module Puppet::Util::ProviderFeatures

feature(name, docs, hash = {}) click to toggle source

Defines one feature. At a minimum, a feature requires a name and docs, and at this point they should also specify a list of methods required to determine if the feature is present. @todo How methods that determine if the feature is present are specified.

# File lib/puppet/util/provider_features.rb, line 64
def feature(name, docs, hash = {})
  @features ||= {}
  raise(Puppet::DevError, "Feature #{name} is already defined") if @features.include?(name)
  begin
    obj = ProviderFeature.new(name, docs, hash)
    @features[obj.name] = obj
  rescue ArgumentError => detail
    error = ArgumentError.new(
      "Could not create feature #{name}: #{detail}"
    )
    error.set_backtrace(detail.backtrace)
    raise error
  end
end

feature_module() click to toggle source

Generates a module that sets up the boolean predicate methods to test for given features.

# File lib/puppet/util/provider_features.rb, line 117
def feature_module
  unless defined?(@feature_module)
    @features ||= {}
    @feature_module = ::Module.new
    const_set("FeatureModule", @feature_module)
    features = @features
    # Create a feature? method that can be passed a feature name and
    # determine if the feature is present.
    @feature_module.send(:define_method, :feature?) do |name|
      method = name.to_s + "?"
      return !!(respond_to?(method) and send(method))
    end

    # Create a method that will list all functional features.
    @feature_module.send(:define_method, :features) do
      return false unless defined?(features)
      features.keys.find_all { |n| feature?(n) }.sort { |a,b|
        a.to_s <=> b.to_s
      }
    end

    # Create a method that will determine if a provided list of
    # features are satisfied by the curred provider.
    @feature_module.send(:define_method, :satisfies?) do |*needed|
      ret = true
      needed.flatten.each do |feature|
        unless feature?(feature)
          ret = false
          break
        end
      end
      ret
    end

    # Create a boolean method for each feature so you can test them
    # individually as you might need.
    @features.each do |name, feature|
      method = name.to_s + "?"
      @feature_module.send(:define_method, method) do
        (is_a?(Class) ?  declared_feature?(name) : self.class.declared_feature?(name)) or feature.available?(self)
      end
    end

    # Allow the provider to declare that it has a given feature.
    @feature_module.send(:define_method, :has_features) do |*names|
      @declared_features ||= []
      names.each do |name|
        @declared_features << name.intern
      end
    end
    # Aaah, grammatical correctness
    @feature_module.send(:alias_method, :has_feature, :has_features)
  end
  @feature_module
end

featuredocs() click to toggle source

@return [String] Returns a string with documentation covering all features.

# File lib/puppet/util/provider_features.rb, line 80
def featuredocs
  str = ""
  @features ||= {}
  return nil if @features.empty?
  names = @features.keys.sort { |a,b| a.to_s <=> b.to_s }
  names.each do |name|
    doc = @features[name].docs.gsub(/\n\s+/, " ")
    str += "- *#{name}*: #{doc}\n"
  end

  if providers.length > 0
    headers = ["Provider", names].flatten
    data = {}
    providers.each do |provname|
      data[provname] = []
      prov = provider(provname)
      names.each do |name|
        if prov.feature?(name)
          data[provname] << "*X*"
        else
          data[provname] << ""
        end
      end
    end
    str += doctable(headers, data)
  end
  str
end

features() click to toggle source

@return [Array<String>] Returns a list of features.

# File lib/puppet/util/provider_features.rb, line 110
def features
  @features ||= {}
  @features.keys
end

provider_feature(name) click to toggle source

@return [ProviderFeature] Returns a provider feature instance by name. @param name [String] the name of the feature to return @note Should only be used for testing. @api private

# File lib/puppet/util/provider_features.rb, line 178
def provider_feature(name)
  return nil unless defined?(@features)

  @features[name]
end

Public Instance Methods