From: Jeremy Hinegardner <jeremy@...>
Date: 2012-03-19T08:40:13+09:00
Subject: [ANN] qup-1.2.0 - API for Message Queue and Pub/Sub messaging

* https://github.com/copiousfreetime/qup
* http://rubygems.org/gems/qup

I'd like to announce the first public release of qup, generalized API for
Message Queue and Publish/Subscribe messaging patterns with the ability to plug
in an appropriate messaging infrastructure based upon your needs.

Qup ships with support for Kestrel, Redis, and a filesystem infrastructure
based on Maildir. Additional Adapters will be developed as needs arise. Please
submit an Issue (https://github.com/copiousfreetime/qup/issues) to have a new
Adapter created. Pull requests gladly accepted. Instructions on how to write an
Adapter are provided:

     https://github.com/copiousfreetime/qup/blob/master/ADAPTER_API.rdoc

== FEATURES

Qup provides an abstract implementation of two common messaging patterns.

1) Basic Message Queue

  Examples of the basic message queue concept are:

    * Work/Task Queues - http://www.rabbitmq.com/tutorials/tutorial-two-python.html
    * JMS Queue - http://docs.oracle.com/javaee/6/api/javax/jms/Queue.html
    * Amazon SQS - http://aws.amazon.com/sqs/ 

  This is a pattern where one or more Producers puts Messages on a Queue and
  one or more Consumers received those Messages. Each Message is delivered only 1
  time to a Consumer.

2) Publish/Subscribe

  http://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern

  Qup implements a Topic based system, where Publishers send Messages on a Topic
  and all Subscribers to that topic each receive their own copy of the message.

Qup assumes that the messaging systems it has adapters for provided durable and
acknowledgeable messaging.

[Durability]

  When message is sent to the messaging system by Qup, the message is persisted to
  disk.

[Acknowledgeable Messages]

  When a Consumer receives a Message, and then processes it, Qup assumes that
  the messaging infrastructure requires that the Message be positively
  acknowledged. In other words, if the Consumer does not acknowledge the message
  then the messages infrastructure will put the Message back onto the Queue.

=== Basic Message Queue

  session  = Qup::Session.new( "maildir:///tmp/test-queue" )
  queue    = session.queue( 'basic-messaging' )
  producer = queue.producer

  consumer_1 = queue.consumer
  consumer_2 = queue.consumer

  producer.produce( 'message_1' )
  producer.produce( 'message_2' )

  message_1 = consumer_1.consume
  puts message_1.data                 # => 'message_1'
  consumer_1.acknowledge( message_1 )

  consumer_2.consume do |message_2|
    puts message_2.data               # => 'message_2'
  end  # auto acknowledged at the end of the block

=== Publish/Subscribe

  session   = Qup::Session.new( "kestrel://messaging.example.com:22133" )
  topic     = session.topic( 'topic-messaging' )
  publisher = topic.publisher

  subscribers = []
  3.times do |n|
    subscribers << topic.subscriber( "subscriber-#{n}" )
  end

  publisher.publish( 'a fine message on a topic' )

  subscribers.each do |sub|
    sub.consume do |msg|
      puts msg.data                   # => 'a fine message on a topic'
    end                               # auto acknowledge an end of block
  end

-- 
========================================================================
 Jeremy Hinegardner                              jeremy@hinegardner.org