Kettle插件开发之Elasticsearch篇

以数据之名 2021-06-08

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一、开发背景

知己知彼，百战不殆。既然要开发Elasticsearch批量写入插件，那我们首先了解下ElasticSearch。

Elasticsearch是一个实时分布式存储、搜索和数据分析引擎。它让你以前所未有的速度处理大数据成为可能。它用于全文搜索、结构化搜索、分析以及将这三者混合使用。
Elasticsearch也使用Java开发并使用Lucene作为其核心来实现所有索引和搜索的功能，但是它的目的是通过简单的RESTful API来隐藏Lucene的复杂性，从而让全文搜索变得简单。
Elasticsearch很快，快到不可思议。强大的设计，方便我们通过有限状态转换器实现了用于全文检索的倒排索引，实现了用于存储数值数据和地理位置数据的 BKD 树，以及用于分析的列存储。
Elasticsearch和传统数据库RDBMS比较

序号	Elasticsearch	RDBMS
1	index（索引）	database（数据库）
2	mapping（映射）	schema（表结构）
3	type（类型）6.X后废弃	table（表）
4	doucment（文档）	row（行）
5	field（字段）	column（列）
6	反向索引	索引
7	DSL	SQL
8	Get Http://……	select * from tablename
9	Put Http://……	update tablename set 1=1
10	Detele Http://……	delete from tablename

二、索引创建

基于Kettle环境平台，构建app-pentaho-es6或app-pentaho-es7插件，实现原理是动态数据流字段，自定动态索引，来实现ElasticSearch Bulk Insert批量写入。所以，我们首先要了解如何基于索引模板（kettle-es）模式，按日期分片创建动态索引（kettle-es_*）实现写入，按别名kettle-es-query来实现索引检索。具体示例如下：

PUT _template/kettle-es
{
  "index_patterns": [
    "kettle-es_*"
  ],
  "settings": {
    "index": {
      "max_result_window": "100000",
      "number_of_shards": "3",
      "number_of_replicas": "1"
    }
  },
  "aliases": {
    "kettle-es-query": {}
  },
  "mappings": {
    "properties": {
      "agent_ip": {
        "type": "ip"
      },
      "record_id": {
        "type": "integer"
      },
      "start_time": {
        "format": "yyyy-MM-dd HH:mm:ss",
        "type": "date"
      },
      "fire_time": {
        "format": "yyyy-MM-dd HH:mm:ss",
        "type": "date"
      },
      "end_time": {
        "format": "yyyy-MM-dd HH:mm:ss",
        "type": "date"
      },
      "pid": {
        "type": "keyword"
      },
      "message": {
        "index": false,
        "type": "text"
      }
    }
  }
}

三、ElasticSearch Bulk Insert源代码介绍

3.1、源代码目录结构

无论是app-pentaho-es6或app-pentaho-es7，从代码目录结构来看，都是ElasticSearchBulk步骤类、ElasticSearchBulkData数据类、ElasticSearchBulkMeta元数据类和ElasticSearchBulkDialog对话框类、日志消息提醒配置message。具体可查看源代码

3.1.1、目录结构对比

3.1.2、maven配置对比

<properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
        <pdi.version>6.1.0.1-SNAPSHOT</pdi.version>
        <build.revision>${project.version}</build.revision>
        <timestamp>${maven.build.timestamp}</timestamp>
        <build.description>${project.description}</build.description>
        <maven.build.timestamp.format>yyyy/MM/dd hh:mm</maven.build.timestamp.format>
        <elasticsearch.version>6.4.2</elasticsearch.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>${elasticsearch.version}</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>transport</artifactId>
            <version>${elasticsearch.version}</version>
            <scope>compile</scope>
        </dependency>
   <dependencies>

<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>
        <pdi.version>6.1.0.1-SNAPSHOT</pdi.version>
        <build.revision>${project.version}</build.revision>
        <timestamp>${maven.build.timestamp}</timestamp>
        <build.description>${project.description}</build.description>
        <maven.build.timestamp.format>yyyy/MM/dd hh:mm</maven.build.timestamp.format>
        <elasticsearch.version>7.2.0</elasticsearch.version>
    </properties>
    <dependencies>
       <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>${elasticsearch.version}</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>${elasticsearch.version}</version>
            <scope>compile</scope>
        </dependency>
   <dependencies>

