[ML] Transform advanced editor does not allow you to indent painless

[sophiec20]

Found in 7.3.0-BC5

In Dev tools, you can indent your painless code using a """ notation .. see below for example. However if you try this in the transform advanced editor, you get a red-square-invalid-json warning.. If you remove the indents and convert painless to a single line then it works fine.

For complex scripted fields, it's very useful to be able to indent and space out your painless code. Is it possible to achieve this with the adv json editor?

Example that works in Dev Tools

POST _data_frame/transforms/_preview
{
  "source": {
    "index": "filebeat*"
  },
  "pivot": {
    "group_by": {
      "clientip": {
        "terms": {
          "field": "source.address"
        }
      }
    },
    "aggregations": {
      "responses.total": {
        "value_count": {
          "field": "timestamp"
        }
      },
      "responses.counts": {
        "scripted_metric": {
          "init_script": "state.responses = ['error':0L,'success':0L,'other':0L]",
          "map_script": """
            def code = doc['http.response.status_code'].value;
            if (code.startsWith('5') || code.startsWith('4')) {
              state.responses.error += 1 ;
            } else if(code.startsWith('2')) {
              state.responses.success += 1;
            } else {
              state.responses.other += 1;
            }
            """,
          "combine_script": "state.responses",
          "reduce_script": """
            def counts = ['error': 0L, 'success': 0L, 'other': 0L];
            for (responses in states) {
              counts.error += responses['error'];
              counts.success += responses['success'];
              counts.other += responses['other'];
            }
            return counts;
            """
        }
      }
    }
  }
}

[elasticmachine]

Pinging @elastic/ml-ui

[walterra]

I started a conversation with the Elasticsearch UI team which owns dev console, we'll try to re-use dev console's features so we don't have to re-implemented these features.