How to test for existence of a file on the Puppet Master

In a customized modules on Puppet I have

g_iptables
├── files
│   └── fqdn-of-server
├── lib
│   └── puppet
│       └── parser
│           └── functions
│               └── file_exists.rb
└── manifests
    └── init.pp

and I want to let the module do something whether or not the file “fqdn-of-server” exist on the Puppet Master. Googling did get me a file_exists.rb function:

#!/usr/bin/ruby

require 'puppet'

module Puppet::Parser::Functions
  newfunction(:file_exists, :type => :rvalue) do |args|
    if File.exists?(args[0])
      return 1
    else
      return 0
    end
  end
end

and this does work when put in something like:

$does_fqdn_file_exists = file_exists("/tmp/$fqdn")

if $does_fqdn_file_exists == 1 {
 ...
}

in my manifest init.pp (of course $fqdn is a facter). The problem is that it works only on the client (so $does_fqdn_file_exists is 1 if the /tmp/$fqdn exist on the client $fqdn, it does not work on the puppet master.

Also, I want to use puppet:/// uri structures in this construct, but thus sofar, my function doesn’t understand this uri.

Can somebody help me ? The ruby function stems from someone on the web, who claims that it checks the file existence on the master, which is not the case (at least not what I can see).

Answer

In the puppet master you could test it like this:

# create a temporary file that may look like this :

]$ cat /tmp/checkfile.pp
$does_fqdn_file_exists = file_exists("/tmp/$fqdn")
notify{ "Check File = $does_fqdn_file_exists" : }

# Then run it :

]$ puppet apply /tmp/checkfile.pp