Configure Slice

configure-slice

Use this skill when configuring Hanami 2.x Slices.

Core principle: Each Slice configures its own container, settings, and providers independently of the main app.

Quick Reference

Core Rules

1. Create the Slice configuration file:

   # slices/api/config/slice.rb
   # frozen_string_literal: true
   
   module MyApp
     module Slices
       module Api
         class Slice < Hanami::Slice
           # Slice-level configuration
         end
       end
     end
   end
   

2. Define slice-level settings:

   class Slice < Hanami::Slice
     config.settings do
       setting :api_key, constructor: Types::String
       setting :rate_limit, default: 100, constructor: Types::Integer
     end
   end
   

3. Register slice-specific providers:

   class Slice < Hanami::Slice
     register_provider(:api_client) do
       start do
         client = ApiClient.new(
           api_key: target[:settings].api_key,
           base_url: "https://api.example.com"
         )
         register("api.client", client)
       end
     end
   end
   

4. Configure auto-registration paths:

   class Slice < Hanami::Slice
     config.auto_register_paths = ["app/actions", "app/views", "app/repos"]
     config.no_auto_register_paths = ["app/relations", "app/structs", "app/entities"]
   end
   

5. Import components from another Slice:

   class Slice < Hanami::Slice
     import from: :main do
       # Import all exported components from the main slice
     end
   end
   

6. Export components for other slices:

   class Slice < Hanami::Slice
     export ["repositories.users", "services.auth"]
   end
   

7. Override main app configuration for slice-specific needs:

   class Slice < Hanami::Slice
     # Use a different database for this slice
     config.database_url = target[:settings].database_url
   end
   

8. Keep configuration minimal. Only override defaults when necessary. Prefer convention over configuration.

9. Verify configuration after changes. Run bundle exec hanami console and confirm components resolve correctly:

   # Verify settings are loaded
   MyApp::Slices::Api::Slice[:settings].api_key  # => expected value
   
   # Verify a registered provider component is available
   MyApp::Slices::Api::Slice["api.client"]  # => #<ApiClient ...>
   
   # Verify an imported component resolves
   MyApp::Slices::Api::Slice["repositories.users"]  # => #<Repositories::Users ...>
   

Common Mistakes

Integration