.NET Day 19 - Finding Your Service Boundaries - A Practical Guide by Adam Ralph

We know it's useful to split up complex systems. We've seen the benefits of modular deployment of microservices. Dealing with only one piece of code at a time eases our cognitive load. But how do we know where to draw the service boundaries? In complex business domains, it's often difficult to know where to start. When we get our boundaries wrong, the clocks starts ticking. Before long, we hear ourselves say "it would be easier to re-write it".
Join Adam for practical advice on discovering the hidden boundaries in your systems. Help tease out the natural separation of concerns in a sample business domain. During 20 years of developing complex systems, Adam has had plenty of time to get things wrong. Learn to avoid the common pitfalls that can lead us down the path to "the big re-write".

Transcript

1. @adamralph FINDING YOUR SERVICE BOUNDARIES A PRACTICAL GUIDE Adam Ralph
2. @adamralph
3. @adamralph
4. @adamralph BIG BALL OF MUD
5. @adamralph Service Service Service Service
6. @adamralph Machine Machine Machine Machine BIG BALL OF MUD
7. @adamralph WORKFLOWS Adam Ralph Im Mediapark 7 50670 Köln Germany
8. @adamralph OrderPlaced WORKFLOW EVENTS Finance Shipping Sales OrderBilled OrderShipped PlaceOrder
9. @adamralph WORKFLOW EVENTS SetOrderId = 022032ba-1337-43a5-90c9-d48b58742c7
10. @adamralph Adam Ralph Im Mediapark 7 50670 Köln Germany Shipping Shipping Finance Finance Sales Sales WORKFLOW MESSAGES
11. @adamralph OrderPlaced WORKFLOW EVENTS Finance Shipping Sales OrderBilled OrderShipped PlaceOrder
12. @adamralph Machine Machine Machine Machine BIG BALL OF MUD
13. @adamralph Service Service Service Service
14. @adamralph WHAT A SERVICE IS NOT - A service that has only functionality is a function not a service: Like calculation, validation, etc. - A service that has only data is a database not a service: Like [create, read, update, delete] entity - HTTP/WSDL doesn’t change logical responsibility
15. @adamralph WHAT IS A SERVICE? A service is the technical authority for a specific business capability - All data & business rules reside within the service (bounded context?) - Nothing is “left over” after identifying services. Everything must be in some service
16. @adamralph S1 S2 S3 MOBILE BACK END PORTAL SYSTEMS & SERVICES
17. @adamralph DECOMPOSING A DOMAIN public class Customer { FirstName LastName Status // etc } public class Product { Name Description Price // etc } • Customer status • Product price • Customer’s first name • Customer’s last name • Product name • Product description RED GREEN YELLOW
18. @adamralph Home insurance Travel insurance Car insurance Policy Service Home insurance Travel insurance Car insurance Claims Service Insured vehicle Coverage PolicyId ClaimId Car Insurance Home owner Coverage PolicyId ClaimId Home Insurance Insured persons Coverage PolicyId ClaimId Travel Insurance INSURANCE
19. @adamralph ORGANISATIONS
20. @adamralph MICROSERVICES
21. @adamralph BIG BALL OF MUD
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26. @adamralph BIG BALL OF MUD Microservices Edition™
27. @adamralph ID ID ID ID ID ID STATE- MENTS FRAUD
28. @adamralph go.particular.net/dnd19-boundaries
29. @adamralph
30. @adamralph FINDING YOUR SERVICE BOUNDARIES A PRACTICAL GUIDE Adam Ralph