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Layered Libraries

The 'L' of MonoLISA.

MonoLISA achieves separation of concerns (SoC) with:

  • Layers to separate technical concerns.

  • Libraries to separate the concerns of actors.

Layers​

Define a layer for each high-level technical concern.

Domain (business rules), API (endpoints), database (repositories), and integration (to downstream services) are examples of backend layers.

Create a folder for each layer in the libs folder. For example:

libs
- domain
- api
- db
- integration

Libraries​

Create libraries for actors within the layers.

Actors​

An actor is a role an entity plays when it interacts with the system. The entity may be a human or an external system.

For example, if you are developing an email app, the user could be seen as an ‘inbox viewer’ actor when they view the inbox and a ‘draft editor’ when they write an email.

libs
- domain (layer)
  - inbox (lib)
  - draft-editor (lib)
- api (layer)
  - inbox (lib)
  - draft-editor (lib)
etc.