[OC-3564] move core Chef to the repo root \o/ \m/

The opscode/chef repository now only contains the core Chef library code
used by chef-client, knife and chef-solo!

1 files changed, 853 insertions, 0 deletions

diff --git a/lib/chef/resource.rb b/lib/chef/resource.rb
new file mode 100644
index 0000000000..9a1b983360
--- /dev/null
+++ b/lib/chef/resource.rb
@@ -0,0 +1,853 @@
+#
+# Author:: Adam Jacob (<adam@opscode.com>)
+# Author:: Christopher Walters (<cw@opscode.com>)
+# Copyright:: Copyright (c) 2008 Opscode, Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+require 'chef/mixin/params_validate'
+require 'chef/mixin/check_helper'
+require 'chef/dsl/platform_introspection'
+require 'chef/mixin/convert_to_class_name'
+require 'chef/resource/conditional'
+require 'chef/resource_collection'
+require 'chef/resource_platform_map'
+require 'chef/node'
+
+require 'chef/mixin/deprecation'
+
+class Chef
+  class Resource
+    class Notification < Struct.new(:resource, :action, :notifying_resource)
+
+      def duplicates?(other_notification)
+        unless other_notification.respond_to?(:resource) && other_notification.respond_to?(:action)
+          msg = "only duck-types of Chef::Resource::Notification can be checked for duplication "\
+                "you gave #{other_notification.inspect}"
+          raise ArgumentError, msg
+        end
+        other_notification.resource == resource && other_notification.action == action
+      end
+
+      # If resource and/or notifying_resource is not a resource object, this will look them up in the resource collection
+      # and fix the references from strings to actual Resource objects.
+      def resolve_resource_reference(resource_collection)
+        return resource if resource.kind_of?(Chef::Resource) && notifying_resource.kind_of?(Chef::Resource)
+
+        if not(resource.kind_of?(Chef::Resource))
+          fix_resource_reference(resource_collection)
+        end
+
+        if not(notifying_resource.kind_of?(Chef::Resource))
+          fix_notifier_reference(resource_collection)
+        end
+      end
+
+      # This will look up the resource if it is not a Resource Object.  It will complain if it finds multiple
+      # resources, can't find a resource, or gets invalid syntax.
+      def fix_resource_reference(resource_collection)
+        matching_resource = resource_collection.find(resource)
+        if Array(matching_resource).size > 1
+          msg = "Notification #{self} from #{notifying_resource} was created with a reference to multiple resources, "\
+          "but can only notify one resource. Notifying resource was defined on #{notifying_resource.source_line}"
+          raise Chef::Exceptions::InvalidResourceReference, msg
+        end
+        self.resource = matching_resource
+
+      rescue Chef::Exceptions::ResourceNotFound => e
+        err = Chef::Exceptions::ResourceNotFound.new(<<-FAIL)
+resource #{notifying_resource} is configured to notify resource #{resource} with action #{action}, \
+but #{resource} cannot be found in the resource collection. #{notifying_resource} is defined in \
+#{notifying_resource.source_line}
+FAIL
+        err.set_backtrace(e.backtrace)
+        raise err
+      rescue Chef::Exceptions::InvalidResourceSpecification => e
+          err = Chef::Exceptions::InvalidResourceSpecification.new(<<-F)
+Resource #{notifying_resource} is configured to notify resource #{resource} with action #{action}, \
+but #{resource.inspect} is not valid syntax to look up a resource in the resource collection. Notification \
+is defined near #{notifying_resource.source_line}
+F
+          err.set_backtrace(e.backtrace)
+        raise err
+      end
+
+      # This will look up the notifying_resource if it is not a Resource Object.  It will complain if it finds multiple
+      # resources, can't find a resource, or gets invalid syntax.
