[Rollup] incorrect check on histo group field type

[kaem2111]

Elasticsearch version: 6.3.1

Description of the problem including expected versus actual behavior:

{
  "error": {
    "root_cause": [
      {
        "type": "remote_transport_exception",
        "reason": "[XXXX][XXXX:9300][cluster:admin/xpack/rollup/put]"
      }
    ],
    "type": "illegal_argument_exception",
    "reason": "Validation Failed: 1: The field referenced by a histo group must be a [numeric] type, but found [scaled_float] for field [system.cpu.idle.pct];"
  },
  "status": 400
}

I expect scaled_float is a numeric type and the check for allowed types has to be adjusted/extended

Steps to reproduce:

at console exec:

PUT _xpack/rollup/job/metricbeat_test
{
  "index_pattern": "metricbeat-*",
  "rollup_index": "metricbeat_1h",
  "cron": "12 * * * * ?",
  "page_size": 1000,
  "groups": {
    "date_histogram": {
      "field": "@timestamp",
      "interval": "1h",
      "delay": "3h"
    },
    "terms": {
      "fields": [
        "host.name",
        "metricset.module",
        "metricset.name"
      ]
    },
    "histogram": {
      "fields": [
        "system.cpu.idle.pct"
      ],
      "interval": 12
    }
  },
  "metrics": [
    {
      "field": "system.cpu.total.pct",
      "metrics": [
        "max"
      ]
    }
  ]
}

Provide logs (if relevant):

[elasticmachine]

Pinging @elastic/es-search-aggs

[colings86]

@polyfractal could you take a look?

[polyfractal]

@kaem2111 ah sorry about that, it is indeed a bug! This was fixed for metrics in 2d6d3c3, but I didn't think about the histogram at the time. Histo should definitely support scaled_floats.

Will get a bugfix up soon! Thanks for the report.