inet6 prefix utility

Utility to handle prefixing IPv6 address with `inet6:`.

This is useful for services relying on python-memcached
which require the inet6:[<ip_address]:<port> format.

Change-Id: Ibd280929f62bae61f34b2984af7710fbd422264b

lib/puppet/functions/inet6_prefix.rb

@@ -0,0 +1,31 @@
+# Add inet6 prefix if the argument is an IPv6 address.
+#
+# This is useful for services relying on python-memcached which require
+# the inet6:[<ip_address]:<port> format.
+#
+# Returns the argument untouched otherwise.
+Puppet::Functions.create_function(:inet6_prefix) do
+  def inet6_prefix(*args)
+    require 'ipaddr'
+
+    result = []
+    args = args[0] if args[0].kind_of?(Array)
+    args = [args] unless args.kind_of?(Array)
+    args.each do |ip|
+      begin
+        unless ip.match(/^inet6:.+/)
+          ip_parts = ip.split(/\s|\[|\]/).reject { |c| c.empty? }
+          if IPAddr.new(ip_parts[0]).ipv6?
+            Puppet.debug("#{ip} is changed to inet6:[#{ip}]")
+            ip = "inet6:[#{ip_parts.shift}]#{ip_parts.join}"
+          end
+        end
+      rescue IPAddr::AddressFamilyError, IPAddr::Error, IPAddr::InvalidAddressError, IPAddr::InvalidPrefixError, ArgumentError, NoMethodError => e
+        # ignore it
+      end
+      result << ip
+    end
+    return result[0] if args.size == 1
+    result
+  end
+end

releasenotes/notes/memcached-inet6-prefix-91e867d03bc5f6e2.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Utility to handle prefixing IPv6 address with ``inet6:``. This is useful
+    for services relying on python-memcached which require the
+    ``inet6:[<ip_address]:<port>`` format.

spec/functions/inet6_prefix_spec.rb

@@ -0,0 +1,18 @@
+require 'spec_helper'
+
+describe 'inet6_prefix' do
+  it { should run.with_params(false).and_return(false)}
+  it { should run.with_params('not_an_ip').and_return('not_an_ip')}
+  it { should run.with_params('127.0.0.1').and_return('127.0.0.1')}
+  it { should run.with_params('::1').and_return('inet6:[::1]')}
+  it { should run.with_params('[::1]:80').and_return('inet6:[::1]:80')}
+  it { should run.with_params('[2001::01]').and_return('inet6:[2001::01]')}
+  it { should run.with_params('[2001::01]:80').and_return('inet6:[2001::01]:80')}
+  # You're not forced to pass an array, a list of argument will do.
+  it { should run.with_params('::1','::2').and_return(['inet6:[::1]','inet6:[::2]'])}
+  it { should run.with_params(['::1','::2']).and_return(['inet6:[::1]','inet6:[::2]'])}
+  it { should run.with_params(['::1','[::2]','::3']).and_return(['inet6:[::1]','inet6:[::2]','inet6:[::3]'])}
+  it { should run.with_params(['192.168.0.1','[::2]']).and_return(['192.168.0.1','inet6:[::2]'])}
+  it { should run.with_params(['192.168.0.1','[::2]:80']).and_return(['192.168.0.1','inet6:[::2]:80'])}
+  it { should run.with_params(['192.168.0.1','::2']).and_return(['192.168.0.1','inet6:[::2]'])}
+end