3.2、app-pentaho-es6插件

3.2.1、TransportClient API说明

app-pentaho-es6插件，基于TransportClient使用传输模块远程连接到集群。后面，elastic计划在Elasticsearch 7.0中弃用TransportClient，并在8.0中完全删除它。

　　获取Elasticsearch客户端最常用方法是创建连接到群集的TransportClient。它不加入集群，而只是获取一个或多个初始传输地址，并在每个操作上以循环方式与它们通信。

3.2.2、客户端初始化

(1)确定PreBuiltTransportClient连接es集群名称、地址、端口和协议等信息，设置TransportAddress配置

(2)测试制定Index是否正常连接成功，得到Client

private void initClient() throws UnknownHostException {
        Settings.Builder settingsBuilder = Settings.builder();
        settingsBuilder.put(Settings.Builder.EMPTY_SETTINGS);
        Map<String, String> tMetaMap = meta.getSettingsMap();
        Iterator<Entry<String, String>> iter = tMetaMap.entrySet().iterator();
        while (iter.hasNext()) {
            Entry<String, String> entry = (Entry<String, String>) iter.next();
            settingsBuilder.put(entry.getKey(),
                    environmentSubstitute(entry.getValue()));
        }
        PreBuiltTransportClient tClient = new PreBuiltTransportClient(
                settingsBuilder.build());
        for (Server server : meta.getServers()) {
            tClient.addTransportAddress(new TransportAddress(InetAddress
                    .getByName(environmentSubstitute(server.getAddress())),
                    server.getPort()));
        }
        client = tClient;
        /**
         * With the upgrade to elasticsearch 6.3.0, removed the NodeBuilder,
         * which was removed from the elasticsearch 5.0 API, see:
         * https://www.elastic.co/guide/en/elasticsearch/reference/5.0/
         * breaking_50_java_api_changes .html#_nodebuilder_removed
         */
    }

3.2.3、数据流处理

public boolean processRow(StepMetaInterface smi, StepDataInterface sdi)
            throws KettleException {
        Object[] rowData = getRow();
        if (rowData == null) {
            if (currentRequest != null && currentRequest.numberOfActions() > 0) {
                // didn't fill a whole batch
                processBatch(false);
            }
            setOutputDone();
            return false;
        }
        if (first) {
            first = false;
            setupData();
            currentRequest = client.prepareBulk();
            requestsBuffer = new ArrayList<IndexRequestBuilder>(this.batchSize);
            initFieldIndexes();
        }
        try {
            data.inputRowBuffer[data.nextBufferRowIdx++] = rowData;
            return indexRow(data.inputRowMeta, rowData) || !stopOnError;
        } catch (KettleStepException e) {
            throw e;
        } catch (Exception e) {
            rejectAllRows(e.getLocalizedMessage());
            String msg = BaseMessages.getString(PKG,
                    "ElasticSearchBulk.Log.Exception", e.getLocalizedMessage());
            logError(msg);
            throw new KettleStepException(msg, e);
        }
    }

3.2.4、数据批次处理

private boolean processBatch(boolean makeNew) throws KettleStepException {
        ActionFuture<BulkResponse> actionFuture = currentRequest.execute();
        boolean responseOk = false;
        BulkResponse response = null;
        try {
            if (timeout != null && timeoutUnit != null) {
                response = actionFuture.actionGet(timeout, timeoutUnit);
            } else {
                response = actionFuture.actionGet();
            }
        } catch (ElasticsearchException e) {
            String msg = BaseMessages.getString(PKG,
                    "ElasticSearchBulk.Error.BatchExecuteFail",
                    e.getLocalizedMessage());
            if (e instanceof ElasticsearchTimeoutException) {
                msg = BaseMessages.getString(PKG,
                        "ElasticSearchBulk.Error.Timeout");
            }
            logError(msg);
            rejectAllRows(msg);
        }
        if (response != null) {
            responseOk = handleResponse(response);
            requestsBuffer.clear();
        } else { // have to assume all failed
            numberOfErrors += currentRequest.numberOfActions();
            setErrors(numberOfErrors);
        }
        // duration += response.getTookInMillis(); //just in trunk..
        if (makeNew) {
            currentRequest = client.prepareBulk();
            data.nextBufferRowIdx = 0;
            data.inputRowBuffer = new Object[batchSize][];
        } else {
            currentRequest = null;
            data.inputRowBuffer = null;
        }
        return responseOk;
    }

