Here's a quick way to run a delayed_job job like a cron job. The ensure block is the key to making sure it runs again.

Example of a "cron" delayed_job

class SampleJob
  def perform
    begin
      # do all your work in the begin block.
      puts "hello world"
    rescue Exception => e
      # rescue any errors so that you know something went wrong. Email yourself the error if you need.
      error_msg = "#{Time.now} ERROR (SampleJob#perform): #{e.message} - (#{e.class})\n#{(e.backtrace or []).join("\n")}"
      puts error_msg
    ensure
      # make sure the job gets requeued. the ensure block is always executed, even if there was an exception thrown and caught by rescue.
      Delayed::Job.enqueue SampleJob.new, 5, 1.hour.from_now
    end
  end
end

If you do it that way it will never rescue, because of ensure.