AXR

Ruby architecture for simplicity and team adoption

Architecture's hard. It’s very easy to build a complex system. Much harder to build a simple and adaptable solution. The code doesn't matter. Coding for the sake of writing code is foolish.

Only a few of us get to write software that survives 5-10 years or longer. 90% of our work is garbage that becomes obsolete in 1-3 years after release. Most of our work hours are wasted on features that will never be useful.

This is just a reality.

(c) Volodya Sveredyuk

Motivation

Application engineering it's always about abstractions and how they describe the real world and business which pays our salaries for coding something that might improve it. Maybe. Sometimes.

I hate doing something alone. I am a team player and as a team player, I prefer conventions over configuration. But this is not working with knowledge responsibility segregation inside the software app. In the Ruby world (especially Rails) it's so easy to add a new feature. Just add one line, one dependency, one callback and now you share knowledge about one entity into another entity. More dependencies - more spaghetti and legacy that in future we should REWRITE EVERYTHING!

Architecture's about knowledge responsibility and not the code.

The worst thing that even we write the architecture document wherein a convenient way to agree on architecture and layers and entities, etc - We are not protected from violation of these conventions.

And this the place where AxR comes on the stage.

Please, welcome the DSL that helps:

1. Describes your application layers (modules)
2. Defines knowledge responsibilities between them
3. Checks if you did not violate anything

Setup

In your Gemfile

gem 'axr', group: :development

DSL

In your ruby app: (for rails app put it into config/initializers/axr.rb file)

require 'axr'

AxR.app.define do
  layer 'Api'
  layer 'YourBusinessLogic'
  layer 'Repo'
end

By default, layers will get level from top to bottom.

Api -> 0
YourBusinessLogic -> 1
Repo -> 2

Layers with lower-level have less isolation.

• Api knows about YourBusinessLogic and Repo
• YourBusinessLogic knows about Repo but don't know anything about Api
• Repo fully isolated and don't familiar with Api and YourBusinessLogic

Options

require 'axr'

AxR.app.define do
  layer 'A'
  layer 'B', familiar_with: 'C'
  layer 'C', familiar_with: 'B'
  layer 'D', isolated: true
  layer 'E', isolated: true
end

# app.define options
AxR.app.define(isolated: true) # All layers will be isolated by default
AxR.app.define(familiar_with: ['D', 'E') # All layers will be familiar with D and E by default

# layer options
familiar_with: [...] # Can operate with other layers
isolated: true # 100% isolated and should not operate with other layers
isolated: true, familiar_with: [...] # Isolated from all except familiars

Can organize knowledge structure like:

CLI

Run AxR checker in console

axr check . --load path/to/you/app/autoload.rb

For rails apps

axr check . --load config/environment

Run for a specific directory

axr lib/adapters

Run for a specific file

axr lib/adapters/youtube.rb

Finish scanning with status code 1 in case of any warnings (you can use in CI environment to fail pipeline step)

axr check --exit-on-warnings

More examples

ERP system

if Rails.env.development? || Rails.env.test?
  require 'axr'

  AxR.app.define(isolated: true) do
    layer 'UI',         familiar_with: %w[Docs Inventory Production]
    layer 'API',        familiar_with: %w[Docs Inventory Production]
    layer 'Docs',       familiar_with: %w[Inventory Accounts Repo]
    layer 'Accounts',   familiar_with: %w[Repo]
    layer 'Inventory',  familiar_with: %w[Repo]
    layer 'Production', familiar_with: %w[Repo]
    layer 'Repo'
  end
end

TODO

• Ignore vendor or any other directories dir as configuration
• Add sublayers
• Add rubocop cop
• Add more app examples
• Migrate to AST analyzer