Combine Terms aggregation with Composite aggregation

[mirokrastev (Miroslav)]

I have the following ES Query

GET logstash-*/_search
{
  "size": 0,
  "aggs": {
    "table": {
      "composite": {
        "size": 10000,
        "sources": [
          {
            "stk1": {
              "terms": {
                "field": "geo.src"
              }
            }
          },
          {
            "stk2": {
              "terms": {
                "field": "geo.dest"
              }
            }
          }
        ]
      }
    }
  }

I want the composite bucket to include only geo.src from top X, which I can get with Terms aggregation.

How can I mix both Terms aggregation AND composite aggregation to create buckets for only the top 10 results from Terms aggregation? I want to have at max 10 geo.src with however many geo.dest it connects to.

Terms aggregation query:

GET logstash-*/_search
{
  "size": 0,
  "aggs": {
    "top_10": {
      "terms": {
        "field": "geo.src",
        "size": 10
      }
    }
  }
}

Response from Terms aggregation:

{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 10000,
      "relation" : "gte"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "top_10" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 5444,
      "buckets" : [
        {
          "key" : "CN",
          "doc_count" : 2626
        },
        {
          "key" : "IN",
          "doc_count" : 2326
        },
        {
          "key" : "US",
          "doc_count" : 1201
        },
        {
          "key" : "ID",
          "doc_count" : 461
        },
        {
          "key" : "BR",
          "doc_count" : 396
        },
        {
          "key" : "PK",
          "doc_count" : 368
        },
        {
          "key" : "BD",
          "doc_count" : 348
        },
        {
          "key" : "NG",
          "doc_count" : 313
        },
        {
          "key" : "RU",
          "doc_count" : 272
        },
        {
          "key" : "JP",
          "doc_count" : 250
        }
      ]
    }
  }
}

I've looked up at pipeline aggregation, multi terms and top_hits, but it does not satisfy me. I need the composite aggregation response for Sankey diagram (Sankey Visualization with Vega in Kibana 6.2 | Elastic Blog)