[source, ruby]
----
response = client.ingest.simulate(
  body: {
    pipeline: {
      description: 'monthly date-time index naming',
      processors: [
        {
          date_index_name: {
            field: 'date1',
            index_name_prefix: 'my-index-',
            date_rounding: 'M'
          }
        }
      ]
    },
    docs: [
      {
        _source: {
          "date1": '2016-04-25T12:02:01.789Z'
        }
      }
    ]
  }
)
puts response
----
