1. 借鉴

Elasticsearch自定义过滤插件实现复杂逻辑过滤
还有其他技术文档，比如官网，google上面的一堆，但是都是复制来复制去，计算评分的例子，唉。。

2. 开始

示例插件：过滤指定日期内的最小价格

2019-08-25_20-00-49.png

2.1 创建索引

PUT /demo

POST /demo/_mapping/demo
{
    "properties":{
        "name":{
            "type":"text",
            "analyzer":"ik_max_word",
            "search_analyzer":"ik_smart"
        },
        "counts":{
            "type":"nested",
            "include_in_parent":true,
            "properties":{
                "details":{
                    "type":"nested",
                    "include_in_root":true,
                    "properties":{
                        "level":{
                            "type":"keyword"
                        },
                        "price":{
                            "type":"double"
                        }
                    }
                },
                "date":{
                    "type":"date",
                    "format":"yyyy-MM-dd"
                }
            }
        }
    }
}

2.2 添加测试数据

POST /demo/demo/1
{
  "name": "测试1",
  "counts": [
    {
      "details": [
        {
          "level": "0",
          "price": "10"
        },
        {
          "level": "1",
          "price": "20"
        },
        {
          "level": "2",
          "price": "30"
        }],
        "date": "2019-08-25"
    },
    {
      "details": [
        {
          "level": "0",
          "price": "20"
        },
        {
          "level": "1",
          "price": "30"
        },
        {
          "level": "2",
          "price": "40"
        }],
        "date": "2019-08-26"
    }]
}

POST /demo/demo/2
{
  "name": "测试2",
  "counts": [
    {
      "details": [
        {
          "level": "0",
          "price": "20"
        },
        {
          "level": "1",
          "price": "30"
        },
        {
          "level": "2",
          "price": "40"
        }],
        "date": "2019-08-25"
    },
    {
      "details": [
        {
          "level": "0",
          "price": "50"
        },
        {
          "level": "1",
          "price": "60"
        },
        {
          "level": "2",
          "price": "70"
        }],
        "date": "2019-08-26"
    }]
}

2.3 plugin.xml

需要注意的是plugin.xml文件必须放在assembly文件夹中，与main同级目录

<?xml version="1.0"?>
<assembly>
    <id>plugin</id>
    <formats>
        <format>zip</format>
    </formats>
    <includeBaseDirectory>false</includeBaseDirectory>
    <fileSets>
        <fileSet>
            <directory>${project.basedir}/src/main/resources</directory>
            <outputDirectory>/minPricePlugin</outputDirectory>
        </fileSet>
    </fileSets>
    <dependencySets>
        <dependencySet>
            <outputDirectory>/minPricePlugin</outputDirectory>
            <useProjectArtifact>true</useProjectArtifact>
            <useTransitiveFiltering>true</useTransitiveFiltering>
            <excludes>
                <exclude>org.elasticsearch:elasticsearch</exclude>
                <exclude>org.apache.logging.log4j:log4j-api</exclude>
            </excludes>
        </dependencySet>
    </dependencySets>
</assembly>

2.4 plugin-descriptor.properties

#有些属性已经过时了，可以参考官网
description=minPricePlugin
version=1.0
name=minPricePlugin
#site=${elasticsearch.plugin.site}
#jvm=true
classname=com.ruihong.MinPricePlugin
java.version=1.8
elasticsearch.version=6.5.4
#isolated=${elasticsearch.plugin.isolated}

2.5 pom.xml 配置（关键部分）

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>org.elasticsearch.client</groupId>
      <artifactId>transport</artifactId>
      <version>6.5.4</version>
      <scope>compile</scope>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <artifactId>maven-assembly-plugin</artifactId>
        <version>2.3</version>
        <configuration>
          <appendAssemblyId>false</appendAssemblyId>
          <outputDirectory>${project.build.directory}/releases/</outputDirectory>
          <descriptors>
            <descriptor>${basedir}/src/assembly/plugin.xml</descriptor>
          </descriptors>
        </configuration>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>single</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>

2.6 com.ruihong.MinPricePlugin

package com.ruihong;

import com.ruihong.ex02.MinPriceScriptEngine;
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.util.Arrays;
import java.util.Collection;

public class MinPricePlugin extends Plugin implements ScriptPlugin
{
    @Override
    public ScriptEngine getScriptEngine(Settings settings, Collection<ScriptContext<?>> contexts)
    {
        System.out.println(String.format("contexts: %s", Arrays.toString(contexts.toArray())));
//        log.info("contexts : {} ", Arrays.toString(contexts.toArray()));
        return new MinPriceScriptEngine();
    }
}

2.7 com.ruihong.ex02.MinPriceScriptEngine

package com.ruihong.ex02;

import org.apache.http.impl.nio.reactor.ExceptionEvent;
import org.apache.lucene.index.LeafReaderContext;
import org.elasticsearch.script.FilterScript;
import org.elasticsearch.script.ScriptContext;
import org.elasticsearch.script.ScriptEngine;
import org.elasticsearch.script.SearchScript;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Comparator;
import java.util.Date;
import java.util.List;
import java.util.Map;

public class MinPriceScriptEngine implements ScriptEngine
{
    //每一个线程
    private static final ThreadLocal<SimpleDateFormat> threadLocal = new
            ThreadLocal<SimpleDateFormat>();

