title: Curator for deleting indices older than 30 days or more based on a field that isn’t of type date
body: <pre><code>{
   "_index": "user:1494813192000",
   "_type": "fruits",
   "_id": "pbyac5r88-yghe-v1ez-cpgb-sqdjipr54alzgj/tp4oqalbd-bo2v-ikj1-atfq-wezcoeeuf6wiqpt/apple",
   "_score": 1,
   "_routing": "pbyac5r88-yghe-v1ez-cpgb-sqdjipr54alzgj",
   "_source": {
   "numCal": 442,
   "eventTime": 1497315192000,
   "fruitName": "apple"
  }
  </code></pre>
  
  <p>This is how the index in my elasticsearch looks like. The eventTime is the current time in ms based on UTC. I would want to use that field to delete my indices using the curator.</p>
  
  <p>This is how my ACTION_FILE.YML looks like</p>
  
  <pre><code>actions:
    1:
      action: delete_indices 
      description: &gt;-
        Delete indices older than 45 days (based on index name), for logstash-
        prefixed indices. Ignore the error if the filter does not result in an
        actionable list of indices (ignore_empty_list) and exit cleanly.
      options:
        ignore_empty_list: True
        timeout_override:
        continue_if_exception: False
        disable_action: False
      filters:
      - filtertype: age
        source: field_stats
        field: 'eventTime'
        direction: older
        unit: days
        unit_count: 30
        exclude:
  </code></pre>
  
  <p>Does curator support deleting based on fields that aren't in data format?</p>