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#
# 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.size < 1
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
if defined?(Random) == 'constant' && Random.class == Class
offset = Random.new(seed).rand(elements)
else
old_seed = srand(seed)
offset = rand(elements)
srand(old_seed)
end
end
offset.times {
result.push result.shift
}
result = string ? result.join : result
return result
end
# vim: set ts=2 sw=2 et :
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