Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
#2 NestJS Paris meetup - NestJS & Event Store
Search
Sylvain PONTOREAU
September 10, 2019
Programming
0
850
#2 NestJS Paris meetup - NestJS & Event Store
NestJS & Event Store (CQRS & Event Sourcing)
Presenation made during NestJS Paris meetup.
Sylvain PONTOREAU
September 10, 2019
Tweet
Share
More Decks by Sylvain PONTOREAU
See All by Sylvain PONTOREAU
aMS Lausanne - Préparez-vous à une virée intersidérale avec Azure Cosmos DB 🧑🚀
spontoreau
0
36
TypeScript - 45 minutes pour s’y mettre !
spontoreau
0
130
Event Sourcing avec Azure, quelle base de données choisir
spontoreau
0
48
Decorators in TypeScript 5.0, everything you need to know!
spontoreau
0
450
Leverage your CI/CD at the next level with Github actions
spontoreau
0
32
Commit comme un(e) "Hipster" avec Gitmoji !
spontoreau
0
140
Bird of a Feather - TypeScript (Devoxx 2022)
spontoreau
0
31
GitHub - Du besoin jusqu'à la production avec Github et Azure
spontoreau
0
25
Behavior Driven Development
spontoreau
1
240
Other Decks in Programming
See All in Programming
エンジニアのための”最低限いい感じ”デザイン入門
shunshobon
0
120
CLI ツールを Go ライブラリ として再実装する理由 / Why reimplement a CLI tool as a Go library
ktr_0731
3
1.1k
画像コンペでのベースラインモデルの育て方
tattaka
3
1.8k
新世界の理解
koriym
0
140
Understanding Ruby Grammar Through Conflicts
yui_knk
1
120
Infer入門
riru
4
1.5k
Langfuseと歩む生成AI活用推進
licux
3
290
兎に角、コードレビュー
mitohato14
0
140
CSC305 Summer Lecture 05
javiergs
PRO
0
100
【第4回】関東Kaggler会「Kaggleは執筆に役立つ」
mipypf
0
670
パスタの技術
yusukebe
1
390
オホーツクでコミュニティを立ち上げた理由―地方出身プログラマの挑戦 / TechRAMEN 2025 Conference
lemonade_37
2
480
Featured
See All Featured
Creating an realtime collaboration tool: Agile Flush - .NET Oxford
marcduiker
31
2.2k
Statistics for Hackers
jakevdp
799
220k
Improving Core Web Vitals using Speculation Rules API
sergeychernyshev
18
1.1k
Fight the Zombie Pattern Library - RWD Summit 2016
marcelosomers
234
17k
Rails Girls Zürich Keynote
gr2m
95
14k
A better future with KSS
kneath
239
17k
JavaScript: Past, Present, and Future - NDC Porto 2020
reverentgeek
50
5.5k
How GitHub (no longer) Works
holman
314
140k
Helping Users Find Their Own Way: Creating Modern Search Experiences
danielanewman
29
2.8k
4 Signs Your Business is Dying
shpigford
184
22k
For a Future-Friendly Web
brad_frost
179
9.9k
Product Roadmaps are Hard
iamctodd
PRO
54
11k
Transcript
September 10, 2019 | NestJS Paris | Sylvain Pontoreau NestJS
& Event Store
Formerly Microsoft In ❤ with Co-organizer Who I am? @spontoreau
Paris TypeScript @ParisTypeScript www.typescript.paris
Domain Driven Design • DDD is not a Framework nor
a Methodology… • … it's an approach to dealing with complexity • DDD focusing: • The domain representation • The domain logic • Technical aspects are secondary • Just a part that enforcing the domain
Opposite of Data Driven Development Data Driven Development Domain Driven
Design != Data structure Entity Relationship CRUD Behavior Bounded Context Event
Query Just a read operation Command Data validation Business logic
Persistence CQRS
CQRS GetBookById Query CreateBook Command GetAllBook Query DeleteBook Command …
… Dispatcher Read DB Dispatcher QueryHandler CommandHandler Write DB Validation Plugin Monitoring Plugin Telemetry Plugin … Eventual consistency
https://martinfowler.com/eaaDev/EventSourcing.html Event Sourcing
Event Sourcing & CQRS
CQRS & Event Sourcing GetBookById Query CreateBook Command GetAllBook Query
DeleteBook Command … … Dispatcher Read DB Dispatcher QueryHandler CommandHandler Event Store Projection Projection AggregateRoot State Events
Our focus in this talk GetBookById Query CreateBook Command GetAllBook
Query DeleteBook Command … … Dispatcher Read DB Dispatcher QueryHandler CommandHandler Event Store Projection Projection AggregateRoot State Events
NestJS, Commands, Aggregates & Events Command Bus EventBus EventPublisher Repository
CommandHandler Controller/Service Aggregate Execute Comand Execute Handler Get Aggregate Merge Aggregate Apply events Execute behaviors IEventPublisher Publish events DefaultPubSub Default implementation EventHandler EventStore Publisher
Custom EventPublisher & MessageSource import { IEvent } from './event.interface';
export interface IEventPublisher { publish<T extends IEvent>(event: T); } import { Subject } from 'rxjs'; import { IEvent } from './event.interface'; export interface IMessageSource { bridgeEventsTo< T extends Ievent >(subject: Subject<T>); } • IEventPublisher • MessageSource export class UserModule implements OnModuleInit { constructor( private readonly eventBus: EventBus, private readonly eventStorePublisher: EventStorePublisher ) {} onModuleInit() { this.eventBus.publisher = this.eventStorePublisher; } } • Module
Which database for storing events? Choose what you want! Please
try me!!!
Event Store, the stream database https://eventstore.org
Demo
Resources • CQRS & Event Sourcing • CQRS pattern: https://docs.microsoft.com/en-US/azure/architecture/patterns/cqrs
• Event Sourcing pattern: https://docs.microsoft.com/en-us/azure/architecture/patterns/event-sourcing • Tackle business complexity in a Microservice with DDD and CQRS: https://docs.microsoft.com/en- us/dotnet/standard/microservices-architecture/microservice-ddd-cqrs-patterns/ • NestJS CQRS module: https://docs.nestjs.com/recipes/cqrs • Event Store website: https://eventstore.org • Talk’s sample: https://github.com/spontoreau/nestjs-eventstore-demo • node-eventstore-client NPM package: https://github.com/nicdex/node-eventstore-client • gereventstore-pomise NPM package : https://github.com/RemoteMetering/geteventstore-promise • Jérôme Rouaix presentation on CQRS & ES: https://gitpitch.com/jrouaix/cqrs-es-presentation/master#/ • Arnaud Lemaire talk on CQRS, ES and DDD: https://www.youtube.com/watch?v=qBLtZN3p3FU • Greg Young, A decade of DDD, CQRS and ES: https://www.youtube.com/watch?v=LDW0QWie21s
Questions?
Thank you!