Get sum of doc_count values in aggregation

Elastic Stack Elasticsearch
1

I'd like to get the total number of doc_count values for an aggregation.

At the moment, I have:

{  
   "size": 0,
   "query":{  
      "function_score":{  
         "query":{  
            "bool":{  
               "filter":{  
                  "bool":{  
                     "must":[
                     	{  
                           "range":{  
                              "created_at":{  
                                 "gte":"now-30d",
                                 "format":"yyyy-MM-dd'T'HH:mm:ss.SSSZ"
                              }
                           }
                        },
                        {  
                           "term":{  
                              "client_id":1245
                           }
                        }
                     ]
                  }
               }
            }
         }
      }
   },
   "aggs": {
		"date_range": {
			"date_histogram": {
				"field": "timestamp",
				"interval": "1h"
			}
        }
    }
}

... which returns:

{
    "took": 0,
    "timed_out": false,
    "_shards": {
        "total": 5,
        "successful": 5,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": 830,
        "max_score": 0,
        "hits": []
    },
    "aggregations": {
        "date_range": {
            "buckets": [
                {
                    "key_as_string": "2018-07-17T00:00:00.000+0000",
                    "key": 1531785600000,
                    "doc_count": 113
                },
                {
                    "key_as_string": "2018-07-17T01:00:00.000+0000",
                    "key": 1531789200000,
                    "doc_count": 143
                },
                {
                    "key_as_string": "2018-07-17T02:00:00.000+0000",
                    "key": 1531792800000,
                    "doc_count": 116
                },
                {
                    "key_as_string": "2018-07-17T03:00:00.000+0000",
                    "key": 1531796400000,
                    "doc_count": 119
                },
                {
                    "key_as_string": "2018-07-17T04:00:00.000+0000",
                    "key": 1531800000000,
                    "doc_count": 90
                },
                {
                    "key_as_string": "2018-07-17T05:00:00.000+0000",
                    "key": 1531803600000,
                    "doc_count": 122
                },
                {
                    "key_as_string": "2018-07-17T06:00:00.000+0000",
                    "key": 1531807200000,
                    "doc_count": 93
                },
                {
                    "key_as_string": "2018-07-17T07:00:00.000+0000",
                    "key": 1531810800000,
                    "doc_count": 34
                }
            ]
        }
    }
}

... but I'd like the sum, if possible.

I could perform the calculation in the logic, but it would be pointless if Elastic could do it.

I found Cumulative Sum Aggregation, but that would also require some additional logic to get at the cumulative value.

Any assistance would be much appreciated.

2

I found the value in the hits.total variable, which is good, but it would be useful to know if it's possible to do it within the statement itself.