認知的複雑度から見るGo言語のイベントソーシング実装 / Event Sourcing with Go

Go Conference mini 2022 Autumn IN SENDAI の登壇資料です。

Transcript

1. @suzushin 5 4 - Shinichiro 
 Go Go Conference mini 2 0 2 2 Autumn IN SENDAI #SendaiGo
2. 👨💻 whoami Intro @suzushin 54 - Shinichiro Go 2 C#, PHP SWE@Showcase Gig 2
5. 🍔 Intro 5 😋 👩🍳 Order Created Order Received Pickup Time Changed Order Completed Order Cancelled 🤵 Preparation Completed Customer Server Kitchen
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6. 🗣 Intro 😮💨 Learning Domain-Driven Design 📚 OK MSA C# JVM Go 6
7. 🙇 Intro 7
8. Intro 📋 Agenda 1 . State Sourcing and Event Sourcing 2 . Go examples 3 . Cyclomatic complexity and Cognitive complexity 4 . Conclusion 8
9. ʰਓ݄ͷਆ࿩ʱʢϑϨσϦοΫɾϒϧοΫεɺୌ୔ప ༁ɺؙળग़൛ɺ2014೥ʣ “ࢲʹϑϩʔνϟʔτ͚ͩΛݟͤͯɺςʔϒϧ͸ݟͤͳ͍ͱͨ͠Βɺ ࢲ͸ͣͬͱԎʹר͔Εͨ··ʹͳΔͩΖ͏ɻٯʹςʔϒϧ͕ݟͤͯ ΋Β͑ΔͳΒɺϑϩʔνϟʔτ͸͍͍ͨͯඞཁͳ͘ͳΔɻͦΕ͚ͩ ͰɺΈΜͳ໌നʹ෼͔ͬͯ͠·͏͔Βͩɻ”
10. State sourcing
11. 11 State Sourcing What is State Sourcing Entity CRUD API ID ঎඼ ݸ਺ ঢ়ଶ Version डऔ༧ఆ೔࣌ ࡞੒೔࣌ ߋ৽೔࣌ 1 ಛ্ڇλϯห౰ 2 Complete 4 2022-10-15 09:25:00 2022-10-15 09:00:00 2022-10-15 09:30:00 2 ͣΜͩγΣΠΫ 1 Ready 2 2022-10-15 15:00:00 2022-10-15 10:00:00 2022-10-15 10:15:00 3 Ή͢ͼؙห౰ 2 Create 1 2022-10-15 14:30:00 2022-10-15 10:30:00 2022-10-15 10:30:00 4 ڇλϯห౰ 4 Cancel 5 2022-10-15 13:00:00 2022-10-15 12:00:00 2022-10-15 12:40:00 Orders Order{ id: 4, status: Cancel, orderItem: “ڇλϯห౰”, 
 version: 5, pickupTime: "2022-10-15 13:00:00", orderedAt: "2022-10-15 12:00:00", } Order Entity ͷΠϝʔδ ૬ޓม׵
12. 12 State Sourcing Orders Table (Create) (Ready) (Complete) (Cancel) 🤔 ID: 4 ID ঎඼ ݸ਺ ঢ়ଶ Version डऔ༧ఆ೔࣌ ࡞੒೔࣌ ߋ৽೔࣌ 1 ಛ্ڇλϯห౰ 2 Complete 4 2022-10-15 09:25:00 2022-10-15 09:00:00 2022-10-15 09:30:00 2 ͣΜͩγΣΠΫ 1 Ready 2 2022-10-15 15:00:00 2022-10-15 10:00:00 2022-10-15 10:15:00 3 Ή͢ͼؙห౰ 2 Create 1 2022-10-15 14:30:00 2022-10-15 10:30:00 2022-10-15 10:30:00 4 ڇλϯห౰ 4 Cancel 5 2022-10-15 13:00:00 2022-10-15 12:00:00 2022-10-15 12:40:00 Orders
13. Event Sourcing
14. 14 Event Sourcing What is Event Sourcing 
 貢 SSOT Figure 7-1ʰLearning Domain-Driven Design: Aligning Software Architecture and Business Strategyʱ
 Vladik Khononov Oreilly & Associates Inc (2021/11/2) Interface ͸͜Μͳײ͡ Update, Delete ͸ແ͍
15. 15 Event Sourcing What is Aggregate Eric Evans. (Japanese Edition) (p. 12 5 ). Kindle Edition. ʰϚΠΫϩαʔϏεύλʔϯ: ࣮ફతγεςϜσβΠϯͷͨΊͷίʔυղઆʱ
 Chris Richardson,௕ඌߴ߂,Ḻᖒ޿ږ (2020/03/23) p.174
16. 16 Event Sourcing What is Domain Event “υϝΠϯΠϕϯτͱ͸ɺϏδωευϝΠϯͰൃੜͨ͠ॏཁͳΠϕϯτΛهड़ͨ͠
 ϝοηʔδͷ͜ͱͰ͋Δɻ” ʰLearning Domain-Driven Design: Aligning Software Architecture and Business Strategyʱ
 Vladik Khononov Oreilly & Associates Inc (2021/11/2) “DDDͰυϝΠϯΠϕϯτͱ͍͑͹ɺΞάϦήʔτʹى͖ͨԿ͔ͷ͜ͱͰ͢ɻ
 υϝΠϯΠϕϯτ͸ɺυϝΠϯϞσϧͷΫϥεʹΑͬͯදݱ͞Ε·͢ɻ ” ʰϚΠΫϩαʔϏεύλʔϯ: ࣮ફతγεςϜσβΠϯͷͨΊͷίʔυղઆʱ
 Chris Richardson,௕ඌߴ߂,Ḻᖒ޿ږ (2020/03/23) p.178
17. 17 Event Sourcing Example of Order context 1. Order Created 😋 υϝΠϯ
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18. 18 Event Sourcing Example of Order context 1. Order Created 😋 🤵 2. Order Received ௥ه͍ͯ͘͠
19. 19 Event Sourcing Example of Order context 2 3. Pickup Time Changed 4. Pickup Time Changed 5. Order Cancelled 1. Order Created 😋 2. Order Received 🤵 👩🍳 😡 ͚͍ܽͯͨετʔϦʔ͕ݟ͑ͯ͘Δ