+      def fix_notifier_reference(resource_collection)
+        matching_notifier = resource_collection.find(notifying_resource)
+        if Array(matching_notifier).size > 1
+          msg = "Notification #{self} from #{notifying_resource} was created with a reference to multiple notifying "\
+          "resources, but can only originate from one resource.  Destination resource was defined "\
+          "on #{resource.source_line}"
+          raise Chef::Exceptions::InvalidResourceReference, msg
+        end
+        self.notifying_resource = matching_notifier
+
+      rescue Chef::Exceptions::ResourceNotFound => e
+        err = Chef::Exceptions::ResourceNotFound.new(<<-FAIL)
+Resource #{resource} is configured to receive notifications from #{notifying_resource} with action #{action}, \
+but #{notifying_resource} cannot be found in the resource collection. #{resource} is defined in \
+#{resource.source_line}
+FAIL
+        err.set_backtrace(e.backtrace)
+        raise err
+      rescue Chef::Exceptions::InvalidResourceSpecification => e
+          err = Chef::Exceptions::InvalidResourceSpecification.new(<<-F)
+Resource #{resource} is configured to receive notifications from  #{notifying_resource} with action #{action}, \
+but #{notifying_resource.inspect} is not valid syntax to look up a resource in the resource collection. Notification \
+is defined near #{resource.source_line}
+F
+          err.set_backtrace(e.backtrace)
+        raise err
+      end
+
+    end
+
+    FORBIDDEN_IVARS = [:@run_context, :@node, :@not_if, :@only_if, :@enclosing_provider]
+    HIDDEN_IVARS = [:@allowed_actions, :@resource_name, :@source_line, :@run_context, :@name, :@node, :@not_if, :@only_if, :@elapsed_time, :@enclosing_provider]
+
+    include Chef::Mixin::CheckHelper
+    include Chef::Mixin::ParamsValidate
+    include Chef::DSL::PlatformIntrospection
+    include Chef::Mixin::ConvertToClassName
+    include Chef::Mixin::Deprecation
+
+
+    # Set or return the list of "state attributes" implemented by the Resource
+    # subclass. State attributes are attributes that describe the desired state
+    # of the system, such as file permissions or ownership. In general, state
+    # attributes are attributes that could be populated by examining the state
+    # of the system (e.g., File.stat can tell you the permissions on an
+    # existing file). Contrarily, attributes that are not "state attributes"
+    # usually modify the way Chef itself behaves, for example by providing
+    # additional options for a package manager to use when installing a
+    # package.
+    #
+    # This list is used by the Chef client auditing system to extract
+    # information from resources to describe changes made to the system.
+    def self.state_attrs(*attr_names)
+      @state_attrs ||= []
+      @state_attrs = attr_names unless attr_names.empty?
+
+      # Return *all* state_attrs that this class has, including inherited ones
+      if superclass.respond_to?(:state_attrs)
+        superclass.state_attrs + @state_attrs
+      else
+        @state_attrs
+      end
+    end
+
+    # Set or return the "identity attribute" for this resource class. This is
+    # generally going to be the "name attribute" for this resource. In other
+    # words, the resource type plus this attribute uniquely identify a given
+    # bit of state that chef manages. For a File resource, this would be the
+    # path, for a package resource, it will be the package name. This will show
+    # up in chef-client's audit records as a searchable field.
+    def self.identity_attr(attr_name=nil)
+      @identity_attr ||= nil
+      @identity_attr = attr_name if attr_name
+
+      # If this class doesn't have an identity attr, we'll defer to the superclass:
+      if @identity_attr || !superclass.respond_to?(:identity_attr)
+        @identity_attr
+      else
+        superclass.identity_attr
+      end
+    end
+
+    def self.dsl_name
+      convert_to_snake_case(name, 'Chef::Resource')
+    end
+
+    attr_accessor :params
+    attr_accessor :provider
+    attr_accessor :allowed_actions
+    attr_accessor :run_context
+    attr_accessor :cookbook_name
+    attr_accessor :recipe_name
+    attr_accessor :enclosing_provider
+    attr_accessor :source_line
+    attr_accessor :retries
+    attr_accessor :retry_delay
+
+    attr_reader :updated
+
+    attr_reader :resource_name
+    attr_reader :not_if_args
+    attr_reader :only_if_args
+
+    attr_reader :elapsed_time
+
+    # Each notify entry is a resource/action pair, modeled as an
+    # Struct with a #resource and #action member
+
+    def initialize(name, run_context=nil)
+      @name = name
+      @run_context = run_context
+      @noop = nil
+      @before = nil
+      @params = Hash.new
+      @provider = nil
+      @allowed_actions = [ :nothing ]
+      @action = :nothing
+      @updated = false
+      @updated_by_last_action = false
+      @supports = {}
+      @ignore_failure = false
+      @retries = 0
+      @retry_delay = 2
+      @not_if = []
+      @only_if = []
+      @source_line = nil
+      @elapsed_time = 0
+
+      @node = run_context ? deprecated_ivar(run_context.node, :node, :warn) : nil
+    end
+
+    # Returns a Hash of attribute => value for the state attributes declared in
+    # the resource's class definition.
