elasticsearch6 插件開發變動

es6不支持native

插件開發中會有一些變化

官方文檔：https://www.elastic.co/guide/en/elasticsearch/reference/6.0/modules-scripting-engine.html?nsukey=TC4GNoi7V8SGUZSDocHVHesIeUCTyhBXqud%2BLvKwpuJmmkljLok8itiwuQawSXefZ9Jpy09GCSbKtUBSmTNs6IZmoH9wYePp4zb6Mr1IoS6gopicq56c%2FhIsnXM4x3UAmj%2FklieHp%2FlnSv4iQTTGgeHr%2BO5Cvh0c7bXINcqWxuNMZhPnVzEM5otr8g9JfQRpFEZ0Rq20ffXo36Usc3Ki7Q%3D%3D

 

需要實現ScriptEngine接口

插件入口

package com.esplugin.demo;

import java.util.Collection;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.plugins.Plugin;
import org.elasticsearch.plugins.ScriptPlugin;
import org.elasticsearch.script.ScriptContext;
import org.elasticsearch.script.ScriptEngine;
public class DemoPlugin extends Plugin implements  ScriptPlugin {

    @Override
    public ScriptEngine getScriptEngine(Settings settings, Collection<ScriptContext<?>> contexts) {
        return new MyScriptEngine();
    }
}

 

其中getType方法中return的就是script的lang；插件名稱在complile中用if判斷，scriptSource為插件名稱，執行插件邏輯

package com.esplugin.demo;

import java.io.IOException;
import java.util.Map;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.lucene.index.LeafReaderContext;
import org.elasticsearch.script.ScriptContext;
import org.elasticsearch.script.ScriptEngine;
import org.elasticsearch.script.SearchScript;

public class MyScriptEngine implements ScriptEngine {
    private final static Logger logger = LogManager.getLogger(MyScriptEngine.class);
    @Override
    public String getType() {        
        return "myscript";
    }
    @Override
    public <T> T compile(String scriptName, String scriptSource, ScriptContext<T> context, Map<String, String> params) {
        logger.info("use params the scriptName {} ,scriptSource  {}, context {},params {}",scriptName,scriptSource,context.name,params.entrySet());
        if (!context.equals(SearchScript.CONTEXT)) {
            throw new IllegalArgumentException(getType() + " scripts cannot be used for context [" + context.name + "]");
        }
        if("demoPlugin".equals(scriptSource)){
            SearchScript.Factory factory = (p, lookup) -> new SearchScript.LeafFactory() {
                final String field = p.containsKey("field")?(String)p.get("field"):"";
                final String text = p.containsKey("text")?(String)p.get("text"):"";
                @Override
                public SearchScript newInstance(LeafReaderContext context) throws IOException {
                    return new SearchScript(p, lookup, context) {
                        @Override
                        public double runAsDouble() {
                            final String test = (String) lookup.source().get(field);
                            if (test.indexOf(text) >= 0){
                                return 1.0D;
                            }
                            return Double.MAX_VALUE;
                        }
                    };
                }

                @Override
                public boolean needs_score() {
                    return false;
                }
            };
            return context.factoryClazz.cast(factory);
        }
        throw new IllegalArgumentException("Unknown script name " + scriptSource);

    }

    @Override
    public void close() {
        // optionally close resources
    }
}

　　查詢如下，lang中為getType中的renturn值，source為插件名，params為參數

GET index/_search
{
  "query": {
    "function_score": {
      "query": {
        "match_all": {}
      },
      "script_score": {
        "script": {
          "source": "demoPlugin",
          "lang": "myscript",
          "params": {
            "field": "test",
            "text": "1"
          }
        }
      }
    }
  }
}

 或者

{
  "_source": [
    "*"
  ],
  "query": {
    "match_all": {}
  },
  "script_fields": {
    "myscore": {
      "script": {
        "source": "demoPlugin",
        "lang": "myscript",
        "params": {
          "field": "test",
          "text": "1"
        }
      }
    }
  }
}

 或者

{
"query": {
    "match_all": {}
  },
  "rescore": [
    {
      "window_size": 2000,
      "query": {
        "rescore_query": {
          "function_score": {
            "script_score": {
              "script": {
                "source": "demoPlugin",
                "lang": "myscript",
                "params": {
                  "field": "test",
                  "text": "1"
                }
              }
            }
          }
        },
        "query_weight" : 0,
        "rescore_query_weight" : 1
      }
    }
  ]
}

多個腳本分數進行rescore，如下，其中rescore_mode可以為multiply相乘(默認)、sum累加、avg平均數、max、min、first、只使用第一個函數的結果。

{
  "query": {
    "match_all": {}
  },
  "rescore": [
    {
      "window_size": 2000,
      "query": {
        "rescore_query": {
          "function_score": {
            "score_mode": "sum",
            "functions": [
              {
                "script_score": {
                  "script": {
                    "source": "demoPlugin",
                    "lang": "myscript",
                    "params": {
                      "field": "test",
                      "text": "1"
                    }
                  }
                }
              },
              {
                "script_score": {
                  "script": {
                    "source": "return -9",
                    "lang": "painless"
                  }
                }
              }
            ]
          }
        },
        "query_weight": 0,
        "rescore_query_weight": 1
      }
    }
  ]
}

 

無關內容：score_query的使用

{
    "query": {
        "match": {  
            "title": {
                "query":                "quick brown fox",
                "minimum_should_match": "30%"
            }
        }
    },
    "rescore": {
        "window_size": 50, 
        "query": {         
            "rescore_query": {
                "match_phrase": {
                    "title": {
                        "query": "quick brown fox",
                        "slop":  50
                    }
                }
            }
        }
    }
}