La simplicité comme moyen d'être performant, résilient et de réduire le Time To Market.

Il y a 1 an et demi, la Société Générale a décidé de construire un nouveau service de vente électronique de nos produits financiers. Les contraintes étaient claires : "le système sera performant, auditable, résilient et développé de manière à avoir un Time To Market court". Une seule solution s'imposait à nous : faire simple, très simple !
Ainsi à travers cette présentation, nous vous raconterons notre quête de simplicité. Vous verrez ainsi que notre stack technique ne contient quasiment aucun framework, juste quelques bibliothèques utiles ou indispensables. Notre code se structure autour de quelques principes : l'Event Sourcing, un peu de Domain Driven Design et une discipline de fer en matière de qualité et de tests automatisés (BDD for the win!).

Transcript

1. Construire le SI de demain REX Société Générale La simplicité comme moyen d'être performant, résilient et de réduire le Time To Market
2. Marie-Laure Thuret @mlthuret Développeur chez Clément Héliou @c_heliou Développeur chez Thierry Abaléa @ThierryAbalea Tech Lead à la Société Générale
7. Palladium
9. Commodity Trading Company
10. Today Hedging Commodity Trading Company
11. Commodity Trading Company Few Months Later Hedging Physical Delivery
13. Sales Person Customer Trader Booking Exchanges
14. Automatize the processus
15. Orchestrator Customer Exchanges Pricer Booking Hedger Trading Limit Margin
17. The Constraints Reliability / Resilience Performance Productivity / Time To Market
18. Our Solution Simplicity
19. Simple ≠ Easy
20. Choices are business-oriented
21. Functional and Code Reduce the impedance between Our Goal
22. Orchestration Let’s take an example with our main component
26. Event Sourcing
27. « Capture all changes to an application state as a sequence of events » Martin Fowler
28. Date Money Out Money In 2015/05/14 100 € 2015/05/14 -20 € 2015/05/16 -30 € 2015/05/24 380 € 2015/06/01 -70 € Total -120 € 480 € Balance 360 €
29. WithdrawalPerformed accountId: 9387 amount: 30€ BankAccount id: 9387 balance: 0€ WithdrawalPerformed accountId: 9387 amount: 20€ DepositPerformed accountId: 9387 amount: 100€ BankAccount id: 9387 balance: 50€ BankAccount id: 9387 balance: 100€ BankAccount id: 9387 balance: 80€ Inspired by B. Reitzammer & J. Seitz - http://ookami86.github.io/event-sourcing-in-practice Apply to Apply to Apply to Produces Produces Produces
30. J. Chassaing - http://thinkbeforecoding.com/post/2014/01/04/Event-Sourcing.-Draw-it
31. BankAccount id: 9387 balance: 0€ WithdrawalPerformed accountId: 9387 amount: 20€ DepositPerformed accountId: 9387 amount: 100€ BankAccount id: 9387 balance: 100€ Bug Inspired by B. Reitzammer & J. Seitz - http://ookami86.github.io/event-sourcing-in-practice Apply to Apply to Produces Produces
32. WithdrawalPerformed accountId: 9387 amount: 30€ BankAccount id: 9387 balance: 0€ WithdrawalPerformed accountId: 9387 amount: 20€ DepositPerformed accountId: 9387 amount: 100€ BankAccount id: 9387 balance: 100€ BankAccount id: 9387 balance: 70€ Inspired by B. Reitzammer & J. Seitz - http://ookami86.github.io/event-sourcing-in-practice Apply to Apply to Produces Produces
33. Domain Driven Design
34. « DDD is about designing software based on models of the underlying (business) domain » Martin Fowler
35. Ubiquitous Language Repository Aggregate Root Entity Value Object
36. Durable business model Extensibility Clean Architecture Solid Responsibility Segregation
37. Using Event Sourcing and DDD concepts in Multiplus
38. Multiplus Business Logic ReceiveQuote {command} QuoteReceived {event} QuoteForwarded {event} Customer Event Bus QuoteForwardedHandler {handler} Quote Requesting Quoting QuoteReceived {event} QuoteReceived {event} ForwardQuote {action}
39. Transaction {aggregate root} Pricing {entity} Execution {entity} Orchestration {entity} ReceiveQuote {command/value object} quoteRequestId: 4563 price: 100€ QuoteReceived {event/value object} accountId: 4563 price: 110€ - Multiplus Business Logic -
