3 files changed, 115 insertions, 0 deletions
diff --git a/README.markdown b/README.markdown
index a6b7bda..627e73a 100644
--- a/README.markdown
+++ b/README.markdown
@@ -578,6 +578,15 @@ fqdn_rotate([1, 2, 3], 'custom seed')
 
 *Type*: rvalue.
 
+#### `fqdn_uuid`
+
+Returns a rfc4122 valid version 5 UUID based on an FQDN string under the DNS namespace
+
+  * fqdn_uuid('puppetlabs.com') returns '9c70320f-6815-5fc5-ab0f-debe68bf764c'
+  * fqdn_uuid('google.com') returns '64ee70a4-8cc1-5d25-abf2-dea6c79a09c8'
+
+*Type*: rvalue.
+
 #### `get_module_path`
 
 Returns the absolute path of the specified module for the current environment.
diff --git a/lib/puppet/parser/functions/fqdn_uuid.rb b/lib/puppet/parser/functions/fqdn_uuid.rb
new file mode 100644
index 0000000..30205d0
--- /dev/null
+++ b/lib/puppet/parser/functions/fqdn_uuid.rb
@@ -0,0 +1,92 @@
+require 'digest/sha1'
+
+module Puppet::Parser::Functions
+  newfunction(:fqdn_uuid, :type => :rvalue, :doc => <<-END) do |args|
+
+    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
+
+    if args.length == 0
+      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
+end
diff --git a/spec/functions/fqdn_uuid_spec.rb b/spec/functions/fqdn_uuid_spec.rb
new file mode 100644
index 0000000..a2d1618
--- /dev/null
+++ b/spec/functions/fqdn_uuid_spec.rb
@@ -0,0 +1,14 @@
+require 'spec_helper'
+
+describe 'fqdn_uuid' do
+
+  context "Invalid parameters" do
+    it { should run.with_params().and_raise_error(ArgumentError, /No arguments given$/) }
+  end
+
+  context "given string" do
+    it { should run.with_params('puppetlabs.com').and_return('9c70320f-6815-5fc5-ab0f-debe68bf764c') }
+    it { should run.with_params('google.com').and_return('64ee70a4-8cc1-5d25-abf2-dea6c79a09c8') }
+  end
+
+end