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authornfagerlund <nick.fagerlund@gmail.com>2011-08-17 16:43:22 -0700
committernfagerlund <nick.fagerlund@gmail.com>2011-08-18 12:39:05 -0700
commit8e770b04234aacfc09c7b8ad45ffa304cb83f723 (patch)
treede11ef579d7ffec6c7161945da5e84b75287d629
parent9e87fd14571ba3a75789417e7aa4df05d4a7345c (diff)
Docs: Clarify the use case for the anchor type
This commit tweaks the docs for the anchor resource type to give more context for its existence.
-rw-r--r--lib/puppet/type/anchor.rb27
1 files changed, 18 insertions, 9 deletions
diff --git a/lib/puppet/type/anchor.rb b/lib/puppet/type/anchor.rb
index 0c28b1c..6b81732 100644
--- a/lib/puppet/type/anchor.rb
+++ b/lib/puppet/type/anchor.rb
@@ -2,23 +2,32 @@ Puppet::Type.newtype(:anchor) do
desc <<-'ENDOFDESC'
A simple resource type intended to be used as an anchor in a composite class.
+ In Puppet 2.6, when a class declares another class, the resources in the
+ interior class are not contained by the exterior class. This interacts badly
+ with the pattern of composing complex modules from smaller classes, as it
+ makes it impossible for end users to specify order relationships between the
+ exterior class and other modules.
+
+ The anchor type lets you work around this. By sandwiching any interior
+ classes between two no-op resources that _are_ contained by the exterior
+ class, you can ensure that all resources in the module are contained.
+
class ntp {
+ # These classes will have the correct order relationship with each
+ # other. However, without anchors, they won't have any order
+ # relationship to 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': }
+ # These two resources "anchor" the composed classes within the ntp
+ # class.
+ 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:
+ relationships with Class['ntp']:
class { 'ntp': } -> class { 'mcollective': }
class { 'mcollective': } -> class { 'ntp': }