The road to a Service Oriented

Architectureis paved with a message based infrastructure

Mauro ServientiSolution Architect @ Particular Software, makers of NServiceBus

mauro.servienti@particular.net@mauroservienti

All I want to do when I wake up in the morning is…(cit. Rosanna, Toto, Toto IV)

Tickets web site

Buy a ticket

Stage dive… :-)

All what they want to do is…

Display available ticketsReserve with the theater

Charge my credit card

Deal with insuranceShip tickets

Deal with their stuff

Sometimes order is important…

Sometimes not

spot the

ISSUE

Multiple resources --

Multiple owners

Transaction boundaries• user perspective: single operation• ticketing system perspective: multiple operations

• That should be “atomic”

• The business TX crosses multiple boundaries• Theater reservation• Credit card• Insurance• Shipping• Internal stuff

• End we’ll end up in a…

…big ball of mud…When crossing service boundarieswe cannot expect

transactions to work

SOABoundariesare explicit

DTC forget you must

Compensation you should welcome

Idempotency your best friend is

Messages you wantMessages are

AtomicMessages are

UniqueEasily implements

Ledgersemantic

Messaging PatternsBecause not all communication is born equal

Request/Response

message sent to someone

implies some coupling

we know each other

Pub/Sub

broadcasted event, in the past

implies less coupling

subscribers know the publisher

Tickets reservation service

Tickets reservation service

Order management service

Order management service

Tickets reservation service

Credit Card service

Marketing service

Other stuff

Buy ticket

Charge Card

Ticket reserved

Reserve Tickets

Messages in a nutshell• Less coupling• respect your boundaries

• No temporal coupling• messages are asynchronous

• Much less maintenance/deployment headaches• autonomous components

• Easy scale-out• competing consumers

• Guaranteed delivery• with error management

Do you want more?

Free e-book available at:

http://go.particular.net/cloudconfE

Thank youGo! SOA-fy your world