Devoxx: Event storming a DDD/MicroService landscape using post-it's and markers
•
1 like•397 views
During this hands-on workshop you'll learn about Domain Driven Design, CQRS, Event Sourcing and Microservices. You'll learn all of this during an active workshop standing up and contributing with a marker and post-it's in your hand. We'll be extracting events from a hypothetically business case. The workshop will cover some theory but 80% of our time will be spent hands-on in small groups of 4-6 people. After this workshop you'll have learned how to pick and choose the boundaries of your isolated Microservices as Bounded Context's, how to thread events as first-class citizens and how to present them to the users. https://cfp.devoxx.be/2017/talk/EVE-8066/Event_storming_a_DDD%2FMicroService_landscape_using_post-it's_and_markers
Recommended
More Related Content
Similar to Devoxx: Event storming a DDD/MicroService landscape using post-it's and markers
Similar to Devoxx: Event storming a DDD/MicroService landscape using post-it's and markers (20)
Recently uploaded
Recently uploaded (20)
Devoxx: Event storming a DDD/MicroService landscape using post-it's and markers
- 2. #DDD_ES @stijnvp Learning DDD by Event Storming Stijn Vanpoucke @stijnvp blogs.aca-it.be www.aca-it.be
- 3. #DDD_ES @stijnvp Me and my company • Technical Architect @ A.C.A IT-Solutions • Multi-customer software factory @ Ghent - Belgium • Agile all over • Domain Driven Design, Customer Centric • Modularity • Java / Open Source • Open culture, horizontal organisation (Podular)
- 4. #DDD_ES @stijnvp Plan of attack • Why DDD? Why Events • Workshop kick-off, forming groups • You working on the events • Me talking about the commands • You working on the commands • Me Talking about bounded contexts and the relation with microservices • You working with bounded contexts • Final
- 5. #DDD_ES @stijnvp Domain Driven Design
- 6. #DDD_ES @stijnvp It’s a constant discovery process to understand the problem that a business want’s to be worked out in software.
- 7. #DDD_ES @stijnvp Anemic Domain Model
- 10. #DDD_ES @stijnvp
- 11. #DDD_ES @stijnvp The catch comes when you look at the behavior, and you realize that there is hardly any behavior on these objects. ... The anemic domain model is really just a procedural style design, exactly the kind of thing that object bigots like me (and Eric) have been fighting since our early days in Smalltalk. What's worse, many people think that anemic objects are real objects, and thus completely miss the point of what object-oriented design is all about. Martin Fowler https://martinfowler.com/bliki/AnemicDomainModel.html
- 12. #DDD_ES @stijnvp Strategic and Tactical DDD
- 13. #DDD_ES @stijnvp The business wants to reach business goals. Domain Driven Design assist in realising those goals by creating applications who deliver true business value. Strategical Domain Driven Design
- 14. #DDD_ES @stijnvp We want to create software which is comprehensible, easy to refactor, easy to scale etc. Tactical Domain Driven Design
- 15. #DDD_ES @stijnvp How can we let developers works as one team with the business and focus on creating business value?
- 16. #DDD_ES @stijnvp Code a Behavior Rich Domain
- 17. #DDD_ES @stijnvp Ubiquitous Language “One Team, One Language” - Eric Evans
- 18. #DDD_ES @stijnvp
- 21. #DDD_ES @stijnvp - Something that happened (behavior) - Phrased at past-tense - Relevant for domain experts - Caused by a - user/actor - another Event - time - external system Ticket Payed A talk is scheduled Received a CFP
- 23. #DDD_ES @stijnvp
- 25. #DDD_ES @stijnvp Setup -Form a group from ~8 people -Every participant has a pen or marker -Every group has paper roll -No sitting, so that everyone participates -Assign one product owner -Assign one time keeper
- 26. #DDD_ES @stijnvp Problem Space - Call For Papers - Register Speakers, talks, hand-ons, keynotes, topics, voting, sponsor slots - Scheduling - Spread by topic, hands-on, keynote, conference talks, supporting volunteers - Sponsors - Gold, Silver, Bronze, Logo, Commercial, Stand, Internet, Electricity - Ticket Ordering - Early Bird, Pricing, Company group buys, Validating Ticket @ entrance - Venue - Rooms, Sponsor stands, Entrance check - Voting - Feedback, Pre-voting, After-voting - Food & drinks - Soup, Vegetarian, Non-Vegetarian, Drinks, Reception, Waiters - Volunteers - Specialisation (Sound&Light, Sponsors, Scheduling, Entrance check), ... - …
- 30. #DDD_ES @stijnvp What is a command? - User initiated action - Explain the origin of the event - Reason why a user will perform a given step
- 37. #DDD_ES @stijnvp public class Product extends ConcurrencySafeEntity { private Set<BacklogItem> backlogItems; private String description; private String name; private ProductId productId; private Set<Release> releases; private Set<Sprint> sprints; private TenantId tenantId; ... } Bigger is not always better!
- 39. #DDD_ES @stijnvp Aggregate design - Aggregate root > Aggregate Name > Ubiquitous Language - Design small aggregates (not tiny) - Small aggregates avoid optimistic locking - Grouped by transactional invariants (7 = 5 + 2) - Reference other aggregates by identity - Eventual consistency - Use strong Encapsulation Paper Vaughn Vernon: https://vaughnvernon.co/?p=838
- 42. #DDD_ES @stijnvp Bounded Context & Microservices
- 44. #DDD_ES @stijnvp Tackle complexity by splitting it up into smaller understandable parts and choose investments wisely.
- 46. - Big Ball Of Mud - Spaghetti Code - ...
- 47. Teams
- 48. #DDD_ES @stijnvp Teams take autonomous decisions - Team and Domain Expert - Things that change together for a business reason. - Independent releases
- 51. Business Unit Marketing Business Unit Book keeping Business Unit Delivery Business Unit Purchase Business Unit Sales
- 53. #DDD_ES @stijnvp Core Domain? - What makes the system worth writing? - Why not buy it off the shelf? - Why not outsource it? - With what do you want to differentiate yourself in the market? - Where do you want your best developers to be working on?
- 54. #DDD_ES @stijnvp Supporting & Generic subdomain - Optionally bought of the shelve or outsourced - Supportive to the core domain
- 55. #DDD_ES @stijnvp Here’s conway’s law again…
- 56. #DDD_ES @stijnvp What is a bounded context?
- 59. #DDD_ES @stijnvp “Ubiquitous Language” Better Communication between the team and the domain experts by using the same language.
- 60. #DDD_ES @stijnvp “One team, one language”
- 61. #DDD_ES @stijnvp “The bigger the Bounded Context the harder it become to have a uniform language.”
- 63. Business Unit Marketing Business Unit Book keeping Business Unit Delivery Business Unit Purchase Business Unit Sales
- 64. Marketing Book keeping DeliveryPurchase Sales Recom mendati ons ERP ADWORDS BK.com Shop Basket Deals
- 65. #DDD_ES @stijnvp Creating Explicit Boundary - Package - Maven Module - Bundle - Subsystem - Microservice - Git Repository - Circle on paper - Angular Module - …
- 66. #DDD_ES @stijnvp Microservices - Building Microservice around Bounded Context’s (Sam Newman, Netflix, …)
- 67. #DDD_ES @stijnvp 15 m ins ● Core Domain? ● Linguistic Boundaries? ● Organisational Boundaries? ● Technology Needs? ● Purpose? Meaning? Definition? ● Teams? ● ...
- 68. #DDD_ES @stijnvp - Integration of Bounded Context’s - Book: Eric Evans - Migration More...