# fqdn_rotate.rb
#
-module Puppet::Parser::Functions
- newfunction(:fqdn_rotate, :type => :rvalue, :doc => <<-EOS
-Rotates an array a random number of times based on a nodes fqdn.
- EOS
- ) do |arguments|
-
- raise(Puppet::ParseError, "fqdn_rotate(): Wrong number of arguments " +
- "given (#{arguments.size} for 1)") if arguments.size < 1
-
- value = arguments[0]
+Puppet::Parser::Functions.newfunction(
+ :fqdn_rotate,
+ :type => :rvalue,
+ :doc => "Usage: `fqdn_rotate(VALUE, [SEED])`. VALUE is required and
+ must be an array or a string. SEED is optional and may be any number
+ or string.
+
+ Rotates VALUE a random number of times, combining the `$fqdn` fact and
+ the value of SEED for repeatable randomness. (That is, each node will
+ get a different random rotation from this function, but a given node's
+ result will be the same every time unless its hostname changes.) Adding
+ a SEED can be useful if you need more than one unrelated rotation.") do |args|
+
+ raise(Puppet::ParseError, "fqdn_rotate(): Wrong number of arguments given (#{args.size} for 1)") if args.size < 1
+
+ value = args.shift
require 'digest/md5'
unless value.is_a?(Array) || value.is_a?(String)
- raise(Puppet::ParseError, 'fqdn_rotate(): Requires either ' +
- 'array or string to work with')
+ raise(Puppet::ParseError, 'fqdn_rotate(): Requires either array or string to work with')
end
result = value.clone
elements = result.size
- seed = Digest::MD5.hexdigest([lookupvar('::fqdn'),arguments].join(':')).hex
+ seed = Digest::MD5.hexdigest([lookupvar('::fqdn'),args].join(':')).hex
# deterministic_rand() was added in Puppet 3.2.0; reimplement if necessary
if Puppet::Util.respond_to?(:deterministic_rand)
offset = Puppet::Util.deterministic_rand(seed, elements).to_i
if defined?(Random) == 'constant' && Random.class == Class
offset = Random.new(seed).rand(elements)
else
- srand(seed)
+ old_seed = srand(seed)
offset = rand(elements)
- srand()
+ srand(old_seed)
end
end
offset.times {
result = string ? result.join : result
return result
- end
end
# vim: set ts=2 sw=2 et :