MESSAGING WITH AMQP AND RABBITMQ

What is AMQP?AMQP (Advanced Message Queuing Protocol) is a networking protocol that enables conforming client applications to communicate with conforming messaging middleware brokers.

WHAT ARE BROKERS

Messaging brokers receive messages from publishers (applications that publish them, also known as producers) and route them to consumers (applications that process them).

EXAMPLE OF BROKERS

• RabbitMQ (by VMWARE)!• Microsoft's Windows Azure

Service Bus!• Red Hat Enterprise MRG!• StormMQ

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RABBITMQ Open Source message broker / queueing system written in Erlang implementing AMQP

Who Uses AMQP • JPMorgan - 1 billion AMQP messages per day; used in

dozens of mission critical systems worldwide!• VMware - Makes extensive use of RabbitMQ in its

virtualization products and cloud service!• Google!• UIDAI, Government of India - the largest online

identity project in the world aiming to provide each of India's 1.2 billion residents with a unique identity number!

• AT&T, Smith Electric Vehicles, Mozilla, RED HAT cloud services

INDUSTRIES Telecommunications, Defense, Manufacturing, Internet and Cloud Computing

Installing RABBitMQ

• MAC OSX - brew install rabbitmq !

• Windows - download the exe

Running It rabbitmq-server

Enabling the admin console

• rabbitmq-plugins enable rabbitmq_management!

!• http://http://localhost:

15672/

How to talk to RABBITMQ

An AMQP Client. Available in most languages.

Ruby clients • Bunny!• Ruby AMQP Gem

INSTALLING BUNNY

• gem install bunny !• add to gem file -> gem

‘bunny’

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AMQP-MODEL• messages can be anything,!plain text, json, bytes, etc.!• Publisher and Consumer

are typically decoupled in big apps

Exchanges and Exchange Types

• Direct exchange - specific routing key!

• Fanout exchange - braodcast!• Topic exchange - regex style

routing key!• Headers exchange

DIRECT EXCHANGE

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DIRECT EXCHANGE 2

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FAN-OUT• leaderboard updates or other

global events!• Sport news sites can use score

updates to mobile clients in near real-time!

• Group chats can distribute messages between participants

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TOPIC EXCHANGE

• delimeter is dots!• * = 1!• # = anything

USING BUNNYrequire “bunny”!

#connect to rabbitmq!

conn = Bunny.new!

conn.start!

#create channel!

channel = conn.create_channel!

#create / subscribe to a queue!

queue = ch.queue(“hello”)!

exchange = ch.default_exchange!

#bind queue to an exchange!

queue.bind(exchange, :routing_key => severity)

exchange.publish("Hello World!", :routing_key => queue.name)

queue.subscribe(:block => true) do |delivery_info, properties, body|!

puts " [x] Received #{body}"!!

# cancel the consumer to exit! delivery_info.consumer.cancel!

end

DEMOcode: https://github.com/selasiehanson/rabbitmq_presentaion_code.git

FANOUT

❖ cd pubsub!

❖ ruby receive_logs.rb > logs_from_rabbit.log!

❖ ruby receive_logs.rb!

❖ ruby emit_log.rb!

❖ ruby emit_log.rb "Hello my peeps"

DIRECT (3 receivers)❖ cd ../routing/!

❖ ruby receive_logs_direct.rb warning error > logs_from_rabbit.log!

❖ ruby receive_logs_direct.rb info warning error!

❖ ruby receive_logs_direct.rb info warning!

❖ ruby emit_log_direct.rb error “Message 1”!

❖ ruby emit_log_direct.rb warning “Message 2”

TOPIC❖ cd ../topic/!

❖ ruby receive_logs_topic.rb "#"!

❖ ruby receive_logs_topic.rb "kern.*"!

❖ ruby receive_logs_topic.rb "*.critical"!

❖ ruby receive_logs_topic.rb "kern.*" "*.critical"!

❖ ruby emit_log_topic.rb "kern.critical" "A critical kernel error"

THE END

RESOURCES❖ http://www.amqp.org/!

❖ http://www.rabbitmq.com/!

❖ http://www.rabbitmq.com/getstarted.html!

❖ http://www.rabbitmq.com/tutorials/amqp-concepts.html!

❖ http://rubybunny.info/!

❖ http://rubybunny.info/articles/getting_started.html!

❖ read the bunny docs!

❖ http://www.rubyinside.com/rabbitmq-a-fast-reliable-queuing-option-for-rubyists-1681.html