Type & Providers: Defining

tp_defining.md

Declaration

Providers are always associated with a single resource type, so they are created by calling the provide method on that resource type. The provide method takes three arguments plus a block:

• The first argument must be the name of the provider, as a :symbol.
• The optional :parent argument should be the name of a parent class.
• The optional :source argument should be a symbol.
• The block takes no arguments, and implements the behavior of the provider.

Parent Classes

When declaring a provider, you can specify a parent class. There are several different kinds of parent you can use.

Base Provider

A provider can inherit from a base provider, which is never used alone and only exists for other providers to inherit from. Use the full name of the class.

For example, all package providers have a common parent class:

Puppet::Type.type(:package).provide(:dpkg, :parent => Puppet::Provider::Package) do
  desc "..."
  ...
end

Note the call to the desc method; this sets the documentation for this provider, and should include everything necessary for someone to use this provider.

Another Provider of the Same Resource Type

Providers can also specify another provider as their parent. If it’s a provider for the same resource type, you can use the name of that provider as a symbol.

Puppet::Type.type(:package).provide(:apt, :parent => :dpkg, :source => :dpkg) do
    ...
end

Note that we’re also specifying that this provider uses the dpkg source; this tells Puppet to deduplicate packages from dpkg and apt, so the same package does not show up in an instance list from each provider type. Puppet defaults to creating a new source for each provider type, so you have to specify when a provider subclass shares a source with its parent class.

A Provider of Any Resource Type

Providers can also specify a provider of any resource type as their parent. Use the ruby Puppet::Type.type(<NAME>).provider(<NAME>) methods to locate the provider.

For example, the ini_setting type’s ruby provider (from the puppetlabs/inifile module) can be re-used to implement new resource types that act like INI settings:

    # my_module/lib/puppet/provider/glance_api_config/ini_setting.rb
    Puppet::Type.type(:glance_api_config).provide(
      :ini_setting,
      # set ini_setting as the parent provider
      :parent => Puppet::Type.type(:ini_setting).provider(:ruby)
    ) do
      # implement section as the first part of the namevar
      def section
        resource[:name].split('/', 2).first
      end
      def setting
        # implement setting as the second part of the namevar
        resource[:name].split('/', 2).last
      end
      # hard code the file path (this allows purging)
      def self.file_path
        '/etc/glance/glance-api.conf'
      end
    end

Initial material pulled from Provider Development