title of the image."""
r = requests.get(url)
tree = etree.HTML(r.content)
title = tree.xpath('//div[@id="comic"]/img/@title')
if title:
return title[0]
else:
return None

18. XKCD Task Worker
context = zmq.Context()
# Socket to receive messages on
receiver = context.socket(zmq.PULL)
receiver.connect("tcp://localhost:5557")
# Socket to send messages to
sender = context.socket(zmq.PUSH)
sender.connect("tcp://localhost:5558")
# Process tasks forever
while True:
s = receiver.recv()
title = get_title(s)
print s, title
# Send a JSON payload to sink
sender.send(json.dumps({"url":s, "title":title}))

19. XKCD Sink
import zmq
context = zmq.Context()
# Socket to receive messages on
receiver = context.socket(zmq.PULL)
receiver.bind("tcp://*:5558")
while True:
s = receiver.recv()
print s

20. Transport Types
• inproc://name
• ipc:///tmp/filename
• tcp://hostname:port
• pgm://interface:address:port &
epgm://interface:address:port

21. Languages
• C/C++
• C#
• Java
• Erlang
• Go
• Ruby
• Node.js
• Objective-C
…

22. http://zero.mq/
http://zguide.zeromq.org/py:all
https://github.com/cnu/zeromq-talk
Links