The Microfrontend Revolution Module Federation with Angular -- Director's Cut

@ManfredSteyer ManfredSteyer

@ManfredSteyer Do you remember her?

@ManfredSteyer Software Engineering is a Team Sport

@ManfredSteyer Coordination b/w Teams

@ManfredSteyer Monolith Flight System

@ManfredSteyer Booking Service Check-in Service Boarding Service Luggage Service Microservices
Sub-Domains (DDD)

@ManfredSteyer Booking App Check-in App Boarding App Luggage App Microfrontends

@ManfredSteyer How to implement Microfrontends? ?

@ManfredSteyer Webpack 5 Module Federation

@ManfredSteyer Contents #1: Consequences of Microfrontends #2: Module Federation #3:
Microfrontends FAQ

@ManfredSteyer About me… Manfred Steyer, ANGULARarchitects.io (Remote) Angular Workshops and
Consulting Google Developer Expert for Angular Trusted Collaborator in the Angular Team Manfred Steyer

@ManfredSteyer #1: Consequences of Microfrontends

@ManfredSteyer Booking App Check-in App Boarding App Luggage App Autonomous
Teams

@ManfredSteyer Autonomous Teams Separate Development Separate Deployment Own architecture decisions
Own technology descisions

@ManfredSteyer Microfrontends are first and foremost about scaling teams!

@ManfredSteyer Challenges

@ManfredSteyer Challenges UI Composition UI Consistency Bundle Size/ Sharing Dependencies
Version Conflicts between Microfrontends …

@ManfredSteyer Module Federation Solves Some of Them! UI Composition UI
Consistency Bundle Size/ Sharing Dependencies Version Conflicts between Microfrontends …

@ManfredSteyer #2: Webpack 5 Module Federation

@ManfredSteyer DEMO

@ManfredSteyer How to load separately compiled code?

@ManfredSteyer Idea const Component = import('http://other-app/xyz') Does not work with
webpack/ Angular CLI Even lazy parts must be known at compile time!

@ManfredSteyer Webpack 5 Module Federation Shell (Host) Microfrontend (Remote) //
Maps Urls in // webpack config remotes: { mfe1: "mfe1" } // Expose files in // webpack config exposes: { Cmp: './my.cmp.ts' } import('mfe1/Cmp')

@ManfredSteyer How to Get the Microfrontend's URL? Shell (Host) Microfrontend
(Remote) RemoteEntrypoint.js <script src="…"></script>

@ManfredSteyer How to Share Libs? Shell (Host) Microfrontend (Remote) shared:
[ "@angular/core", "…" ] shared: [ "@angular/core", "…" ]

@ManfredSteyer Conflicting Shared Libs Option A: Reuse it anyway Option
B: Load own Both might be bad Prevent organizationally (e. g. conventions, contracts, monorepos) Integration-Testing

@ManfredSteyer DEMO

@ManfredSteyer Challenge for You

@ManfredSteyer ngx-Snake MIT License Credits: Samir Hodzic

@ManfredSteyer DEMO

@ManfredSteyer Challenge • Create a proper snake strategy • Publish
it as a Module Federation Remote • Award Ceremony: ngCopenhagen Online Meetup • June 23th, 2020 • https://www.meetup.com/de-DE/ngCopenhagen/ • All Details • https://github.com/manfredsteyer/snake

@ManfredSteyer When can we have it?

@ManfredSteyer Well … Webpack 5 is currently beta Shown examples:
PoC w/ custom webpack conf + patched CLI lib CLI: Not before version 11 (fall 2020) Squeeze federation config into CLI's webpack config Custom Builder (e. g. ngx-build-plus)

@ManfredSteyer #3: FAQ

@ManfredSteyer How To Identify Good Sub-Domains and hence Microfrontends?

@ManfredSteyer Request Product Specify Order Approve Order Send Order Budget
Hierarchy Employee IT-Expert Manager Buying Agent Product

@ManfredSteyer "Right" Domain Size Should mirror a real-world domain Large
enough: Most use cases don't overlap domains Small enough: One team per domain

@ManfredSteyer Domain Driven Design gives a lot of advice! Also
see blog at: http://angulararchitects.io

@ManfredSteyer Monorepo or Polyrepo

@ManfredSteyer Catalog Approval Shared Feature Feature Feature Feature Feature …
… … … … … … … … @ManfredSteyer Catalog App Approval App Option 1: One Monorepo w/ several Domains

@ManfredSteyer Consequences Easy to share code Decoupling b/w domains: Conventions
or Tools (Linting) Easy to enforce one version policy Different technologies: possible