    @Override
    public String getType()
    {
        return "min-price";
    }

    @Override
    public <FactoryType> FactoryType compile(String name, String code, ScriptContext<FactoryType> context, Map<String, String> params)
    {
        System.out.println(String.format("MinPriceScriptEngine use params the scriptName %s, scriptSource %s, context %s, params %s", name, code, context.name, params.entrySet()));

        if (!context.equals(FilterScript.CONTEXT))
        {
            throw new IllegalArgumentException(getType() + " scripts cannot be used for context [" + context.name + "]");
        }

        if ("min-price-filter".equals(code))
        {
            FilterScript.Factory factory = (p, lookupl) -> (FilterScript.LeafFactory) ctx ->
                    new FilterScript(p, lookupl, ctx) {
                        @Override
                        public boolean execute()
                        {
                            try
                            {
                                final Double min = Double.valueOf(p.get("price-gte").toString());
                                final Double max = Double.valueOf(p.get("price-lt").toString());
                                final Date start = covertDateStrToDate(p.get("time-gte").toString(), "yyyy-MM-dd");
                                final Date end = covertDateStrToDate(p.get("time-lt").toString(), "yyyy-MM-dd");
                                final String level = p.get("level").toString();

                                Double minPrice = ((List<Map<String, Object>>) lookupl.source().get("counts"))
                                        .stream().filter(item ->
                                        {
                                            Date sellDate = covertDateStrToDate(item.get("date").toString(), "yyyy-MM-dd");
                                            return sellDate.compareTo(start) >= 0 && sellDate.compareTo(end) < 0);
                                        })
                                        .flatMap(item -> ((List<Map<String, Object>>) item.get("details")).stream())
                                        .filter(item -> item.get("level").toString().equals(level))
                                        .map(item -> Double.valueOf(item.get("price").toString()))
                                        .min(Comparator.naturalOrder())
                                        .orElse(-1.0);
                                if (minPrice >= min && minPrice < max)
                                {
                                    return true;
                                }
                            }catch (Exception ex)
                            {
                                ex.printStackTrace();
                            }
                            return false;
                        }
                    };
            return context.factoryClazz.cast(factory);
        }
        throw new IllegalArgumentException("Unknown script name " + code);
    }

    public static Date covertDateStrToDate(String dateStr, String format)
    {
        SimpleDateFormat sdf = null;
        sdf = threadLocal.get();
        if (sdf == null)
        {
            sdf = new SimpleDateFormat(format);
        }

        Date date = null;
        try
        {
            date = sdf.parse(dateStr);
        } catch (ParseException e)
        {
            e.printStackTrace();
        }
        return date;
    }
}

2.8 打包

maven clean install -Dmaven.test.skip=true

2019-08-25_21-00-06.png

将releases目录下的zip放到es的plugins目录下，解压zip并重启es

2.9 测试

使用kibana

GET /demo/_search
{
  "query": {
    "bool": {
      "filter": {
        "script": {
          "script": {
            "source": "min-price-filter",
            "lang": "min-price",
            "params": {
              "price-gte": "0",
              "price-lt": "100",
              "level": "0",
              "time-gte": "2019-08-25",
              "time-lt": "2019-08-26"
            }
          }
        }
      }
    }
  }
}

或者是使用rest api

public interface ElasticsearchPluginConstants
{
    // 最低价插件
    interface MinPrice
    {
        String SOURCE = "min-price-filter";
        String LANG = "min-price";

        interface Param
        {
            String PARAM_PRICE_GTE = "price-gte";
            String PARAM_PRICE_LT = "price-lt";
            String PARAM_LEVEL = "level";
            String PARAM_TIME_GTE = "time-gte";
            String PARAM_TIME_LT = "time-lt";
        }
    }
}

Map<String, Object> params = new HashMap<>();        
params.put(ElasticsearchPluginConstants.MinPrice.Param.PARAM_LEVEL, "0");
params.put(ElasticsearchPluginConstants.MinPrice.Param.PARAM_PRICE_GTE,  0);
params.put(ElasticsearchPluginConstants.MinPrice.Param.PARAM_PRICE_LT,  100);
params.put(ElasticsearchPluginConstants.MinPrice.Param.PARAM_TIME_GTE, "2019-08-25");
params.put(ElasticsearchPluginConstants.MinPrice.Param.PARAM_TIME_LT, "2019-08-26");
boolQueryBuilder.filter(QueryBuilders.scriptQuery(new Script(ScriptType.INLINE, ElasticsearchPluginConstants.MinPrice.LANG, ElasticsearchPluginConstants.MinPrice.SOURCE, params)));

3. 大功告成

这里进行判断context是否是：FilterScript.CONTEXT，由此可见还有其他类型，这个用idea看下包结构，看下继承关系就能定义其他插件了。另外，es的版本差别真的有点大。