脚本语言入门

1. 准备数据

curl -X PUT "localhost:9200/hockey/player/_bulk?refresh" -H 'Content-Type: application/json' -d'
{"index":{"_id":1}}
{"first":"johnny","last":"gaudreau","goals":[9,27,1],"assists":[17,46,0],"gp":[26,82,1],"born":"1993/08/13"}
{"index":{"_id":2}}
{"first":"sean","last":"monohan","goals":[7,54,26],"assists":[11,26,13],"gp":[26,82,82],"born":"1994/10/12"}
{"index":{"_id":3}}
{"first":"jiri","last":"hudler","goals":[5,34,36],"assists":[11,62,42],"gp":[24,80,79],"born":"1984/01/04"}
{"index":{"_id":4}}
{"first":"micheal","last":"frolik","goals":[4,6,15],"assists":[8,23,15],"gp":[26,82,82],"born":"1988/02/17"}
{"index":{"_id":5}}
{"first":"sam","last":"bennett","goals":[5,0,0],"assists":[8,1,0],"gp":[26,1,0],"born":"1996/06/20"}
{"index":{"_id":6}}
{"first":"dennis","last":"wideman","goals":[0,26,15],"assists":[11,30,24],"gp":[26,81,82],"born":"1983/03/20"}
{"index":{"_id":7}}
{"first":"david","last":"jones","goals":[7,19,5],"assists":[3,17,4],"gp":[26,45,34],"born":"1984/08/10"}
{"index":{"_id":8}}
{"first":"tj","last":"brodie","goals":[2,14,7],"assists":[8,42,30],"gp":[26,82,82],"born":"1990/06/07"}
{"index":{"_id":39}}
{"first":"mark","last":"giordano","goals":[6,30,15],"assists":[3,30,24],"gp":[26,60,63],"born":"1983/10/03"}
{"index":{"_id":10}}
{"first":"mikael","last":"backlund","goals":[3,15,13],"assists":[6,24,18],"gp":[26,82,82],"born":"1989/03/17"}
{"index":{"_id":11}}
{"first":"joe","last":"colborne","goals":[3,18,13],"assists":[6,20,24],"gp":[26,67,82],"born":"1990/01/30"}
'

2. 案例

可以从名为doc的Map访问文档值。

• 获取所有id下的goals的总和

  GET hockey/_search
  {
    "query": {
      "match_all": {}
    },
    "script_fields": {
      "total_goals": {
        "script": {
          "lang": "painless",
          "source": """
            int total = 0;
            for (int i = 0; i < doc['goals'].length; ++i) {
              total += doc['goals'][i];
            }
            return total;
          """
        }
      }
    }
  }
  

kibana中执行结果如下：

1.png

• 获取字段first和last的拼接的结果

GET hockey/_search
{
  "query": {
    "match_all": {}
  },
  "sort": {
    "_script": {
      "type": "string",
      "order": "asc",
      "script": {
        "lang": "painless",
        "source": "doc['first.keyword'].value + ' ' + doc['last.keyword'].value"
      }
    }
  }
}

说明1：如果doc['field'].value 中的field不存在。那么返回的结果如下：

• 0if afield has a numeric datatype (long, double etc.)
• false is a field has a boolean datatype
• epoch date if a field has a date datatype
• null if a field has a string datatype
• null if a field has a geo datatype
• "" if a field has a binary datatype

说明2：从es7.0开始，如果doc['field'].value 中的field不存在，将抛出异常。但是这里有个前提是你必须设置jvm.option - Des.scripting.exception_for_missing_value=true 。可以通过doc['field'].size() == 0 来判断是都存在field

更新字段的值

先查看一下内容：

```
GET hockey/_search
{
  "stored_fields": [
    "_id",
    "_source"
  ],
  "query": {
    "term": {
      "_id": 1
    }
  }
}
```

部分内容如下：

```
{
    "_index" : "hockey",
    "_type" : "player",
    "_id" : "1",
    "_score" : 1.0,
    "_source" : {
    "first" : "johnny",
    "last" : "gaudreau",
    "goals" : [9,27,1],
    "assists" : [17,46,0],
    "gp" : [26,82,1],
    "born" : "1993/08/13"
}
```

更新脚本如下：

```
POST hockey/player/1/_update
{
  "script": {
    "lang": "painless",
    "source": "ctx._source.last = params.last",
    "params": {
      "last": "hockey"
    }
  }
}
```

执行结果如下：

```
{
  "_index" : "hockey",
  "_type" : "player",
  "_id" : "1",
  "_version" : 2,
  "result" : "updated",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 3,
  "_primary_term" : 3
}
```

再次查看内容即可，结果不在显示。

更新多个字段：

```
POST hockey/player/1/_update
{
  "script": {
    "lang": "painless",
    "source": """
      ctx._source.last = params.last;
      ctx._source.nick = params.nick
    """,
    "params": {
      "last": "gaudreau",
      "nick": "hockey"
    }
  }
}
```

会新增一个字段：nick，结果如下：

```
{
    "_index" : "hockey",
    "_type" : "player",
    "_id" : "1",
    "_score" : 1.0,
    "_source" : {
    "first" : "johnny",
    "last" : "gaudreau",
    //删掉了部分字段
    "born" : "1993/08/13",
    "nick" : "hockey"
}
```