一.使用java编写elasticsearch 自定义插件,对应的elasticsearch版本为6.8.4,以下代码用到三个类

com.suntown.UserScriptEnginePlugin、com.suntown.MyExpertScriptEngine、com.suntown.UserUpdateFactory

package com.suntown;


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;

import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.List;

public class UserScriptEnginePlugin extends Plugin implements ScriptPlugin{
    @Override
    public ScriptEngine getScriptEngine(Settings settings, Collection<ScriptContext<?>> contexts){
        return new MyExpertScriptEngine();
    }


}

package com.suntown;

import org.elasticsearch.script.ScoreScript;
import org.elasticsearch.script.ScriptContext;
import org.elasticsearch.script.ScriptEngine;
import org.elasticsearch.script.UpdateScript;

import java.util.Map;
import java.util.Set;

public class MyExpertScriptEngine implements ScriptEngine{

    @Override
    public String getType() {
        return "myscript";
    }

    @Override
    public <FactoryType> FactoryType compile(String scriptName, String scriptSource, ScriptContext<FactoryType> scriptContext, Map<String, String> map) {
        UpdateScript.Factory factory = new UserUpdateFactory(scriptName,scriptSource);
        return scriptContext.factoryClazz.cast(factory);
    }

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


}

package com.suntown;

import org.elasticsearch.script.UpdateScript;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.HashMap;
import java.util.Map;

public class UserUpdateFactory implements UpdateScript.Factory{
    PrintStream ps = null;

    static int counter = 0;
    private String scriptName;
    private String scriptSource;
    private Map<String,String> globalMap = new HashMap<>();

    public UserUpdateFactory(String _scriptName,String _scriptSource){
        this.scriptName = _scriptName;
        this.scriptSource = _scriptSource;

        String userdir = System.getProperty("user.dir");
        try{
            ps = new PrintStream(new FileOutputStream(userdir + "\\logs\\update.log",true));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        engine.put("ps",ps);
        engine.put("userdir",userdir);
    }

    ScriptEngineManager sem = new ScriptEngineManager();
    ScriptEngine engine = sem.getEngineByName("javascript");

    @Override
    public UpdateScript newInstance(Map<String, Object> params, Map<String, Object> ctx){
        counter++;
        return new UpdateScript(params,ctx){

            @Override
            public void execute() {
                java.util.HashMap hashMap = (java.util.HashMap)ctx.get("_source");
                engine.put("owner",UserUpdateFactory.this);
                engine.put("row",hashMap);
                engine.put("rownum",counter);
                engine.put("thread",Thread.currentThread().getId());
                try{
                    engine.eval(UserUpdateFactory.this.scriptSource);
                } catch (ScriptException e) {
                    e.printStackTrace();
                }
            }
        };
    }
}

将java代码编译后直接打包成普通的jar包，可以使用命令行

jar cvf es-user-scriptengine.jar

二.在elasticsearch中部署插件

1、切换到elasticsearch根目录,如 F:\esesarch\es684-20220311\elasticsearch-6.8.4

2、再切换到目录 F:\esesarch\es684-20220311\elasticsearch-6.8.4\modules 并新建目录 es-user-scriptengine

3、将 文件 es-user-scriptengine.jar 复制到 目录 F:\esesarch\es684-20220311\elasticsearch-6.8.4\modules\下 并新建配置文件 plugin-descriptor.properties,如下图所示

 

plugin-descriptor.properties 文件可从modules 目录下的其它插件子目录下拷贝过来进行修改,

主要修改上图中classname=com.suntown.UserScriptEnginePlugin  这个类就是上述 es-user-scriptengine.jar 中的类

修改完成之后、重启elasticsearch服务

三.使用postman测试插件功能

1.切换到目录 F:\esesarch\es684-20220311\elasticsearch-6.8.4\bin,运行 elasticsearch-sql-cli.bat

此时索引 zyzkwjj 中 还没有 列 rownum2

2.postman请求如下图

上图中的 "lang":"myscript" 即对应 类 com.suntown.MyExpertScriptEngine中getType()方法的返回值

 

3. 再使用 elasticsearch-sql-cli 查看索引zyzkwjj中的rownum2字段

发现rownum2确实更新成了从1开始递增的自增里额。