40. What we’ve learned
41. Be aware of Command Sourcing
42. Multiplus Business Logic ReceiveQuote {command} quoteRequestId: 4563 price: 100€ QuoteForwarded {event} accountId: 4563 price: 101€ Multiplus Business Logic ReceiveQuote {command} quoteRequestId: 4563 price: 100€ QuoteForwarded {event} accountId: 4563 price: 102€ 2015/06/01 Margin: 1% 2015/11/01 Margin: 2%
44. Multiplus Business Logic ReceiveQuote {command} QuoteForwarded {event} Customer Event Bus QuoteForwardedHandler {handler} {Quote n° 65746} {Quote n° 65746} ?? QuoteReceived {event} ForwardQuote {action}
45. Multiplus Business Logic ReceiveQuote {command} QuoteForwarded {event} Customer Event Bus QuoteForwardedHandler {handler} Customer gateway {Quote n° 65746} {Quote n° 65746} QuoteReceived {event} ForwardQuote {action}
46. Store the events produced by the Decide function
47. Multiplus Business Logic ReceiveQuote {command} quoteRequestId: 4563 price: 100€ QuoteForwarded {event} accountId: 4563 price: 101€ Multiplus Business Logic 2015/06/01 Margin: 1% 2015/11/01 Margin: 2% QuoteForwarded {event} accountId: 4563 price: 101€
48. Multiplus Business Logic ReceiveQuote {command} QuoteForwarded {event} Customer Event Bus QuoteForwardedHandler {handler} QuoteReceived {event} ForwardQuote {action}
49. It’s all in the past !
50. Date Money Out Money In 2015/05/14 100 € 2015/05/14 -20 € 2015/05/16 -30 € 2015/05/24 30 € 2015/06/01 -70 € Total -120 € 130 € Balance 10 €
51. Behavior Driven Development Conversation Collaboration Specifications By Examples Three Amigos Automation Ubiquitous Language
52. deliver the right software
53. Your documentation will become alive
54. you will new comers thank
55. you will new comers thank … but you’ll enjoy it too !
56. warning
57. doing BDD right easy is not
58. BDD Common Issues Business and developper faces collaboration difficulties Mess with the scenario writing Automation Nightmare
59. BDD Common Issues Business and developper faces collaboration difficulties Mess with the scenario writing Automation Nightmare
60. our complex application are often
61. we tend to let everywhere business rules being dispatch
62. … making them hard to test
63. Hexagonal Architecture the onion architecture the clean architecture ports and adapters
64. domain adapters Port ( inbound) Port ( outbound) Web Message Queue Database
65. Advantages Testability Flexibility Business Centric
66. domain driven app structure
67. that’s not enough !
68. use different granularity business scenarios when expressing your levels
69. Given a quantity value of 1000 in G When the quantity is converted in OZ Then the converted quantity is 32.1507 OZ Given a quote request with a way BUY And the credit check request has been sent When the credit check response is in error Then the pricer does not receive a quote request And the platform quote status is REJECTED Given an authorized product type When the customer sends the rfs Then the pricer receives the rfs When the pricer sends a quote Then the customer receives the quote Workflow Feature Unit
70. « l’enfer c’est les autres » Jean-Paul Sartre
71. at any time business validation
73. steroids integration testing on
74. care about the contract between your app and another
75. avoid accidental complexity
76. there’s always implicit a schema even if it’s
77. Hexagonal Architecture DDD Event Sourcing BDD State Machine
78. Hexagonal Architecture Java DDD Event Sourcing BDD State Machine
79. Hexagonal Architecture Dagger Java DDD Event Sourcing BDD State Machine
80. Hexagonal Architecture Dagger Java Guava DDD Event Sourcing BDD State Machine
81. Our architecture is easy to deploy !
82. Simple
83. Simple No More Technologies Than Required
84. Simple No More Technologies Than Required Business Centric
85. Simple No More Technologies Than Required Business Centric Code Understanding is Key
86. Simple No More Technologies Than Required Business Centric Courage Code Understanding is Key
87. Any Questions ?