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-rw-r--r--lib/puppet/parser/functions/fqdn_rotate.rb46
-rw-r--r--spec/unit/puppet/parser/functions/fqdn_rotate_spec.rb40
2 files changed, 86 insertions, 0 deletions
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 :
diff --git a/spec/unit/puppet/parser/functions/fqdn_rotate_spec.rb b/spec/unit/puppet/parser/functions/fqdn_rotate_spec.rb
new file mode 100644
index 0000000..dd1c3f3
--- /dev/null
+++ b/spec/unit/puppet/parser/functions/fqdn_rotate_spec.rb
@@ -0,0 +1,40 @@
+#!/usr/bin/env rspec
+require 'spec_helper'
+
+describe "the fqdn_rotate function" do
+ before :all do
+ Puppet::Parser::Functions.autoloader.loadall
+ end
+
+ before :each do
+ @scope = Puppet::Parser::Scope.new
+ end
+
+ it "should exist" do
+ Puppet::Parser::Functions.function("fqdn_rotate").should == "function_fqdn_rotate"
+ end
+
+ it "should raise a ParseError if there is less than 1 arguments" do
+ lambda { @scope.function_fqdn_rotate([]) }.should( raise_error(Puppet::ParseError))
+ end
+
+ it "should rotate a string and the result should be the same size" do
+ @scope.expects(:lookupvar).with("::fqdn").returns("127.0.0.1")
+ result = @scope.function_fqdn_rotate(["asdf"])
+ result.size.should(eq(4))
+ end
+
+ it "should rotate a string to give the same results for one host" do
+ @scope.expects(:lookupvar).with("::fqdn").returns("127.0.0.1").twice
+ @scope.function_fqdn_rotate(["abcdefg"]).should eql(@scope.function_fqdn_rotate(["abcdefg"]))
+ end
+
+ it "should rotate a string to give different values on different hosts" do
+ @scope.expects(:lookupvar).with("::fqdn").returns("127.0.0.1")
+ val1 = @scope.function_fqdn_rotate(["abcdefghijklmnopqrstuvwxyz01234567890987654321"])
+ @scope.expects(:lookupvar).with("::fqdn").returns("127.0.0.2")
+ val2 = @scope.function_fqdn_rotate(["abcdefghijklmnopqrstuvwxyz01234567890987654321"])
+ val1.should_not eql(val2)
+ end
+
+end