elasticsearch使用painless的一些简单例子

1、背景

此篇文档仅仅是简单的记录一下painless的一些简单的例子，防止以后忘记，不过多涉及painless的语法。

2、准备数据

2.1 mapping

PUT /index_person
{
  "mappings": {
    "properties": {
      "name": {
        "type": "keyword"
      },
      "age": {
        "type": "integer"
      },
      "province": {
        "type": "keyword"
      }
    }
  }
}

2.2 插入数据

PUT /index_person/_bulk
{"index":{"_id":1}}
{"name":"张三","age":20,"province":"湖北"}
{"index":{"_id":2}}
{"name":"李四","age":25,"province":"北京"}
{"index":{"_id":3}}
{"name":"王五","age":30,"province":"湖南"}

3、例子

3.1 (update)更新文档 id=1 的文档，将 age 加 2岁

POST index_person/_update/1
{
  "script": {
    "lang": "painless",
    "source": """
      ctx['_source']['age'] += params['incrAge']
    """,
    "params": {
      "incrAge": 2
    }
  }
}

3.2 (update_by_query)如果 province 是北京的话，就将 age 减少1岁

POST index_person/_update_by_query
{
  "query": {
    "term": {
      "province": {
        "value": "北京"
      }
    }
  },
  "script": {
    "lang": "painless",
    "source": """
      ctx['_source']['age'] -= params['decrAge']
    """,
    "params": {
      "decrAge": 1
    }
  }
}

3.3 (ctx.op)如果张三的年龄小于20岁就不处理，否则就删除这个文档

POST index_person/_update/1
{
  "script": {
    "lang": "painless",
    "source": """
      // 这是默认值，表示的是更新值，重新索引记录
      ctx.op = 'index';
      if(ctx._source.age < 20){
        // 表示不处理
        ctx.op = 'none';
      }else{
        // 表示删除这个文档
       ctx.op = 'delete'; 
      }
    """
  }
}

3.4 (stored script)如果是湖南省则增加地市字段，值为长沙

3.4.1 创建存储脚本

PUT _scripts/add_city
{
  "script":{
    "lang": "painless",
    "source": "ctx._source.city = params.city"
  }
}

add_city为脚本的id

3.4.2 使用存储脚本

POST index_person/_update_by_query
{
  "query": {
    "term": {
      "province": {
        "value": "湖南"
      }
    }
  },
  "script": {
    "id": "add_city",
    "params": {
      "city": "长沙"
    }
  }
}

3.5 (pipeline)通过pipeline如果插入的文档的age<10则放入到index_person_small索引中

3.5.1 创建pipeline

PUT _ingest/pipeline/pipeline_index_person_small
{
  "description": "如果插入的文档的age<10则放入到index_person_small索引中",
  "processors": [
    {
      "script": {
        "source": """
            if(ctx.age < 10){
              ctx._index = 'index_person_small';
            }
          """
      }
    }
  ]
}

3.5.2 使用pipeline

PUT index_person/_doc/4?pipeline=pipeline_index_person_small
{
  "name":"赵六",
  "age": 8,
  "province":"四川"
}

3.5.3 运行结果

运行结果

3.6 function_score中使用script_score算分

3.6.1 需求

如果这个用户是湖南的，则使用 age作为分数

3.6.2 dsl

GET index_person/_search
{
  "query": {
    "function_score": {
      "query": {
        "match_all": {}
      },
      "functions": [
        {
          "script_score": {
            
            "script": """
              if(doc.province.value == 0){
                return 0;
              }
            
              if(doc.province.value == '湖南'){
                return doc.age.value;
              }
              return 0;
            """
          }
        }
      ],
      "boost_mode": "sum",
      "score_mode": "sum"
    }
  }
}

3.6.3 运行结果

运行结果

3.7 script_fields 增加字段

GET index_person/_search
{
  "query": {"match_all": {}},
  "fields": [
    "double_age"
  ], 
  "script_fields": {
    "double_age": {
      "script": {
        "lang": "painless",
        "source": "doc.age.value * 2"
      }
    }
  }
}

3.8 runtime field 增加字段

3.8.1 需求

针对age<25的文档，返回double_age字段，否则不处理。

3.8.2 dsl

GET index_person/_search
{
  "query": {
    "match_all": {}
  },
  "fields": [
    "double_age"
  ],
  "runtime_mappings": {
    "double_age":{ 
      "type": "keyword",
      "script": """
        if(doc.age.size() == 0){
          return;
        }
        if(doc.age.value < 25){
          emit(doc.age.value * 2 + '');
        }
      """
    }
  }
}

在runtime field 中，需要使用emit来返回数据，但是不是emit(null)

3.9 _reindex 中使用

3.9.1 dsl

POST _reindex
{
  "source": {
    "index": "index_person"
  },
  "dest": {
    "index": "index_person_new"
  },
  "script": {
    "lang": "painless",
    "source": """
      if(ctx._source.age < 25){
        ctx._source.tag = '年轻人';
      }else{
        ctx._source.tag = '中年人';
      }
    """
  }
}

3.9.2 运行结果

运行结果

3.10 script query 查询age<25

GET index_person/_search
{
  "query": {
    "script": {
      "script": {
        "lang": "painless",
        "source": """
          if(doc.age.size() == 0){
            return false;
          }
          return doc.age.value < 25;
        """
      }
    }
  }
}

3.11 script 聚合

GET index_person/_search
{
  "size": 0, 
  "aggs": {
    "agg_province": {
      "terms": {
        "script": {
          "lang": "painless",
          "source": """
            return doc.province
          """
        }, 
        "size": 10
      }
    },
    "agg_age":{
      "avg": {
        "script": "params._source.age"
      }
    }
  }
}