3. 3
About WSO2
๏ Global enterprise, founded in
2005 by acknowledged leaders in
XML, web services technologies,
standards and open source
๏ Provides only open source
platform-as-a-service for private,
public and hybrid cloud
deployments
๏ All WSO2 products are 100% open
source and released under the
Apache License Version 2.0.
๏ Is an Active Member of OASIS,
Cloud Security Alliance, OSGi
Alliance, AMQP Working Group,
OpenID Foundation and W3C.
๏ Driven by Innovation
๏ Launched first open source API
Management solution in 2012
๏ Launched App Factory in 2Q 2013
๏ Launched Enterprise Store and
first open source Mobile solution
in 4Q 2013
5. Outline
1. A Brief Introduction to WSO2 Message Broker
2. What is new in MB 2.2.0
3. Example Use Cases
4. Pre-recorded demo (ESB + MB Integration using
Message Store Processor)
5. Conclusion and future work
5
6. Why Messaging?
๏ Enhanced reliability
๏ E.g. via persistence, transactions
๏ Decoupling
๏ Space
๏ Time
๏ Synchronization
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7. Basic Messaging Models
๏ Messaging is implemented with a broker (or brokers in
the middle)
๏ Participants send messages, and broker delivers them
to recipients
๏ There are two main models
๏ Queues - A message is delivered only once to a single consumer.
๏ Publish/Subscribe: Broadcast a message to many message consumers
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8. Queues
8
• A queue is a destination that contains messages sent from a producer
that await delivery to one consumer.
• Messages are delivered in the sent order.
• A message is removed from the queue once it has been acknowledged
as received by the consumer.
9. Topics
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• Topics are used to send messages to one or more consumers. Producers publish
messages to a topic and each consumer subscribed to the topic receives a copy of
message
• Brokers matches events (messages) and delivers to all interested parties
• In this one-to-many messaging scenario, producers are also referred to as
publishers and consumers as subscribers
10. Durable Topics
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• Broker collects messages while subscriber is offline – like a queue
• Broker distributes the messages to all interested parties – like a topic
• Each subscriber has its own internal queue until it unsubscribes
11. AMQP, JMS and WSO2 MB
๏ JMS (Java Message Service)
๏ A specification that define a standard API for java programmer to perform
messaging by interacting with a message broker
๏ It does not define the message format or how java API interacts with the message
broker
๏ AMQP (Advanced Message Queuing Protocol)
๏ Open standard for passing business messages between applications or
organizations.
๏ AMQP let different systems (e.g. .NET and Java) to interact with each other by
agreeing on the message format at the wire level just like Web Services.
๏ WSO2 MB (Broker)
๏ Implements and supports JMS API using AMQP protocol for messaging (All the
same, we are not limited to JMS)
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12. How WSO2 MB is Different?
๏ Use Apache Cassandra as the storage for messages
those require persistence
Apache Cassandra is an open source distributed database management system. It is
designed to handle very large amounts of data spread out across many commodity
servers while providing a highly available service with no single point of failure. It has
very fast search schemes built in. Thus Cassandra is a good choice for WSO2 MB with
clustering support.
๏ Scaling – WSO2 MB can be clustered adding nodes to
meet business requirements.
Nodes can be dynamically added and removed
๏ Supports Distributed Queuing with clustering enabled
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13. Why WSO2 MB is Different?
๏ Failover with no message lost – Clustering + Failover
capability brings this feature
๏ Ability to handle large message transfers in real time
As Cassandra is our storage, messages are written fast to store and we create only one
copy of message while delivery
๏ High Availability and Fault Tolerance
No single point of failure with MB cluster + Cassandra cluster + Zookeeper Cluster. All
nodes are vertically and horizontally scalable. Cassandra keep replicates of messages.
๏ Interoperability with many languages / platforms via
AMQP clients for Java, .Net, C, C++, PHP, Ruby, Erlang
and more13
14. Why WSO2 MB is Different?
๏ Interoperability with many languages / platforms via
AMQP clients for Java, .Net, C, C++, PHP, Ruby, Erlang
and more
We use AMQP internally. Thus any AMQP client is theoretically compliant
๏ Fair effort to scale in all 3 dimensions (reliability,
performance and resources)
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15. WSO2 MB 2.2.0 Release
๏ A lot of bug fixes with respect to WSO2 2.1.0
๏ Fixed a lot of clustering related issues with edge cases.
๏ Stabilization of message delivery with high message concurrency.
๏ Concurrent issues arises with a Cassandra cluster.
๏ Four new features
๏ Dead Letter Channel implementation
๏ Publisher Flow control implementation
๏ MB profile support for Cassandra and Zookeeper
๏ JMS Message selectors support which was missing in 2.1.0 release
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16. WSO2 MB 2.2.0 Release
๏ New features added to WSO2 MB management console
UI
๏ View active queue subscriptions in whole MB cluster
๏ View active topic subscriptions in whole MB cluster
๏ View inactive durable topic subscriptions specifically.
