chef

Chef::Resource::Template#helper

Declares a helper method to be defined in the template context when
rendering.

=== Example:

==== Basic usage:
Given the following helper:
  helper(:static_value) { "hello from helper" }
A template with the following code:
  <%= static_value %>
Will render as;
  hello from helper

==== Referencing Instance Variables:
Any instance variables available to the template can be referenced in
the method body. For example, you can simplify accessing app-specific
node attributes like this:
  helper(:app) { @node[:my_app_attributes] }
And use it in a template like this:
  <%= app[:listen_ports] %>
This is equivalent to the non-helper template code:
  <%= @node[:my_app_attributes][:listen_ports] %>

==== Method Arguments:
Helper methods can also take arguments. The syntax available for
argument specification supports full syntax available for method
definition.

Continuing the above example of simplifying attribute access, we can
define a helper to look up app-specific attributes like this:
  helper(:app) { |setting| @node[:my_app_attributes][setting] }
The template can then look up attributes like this:
  <%= app(:listen_ports) %>

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