title: ignore incoming logstash entries that are older than a given date
body: <p>I want Logstash, when it's processing input entries, to simply drop entries that are older than N days.</p>
  
  <p>I assume I'll use <a href="http://logstash.net/docs/1.4.2/filters/date" rel="noreferrer">the date module</a> and obviously <a href="http://logstash.net/docs/1.4.2/filters/drop" rel="noreferrer">drop</a>, but I don't know how to connect them.</p>