@ManfredSteyer Catalog Approval Shared Feature Feature Feature Feature Feature …
… … … … … … … … @ManfredSteyer Catalog App Approval App Option 2: One Repo per Domains Publish shared libs seperately via npm

@ManfredSteyer Consequences Enforces decoupling b/w domains Allows different versions (good
or bad?) Allows different technologies Needs lots of automation Sharing Code via npm and versioning might be a pain

@ManfredSteyer Recommentation, if you are not sure Start with a
monorepo Enforce decoupling via linting Reconsider splitting into several repos later

@ManfredSteyer Pro Tip: Tooling for Monorepos https://nrwl.io/nx

@ManfredSteyer Communication

@ManfredSteyer Communication is a Trade-Off Decoupled Sub-Domains Communication b/w Sub-Domains

@ManfredSteyer Ideas As little as possible! Messaging/ Eventing: Loosly Coupling
Trigger a (Domain) Event Don't expect an answer!

@ManfredSteyer Very Simple Message Bus @Injectable({ providedIn: 'root' }) export
class MessageBus { events$ = new ReplaySubject<DomainEvent>(1); }

@ManfredSteyer Also Consider: Server-Side Messaging µService µFrontend µService µFrontend µService
µFrontend

@ManfredSteyer Redux for Communication?

@ManfredSteyer Well … Don't directly share state b/w sub-domains (coupling!)
You might use Redux for eventing (like a Message Bus)

@ManfredSteyer Sharing Widgets

@ManfredSteyer Sharing Widgets is a Trade-Off too Decoupled Sub-Domains Shared
Widgets Prevent duplicate code (DRY) Separate Ways

@ManfredSteyer Recommentation Technical Widgets (e. g. Design System): Sharing ok
Use Case-specific widgets: Try to avoid (coupling!)

@ManfredSteyer You can't have both: Decoupling and DRY ! Know
your Architecture Goals!

@ManfredSteyer Good Message: Very often, Separate Ways DOES NOT mean
duplicate code!

@ManfredSteyer Catalog Approval Bounded Context Ubiquitous Language

@ManfredSteyer Bounded Context per Sub-Domain Also see blog at: http://angulararchitects.io

@ManfredSteyer Web Components

@ManfredSteyer

@ManfredSteyer Recommentation Try to stick with one technology (e. g.
Angular) --> Share framework-specific components Works in the short and mid run Eventually, when needed, export them as web components (e. g. w/ Angular Elements)

@ManfredSteyer Authentication and Authorization

@ManfredSteyer Possibilities HTTP Only Cookie: Tunnel through one origin (+XSRF
Token) Token via Header: Different origins (consider OAuth2/OIDC) • Share token via message bus or session storage

@ManfredSteyer Microservice per Microfrontend?

@ManfredSteyer Recommendation: Verticals µService µFrontend µService µFrontend µService µFrontend

@ManfredSteyer Backend for Frontend (BFF) BFF µFrontend BFF µFrontend BFF
µFrontend µServices µServices µServices µServices

@ManfredSteyer Nevertheless, try this approach if possible! µService µFrontend µService
µFrontend µService µFrontend

@ManfredSteyer Dashboards

@ManfredSteyer Dashboard: Special Forces Decoupled Sub-Domains Dashboard Data and widgets
from each subdomain

@ManfredSteyer Approaches Dashboard loads widgets from each sub-domain • Flexibility
• Needs stable contracts • Agreements on common look and feel • Lots HTTP Calls Dashboard as a own sub-domain • Pros and Cons are inversed

@ManfredSteyer Backend for Frontend (BFF) Dashboard µBFF Dashboard µFrontend BFF
µFrontend BFF µFrontend µServices µServices µServices µServices Messaging

@ManfredSteyer Free eBook ANGULARarchitects.io/book Updated for Module Federation and Alternatives

@ManfredSteyer Conclusion Main Purpose of µFrontends: Scaling Teams Decoupling Federation:
Import From Other App Sharing Libs Take Care of Conflicts Know your Architecture Goals

@ManfredSteyer Be like Bonnie and think first! Evaluate whether you
need µFrontends No: Majestic Monolith Yes: Consider Module Federation

@ManfredSteyer Contact and Downloads [web] ANGULARarchitects.io [twitter] ManfredSteyer d Slides
& Examples Remote Company Workshops and Consulting

The Microfrontend Revolution Module Federation with Angular -- Director's Cut

The Microfrontend Revolution Module Federation with Angular -- Director's Cut

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