Module: Puppet::DataProviders::DataFunctionSupport

Included in:
FunctionEnvDataProvider, FunctionModuleDataProvider
Defined in:
lib/puppet/data_providers/data_function_support.rb

Instance Method Summary collapse

Instance Method Details

#data(key, scope) {|data| ... } ⇒ Hash

Gets the data from the compiler, or initializes it from a function call if not present in the compiler. This means, that the function providing the data is called once per compilation, and the data is cached for as long as the compiler lives (which is for one catalog production). This makes it possible to return data that is tailored for the request. The class including this module must implement ‘loader(scope)` to return the apropriate loader.

If a block is given, it will be called to validate the data hash when it is retrieved from a function call. The block must return the validated data or raise a Error to indicate that the data is invalid. The block is not called when the data is found in the compiler or in the cache.

Parameters:

  • key (String) —

    The data key such as the name of a module or the constant ‘environment’

  • scope (Parser::Scope) —

    The scope

Yields:

  • An optional block that can be used for validation of the data returned from the function

Yield Parameters:

  • data (Hash) —

    The data to validate

Yield Returns:

  • (Hash) —

    The validated data

Returns:

  • (Hash) —

    The data hash for the given key



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# File 'lib/puppet/data_providers/data_function_support.rb', line 19

def data(key, scope, &block)
  compiler = scope.compiler
  adapter = Puppet::DataProviders::DataAdapter.get(compiler) || Puppet::DataProviders::DataAdapter.adapt(compiler)
  adapter.data[key] ||= initialize_data_from_function("#{key}::data", key, scope, &block)
end

#initialize_data_from_function(name, key, scope) ⇒ Object 



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# File 'lib/puppet/data_providers/data_function_support.rb', line 25

def initialize_data_from_function(name, key, scope)
  Puppet::Util::Profiler.profile("Called #{name}", [ :functions, name ]) do
    loader = loader(key, scope)
    if loader && func = loader.load(:function, name)
      # function found, call without arguments, must return a Hash
      # TODO: Validate the function - to ensure it does not contain unwanted side effects
      #       That can only be done if the function is a puppet function
      #
      result = func.call(scope)
      unless result.is_a?(Hash)
        raise Puppet::Error.new("Expected '#{name}' function to return a Hash, got #{result.class}")
      end
      # validate result if block given
      result = yield(result) if block_given?
    else
      raise Puppet::Error.new("Data from 'function' cannot find the required '#{name}' function")
    end
    result
  end
end