class Chef::GuardInterpreter::ResourceGuardInterpreter

Public Class Methods

new(parent_resource, command, opts) click to toggle source
# File lib/chef/guard_interpreter/resource_guard_interpreter.rb, line 25
def initialize(parent_resource, command, opts)
  super(command, opts)
  @parent_resource = parent_resource
  @resource = get_interpreter_resource(parent_resource)
end

Public Instance Methods

evaluate() click to toggle source
# File lib/chef/guard_interpreter/resource_guard_interpreter.rb, line 31
def evaluate
  # Add attributes inherited from the parent class
  # to the resource
  merge_inherited_attributes

  # Only execute and script resources and use guard attributes.
  # The command to be executed on them are passed via different attributes.
  # Script resources use code attribute and execute resources use
  # command property. Moreover script resources are also execute
  # resources. Here we make sure @command is assigned to the right
  # attribute by checking the type of the resources.
  # We need to make sure we check for Script first because any resource
  # that can get to here is an Execute resource.
  if @resource.is_a? Chef::Resource::Script
    block_attributes = @command_opts.merge({ code: @command })
  else
    block_attributes = @command_opts.merge({ command: @command })
  end

  # Handles cases like powershell_script where default
  # attributes are different when used in a guard vs. not. For
  # powershell_script in particular, this will go away when
  # the one attribue that causes this changes its default to be
  # the same after some period to prepare for deprecation
  if @resource.class.respond_to?(:get_default_attributes)
    block_attributes = @resource.class.send(:get_default_attributes, @command_opts).merge(block_attributes)
  end

  resource_block = block_from_attributes(block_attributes)
  evaluate_action(nil, &resource_block)
end

Protected Instance Methods

block_from_attributes(attributes) click to toggle source
# File lib/chef/guard_interpreter/resource_guard_interpreter.rb, line 109
def block_from_attributes(attributes)
  Proc.new do
    attributes.each_key do |attribute_name|
      send(attribute_name, attributes[attribute_name]) if respond_to?(attribute_name)
    end
  end
end
evaluate_action(action = nil, &block) click to toggle source
# File lib/chef/guard_interpreter/resource_guard_interpreter.rb, line 65
def evaluate_action(action = nil, &block)
  @resource.instance_eval(&block)

  run_action = action || @resource.action

  begin
    # Coerce to an array to be safe. This could happen with a legacy
    # resource or something overriding the default_action code in a
    # subclass.
    Array(run_action).each { |action_to_run| @resource.run_action(action_to_run) }
    resource_updated = @resource.updated
  rescue Mixlib::ShellOut::ShellCommandFailed
    resource_updated = nil
  end

  resource_updated
end
get_interpreter_resource(parent_resource) click to toggle source
# File lib/chef/guard_interpreter/resource_guard_interpreter.rb, line 83
def get_interpreter_resource(parent_resource)
  if parent_resource.nil? || parent_resource.node.nil?
    raise ArgumentError, "Node for guard resource parent must not be nil"
  end

  resource_class = Chef::Resource.resource_for_node(parent_resource.guard_interpreter, parent_resource.node)

  if resource_class.nil?
    raise ArgumentError, "Specified guard_interpreter resource #{parent_resource.guard_interpreter} unknown for this platform"
  end

  if ! resource_class.ancestors.include?(Chef::Resource::Execute)
    raise ArgumentError, "Specified guard interpreter class #{resource_class} must be a kind of Chef::Resource::Execute resource"
  end

  # Duplicate the node below because the new RunContext
  # overwrites the state of Node instances passed to it.
  # See https://github.com/chef/chef/issues/3485.
  empty_events = Chef::EventDispatch::Dispatcher.new
  anonymous_run_context = Chef::RunContext.new(parent_resource.node.dup, {}, empty_events)
  interpreter_resource = resource_class.new("Guard resource", anonymous_run_context)
  interpreter_resource.is_guard_interpreter = true

  interpreter_resource
end
merge_inherited_attributes() click to toggle source
# File lib/chef/guard_interpreter/resource_guard_interpreter.rb, line 117
def merge_inherited_attributes
  inherited_attributes = []

  if @parent_resource.class.respond_to?(:guard_inherited_attributes)
    inherited_attributes = @parent_resource.class.send(:guard_inherited_attributes)
  end

  if inherited_attributes && !inherited_attributes.empty?
    inherited_attributes.each do |attribute|
      if @parent_resource.respond_to?(attribute) && @resource.respond_to?(attribute)
        parent_value = @parent_resource.send(attribute)
        child_value = @resource.send(attribute)
        if parent_value || child_value
          @resource.send(attribute, parent_value)
        end
      end
    end
  end
end