2012-03-16 16:23:27 +01:00
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#
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# fqdn_rotate.rb
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#
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2015-06-02 01:09:47 +02:00
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Puppet::Parser::Functions.newfunction(
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:fqdn_rotate,
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:type => :rvalue,
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:doc => "Usage: `fqdn_rotate(VALUE, [SEED])`. VALUE is required and
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must be an array or a string. SEED is optional and may be any number
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or string.
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Rotates VALUE a random number of times, combining the `$fqdn` fact and
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the value of SEED for repeatable randomness. (That is, each node will
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get a different random rotation from this function, but a given node's
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result will be the same every time unless its hostname changes.) Adding
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a SEED can be useful if you need more than one unrelated rotation.") do |args|
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2012-03-16 16:23:27 +01:00
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raise(Puppet::ParseError, "fqdn_rotate(): Wrong number of arguments " +
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2015-06-02 01:09:47 +02:00
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"given (#{args.size} for 1)") if args.size < 1
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2012-03-16 16:23:27 +01:00
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2015-06-02 01:09:47 +02:00
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value = args.shift
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2012-03-16 16:23:27 +01:00
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require 'digest/md5'
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2014-04-22 09:36:28 +02:00
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unless value.is_a?(Array) || value.is_a?(String)
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2012-03-16 16:23:27 +01:00
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raise(Puppet::ParseError, 'fqdn_rotate(): Requires either ' +
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'array or string to work with')
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end
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result = value.clone
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string = value.is_a?(String) ? true : false
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# Check whether it makes sense to rotate ...
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return result if result.size <= 1
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# We turn any string value into an array to be able to rotate ...
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result = string ? result.split('') : result
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elements = result.size
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2015-06-02 01:09:47 +02:00
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seed = Digest::MD5.hexdigest([lookupvar('::fqdn'),args].join(':')).hex
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2015-01-29 00:28:54 +01:00
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# deterministic_rand() was added in Puppet 3.2.0; reimplement if necessary
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if Puppet::Util.respond_to?(:deterministic_rand)
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offset = Puppet::Util.deterministic_rand(seed, elements).to_i
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else
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if defined?(Random) == 'constant' && Random.class == Class
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offset = Random.new(seed).rand(elements)
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else
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2015-05-12 16:01:55 +02:00
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old_seed = srand(seed)
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2015-01-29 00:28:54 +01:00
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offset = rand(elements)
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2015-05-12 16:01:55 +02:00
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srand(old_seed)
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2015-01-29 00:28:54 +01:00
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end
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end
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offset.times {
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2012-03-16 16:23:27 +01:00
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result.push result.shift
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}
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result = string ? result.join : result
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return result
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end
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# vim: set ts=2 sw=2 et :
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