๏ Ability to unsubscribe inactive durable topic subscriptions with UI.
๏ Ability to deal with messages at Dead Letter Channel.
๏ Improved reliability with deleting a queue (remove queue from whole cluster).
๏ Improved reliability with message count displayed for queues.
๏ Improved security and role based access model for
queues and topics
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17. WSO2 MB 2.2.0 Release
๏ Now it is even more easier to deploy WSO2 MB
๏ Tested ability to handle up to 3 million message burst
from concurrent producers with simultaneous
concurrent subscribers for queues.
๏ Improved logging – trace level logs are now separated
for easy debugging.
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18. Dead Letter Channel
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• If the subscriber
• Rejected the message
• Did not ack the sever within a configured time
• Could not receive message due to connection fail
Server will try to resend the message.
• MB server will do this for a maximum number of configured times.
• After that it will route message to DLC.
19. Dead Letter Channel contd..
๏ Able to view DLC messages in the Management Console
(Queue vise display).
๏ You can perform following actions on DLC messages
๏ Delete (discard mal-formatted message)
๏ Restore message to the queue (fixed the message subscribe Back End. Now ready
to go)
๏ Re-route the message to any other existing queue in MB cluster (allow some
other subscriber in the system to handle the message)
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20. Flow Control – Backpressure
๏ Every system has its limits.
๏ What happens to the broker cluster if a message burst
continued to come and they need to be persisted…!!
๏ WSO2 MB 2.2.0 comes with following flow control
mechanisms.
1. Throttling based on global memory threshold
2. Throttling based on message count per connection
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21. MB Profile Support
๏ You can start WSO2 MB purely as a Apache Cassandra
server.
๏ All configurations files of Cassandra are there
๏ Port is configurable with an offset
๏ Logs are written to Carbon Log
๏ Cassandra tools are also packed inside MB
๏ You can start WSO2 MB purely as a Apache Zookeeper
server.
๏ To create a complete broker cluster you only need a
WSO2 MB distribution.
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22. Message Selectors
๏ A Subscriber might be interested in particular set of
messages having certain properties.
๏ It only likes to consume those messages.
๏ When subscription is make to the broker, it can specify
the message properties as a query.
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queueReceiver= queueSession.createReceiver(queue,"(S1_double > 3.7 OR JMSType = 'TWO') AND Number > 20")
23. Other tit-bits
Improved SSL Support for MB 2.2.0
๏ The wire level connection between client-server can be
encrypted using SSL to provide maximum protection.
๏ Supported in both standalone and clustered mode with
failover as well.
๏ Easily configurable at the client side using AMQP
connection url.
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24. A Few Example Use cases
๏ WSO2 Message Broker is part of Messaging Middleware
๏ Rather than using WSO2 MB alone, most of the time for
an integrated platform it sits in the middle of messaging
clients where message delivery reliability is needed, or
some message throttling is needed or some
asynchronous message processing is OK.
๏ Following is some real world use cases where Message
Broker comes into play.
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25. Asynchronous Messaging
๏ Timely decoupled (transactions - inter departmental job
submitting and processing)
25
University Grant
Commission UniversityMessaging Middleware
Web App Messaging
27. Reliable Messaging
๏ Message store processor pattern with WSO2 ESB
27
Web
Application
Enterprise Service Bus
Msg Store Msg
Processor
Data Services
Server
Oracle DB
WSO2 MB
Message Queue
HTTP to JMS JMS to HTTP
28. Reliable Messaging contd..
๏ Want to reliably store information to database?
๏ Message order is guaranteed
๏ Message reliability is guaranteed
๏ No message duplication is possible
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30. Throttling – SAP/ESB/MB
๏ Same as above setup for reliable messaging, but
addresses a different concern.
๏ If messages are coming out from SAP very fast, we
directly store it in a WSO2 MB queue via message store.
๏ Message processor can work slowly and process the
messages with a tolerable speed.
๏ Alternatively, can use JMS proxies to send and receive
messages as JMS.
๏ Doable with an ESB cluster as well.
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32. Future Work
๏ Support for Message Queuing Telemetry Transport
(MQTT)
๏ Dynamic queue support in WSO2 MB
๏ CQL support integration over Hector to interact with
Cassandra storage
๏ Support message priority levels
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33. Papers Published
๏ Perera H.S, Wickramarachchi C, Jayasinghe S.D,
Weeravarana S, *“Andes: a highly scalable persistent
messaging system”+, Web Services (ICWS), 2012 IEEE
19th International Conference, Honolulu, HI
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34. Conclusion
๏ WSO2 MB 2.2.0 comes out as a more stabilized and
improved AMQP message broker with several high
demand features like DLC and Flow Control
implementation etc. The new version also includes a lot
of bug fixes which makes it robust enough to reliably
handle a bulk amount of messages with high
concurrency in a clustered environment
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