+    def state
+      self.class.state_attrs.inject({}) do |state_attrs, attr_name|
+        state_attrs[attr_name] = send(attr_name)
+        state_attrs
+      end
+    end
+
+    # Returns the value of the identity attribute, if declared. Falls back to
+    # #name if no identity attribute is declared.
+    def identity
+      if identity_attr = self.class.identity_attr
+        send(identity_attr)
+      else
+        name
+      end
+    end
+
+
+    def updated=(true_or_false)
+      Chef::Log.warn("Chef::Resource#updated=(true|false) is deprecated. Please call #updated_by_last_action(true|false) instead.")
+      Chef::Log.warn("Called from:")
+      caller[0..3].each {|line| Chef::Log.warn(line)}
+      updated_by_last_action(true_or_false)
+      @updated = true_or_false
+    end
+
+    def node
+      run_context && run_context.node
+    end
+
+    # If an unknown method is invoked, determine whether the enclosing Provider's
+    # lexical scope can fulfill the request. E.g. This happens when the Resource's
+    # block invokes new_resource.
+    def method_missing(method_symbol, *args, &block)
+      if enclosing_provider && enclosing_provider.respond_to?(method_symbol)
+        enclosing_provider.send(method_symbol, *args, &block)
+      else
+        raise NoMethodError, "undefined method `#{method_symbol.to_s}' for #{self.class.to_s}"
+      end
+    end
+
+    def load_prior_resource
+      begin
+        prior_resource = run_context.resource_collection.lookup(self.to_s)
+        Chef::Log.debug("Setting #{self.to_s} to the state of the prior #{self.to_s}")
+        prior_resource.instance_variables.each do |iv|
+          unless iv.to_sym == :@source_line || iv.to_sym == :@action
+            self.instance_variable_set(iv, prior_resource.instance_variable_get(iv))
+          end
+        end
+        true
+      rescue Chef::Exceptions::ResourceNotFound
+        true
+      end
+    end
+
+    def supports(args={})
+      if args.any?
+        @supports = args
+      else
+        @supports
+      end
+    end
+
+    def provider(arg=nil)
+      klass = if arg.kind_of?(String) || arg.kind_of?(Symbol)
+                lookup_provider_constant(arg)
+              else
+                arg
+              end
+      set_or_return(
+        :provider,
+        klass,
+        :kind_of => [ Class ]
+      )
+    end
+
+    def action(arg=nil)
+      if arg
+        action_list = arg.kind_of?(Array) ? arg : [ arg ]
+        action_list = action_list.collect { |a| a.to_sym }
+        action_list.each do |action|
+          validate(
+            {
+              :action => action,
+            },
+            {
+              :action => { :kind_of => Symbol, :equal_to => @allowed_actions },
+            }
+          )
+        end
+        @action = action_list
+      else
+        @action
+      end
+    end
+
+    def name(name=nil)
+      set_if_args(@name, name) do
+        raise ArgumentError, "name must be a string!" unless name.kind_of?(String)
+        @name = name
+      end
+    end
+
+    def noop(tf=nil)
+      set_if_args(@noop, tf) do
+        raise ArgumentError, "noop must be true or false!" unless tf == true || tf == false
+        @noop = tf
+      end
+    end
+
+    def ignore_failure(arg=nil)
+      set_or_return(
+        :ignore_failure,
+        arg,
+        :kind_of => [ TrueClass, FalseClass ]
+      )
+    end
+
+    def retries(arg=nil)
+      set_or_return(
+        :retries,
+        arg,
+        :kind_of => Integer
+      )
+    end
+
+    def retry_delay(arg=nil)
+      set_or_return(
+        :retry_delay,
+        arg,
+        :kind_of => Integer
+      )
+    end
+
+    def epic_fail(arg=nil)
+      ignore_failure(arg)
+    end
+
+    # Sets up a notification from this resource to the resource specified by +resource_spec+.
