Cannot use scripted field in a date range bucket aggregation

[kspe]

Hey,

I have a time field in my document which is a timestamp number. It is not set as a date type field so cannot use it in the date range bucket aggregation directly (Kibana complains that the index does not contain any compatible field types: date).

My idea was so create a scripted field e.g. parsed_date with type date on the same index and return a Date object based on the timestamp. I've managed to add it with painless script as following:

return new Date(doc["time"].value * 1000);

So far all good, the timestamp is parsed properly and on the preview, I can see that my new field is returned:

The issue is that the scripted field is always returned as an array hence the result I get is:

"parsed_date": [
   "2020-11-19T00:00:00.000Z"
  ]

instead of:

"parsed_date": "2020-11-19T00:00:00.000Z"

I've found this brief explanation of why is it so: Script_fields always returns array. how to return an object or simple data type? and it does make sense to me.

Now when I try to use that new scripted field in a date range agg. I get 500 error with the error message:

Unsupported script value [Tue Nov 17 00:00:00 UTC 2020], expected a number, date, or boolean

This again makes sense as this date object is within array but not sure how I can overcome this, as I understand it, date range agg. expects object not array but seems I cannot achieve this with scripted fields.

Any hints would be much appreciated, thanks!

[flash1293 (Joe Reuter)]

Could you try to return the timestamp directly without creating a Date instance? (still keeping thge "date" type of the field)

return doc["time"].value * 1000;

[kspe]

This does work, thanks a lot!