Puppet Function: fqdn_uuid

Defined in:
puppet/modules/stdlib/lib/puppet/parser/functions/fqdn_uuid.rb
Function type:
Ruby 3.x API

Overview

fqdn_uuid()Any

Creates a UUID based on a given string, assumed to be the FQDN

For example, to generate a UUID based on the FQDN of a system:

Usage:

$uuid = fqdn_uuid($::fqdn)

The generated UUID will be the same for the given hostname

The resulting UUID is returned on the form:

1d839dea-5e10-5243-88eb-e66815bd7d5c

(u.e. without any curly braces.)

The generated UUID is a version 5 UUID with the V5 DNS namespace:

6ba7b810-9dad-11d1-80b4-00c04fd430c8

This only supports a the V5 SHA-1 hash, using the DNS namespace.

Please consult www.ietf.org/rfc/rfc4122.txt for the details on UUID generation and example implementation.

No verification is present at the moment as whether the domain name given is in fact a correct fully-qualified domain name. Therefore any arbitrary string and/or alpha-numeric value can subside for a domain name. E

Returns:

  • (Any)


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# File 'puppet/modules/stdlib/lib/puppet/parser/functions/fqdn_uuid.rb', line 4

newfunction(:fqdn_uuid, :type => :rvalue, :doc => <<-END) do |args|

  if args.length == 0

  Creates a UUID based on a given string, assumed to be the FQDN

  For example, to generate a UUID based on the FQDN of a system:

  Usage:

    $uuid = fqdn_uuid($::fqdn)

  The generated UUID will be the same for the given hostname

  The resulting UUID is returned on the form:

    1d839dea-5e10-5243-88eb-e66815bd7d5c

  (u.e. without any curly braces.)

  The generated UUID is a version 5 UUID with the V5 DNS namespace:

    6ba7b810-9dad-11d1-80b4-00c04fd430c8

  This only supports a the V5 SHA-1 hash, using the DNS namespace.

  Please consult http://www.ietf.org/rfc/rfc4122.txt for the details on
  UUID generation and example implementation.

  No verification is present at the moment as whether the domain name given
  is in fact a correct fully-qualified domain name.  Therefore any arbitrary
  string and/or alpha-numeric value can subside for a domain name.
  EOS

  END
    raise(ArgumentError, "fqdn_uuid: No arguments given")
  elsif args.length == 1
    fqdn = args[0]
  else
    raise(ArgumentError, "fqdn_uuid: Too many arguments given (#{args.length})")
  end

  # Code lovingly taken from
  # https://github.com/puppetlabs/marionette-collective/blob/master/lib/mcollective/ssl.rb

  # This is the UUID version 5 type DNS name space which is as follows:
  #
  #  6ba7b810-9dad-11d1-80b4-00c04fd430c8
  #
  uuid_name_space_dns = [0x6b,
    0xa7,
    0xb8,
    0x10,
    0x9d,
    0xad,
    0x11,
    0xd1,
    0x80,
    0xb4,
    0x00,
    0xc0,
    0x4f,
    0xd4,
    0x30,
    0xc8
  ].map {|b| b.chr}.join

  sha1 = Digest::SHA1.new
  sha1.update(uuid_name_space_dns)
  sha1.update(fqdn)

  # first 16 bytes..
  bytes = sha1.digest[0, 16].bytes.to_a

  # version 5 adjustments
  bytes[6] &= 0x0f
  bytes[6] |= 0x50

  # variant is DCE 1.1
  bytes[8] &= 0x3f
  bytes[8] |= 0x80

  bytes = [4, 2, 2, 2, 6].collect do |i|
    bytes.slice!(0, i).pack('C*').unpack('H*')
  end

  bytes.join('-')
end