Reformate sources from elastic search

Question

Through the dev tools in Elastic with this command :

GET "my_index"/_search/?filter_path=hits.hits._source&size=1

I have :

{
  "hits" : {
    "hits" : [
      {
        "_source" : {
          "@timestamp" : "2020-10-10T14:00:00.000Z",
          "Date" : "2020-10-10T14:00:00Z",
          "MeanValue" : 58.23516987
        }
      }
    ]
  }
}

It is an exemple of 1 hit

I wanted to know if it is possible with maybe a Painless Code or any other solution in Elastic to change the name of the source key and get :

{
  "timestamp": "2020-10-10T14:00:00Z"
  "value" : 58.23516987
}

I did it with Python by getting the data with REST API but I wonder if there is a solution to have that output directly from Elastic search

Answer 1

No, it's not possible to change the structure of the response you get from Elasticsearch.

As you've discovered, you can use filter_path to only return a selected set of fields, but the structure itself cannot be changed.