Singleton Puppet Module

The Singleton module provides functions that dynamically create resources defined either by built-in defaults or by hiera-supplied parameters.

Dependencies

This module depends on Hiera and Puppet 3.2 or higher.

Functions

singleton_packages

singleton_packages is intended to be used as a tool to address the problem of simple package inclusion in puppet manifests.

Because resources can only be declared once in a puppet manifest, including "simple" packages in multiple places can become a complicated and verbose endeavour -- where "simple packages" are loosely defined as those which are too inconsequential to merit their own classes or modules. The singleton_packages function aims to detach inclusion of these kinds of trivial packages from the complexity of the Puppet DAG and eliminate the need to a-priori enumerate the entire list of trivial packages that you might want to include (via means such as classes, virtual resources, or other contrivances), while simultaneously allowing for a small level of user-excersised power and control beyond global or function-wide default parameters.

The singleton_package function is called with the name(s) of the package(s) to install. It does not matter how many times the function is called for a given package name, the resource will only be defined once, and will be defined within the scope of Class[singleton].

singleton_resources

singleton_resources is a generalization from singleton_packages to arbitrary resource types. While singleton_packages expects string arguments, singleton_resources expects resource specifiers such as Package['vim'].

Examples

singleton_packages

The following puppet code can be used to install three packages, "vim", "emacs", and "nano".

singleton_packages("vim", "emacs", "nano")

By default, each package will be created as if it had been given the parameters:

package { "singleton_package_$name":
  ensure => present,
  name   => $name,
}

Additional customization can be supplied by adding hiera data. You may supply parameters, additional singleton_packages to chain-include, and additional classes to include.

YAML Example for "vim" Package

File: $confdir/data/common.yaml (or other appropriate file, per hiera configuration)

---
:singleton_package_vim:
  :parameters:
    :name: vim
    :ensure: present
  :include_singleton_packages:
  - vim-puppet
  :include_classes:
  - stdlib
  - obviouslyfakeclass

Puppet Example for "vim" Package

File: $modulepath/data/manifests/common.pp (or other appropriate file/class, per hiera configuration)

class data::common {
  $singleton_package_vim = {
    parameters => {
      ensure => present,
      name   => 'vim',
    },
    include_singleton_packages => [
      "vim-puppet",
    ],
    include_classes => [
      "stdlib",
      "obviouslyfakeclass",
    ],
  }
}

singleton_resources

The following puppet code can be used to install three packages, "vim", "emacs", and "nano".

singleton_resources(
  Package['vim'],
  Package['emacs'],
  Package['nano'],
)

Default parameters must be supplied for every type used with singleton_resources. The singleton module comes with a set of defaults only for the Package resource type. Other defaults must be supplied by the user.

For the Package['vim'] example and the module-supplied package resource defaults, Package['vim'] will be created as if it had been given the parameters:

package { "$title":
  ensure => present,
  name   => $title,
}

Defaults for Package resource type (YAML)

---
:singleton_resource_package:
  :parameters:
    :ensure: present

Package['vim'] Customization (YAML)

---
:singleton_resource_package_vim:
  :parameters:
    :name: vim
    :ensure: present
  :include_singleton_resources:
  - Package[vim-puppet]
  :include_classes:
  - stdlib
  - obviouslyfakeclass

Package['vim'] Customization (Puppet)

class data::common {
  $singleton_resource_package_vim = {
    parameters => {
      ensure => present,
      name   => 'vim',
    },
    include_singleton_resources => [
      "Package[vim-puppet]",
    ],
    include_classes => [
      "stdlib",
      "obviouslyfakeclass",
    ],
  }
}

2014-02-26 Release 0.0.5

Summary:

This release has a minor bug fix and readme update.

Bugfixes:

• flatten arguments to singleton_packages()
• README updates

0.0.4 - pdxcat/singleton - 2013/05/30

b19d111 Modify singleton for use with Puppet 3.0

0.0.3 - pdxcat/singleton - 2012/10/06

ccfe971 Initial forge release, bump version to 0.0.3 c3d65be Remove local create_resources definition b6a0b0b Symbolize parameter hashes f7fd897 Add new function singleton_resources 61217cc Stub out new function singleton_resources ebc3a09 Remove unnecessary block argument "params" e75ded7 Correct README - wrong filepath in example 7885f4d Correct README - "iterate" should be "enumerate" a66e0dc Initial Commit