20. How to Restore Aggregate ? Event Sourcing 20 Order{ id: 4, status: Cancel, orderItem: “ڇλϯห౰”, 
 version: 5, pickupTime: "2022-10-15 13:00:00", orderedAt: "2022-10-15 12:00:00", } 1 . Order structure 2 . 1 3 .
21. Pros 😄 Event Sourcing Time traveling Deep insight Audit log Advanced optimistic Concurrency management 
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22. Cons 🫤 Event Sourcing Learning curve Evolving the model Architectural complexity 22 7MBEJL
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23. Go examples
24. Sample system Go examples Controller UseCase Domain Infrastructure Layered Architecture HTTP Request Repository pattern (DIP) MySQL 
 24 MySQL 📱 ίʔυ͸ͪ͜Βʹ্͛ͯ͋Γ·͢ɻ https://github.com/suzushin54/event-sourcing-with-go
25. UseCase: OrderCancel State Sourcing Go examples 25 UseCase Controller UseCase Domain Infrastructure EntityΛऔಘ
26. UseCase: OrderCancel State Sourcing Go examples 26 UseCase Controller UseCase Domain Infrastructure ΩϟϯηϧΛ࣮ߦ
27. UseCase: OrderCancel State Sourcing Go examples 27 UseCase Controller UseCase Domain Infrastructure ӬଓԽ
28. UseCase: OrderCancel Event Sourcing Go examples 28 Controller UseCase Domain Infrastructure UseCase EventsΛऔಘ
29. UseCase: OrderCancel Event Sourcing Go examples 29 Controller UseCase Domain Infrastructure UseCase ू໿Λ෮ݩ
30. OrderCreatedEvent Go examples 30 Domain Controller UseCase Domain Infrastructure
31. Entity Go examples 31 Domain Controller UseCase Domain Infrastructure (1) (2)
32. Entity Go examples 32 Domain Controller UseCase Domain Infrastructure (2) (3)
33. UseCase: OrderCancel Event Sourcing Go examples 33 Controller UseCase Domain Infrastructure UseCase Ωϟϯηϧ
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34. What is Command? Go examples 34 CQRS Documents by Greg Young. http://www.minato.tv/cqrs/cqrs_documents_jp.pdf p. 11 ίϚϯυͱΠϕϯτͷҧ͍
35. Go examples 35 Controller UseCase Domain Infrastructure Domain
36. UseCase: OrderCancel Event Sourcing Go examples 36 Controller UseCase Domain Infrastructure UseCase ίϚϯυΛ࣮ߦ
37. Go examples 37 Controller UseCase Domain Infrastructure Domain ৚݅νΣοΫ Πϕϯτ࡞੒ append
38. UseCase: OrderCancel Event Sourcing Go examples 38 Controller UseCase Domain Infrastructure UseCase ӬଓԽ
39. Go examples Overload 39 https://github.com/vladikk/learning-ddd/blob/main/listings/07-06.cs https://github.com/vladikk/learning-ddd/blob/main/listings/07-07.cs
40. Overloading Go examples Go - - Go - 40 Why does Go not support overloading of methods and operators? Method dispatch is simpli fi ed if it doesn't need to do type matching as well. Experience with other languages told us that having a variety of methods with the same name but di ff erent signatures was occasionally useful but that it could also be confusing and fragile in practice. Matching only by name and requiring consistency in the types was a major simplifying decision in Go's type system. Regarding operator overloading, it seems more a convenience than an absolute requirement. Again, things are simpler without it. 
