How to add Bucket Sort to Query Aggregation

I have a ElasticSearch Query that is working well (curl), is my first Query,

First I am filtering by Organization (Multitenancy), then group by Customer, Finally sum the amount of the sales but I only want to have the 3 best customers.

My question is.. How to build the aggregation with the AggregationBuilders to get “bucket_sort” statement. I got the sales grouping by customer with Java API.

Elastic Query is:

 curl -X POST 'http://localhost:9200/sales/sale/_search?pretty'  -H 'Content-Type: application/json' -d '
     {
         "aggs": {

     "filtered": {
       "filter": {
         "bool": {
           "must": [
             {
               "term": {
                 "organization_id": "15"
               }
             }
           ]
         }
       },
       "aggs": {
               "by_customer": {
                 "terms": {
                   "field": "customer_id"
                 },
                  "aggs": {
                      "sum_total" : {
                          "sum": {
                              "field": "amount"
                          }
                      },
                      "total_total_sort": {
                           "bucket_sort": {
                               "sort": [
                                 {"sum_total": {"order": "desc"}}
                               ],
                               "size": 3
                           }
                       }

                  }
               }
           }
     }
 }
 }'

My Java Code:

@Test
public void queryBestCustomers() throws UnknownHostException {
    Client client = Query.client();
    AggregationBuilder sum = AggregationBuilders.sum("sum_total").field("amount");
    AggregationBuilder groupBy = AggregationBuilders.terms("by_customer").field("customer_id").subAggregation(sum);
    AggregationBuilder aggregation =
            AggregationBuilders
                    .filters("filtered",
                            new FiltersAggregator.KeyedFilter("must", QueryBuilders.termQuery("organization_id", "15"))).subAggregation(groupBy);

    SearchRequestBuilder requestBuilder = client.prepareSearch("sales")
            .setTypes("sale")
            .addAggregation(aggregation);
    SearchResponse response = requestBuilder.execute().actionGet();
}

Answer

I hope I got your question right. Try adding “order” to your groupBy agg:

AggregationBuilder groupBy = AggregationBuilders.terms("by_customer").field("customer_id").subAggregation(sum).order(Terms.Order.aggregation("sum_total", false));

One more thing, if you want the top 3 clients than your .size(3) should be set on groupBy agg as well and not on sorting. like that:
AggregationBuilder groupBy = AggregationBuilders.terms("by_customer").field("customer_id").subAggregation(sum).order(Terms.Order.aggregation("sum_total", false)).size(3);