elasticsearch script field

I often need to compute some fields of a Elasticsearch record and make it part of the result.

For example, I have this document:

{
  "fields": {
    "connected": [true],
    "incall": [false],
    "timestamp": ["2021-09-02T10:35:06.000Z"]
  }
}

And I want to have a field named "lack_of_optimization" which is 1 when "connected" is "true" AND "incall" is "false"
See this from the point of view of a callcenter manager: when the callcenter agent is "connected" but not in call, it can be rated as a lack of optimization

In other words:

if( connected && incall)
  lack_of_optimization = 0
else
  lack_of_optimization = 1

To achieve this, we need to write a script that will compute the value of the fields "connected" and "incall" then return a 0 or a 1 depending on the result. HEre is the query:

{
  "size": 750, 
  "sort":[
    {
      "timestamp":{
        "order":"desc",
        "unmapped_type":"boolean"
      }
    }
  ],
  "fields": [
    {"field": "incall"},
    {"field": "connected"}
  ],
  "script_fields":{
    "lack_of_optimization":{
      "script":{
        "source":"""
           if (doc['connected'].value == true && doc['incall'].value == true) 
           { 
             0; 
           } else { 
             1; 
           }
        """
      }
    }
  },
  "_source":false,
  "query":{
    "bool":{
      "must":[],
      "filter":[
        {"match_all":{}},
        {
          "range":{
            "timestamp":{
              "gte":"2021-08-15T00:30:00+0300",
              "lte":"2021-08-15T01:00:00+0300",
              "format":"strict_date_optional_time"
            }
          }
        },
        {"match_phrase":{"connected":true}}
      ],
      "should":[],
      "must_not":[]
    }
  }
}
	

The needed script is the value of the "source"

  "script_fields":{
    "animation_value":{
      "script":{
        "source":"""
           if (doc['connected'].value == true && doc['incall'].value == true) 
           { 
             0; 
           } else { 
             1; 
           }
        """
      }
    }
	

In the Elasticsearch documentation, it is refered as a "script field", written in the "Painless language"

The final document will then include the computed field:

    {
        "fields" : {
          "connected" : [
            true
          ],
          "incall" : [
            false
          ],
          "lack_of_optimization" : [
            1
          ]
        }
      }