Chef ruby_block and dynamic resource creation

demo.rb

ruby_block "sync_build_from_s3" do
  action :nothing
  block do
    # latest_file contains path to the latest.txt, which lists files to sync
    file = File.new(latest_file, "r");
    run_context = Chef::RunContext.new(node, {})

    #
    # Create the directory to hold the new build files
    #
    tmpDir = "/opt/builds/#{File.dirname(file.first)}"   # get the build path
    dir = Chef::Resource::Directory.new(tmpDir, run_context)
    dir.recursive(true)
    dir.run_action(:create)

    #
    # Download the build files listed in the downloaded manifest file
    #
    file.rewind
    while (line = file.gets) do
       #
       # Define the S3 remote file resources based on data in manifest file
       # -- this is the only way (I found) to inject new resources dynamically at runtime
       #
       local_file = "/opt/builds/#{line}"
       f = Chef::Resource::S3AwareRemoteFile.new(local_file, run_context)
       f.access_key_id      aws_access_key
       f.secret_access_key  aws_secret_key
       f.source             "s3://my_bucket/#{line}"
       f.owner              "root"
       f.group              "root"
       f.mode               0644
       f.run_action         :create_if_missing
    end
  end
end