 https://go.dev/doc/faq#overloading
41. Cyclomatic complexity and Cognitive complexity
42. Overview Cyclomatic complexity and Cognitive Complexity 42 Cyclomatic complexity 1976 Cognitive Complexity 2016 Software metric 1 Fortran developed by SonarSource. 
 if, for +1 
 +1 https://docs.codeclimate.com/docs/cognitive-complexity
43. Go Conference 2 0 2 2 Spring Online Go Conference 2022 Spring Online https://gocon.jp/ 2022 spring/ https://www.youtube.com/watch?v=GZCr-Dbi 0 YM&t= 814 s 13 : 3 4 [A 1 -C] Cognitive Complexity go/ast 43
44. Cyclomatic complexity and Cognitive Complexity 44 https://pkg.go.dev/github.com/uudashr/gocognit#section-readme ܦ࿏ͷ਺͚ͩՃࢉ ωετΛߟྀ
45. Score Cyclomatic complexity and Cognitive Complexity Interpretation In his presentation 'Software Quality Metrics to Identify Risk'[ 8 ] for the Department of Homeland Security, Tom McCabe introduces the following categorisation to interpret cyclomatic complexity: • 1 - 10 Simple procedure, little risk • 1 1 - 20 More complex, moderate risk • 2 1 - 50 Complex, high risk • > 50 Untestable code, very high risk 45 https://en.wikipedia.org/wiki/Cyclomatic_complexity
46. https://github.com/uudashr/gocognit Cognitive Complexity Gocognit Go 
 46 $ go install github.com/uudashr/gocognit/cmd/gocognit@latest # e.g. $ gocognit . $ gocognit main.go $ gocognit -top 10 src/ $ gocognit -over 25 docker $ gocognit -avg . https://github.com/golangci/golangci-lint
47. https://github.com/uudashr/gocognit Cognitive Complexity 47 $ gocognit -top 5 ./app 5 aggregate (*Order).Execute app/domain/aggregate/order.go:94:1 5 usecase (*orderUseCaseV1).ReceiveV1 app/usecase/receive_v1.go:16:1 5 vo (OrderItem).Equals app/domain/vo/order_item.go:26:1 5 usecase (*orderUseCaseV1).CancelV1 app/usecase/cancel_v1.go:15:1 4 controller (*OrderController).CancelOrderV2 app/controller/cancel_order_v2.go:13:1 Sample system v 1 (StateSourcing) v 2 (EventSourcing) ES
48. 48 Controller UseCase Domain Infrastructure Domain Cognitive Complexity // + 1 // + 2 (nesting = 1 ) // + 2 (nesting = 1 ) // Cognitive Complexity = 5
49. 49 Controller UseCase Domain Infrastructure Domain // + 1 // Cognitive Complexity = 2 // + 1 Execute: 5 → 1 ExecuteCancel: 2 શମͷೝ஌తෳࡶ౓ΛԼ͛Δ͜ͱ͕Ͱ͖Δ Cognitive Complexity
50. Conclusion Pros/Cons Go 💪 50
51. Appendix
52. Projection Logic ReadModel Projection Logic 52
53. Snapshot CQRS https://docs.google.com/presentation/d/ 1 YKL 0 UPIDLN 34 A 1 REB 4 l 7 omsXv 9 f 4 hmmcvL 4 fdwVXweA/ edit#slide=id.g 13 e 14442 5 65 _ 0 _ 3 5 5 53
54. CQRS DB Materialized view 54
55. EventStore RDB Event Store 55 MicrosoftSQLServer Oracle MySQL NoSQL MongoDB RavenDB Azure Blob . (Japanese Edition) (p. 52 5 ). Kindle Edition.