+    def notifies(action, resource_spec, timing=:delayed)
+      # when using old-style resources(:template => "/foo.txt") style, you
+      # could end up with multiple resources.
+      resources = [ resource_spec ].flatten
+      resources.each do |resource|
+        case timing.to_s
+        when 'delayed'
+          notifies_delayed(action, resource)
+        when 'immediate', 'immediately'
+          notifies_immediately(action, resource)
+        else
+          raise ArgumentError,  "invalid timing: #{timing} for notifies(#{action}, #{resources.inspect}, #{timing}) resource #{self} "\
+                                "Valid timings are: :delayed, :immediate, :immediately"
+        end
+      end
+
+      true
+    end
+
+    # Iterates over all immediate and delayed notifications, calling
+    # resolve_resource_reference on each in turn, causing them to
+    # resolve lazy/forward references.
+    def resolve_notification_references
+      run_context.immediate_notifications(self).each { |n| n.resolve_resource_reference(run_context.resource_collection) }
+      run_context.delayed_notifications(self).each {|n| n.resolve_resource_reference(run_context.resource_collection) }
+    end
+
+    def notifies_immediately(action, resource_spec)
+      run_context.notifies_immediately(Notification.new(resource_spec, action, self))
+    end
+
+    def notifies_delayed(action, resource_spec)
+      run_context.notifies_delayed(Notification.new(resource_spec, action, self))
+    end
+
+    def immediate_notifications
+      run_context.immediate_notifications(self)
+    end
+
+    def delayed_notifications
+      run_context.delayed_notifications(self)
+    end
+
+    def resources(*args)
+      run_context.resource_collection.find(*args)
+    end
+
+    def subscribes(action, resources, timing=:delayed)
+      resources = [resources].flatten
+      resources.each do |resource|
+        if resource.is_a?(String)
+          resource = Chef::Resource.new(resource, run_context)
+        end
+        if resource.run_context.nil?
+          resource.run_context = run_context
+        end
+        resource.notifies(action, self, timing)
+      end
+      true
+    end
+
+    def is(*args)
+      if args.size == 1
+        args.first
+      else
+        return *args
+      end
+    end
+
+    def to_s
+      "#{@resource_name}[#{@name}]"
+    end
+
+    def to_text
+      ivars = instance_variables.map { |ivar| ivar.to_sym } - HIDDEN_IVARS
+      text = "# Declared in #{@source_line}\n\n"
+      text << self.class.dsl_name + "(\"#{name}\") do\n"
+      ivars.each do |ivar|
+        if (value = instance_variable_get(ivar)) && !(value.respond_to?(:empty?) && value.empty?)
+          value_string = value.respond_to?(:to_text) ? value.to_text : value.inspect
+          text << "  #{ivar.to_s.sub(/^@/,'')} #{value_string}\n"
+        end
+      end
+      [@not_if, @only_if].flatten.each do |conditional|
+        text << "  #{conditional.to_text}\n"
+      end
+      text << "end\n"
+    end
+
+    def inspect
+      ivars = instance_variables.map { |ivar| ivar.to_sym } - FORBIDDEN_IVARS
+      ivars.inject("<#{to_s}") do |str, ivar|
+        str << " #{ivar}: #{instance_variable_get(ivar).inspect}"
+      end << ">"
+    end
+
+    # as_json does most of the to_json heavy lifted. It exists here in case activesupport
+    # is loaded. activesupport will call as_json and skip over to_json. This ensure
+    # json is encoded as expected
+    def as_json(*a)
+      safe_ivars = instance_variables.map { |ivar| ivar.to_sym } - FORBIDDEN_IVARS
+      instance_vars = Hash.new
+      safe_ivars.each do |iv|
+        instance_vars[iv.to_s.sub(/^@/, '')] = instance_variable_get(iv)
+      end
+      {
+        'json_class' => self.class.name,
+        'instance_vars' => instance_vars
+      }
+    end
+
+    # Serialize this object as a hash
+    def to_json(*a)
+      results = as_json
+      results.to_json(*a)
+    end
+
+    def to_hash
+      safe_ivars = instance_variables.map { |ivar| ivar.to_sym } - FORBIDDEN_IVARS
+      instance_vars = Hash.new
+      safe_ivars.each do |iv|
+        key = iv.to_s.sub(/^@/,'').to_sym
+        instance_vars[key] = instance_variable_get(iv)
+      end
+      instance_vars
+    end
+
+    # If command is a block, returns true if the block returns true, false if it returns false.
