puppetlabs-stdlib/load_vars.rb

#
# load_vars.rb
#
# This script will allow for loading variables from an external YAML
# file and expose them for further use inside the Puppet manifest file ...
#
# For example:
#
# Given following content of the data.yaml file:
#
#  ---
#  host1.example.com:
#    foo: bar
#    baz: quux
#    question: 42
#  host2.example.com:
#    abc: def
#    this: that
#    darth: vader
#
# Then calling load_vars in Puppet manifest file as follows:
#
#  load_vars("/etc/puppet/data.yaml", $fqdn)
#
# Will result in addition of variables $foo, $baz and $question
# for matching host name as per the variable $fqdn ...
#
# Another example which uses per-host file:
#
# Given following content of the file data-host1.example.com.yaml:
#
#  ---
#  foo: bar
#
# Then when we call load_vars like this:
#
#  load_vars("/etc/puppet/data-$fqdn.yaml")
#
# This will result in a variable $foo being added and ready for use.
#

module Puppet::Parser::Functions
  newfunction(:load_vars, :type => :statement) do |args|
    data = {}

    file = args[0]
    key  = args[1] if args[1]

    if File.exists?(file)

      begin
        data = YAML.load_file(file)
      rescue => error
        raise(Puppet::ParseError,
          "Unable to load data from the file `%s': %s" % file, error.to_s)
      end

      raise(Puppet::ParseError,
        "Data in the file `%s' is not a hash" % file) unless data.is_a?(Hash)

      data = data[key] if key and data[key].is_a?(Hash)
    end

    data.each { |param, value| setvar(param, strinterp(value)) }
  end
end

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