chef

Chef::Resource::Template#helpers

Declares a module to define helper methods in the template's context
when rendering. There are two primary forms.

=== Inline Module Definition
When a block is given, the block is used to define a module which is
then mixed in to the template context w/ `extend`.

==== Inline Module Example
Given the following code in the template resource:
  helpers do
    # Add "syntax sugar" for referencing app-specific attributes
    def app(attribute)
      @node[:my_app_attributes][attribute]
    end
  end
You can use it in the template like so:
  <%= app(:listen_ports) %>
Which is equivalent to:
  <%= @node[:my_app_attributes][:listen_ports] %>

=== External Module Form
When a module name is given, the template context will be extended with
that module. This is the recommended way to customize template contexts
when you need to define more than an handful of helper functions (but
also try to keep your template helpers from getting out of hand--if you
have very complex logic in your template helpers, you should further
extract your code into separate libraries).

==== External Module Example
To extract the above inline module code to a library, you'd create a
library file like this:
  module MyTemplateHelper
    # Add "syntax sugar" for referencing app-specific attributes
    def app(attribute)
      @node[:my_app_attributes][attribute]
    end
  end
And in the template resource:
  helpers(MyTemplateHelper)
The template code in the above example will work unmodified.

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