+    # ("Only run this resource if the block is true")
+    #
+    # If the command is not a block, executes the command.  If it returns any status other than
+    # 0, it returns false (clearly, a 0 status code is true)
+    #
+    # === Parameters
+    # command<String>:: A a string to execute.
+    # opts<Hash>:: Options control the execution of the command
+    # block<Proc>:: A ruby block to run. Ignored if a command is given.
+    #
+    # === Evaluation
+    # * evaluates to true if the block is true, or if the command returns 0
+    # * evaluates to false if the block is false, or if the command returns a non-zero exit code.
+    def only_if(command=nil, opts={}, &block)
+      if command || block_given?
+        @only_if << Conditional.only_if(command, opts, &block)
+      end
+      @only_if
+    end
+
+    # If command is a block, returns false if the block returns true, true if it returns false.
+    # ("Do not run this resource if the block is true")
+    #
+    # If the command is not a block, executes the command.  If it returns a 0 exitstatus, returns false.
+    # ("Do not run this resource if the command returns 0")
+    #
+    # === Parameters
+    # command<String>:: A a string to execute.
+    # opts<Hash>:: Options control the execution of the command
+    # block<Proc>:: A ruby block to run. Ignored if a command is given.
+    #
+    # === Evaluation
+    # * evaluates to true if the block is false, or if the command returns a non-zero exit status.
+    # * evaluates to false if the block is true, or if the command returns a 0 exit status.
+    def not_if(command=nil, opts={}, &block)
+      if command || block_given?
+        @not_if << Conditional.not_if(command, opts, &block)
+      end
+      @not_if
+    end
+
+    def defined_at
+      if cookbook_name && recipe_name && source_line
+        "#{cookbook_name}::#{recipe_name} line #{source_line.split(':')[1]}"
+      elsif source_line
+        file, line_no = source_line.split(':')
+        "#{file} line #{line_no}"
+      else
+        "dynamically defined"
+      end
+    end
+
+    def cookbook_version
+      if cookbook_name
+        run_context.cookbook_collection[cookbook_name]
+      end
+    end
+
+    def events
+      run_context.events
+    end
+
+    def run_action(action, notification_type=nil, notifying_resource=nil)
+      # reset state in case of multiple actions on the same resource.
+      @elapsed_time = 0
+      start_time = Time.now
+      events.resource_action_start(self, action, notification_type, notifying_resource)
+      # Try to resolve lazy/forward references in notifications again to handle
+      # the case where the resource was defined lazily (ie. in a ruby_block)
+      resolve_notification_references
+      validate_action(action)
+
+      if Chef::Config[:verbose_logging] || Chef::Log.level == :debug
+        # This can be noisy
+        Chef::Log.info("Processing #{self} action #{action} (#{defined_at})")
+      end
+
+      # ensure that we don't leave @updated_by_last_action set to true
+      # on accident
+      updated_by_last_action(false)
+
+      begin
+        return if should_skip?(action)
+        provider_for_action(action).run_action
+      rescue Exception => e
+        if ignore_failure
+          Chef::Log.error("#{self} (#{defined_at}) had an error: #{e.message}; ignore_failure is set, continuing")
+          events.resource_failed(self, action, e)
+        elsif retries > 0
+          events.resource_failed_retriable(self, action, retries, e)
+          @retries -= 1
+          Chef::Log.info("Retrying execution of #{self}, #{retries} attempt(s) left")
+          sleep retry_delay
+          retry
+        else
+          events.resource_failed(self, action, e)
+          raise customize_exception(e)
+        end
+      ensure
+        @elapsed_time = Time.now - start_time
+        events.resource_completed(self)
+      end
+    end
+
+    def validate_action(action)
+      raise ArgumentError, "nil is not a valid action for resource #{self}" if action.nil?
