#
# fqdn_rotate.rb
#
+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.empty?
+
+ 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')
+ end
-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]
- 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')
- end
+ result = value.clone
- result = value.clone
+ string = value.is_a?(String) ? true : false
- string = value.is_a?(String) ? true : false
+ # Check whether it makes sense to rotate ...
+ return result if result.size <= 1
- # Check whether it makes sense to rotate ...
- return result if result.size <= 1
+ # We turn any string value into an array to be able to rotate ...
+ result = string ? result.split('') : result
- # We turn any string value into an array to be able to rotate ...
- result = string ? result.split('') : result
+ elements = result.size
- elements = result.size
+ 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
+ else
+ return offset = Random.new(seed).rand(elements) if defined?(Random) == 'constant' && Random.class == Class
- seed = Digest::MD5.hexdigest([lookupvar('::fqdn'),arguments].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
- else
- if defined?(Random) == 'constant' && Random.class == Class
- offset = Random.new(seed).rand(elements)
- else
- srand(seed)
- offset = rand(elements)
- srand()
- end
- end
- offset.times {
- result.push result.shift
- }
+ old_seed = srand(seed)
+ offset = rand(elements)
+ srand(old_seed)
+ end
+ offset.times do
+ result.push result.shift
+ end
- result = string ? result.join : result
+ result = string ? result.join : result
- return result
- end
+ return result
end
# vim: set ts=2 sw=2 et :