Use content of a file as a variable with Puppet

Every now and then a need to use the content of a file as a variable on an agent node arises. Here's one way to do it with the help of a custom fact.

First create a custom fact on the puppet server:

Facter.add(:my_file_content) do
  setcode do
    path = "/path/to/my_file"
    File.read(path) if File.exist?(path)
   end
end

You can confine this to restrict it to be available only on selected nodes, for example:

Facter.add(:my_file_content) do
  confine :hostname => [ :'my_first_node', :'my_second_node']
  setcode do
    path = "/path/to/my_file"
    File.read(path) if File.exist?(path)
   end
end

Next use this custom fact to load the file content into a variable:

$my_variable=$facts['my_file_content']

You can now split(), join(), regexp(), strip() etc. it to your hearts content.

That's it. As always, be sensible with the possible security implications.