1 files changed, 59 insertions, 0 deletions
diff --git a/code/environments/production/modules/stdlib/lib/puppet/parser/functions/fqdn_rotate.rb b/code/environments/production/modules/stdlib/lib/puppet/parser/functions/fqdn_rotate.rb
new file mode 100644
index 0000000..879e44b
--- /dev/null
+++ b/code/environments/production/modules/stdlib/lib/puppet/parser/functions/fqdn_rotate.rb
@@ -0,0 +1,59 @@
+#
+# 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
+
+  result = value.clone
+
+  string = value.is_a?(String) ? true : false
+
+  # 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
+
+  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
+
+    old_seed = srand(seed)
+    offset = rand(elements)
+    srand(old_seed)
+  end
+  offset.times do
+    result.push result.shift
+  end
+
+  result = string ? result.join : result
+
+  return result
+end
+
+# vim: set ts=2 sw=2 et :