[Elastic][Elasticsearch] Painless

개요

• https://www.elastic.co/guide/en/elasticsearch/painless/current/painless-guide.html
• 간단하고 안전한 스크립팅 언어
• script_fields를 이용하여 스크립트 기반의 검색 가능

예제

• 데이터

   POST painless_test/_doc
   {
     "@timestamp": "2022-05-01T07:00:00.000Z",
     "cluster": "cluster-01",
     "resource": [
       {
         "name": "node-01",
         "cpu": 1,
         "memory": 11,
         "disk": 111
       },
       {
         "name": "node-02",
         "cpu": 2,
         "memory": 22,
         "disk": 222
       },
       {
         "name": "node-03",
         "cpu": 3,
         "memory": 33,
         "disk": 333
       }
     ]
   }
  

• 요청

   GET painless_test/_search
   {
     "query": {
       "bool": {
         "must": [
           {
             "range": {
               "@timestamp": {
                 "gte": "2022-05-01T07:00:00.000Z",
                 "lt": "2022-05-01T07:01:00.000Z"
               }
             }
           }
         ]
       }
     },
     "script_fields": {
       "cluster": {
         "script": {
           "lang": "painless",
           "source": "params._source.cluster"
         }
       },
       "name": {
         "script": {
           "lang": "painless",
           "source": "def list = new ArrayList(); for (item in params._source.resource) {list.add(item.name);} return list;"
         }
       },
       "cpu_sum": {
         "script": {
           "lang": "painless",
           "source": "int sum = 0; for (item in params._source.resource) {sum += item.cpu;} return sum;"
         }
       },
       "memory_sum": {
         "script": {
           "lang": "painless",
           "source": "int sum = 0; for (item in params._source.resource) {sum += item.memory;} return sum;"
         }
       },
       "disk_sum": {
         "script": {
           "lang": "painless",
           "source": "int sum = 0; for (item in params._source.resource) {sum += item.disk;} return sum;"
         }
       },
       "timestamp": {
         "script": {
           "lang": "painless",
           "source": "params._source['timestamp']"
         }
       }
     }
   }
  

• 응답

   {
     "took" : 8,
     "timed_out" : false,
     "_shards" : {
       "total" : 1,
       "successful" : 1,
       "skipped" : 0,
       "failed" : 0
     },
     "hits" : {
       "total" : {
         "value" : 1,
         "relation" : "eq"
       },
       "max_score" : 1.0,
       "hits" : [
         {
           "_index" : "painless_test",
           "_type" : "_doc",
           "_id" : "w2alaYABFxYHVJl7ArL4",
           "_score" : 1.0,
           "fields" : {
             "cluster" : [
               "cluster-01"
             ],
             "cpu_sum" : [
               6
             ],
             "name" : [
               "node-01",
               "node-02",
               "node-03"
             ],
             "disk_sum" : [
               666
             ],
             "memory_sum" : [
               66
             ],
             "datacenter_id" : [
               null
             ],
             "timestamp" : [
               null
             ]
           }
         }
       ]
     }
   }