Download - Building With Open Mq V2

Linda SchneiderTechnical LeadSun Microsystems, Inc.

Using OpenMQ

Copyright Sun Microsystems Inc. All Rights Reserved. [2]

What will be covered ?• An introduction to OpenMQ.• A Customer example.• Basic customer requirements.• Building a piece of the infrastructure.

•Warnings:> No in depth coverage > Assumes basic JMS knowledge


What is OpenMQ ?


• Allows heterogenous applications to reliability and asynchronously pass data between each other.•Open Source Java Message Service (JMS)

implementation (+ additions)• Default Messaging Provider for Glassfish• Useful on its own for standalone JMS applications

Overview


Overview (cont.)• Enterprise level quality (>8 years in development)•Open Source since JavaOne 2006• Available as a supported product: Sun Java System

Message Queue (SJSMQ)


What this looks like ....

A set of loosely coupled applications talking through OpenMQ apis


Ok – maybe a little about JMSSome basic concepts of JMS:• Producers and Consumers• Destinations• Consumer Types• Reliability


What are Producers and Consumers?• Producers >Create messages which are given to the “provider” (e.g.

OpenMQ) to deliver.>Once the message has been handed off to the provider it

goes off and does other processing.

• Consumers>Are sent messages from the “provider” to process>Notify the provider when they are done with the message.


So, what are destinations ?• Named buckets to hold groups of messages.•Messages are sent to “destinations”>Topics: each messages goes to all consumers>Queues: a message goes to only one consumer


What are the types of Consumers ?• Receivers are delivered messages from a Queue• Subscribers are delivered messages from a Topic>Normal subscribers only receive messages sent while they

are running>Messages for durable subscribers are maintained when

the subscriber is not running


And what does reliability mean ?•Messages can be set to be persistent or non-

persistent>Persistent messages are stored>Non-persistent messages are not and could be lost if a

server crashed•Messages can be transacted or non-transacted>Transactions guarantees that a set of messages will be

processed or not processed (not partially processed) if a server fails>XA transactions allow other resources (e.g. databases) to

be processed in a group with messages. [Requires an Application Server]


Tell Me More• Developer and User discussion forums• Stable builds with product releases• Early access, promoted builds available>New features, and fixes

• Dual license support (GPL v2 and CDDL)•Open source version of Java MQ is available from

http://mq.dev.java.net

http://mq.dev.java.net/


Using OpenMQ


An exampleTo mimic problems faced in designing applications, an example:• Represents a complex system with loosely

connected applications• Utilizes various types of messaging• Is easy to understand• Is at least minimally interesting


Our Example: Santa Claus, IncWhy, you ask ?

• Even if you don't believe in Santa Claus, you must still understand that delivering all those presents would be a daunting task• And while its not Christmas which comes but once a

year, but requires year round planning and preparation.• Just because Santa Claus lives at the North Pole,

doesn't imply he can't use technology


Overall System RequirementsSanta Claus, Inc. software applications need do the

following:• Handle gift selection and delivery• Manage resources e.g.> gifts> reindeer> Elves

• Track general status information> how many days before Christmas> etc.


What are we doing:• Focusing on handling christmas gift processing• Steps to design it include:>Determining the high level operation>Coming up with the name and type of destinations>Determining models used for the messaging>Determining load characteristics>Looking at code for some components


Defining the High Level Operation of the System


What do we need to do ?


What do we need to do ? (cont.)


How can Santa Do it ?


What are the destinations ?


The Child Queue


The Naughty/Nice Queues


The Wrap Queue


The Stuff to Pack Queue


Select-a-gift Queues


Topic LogChild


A quick overview to design patterns


Some basic design patterns:Pattern Description

Request/Reply

Step OperationsBroadcast One message goes to many consumers

ConduitBatch Messages are processed in a chunk

Time Critical/Sensitive

Message is sent to another application who sends back a responseMessages go through several iterations, the message is persisted at key points where processing it again would be expensive

Multiple consumers send messages to a single destination

Messages must be processed within a short period of time (e.g. under an hour) and can not be lost


More things to think about:• Use persistent messages if it can not afford to be lost• Use non-persistent messages for:> Non-critical step messages (when it can be repeated> Request/Reply> Anytime a message can be lost on a server crash

• Use durables for Topics when it may need to be retrieved later• Use normal or XA transactions when multiple things

must process together:> XA if it includes other resources like databases


Processing Queue Child• Conduit: many producers to one queue• Persistent: would be time consuming to lose message


Processing Naughty and Nice• Step Pattern: one step of it• Naughty Queue: Non-

Persistent > its OK if a child who is bad

misses their coal• Nice Queue: Persistent. > They must get their present.


