Create Slice

create-slice

Use this skill when creating and configuring Hanami 2.x Slices.

Quick Reference

Core Rules

1. Generate a Slice using the Hanami CLI:

   hanami generate slice api
   

   Creates slices/api/ with subdirectories including config/routes.rb, actions/, views/, and templates/.

   Verify: Run hanami routes and confirm the new slice's routes appear in the output.

2. Register the Slice in the app:

   # config/app.rb
   module MyApp
     class App < Hanami::App
       slice :api, at: "/api" do
         # Slice-specific configuration
       end
     end
   end
   

3. Define Slice routes in slices/<name>/config/routes.rb:

   # slices/api/config/routes.rb
   module MyApp
     module Slices
       module Api
         class Routes < Hanami::Routes
           get "/users", to: "users.index"
           get "/users/:id", to: "users.show"
         end
       end
     end
   end
   

   Routes map to action files under slices/api/actions/ (e.g. /api/users → slices/api/actions/users/index.rb).

   Verify: Run hanami routes and confirm /api/users and /api/users/:id are listed.

4. Import dependencies from another Slice:

   # config/app.rb
   module MyApp
     class App < Hanami::App
       slice :api, at: "/api" do
         import from: :main do
           # Import specific components from the main slice
         end
       end
     end
   end
   

   Verify: Boot the app (hanami console) and resolve the imported component: MyApp::Slices::Api::Container["main.repositories.users"].

5. Export Slice components for use by other slices:

   # slices/api/config/slice.rb
   module MyApp
     module Slices
       module Api
         class Slice < Hanami::Slice
           export ["repositories.users"]
         end
       end
     end
   end
   

   Verify: In hanami console, confirm the consuming slice can resolve the exported key.

6. Keep Slices self-contained and minimize cross-slice dependencies. Use import/export as the formal contract between slices.

7. Use Slices for bounded contexts — each slice encapsulates a distinct domain concern such as a public API, admin dashboard, billing, or main web application.

Common Mistakes

• Circular slice dependencies: Slices should be acyclic. If Slice A imports from Slice B, Slice B must not import from Slice A.
• Direct container access across slices: Use import/export for cross-slice communication. Never access Hanami.app["slices.other.component"] directly.
• Misaligned namespaces: Slice components live under MyApp::Slices::Api::. File paths and module namespaces must align.

Integration