From ab70663d159ff7b59d116ed69b9a455cb22847c4 Mon Sep 17 00:00:00 2001
From: Jeff McCune <jeff@puppetlabs.com>
Date: Wed, 15 Jun 2011 09:40:04 -0700
Subject: (#3) Add an anchor type to provide containment

With Puppet 2.6.x we do not have a way to specify containment
relationships.  In the use case of class ntp { } declaring
ntp::{package,config,service} classes, the ntp class itself should allow
the user to specify before and require relationships to the main ntp
class.

The anchor resource type allows module authors to close the loop on
classes composing the main top level module.  For example:

    class ntp {
      class { 'ntp::package': }
      -> class { 'ntp::config': }
      -> class { 'ntp::service': }
      # These two resources "anchor" the composed classes
      # such that the end user may use "require" and "before"
      # relationships with Class['ntp']
      anchor { 'ntp::begin': } -> class { 'ntp::package': }
      class { 'ntp::service': } -> anchor { 'ntp::end': }
    }

Using this pattern, the module user may then simply declare relationships to
the ntp class as they expect:

    class { 'ntp': } -> class { 'mcollective': }
    # OR
    class { 'mcollective': } -> class { 'ntp': }
---
 lib/puppet/type/anchor.rb | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 lib/puppet/type/anchor.rb

diff --git a/lib/puppet/type/anchor.rb b/lib/puppet/type/anchor.rb
new file mode 100644
index 0000000..0c28b1c
--- /dev/null
+++ b/lib/puppet/type/anchor.rb
@@ -0,0 +1,32 @@
+Puppet::Type.newtype(:anchor) do
+  desc <<-'ENDOFDESC'
+  A simple resource type intended to be used as an anchor in a composite class.
+
+      class ntp {
+        class { 'ntp::package': }
+        -> class { 'ntp::config': }
+        -> class { 'ntp::service': }
+
+        # These two resources "anchor" the composed classes
+        # such that the end user may use "require" and "before"
+        # relationships with Class['ntp']
+        anchor { 'ntp::begin': }   -> class  { 'ntp::package': }
+        class  { 'ntp::service': } -> anchor { 'ntp::end': }
+      }
+
+  This resource allows all of the classes in the ntp module to be contained
+  within the ntp class from a dependency management point of view.
+
+  This allows the end user of the ntp module to establish require and before
+  relationships easily:
+
+      class { 'ntp': } -> class { 'mcollective': }
+      class { 'mcollective': } -> class { 'ntp': }
+
+  ENDOFDESC
+
+  newparam :name do
+    desc "The name of the anchor resource."
+  end
+
+end
-- 
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