Using defined type to build array?

Question

I currently have a class that looks something like this:

class mymodule (
  $files = [],
) {

file { '/my/file':
    ensure  => file,
    content => template(mymodule/mytemplate.erb)
  }
}

And a template:

files:
<% @files.each do |file| -%>
  - <%= file %>
<% end -%>

I'd like to move the files parameter to its own definition so I can more easily include the class closer to the base and define differen't files closer to node definitions like:

mymodule::file { '/my/file': }
mymodule::file { '/my/other_file': }

What is a good way to go about building the files array using defined types?

Answer 1

A structure like that is Very Hard to achieve using templates. There are two common ways to go about this instead.

The concat module

Using the puppetlabs-concat module, you can make your file consist of the concatenation of discreet snippets.

class mymodule {
    concat { '/my/file': ensure => present }
}

define mymodule::file($content) {
    concat::fragment {
        target  => '/my/file',
        content => $content,
        order   => '50',
    }
}

Hiera

If you can move your resources to Hiera with a create_resources construct, you can trivially extract the resource titles and use them in your template.