如何在ElasticSearch 6.x中获取动态/未知字段的聚合?

[
  {
    "name": "Test product 1",
    "features": [
      {
        "name": "color",
        "value": "Blue"
      },
      {
        "name": "size",
        "value": "M"
      },
      {
        "name": "height",
        "value": 124,
      }
    ]
  },
  {
    "name": "Test product 1",
    "features": [
      {
        "name": "color",
        "value": "Red"
      },
      {
        "name": "wifi",
        "value": "ac/g/n"
      }
    ]
  }
]  

我在找下面的东西。请注意 "features.name => value" 在ES中不是真实/有效的符号。

GET /_search
{
    "aggs" : {
        "features" : {
            "terms" : { "field" : "features.name => value" }
        }
    }
}

像这样的回应

{
    ...
    "aggregations" : {
        "genres" : {
            "doc_count_error_upper_bound": 0, 
            "sum_other_doc_count": 0, 
            "buckets" : {"color": [ 
                      {
                        "key" : "red",
                        "doc_count" : 6
                       },
                       {
                       "key" : "blue",
                       "doc_count" : 3
                       },
                     ],
                {"size": [ 
                      {
                        "key" : "M",
                        "doc_count" : 6
                       },
                ],
                {"wifi": [ 
                      {
                        "key" : "ac/g/n",
                        "doc_count" : 1
                       },
                ]
        }
    }
}