+    end
+
+    def provider_for_action(action)
+      # leverage new platform => short_name => resource
+      # which requires explicitly setting provider in
+      # resource class
+      if self.provider
+        provider = self.provider.new(self, self.run_context)
+        provider.action = action
+        provider
+      else # fall back to old provider resolution
+        Chef::Platform.provider_for_resource(self, action)
+      end
+    end
+
+    def customize_exception(e)
+      new_exception = e.exception("#{self} (#{defined_at}) had an error: #{e.class.name}: #{e.message}")
+      new_exception.set_backtrace(e.backtrace)
+      new_exception
+    end
+    # Evaluates not_if and only_if conditionals. Returns a falsey value if any
+    # of the conditionals indicate that this resource should be skipped, i.e.,
+    # if an only_if evaluates to false or a not_if evaluates to true.
+    #
+    # If this resource should be skipped, returns the first conditional that
+    # "fails" its check. Subsequent conditionals are not evaluated, so in
+    # general it's not a good idea to rely on side effects from not_if or
+    # only_if commands/blocks being evaluated.
+    def should_skip?(action)
+      conditionals = only_if + not_if
+      return false if conditionals.empty?
+
+      conditionals.find do |conditional|
+        if conditional.continue?
+          false
+        else
+          events.resource_skipped(self, action, conditional)
+          Chef::Log.debug("Skipping #{self} due to #{conditional.description}")
+          true
+        end
+      end
+    end
+
+    def updated_by_last_action(true_or_false)
+      @updated ||= true_or_false
+      @updated_by_last_action = true_or_false
+    end
+
+    def updated_by_last_action?
+      @updated_by_last_action
+    end
+
+    def updated?
+      updated
+    end
+
+    def self.json_create(o)
+      resource = self.new(o["instance_vars"]["@name"])
+      o["instance_vars"].each do |k,v|
+        resource.instance_variable_set("@#{k}".to_sym, v)
+      end
+      resource
+    end
+
+    # Hook to allow a resource to run specific code after creation
+    def after_created
+      nil
+    end
+
+    extend Chef::Mixin::ConvertToClassName
+
+    def self.attribute(attr_name, validation_opts={})
+      # This atrocity is the only way to support 1.8 and 1.9 at the same time
+      # When you're ready to drop 1.8 support, do this:
+      # define_method attr_name.to_sym do |arg=nil|
+      # etc.
+      shim_method=<<-SHIM
+      def #{attr_name}(arg=nil)
+        _set_or_return_#{attr_name}(arg)
+      end
+      SHIM
+      class_eval(shim_method)
+
+      define_method("_set_or_return_#{attr_name.to_s}".to_sym) do |arg|
+        set_or_return(attr_name.to_sym, arg, validation_opts)
+      end
+    end
+
+    def self.build_from_file(cookbook_name, filename, run_context)
+      rname = filename_to_qualified_string(cookbook_name, filename)
+
+      # Add log entry if we override an existing light-weight resource.
+      class_name = convert_to_class_name(rname)
+      overriding = Chef::Resource.const_defined?(class_name)
+      Chef::Log.info("#{class_name} light-weight resource already initialized -- overriding!") if overriding
+
+      new_resource_class = Class.new self do |cls|
+
+        # default initialize method that ensures that when initialize is finally
+        # wrapped (see below), super is called in the event that the resource
+        # definer does not implement initialize
+        def initialize(name, run_context)
+          super(name, run_context)
+        end
+
+        @actions_to_create = []
+
+        class << cls
+          include Chef::Mixin::FromFile
+
+          attr_accessor :run_context
+          attr_reader :action_to_set_default
+
+          def node
+            self.run_context.node
+          end
+
+          def actions_to_create
+            @actions_to_create
+          end
+
+          define_method(:default_action) do |action_name|
+            actions_to_create.push(action_name)
+            @action_to_set_default = action_name
+          end
+
+          define_method(:actions) do |*action_names|
+            actions_to_create.push(*action_names)
+          end
+        end
+
+        # set the run context in the class instance variable
+        cls.run_context = run_context
+
+        # load resource definition from file
+        cls.class_from_file(filename)
+
+        # create a new constructor that wraps the old one and adds the actions
+        # specified in the DSL
+        old_init = instance_method(:initialize)
+
+        define_method(:initialize) do |name, *optional_args|
+          args_run_context = optional_args.shift
+          @resource_name = rname.to_sym
+          old_init.bind(self).call(name, args_run_context)
+          @action = self.class.action_to_set_default || @action
+          allowed_actions.push(self.class.actions_to_create).flatten!
