"_index": "logstash-2017.02.04",
    "_type": "click",
    "_id": "AVe",
    "_score": 12,
    "_source": {
      "transmissie": "H",
      "position_car_page": 9,
      "model": "V",
      "datum": "2017-02-04 09:27:37",
      "abtest_device": "computer",
      "user_nr": "0"
      "ip_number": "0",
      "bouwjaar": "2013",
      "brandstof": "Benzine",

If user_nr is not empty or zero:
   userId = user_nr
   id_index = 1
else if analytics_clientid is not empty or zero:
   userId = analytics_clientid
   id_index = 2
else if ip_number is not empty or zero:
   userId = ip_number
   id_index = 3