> For the complete documentation index, see [llms.txt](https://notes.bf.wtf/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://notes.bf.wtf/programming/software-architecture.md).

# Software Architecture

* Event-Driven communication
  * Limit direct interaction between components of a system
* Data-Oriented
  * Events -> Components -> Data Updates
  * Data Updates -> Components -> Events
  * Requests -> Components -> Data Queries -> Response
* Unidirectional, immutable, pure, side-effects at boundaries
  * [Functional core, imperative shell](https://app.gitbook.com/@bfollington/s/notes/~/drafts/-M1wtdl3z8PnDUBSFQlc/programming/functional-programming/functional-core-imperative-shell)
* Domain-Driven-Design
  * Carefully architect code around core business concepts

![My take on video-game architecture](/files/-M1wu0da2I2GK3PZJjep)

When considering game architecture specifically a few extra elements become relevant:

* Zero-allocation event dispatch
  * Object pooling
* Minimal-allocation state update
  * Clever immutable data structures
* Minimal-allocation projection update
  * Infrequent projection changes can allocate
  * Frequent projection changes should be computed with no allocation
* Minimal-runtime-instantiation of game entities
  * Object pooling
* Object lifecycle handling, no dangling subscriptions

## Data-Oriented Architecture

{% embed url="<https://blog.eyas.sh/2020/03/data-oriented-architecture/>" %}

<https://engineering.fb.com/data-infrastructure/messenger/>

## Unidirectional Dataflow

{% embed url="<https://guide.elm-lang.org/architecture/>" %}

{% embed url="<https://facebook.github.io/flux/docs/in-depth-overview>" %}

{% embed url="<https://cycle.js.org/>" %}

## Event-Driven (& Event-Sourcing, CQRS)

{% embed url="<https://blog.jacobsdata.com/2020/02/19/a-brief-intro-to-clean-architecture-clean-ddd-and-cqrs>" %}

{% embed url="<https://www.youtube.com/watch?v=US8QG9I1XW0&list=PLKbIl8vl5RyuzNnO3nCUCnbT3WqReNW36&index=3>" %}

{% embed url="<https://danielwhittaker.me/2020/02/20/cqrs-step-step-guide-flow-typical-application/>" %}

{% embed url="<https://www.youtube.com/watch?v=dI91AJVVuNg>" %}

{% embed url="<https://vimeo.com/131632601>" %}

{% embed url="<https://www.youtube.com/watch?v=I3uH3iiiDqY>" %}

{% embed url="<https://www.youtube.com/watch?v=STKCRSUsyP0>" %}

{% embed url="<https://github.com/kgrzybek/modular-monolith-with-ddd>" %}