Service Oriented Architecture (SOA) aims to reduce coupling between software components by separating concerns and allowing loose coupling through messaging. Specifically, SOA advocates for: 1) Using asynchronous messaging and publish-subscribe patterns to reduce temporal coupling regarding how and when components interact. 2) Ensuring application code does not need to know where cooperating services are located to reduce spatial coupling. 3) Standardizing on platform-independent formats like XML and protocols like HTTP to reduce platform coupling between technologies.

1. Why Service Oriented
Architecture?
Sean Farmar
@farmar

2. The Evolution
• Small monolith
• Success == growth == features ++
• Team Scaling
• Maintenance nightmare == high risk
• So we end up with …

3. Big Ball of Mud

4. So I went to my master

5. Solve the problem
you want?
• Coupling your problem is
• SOA your solution is

6. Why SOA?
• SOA's tenets are about reducing coupling.

7. • Afferent (dependents)
• Efferent (depend on)
• Temporal (time, RPC)
• Spatial (deployment, endpoint address)
• Platform (protocols, .Net Remoting)
Coupling

8. Coupling: Solutions
Platform:
•XML on the wire.
•XSD (schema) describing XML structure
•Use standards based transfer protocol like http
•Standards based description of message flow
•WSDL (only supports request/response)
•SSDL(supports richer semantics)

9. Coupling: Solutions
Temporal:
•Asynchronous messaging
•Publish Subscribe

10. Coupling: Solutions
Spatial:
•Application level code should not need to
know where cooperating services are on the
network

11. In practice

12. In practice
• Vertical Slicing
• Using asynchronous messaging
• Using publish subscribe
• Business domain decomposition
• Explicit intentions [naming, context]
• Single Responsibility
• Command Query Separation
• “Clean Code” (Uncle Bob)

13. n-tier architecture

14. Vertical Slicing

15. Publish Subscribe
[pub/sub]

16. Publish Subscribe
[pub/sub]

17. Subscribe to
Customer Status Updated
Publish
Customer Status Updated
Save status locally
Subscribe to Product PricingProduct Pricing
UpdatedUpdated
Publish
Product Pricing Updated
Save pricing locally
Place Order
Publish Order Accepted
Sales
MarketingCustomer
Care

18. Summary
• SOA
• NServiceBus
• Particular.net
• You can do it

19. Learn to build better systems
from Udi Dahan
Advanced Distributed Systems Design
2 days (out of 5) for FREE
Join us at the Particular booth
for more information

20. Q&A
ThankYou!
Sean Farmar
twitter: @farmar
Particular.net