title: ElasticSearch index unix timestamp
body: <p>I have to index documents containing a 'time' field whose value is an integer representing the number of seconds since epoch (aka unix timestamp).</p>
  
  <p>I've been reading ES docs and have found this:</p>
  
  <p><a href="http://www.elasticsearch.org/guide/reference/mapping/date-format.html">http://www.elasticsearch.org/guide/reference/mapping/date-format.html</a></p>
  
  <p>But it seems that if I want to submit unix timestamps and want them stored in a 'date' field (integer field is not useful for me) I have only two options:</p>
  
  <ul>
  <li>Implement my own date format</li>
  <li>Convert to a supported format at the sender</li>
  </ul>
  
  <p>Is there any other option I missed?</p>
  
  <p>Thanks!</p>