Slides for a talk on which messaging layer to use when you want to build a loosely coupled distributed application

1. Which messaging layer to
use in a loosely coupled
distributed app?
!
Narahari (Hari) Allamraju
!
java developer; python enthusiast
working with messaging systems for 9.5 years
!
http://github.com/supercoderz anarahari@gmail.com

2. Mess
everyone talks to everyone

3. Messaging
everyone talks to everyone through a single medium

4. Work Queue
everyone queues their tasks at the same place and waits
for the results

5. So you want
to build a
loosely
coupled app
!
!
what do you need to do?

6. The basics
• Will the application benefit by
splitting up into components?
• What are the components? How
are they dependent on each
other?
• Do we need more than one
instance of each to cope up
with the load?
• Do we need newer components
to handle certain cases that
arise from the new messaging
layer?

7. Identify the patterns
• What sort of interface do we
need - request-reply, publish
subscribe or queuing?
• Do we need to separate out
messages into various types?
• Do we need schemas for the
messages or free form?
• Are there any components that
have a higher or lower
throughput than others?

8. Latency, routing, priority
• Which components need the
message yesterday; and which
can wait till end of day?
• Do we need to expire
messages when they are too
late?
• How easily can we route
messages?
• Can we make some messages
take highest priority?

9. Build, Manage and Support
• Do we have a suitable API?
• Easy to provision and manage
• Good monitoring
• Guaranteed delivery of
messages
• Should be persist messages to
disk for crash recovery?
• Cleanup in case of issues

10. A few options
• RabbitMQ
• ZeroMQ
• Redis
• RDBMS or NOSQL database
• RPC

11. Considering future growth
• What if the loads increased by
15%?
• What if we had a consistent
heavy run for 24 hours or more?
• Storage costs etc
• If we have to switch to a
different underlying - how hard
is it?
Tokyo Metro

12. Questions!
• This presentation can be
found on slideshare at -
http://goo.gl/KVJxoE
!
• The version with speaker
notes will be available
soon
!
• you can also email me at
anarahari@gmail.com