How to createID and pick latest n entries from the set

[kish]

in golang how to use user generated id and increment it for every new entry? I tried

  Index(KpiIndex).
		Type(KpiDocType).
		Id(ids).                                                              => Id will take only stings.
		BodyJson(kpis).
		Do(elasticSearchContext)

And when data is getting stored in ES, it is getting stored in randomly say

{
"took" : 5,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"failed" : 0
},
"hits" : {
"total" : 4,
"max_score" : 1.0,
"hits" : [
{
"_index" : "kpi",
"_type" : "kpi",
"_id" : "AWIexPLwnbh5r7Xr9nsL",
"_score" : 1.0,
"_source" : {
"date" : "2018-03-13 15:20:45",
"kpi" : [
{

          "Static_limit" : 0
        },
        {
          "CpuAverageLoad" : 0,
          ...,
          "NodeType" : "kkk",
          "State" : "online"
        }
      ]
    }
  },
  {
    "_index" : "kpi",
    "_type" : "kpi",
    "_id" : "AWIexYy1_xnN0Y7Qo1HE",
    "_score" : 1.0,
    "_source" : {
      "date" : "2018-03-13 15:21:25",
      "kpi" : [
        {
          "CpuAverageLoad" : 0,
          },
        {
          "CpuAverageLoad" : 0,
          ...,
          "NodeType" : "kkk",
          "State" : "online"
        }
      ]
    }
  },
  {
    "_index" : "kpi",
    "_type" : "kpi",
    "_id" : "AWIexdrLnbh5r7Xr9nsM",
    "_score" : 1.0,
    "_source" : {
      "date" : "2018-03-13 15:21:45",
      "kpi" : [
        {
          
          "Static_limit" : 0
        },
        {
          "CpuAverageLoad" : 0,
          ...,
          "NodeType" : "kkk",
          "State" : "online"
        }
      ]
    }
  },
  {
    "_index" : "kpi",
    "_type" : "kpi",
    "_id" : "AWIexT52BjtG8JuPSysx",
    "_score" : 1.0,
    "_source" : {
      "date" : "2018-03-13 15:21:05",
      "kpi" : [
        {
          
          "Static_limit" : 0
        },
        {
          "CpuAverageLoad" : 0,
          ...,
          "NodeType" : "kkk",
          "State" : "online"
        }
      ]
    }
  }
]

}
}

When we observe the 'data' field, the order is
"date" : "2018-03-13 15:20:45",
"date" : "2018-03-13 15:21:25",
"date" : "2018-03-13 15:21:45",
"date" : "2018-03-13 15:21:05",

where as the correct order should be

"date" : "2018-03-13 15:20:45",
"date" : "2018-03-13 15:21:05",
"date" : "2018-03-13 15:21:25",
"date" : "2018-03-13 15:21:45"

[kish]

there is no proper order in storing the data. For example

curl -XGET 'localhost:9200/kpi/_search?pretty' | grep -w date
"date" : "2018-03-13 15:21:45",
:-- --: "date" : "2018-03-13 15:23:05",
--:-- "date" : "2018-03-13 15:26:05",
--: "date" : "2018-03-13 15:20:45",
--:- "date" : "2018-03-13 15:21:25",

• 7 "date" : "2018-03-13 15:22:45",
  "date" : "2018-03-13 15:24:25",
  "date" : "2018-03-13 15:24:45",
  "date" : "2018-03-13 15:26:25",
  "date" : "2018-03-13 15:25:25"