ElasticSearch - filter query by length of keyword field

Question

I want to search elasticsearch index based on length of text in one of the field. I tried various answers on SO like elasticsearch filter by length of a string field but it didn't work. Below query returns me document with longer value like %230f72e5. What is wrong with my query?

my mapping:

{
    "myindex": {
        "mappings": {
            "properties": {
                "colorcode": {
                    "type": "keyword"
                }

my query GET myindex/_search

{
    "query": {
        "bool" : {
            "must" : {
                "script" : {
                    "script" : "doc['colorcode'].size() < 5"
                }
            }
        }
    }
}

Answer 1

For calculating the length of the string you need to use the below script

For version 7.*

{
  "query": {
    "bool": {
      "filter": {
        "script": {
          "script": {
            "source": "doc['colorcode.keyword'].value.length() < 5",
            "lang": "painless"
          }
        }
      }
    }
  }
}