+        end
+      end
+
+      # register new class as a Chef::Resource
+      class_name = convert_to_class_name(rname)
+      Chef::Resource.const_set(class_name, new_resource_class)
+      Chef::Log.debug("Loaded contents of #{filename} into a resource named #{rname} defined in Chef::Resource::#{class_name}")
+
+      new_resource_class
+    end
+
+    # Resources that want providers namespaced somewhere other than
+    # Chef::Provider can set the namespace with +provider_base+
+    # Ex:
+    #   class MyResource < Chef::Resource
+    #     provider_base Chef::Provider::Deploy
+    #     # ...other stuff
+    #   end
+    def self.provider_base(arg=nil)
+      @provider_base ||= arg
+      @provider_base ||= Chef::Provider
+    end
+
+    def self.platform_map
+      @@platform_map ||= PlatformMap.new
+    end
+
+    # Maps a short_name (and optionally a platform  and version) to a
+    # Chef::Resource.  This allows finer grained per platform resource
+    # attributes and the end of overloaded resource definitions
+    # (I'm looking at you Chef::Resource::Package)
+    # Ex:
+    #   class WindowsFile < Chef::Resource
+    #     provides :file, :on_platforms => ["windows"]
+    #     # ...other stuff
+    #   end
+    #
+    # TODO: 2011-11-02 schisamo - platform_version support
+    def self.provides(short_name, opts={})
+      short_name_sym = short_name
+      if short_name.kind_of?(String)
+        short_name.downcase!
+        short_name.gsub!(/\s/, "_")
+        short_name_sym = short_name.to_sym
+      end
+      if opts.has_key?(:on_platforms)
+        platforms = [opts[:on_platforms]].flatten
+        platforms.each do |p|
+          p = :default if :all == p.to_sym
+          platform_map.set(
+            :platform => p.to_sym,
+            :short_name => short_name_sym,
+            :resource => self
+          )
+        end
+      else
+        platform_map.set(
+          :short_name => short_name_sym,
+          :resource => self
+        )
+      end
+    end
+
+    # Returns a resource based on a short_name anda platform and version.
+    #
+    #
+    # ==== Parameters
+    # short_name<Symbol>:: short_name of the resource (ie :directory)
+    # platform<Symbol,String>:: platform name
+    # version<String>:: platform version
+    #
+    # === Returns
+    # <Chef::Resource>:: returns the proper Chef::Resource class
+    def self.resource_for_platform(short_name, platform=nil, version=nil)
+      platform_map.get(short_name, platform, version)
+    end
+
+    # Returns a resource based on a short_name and a node's
+    # platform and version.
+    #
+    # ==== Parameters
+    # short_name<Symbol>:: short_name of the resource (ie :directory)
+    # node<Chef::Node>:: Node object to look up platform and version in
+    #
+    # === Returns
+    # <Chef::Resource>:: returns the proper Chef::Resource class
+    def self.resource_for_node(short_name, node)
+      begin
+        platform, version = Chef::Platform.find_platform_and_version(node)
+      rescue ArgumentError
+      end
+      resource = resource_for_platform(short_name, platform, version)
+      resource
+    end
+
+    private
+
+    def lookup_provider_constant(name)
+      begin
+        self.class.provider_base.const_get(convert_to_class_name(name.to_s))
+      rescue NameError => e
+        if e.to_s =~ /#{Regexp.escape(self.class.provider_base.to_s)}/
+          raise ArgumentError, "No provider found to match '#{name}'"
+        else
+          raise e
+        end
+      end
+    end
+
+  end
+end