Processing Nice• Step Pattern: more steps of it• Multiple resources so XA


Processing Nice (Select a gift)• Request/Reply Pattern• Non-persistent• Action repeated on failure


The Wrap Queue • Step operation• Persistent: end of an expensive set of steps that they

don't want to repeat


The Log Child Topic• Broadcast Pattern• Persistent because santa wants his database

accurate


In this example:• The batch pattern was not used> Santa does use It for processing HR updates for the

elves• The time sensitive/critical data pattern was not used:> Santa does use it during present delivery on christmas

eve to track where he is• Because he has no time sensitive/critical data,

reliability is important however data availability isn't for gift processing


Performance Requirements• 22 billion kids• 364 days for preparation (since christmas is taken) > 31,526,000 seconds

• 70 children/second must be processed• Assume 60% are “nice”• Assume 40% downtime to cover outages and normal

processing (so goal is approx 100 kids/second)


Performance Requirements (cont)• Naughty Kids use> 1 Persistent queue (child)> 1 Non-persistent queue (naughty)> 1 Persistent Topic (log child)

• Nice Kids Use:> Persistent Queue (child)> Persistent Queue (nice)> 2 Non-Persistent Queues (Inventory request and reply

queues)> Non-persistent queue (Wrap)> 1 Persistent Topic (log child)


The cold hard requirements• Messages:> Child: 100 msgs/second (persistent)> Naughty: 40 msgs/second (non-persistent)> Log Child: 100msgs/second (persistent)> Nice: 60 msgs/second (persistent in XA transaction)> Inventory request/reply: 60 msgs/second *2 (non-

persistent)> Wrap: 60 msgs/second (persistent)

• TOTALS:> Persistent: 380 msgs/second> Non-persistent: 160 msgs/second


Some Sample Code


Sending the “Child” messagepublic void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// retrieve initial context (ic) QueueConnectionFactory qcf = (QueueConnectionFactory) ic.lookup("MyConnectionFactory"); Queue destQueue = (Queue)ic.lookup("Child"); QueueConnection connection = qcf.createQueueConnection(); try { QueueSession session = connection.createQueueSession( False, Session.AUTO_ACKNOWLEDGE); QueueSender sender = session.createSender(destQueue); MapMessage msg = session.createMapMessage(); // Set each item msg.setString(“firstname”, request.getParameter(“firstname”)); // … retrieve other properties …; sender.send(msg); } finally { connection.close(); }}


Processing the “nice” queuepublic void onMessage(Message inMessage) { TextMessage msg = null; try { //Message is of type text and has a unique child id msg = (TextMessage) inMessage; String id = msg.getText(); String[] list = db.getList(id); // makes SQL call String item = null; if (list == null) { // no list, send request String item = getListItem(); //next slide } else { item = list[0]; } //update inventory db.updateInventory(item, id);//makes SQL call // put on packing list pack(item, id); } catch (Exception e) { // things went wrong roll back mdc.setRollbackOnly(); }}


Processing the “nice” queue (step 2)public String getListItem(String childid) throws Exception { QueueConnectionFactory factory = jndiContext.lookup(“MyQueueFactory”); QueueConnection qc = factory.createQueueConnection(); qc.start(); QueueSession session = qc.createSession(true, Session.AUTO_ACKNOWLEDGED); Queue q = session.createQueue(“RandomPresent”); Queue reply = session.createTemporaryQueue(); // get sender and receiver QueueSender sender = session.createSender(q); QueueReceiver receiver = session.createReceiver(q); //send message and wait TextMessage m = session.createTextMessage(childid); m.setJMSReplyTo(reply); //send the message sender.send(m); TextMessage back = (TextMessage) receiver.receive(60*1000); // wait a minute if (back == null) { didn't get anything throw new Exception(“Nothing”); return back.getText();}


Processing the “nice” queue (step 3)

public String pack(String item, String child_id) throws JMSException{ QueueConnectionFactory factory = jndiContext.lookup(“MyQueueFactory”); QueueConnection qc = factory.createQueueConnection(); QueueSession session = qc.createSession(true, Session.AUTO_ACKNOWLEDGED);); Queue q = session.createQueue(“Pack”);

// get sender QueueSender sender = session.createSender(q);

//send message MapMessage m = session.createMapMessage(childid); m.setString(“child_id”, child_id); m.setString(“present”, item); sender.send(m);}


You'll need to fill in the rest


More Information


OpenMQ -- More Information•Visit the product webpage>http://sun.com/software/products/message_queue•Join the Open Message Queue project>https://mq.dev.java.net•Browse the product documentation>http://docs.sun.com/app/docs/coll/1307.3•Take the free technical training>http://www.sun.com/training/catalog/courses/WMT-SMQ-1491.xml

http://sun.com/software/products/message_queue

https://mq.dev.java.net/

http://docs.sun.com/app/docs/coll/1307.3

http://www.sun.com/training/catalog/courses/WMT-SMQ-1491.xml


Related Information•Java Composite Application Platform Suite>http://sun.com/software/javaenterprisesystem/javacaps/•Java System Identity Manager>http://sun.com/software/products/identity•Project GlassFish >https://glassfish.dev.java.net/•The Aquarium, A community forum>http://blogs.sun.com/theaquarium/

Using OpenMQLinda [email protected]

Thank You!