How to increase a date by e.g. 1 day using Painless script?

Elastic Stack Elasticsearch
1

Just starting to use Painless as excercise before certification.

Am wondering how to attack the problem of updating/increasing a date field by using a Painless script?
I know how to for example increase a simple counter:

POST test/_update/1
{
  "script":
  {
    "source": "ctx._source.counter += params.count",
    "lang": "painless",
    "params": {
      "count": 1
    }
  }
}

, but don´t really get it when it comes to date formats.

See extract from my sample mapping below, how would I go about to update any of those by 1 day?

    "revision_date" : {
      "type" : "date"
    },
    "revision_date_epoch" : {
      "type" : "date",
      "format" : "epoch_second"
    },
    "revision_date_epochm" : {
      "type" : "date",
      "format" : "epoch_millis"
    }

Been trying according to posts that I´ve found but hope to get the strategy explained here to get going.

Thx

2

ctx._source is just a hashmap of strings, so it depends on the string representation of the date.

for epochs, you could do something like Instant.ofEpochMilli(ctx._source.revision_date_epochm).plus(Duration.ofDays(1)) - on top of my head and untested...

for epoch seconds there is Instant.ofEpochSecond(), for a string based date you would need to use a dateformatter or hope that something like ZonedDate.parse works out of the box.

3

Hi and thx for answer, will explore your suggestions.
\Johan