CONVERTING.md

Converting cookbooks from the old resource model to the new

Boilerplate

1. Depend on compat_resource
   • Descend resources from ChefCompat::Resource
   • Set resource_name in the class instead of the constructor
2. Convert Attributes to Properties
   • Rename attribute -> property
   • Move set_or_return -> property
   • Take kind_of/equal_to/regexes and make them types
   • Use true/false/nil instead of TrueClass/FalseClass/NilClass
   • Remove default: nil (it's the default)
3. Convert Top-Level Providers to Actions
   • Create any resources that don't already exist (for example in multi-provider cases) and descend from the base resource
   • Remove allowed_actions / @actions
   • @action -> default_action
   • Move provides and action :x to the resource
   • Remove use_inline_resources and def whyrun_safe?
   • Move other methods to action_class.class_eval do

Now you have everything in a resource, are using properties, and have gotten rid of a bunch of boilerplate. Of course, this is just getting it moved.

Advanced Concepts

1. Resource Inheritance
2. Resources That Are Different On Each OS?
3. Coercion: Handling User Input
4. Lazy Defaults
5. Using Load Current Resource
6. Using Converge If Changed
7. Defaults Are For Creation
8. Shared types: using a type multiple places