add delayed_action to the Chef::Resource API

effectively creates a resource which sends itself a delayed notification

useful to create a resource which runs exactly once at the end of a run:

```ruby
with_run_context :root do
  find_resource(:execute, "/bin/true") do
    action :nothing
    delayed_action :run
  end
end
```

avoids using a log resource to force a resource to update and force a
delayed notification which avoids the extra output from the log
resource, and avoids the resource updated count always being updated.

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/chef/resource.rb b/lib/chef/resource.rb
index d11fa1c80c..8048330ce1 100644
--- a/lib/chef/resource.rb
+++ b/lib/chef/resource.rb
@@ -181,6 +181,31 @@ class Chef
     alias_method :action=, :action
 
     #
+    # Force a delayed notification into this resource's run_context.
+    #
+    # This should most likely be paired with action :nothing
+    #
+    # @param arg [Array[Symbol], Symbol] A list of actions (e.g. `:create`)
+    # @return [Array[Symbol]] the list of actions.
+    #
+    def delayed_action(arg = nil)
+      if arg
+        arg = Array(arg).map(&:to_sym)
+        arg.each do |action|
+          validate(
+            { action: action },
+            { action: { kind_of: Symbol, equal_to: allowed_actions } }
+          )
+          # the resource effectively sends a delayed notification to itself
+          run_context.add_delayed_action(Notification.new(self, action, self))
+        end
+        @delayed_action = arg
+      else
+        @delayed_action
+      end
+    end
+
+    #
     # Sets up a notification that will run a particular action on another resource
     # if and when *this* resource is updated by an action.
     #