From fef247b5db492bdfc971036b1a52cbe7ba58fcb3 Mon Sep 17 00:00:00 2001
From: Steve Traylen <steve.traylen@cern.ch>
Date: Fri, 16 Mar 2012 16:23:27 +0100
Subject: (#13205) Rotate array/string randomley based on fqdn, fqdn_rotate()

---
 lib/puppet/parser/functions/fqdn_rotate.rb | 46 ++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 lib/puppet/parser/functions/fqdn_rotate.rb

(limited to 'lib')

diff --git a/lib/puppet/parser/functions/fqdn_rotate.rb b/lib/puppet/parser/functions/fqdn_rotate.rb
new file mode 100644
index 0000000..6558206
--- /dev/null
+++ b/lib/puppet/parser/functions/fqdn_rotate.rb
@@ -0,0 +1,46 @@
+#
+# 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]
+    klass = value.class
+    require 'digest/md5'
+
+    unless [Array, String].include?(klass)
+      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
+
+    srand(Digest::MD5.hexdigest([lookupvar('::fqdn'),arguments].join(':')).hex)
+    rand(elements).times {
+       result.push result.shift
+    }
+
+    result = string ? result.join : result
+
+    return result
+  end
+end
+
+# vim: set ts=2 sw=2 et :
-- 
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