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