3.3、app-pentaho-es7插件

3.3.1、RestHighLevelClient API说明

app-pentaho-es7插件，基于Elasticsearch提供的Java高级REST客户端RestHighLevelClient，它执行HTTP请求而不是序列化的Java请求。Java客户端主要用途有:

(1)在现有集群上执行标准索引，获取，删除和搜索操作

(2)在正在运行的集群上执行管理任务

3.3.2、客户端初始化

(1)使用CredentialsProvider初始化Elasticsearch身份认证

(2)确定RestHighLevelClient连接es集群名称、地址、端口和协议等信息，设置setHttpClientConfigCallback回调配置

(3)测试制定Index是否正常连接成功，得到Client

private void initClient() throws UnknownHostException {
        Settings.Builder settingsBuilder = Settings.builder();
        settingsBuilder.put(Settings.Builder.EMPTY_SETTINGS);
        meta.getSettingsMap()
                .entrySet()
                .stream()
                .forEach(
                        (s) -> settingsBuilder.put(s.getKey(),
                                environmentSubstitute(s.getValue())));
        RestHighLevelClient rclient = null;
        final CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY,
                new UsernamePasswordCredentials(settingsBuilder.get("es.user"),
                        settingsBuilder.get("es.password")));
        for (Server server : meta.getServers()) {
            rclient = new RestHighLevelClient(RestClient.builder(
                    new HttpHost(server.getAddress(), Integer.valueOf(server
                            .getPort()), "http")).setHttpClientConfigCallback(
                    new RestClientBuilder.HttpClientConfigCallback() {
                        public HttpAsyncClientBuilder customizeHttpClient(
                                HttpAsyncClientBuilder httpClientBuilder) {
                            return httpClientBuilder
                                    .setDefaultCredentialsProvider(credentialsProvider);
                        }
                    }));
        }
        client = rclient;
        /**
         * With the upgrade to elasticsearch 6.3.0, removed the NodeBuilder,
         * 
         * which was removed from the elasticsearch 5.0 API, see:
         * 
         * https://www.elastic.co/guide/en/elasticsearch/reference/5.0/
         * breaking_50_java_api_changes
         * 
         * .html#_nodebuilder_removed
         */
    }

3.3.3、数据流处理

public boolean processRow(StepMetaInterface smi, StepDataInterface sdi)
            throws KettleException {
        Object[] rowData = getRow();
        if (rowData == null) {
            if (currentRequest != null && currentRequest.numberOfActions() > 0) {
                processBatch(false);
            }
            setOutputDone();
            return false;
        }
        if (first) {
            first = false;
            setupData();
            requestsBuffer = new ArrayList<IndexRequest>(this.batchSize);
            initFieldIndexes();
        }
        try {
            data.inputRowBuffer[data.nextBufferRowIdx++] = rowData;
            return indexRow(data.inputRowMeta, rowData) || !stopOnError;
        } catch (KettleStepException e) {
            throw e;
        } catch (Exception e) {
            rejectAllRows(e.getLocalizedMessage());
            String msg = BaseMessages.getString(PKG,
                    "ElasticSearchBulk.Log.Exception", e.getLocalizedMessage());
            logError(msg);
            throw new KettleStepException(msg, e);
        }
    }

3.3.4、数据批次处理

private boolean processBatch(boolean makeNew) throws KettleStepException {
        BulkResponse response = null;
        // ActionFuture<BulkResponse> actionFuture = currentRequest.execute();
        try {
            response = client.bulk(currentRequest, RequestOptions.DEFAULT);
        } catch (IOException e1) {
            rejectAllRows(e1.getLocalizedMessage());
            String msg = BaseMessages
                    .getString(PKG, "ElasticSearchBulk.Log.Exception",
                            e1.getLocalizedMessage());
            logError(msg);
            throw new KettleStepException(msg, e1);
        }
        boolean responseOk = false;
        if (response != null) {
            responseOk = handleResponse(response);
            requestsBuffer.clear();
        } else { // have to assume all failed
            numberOfErrors += currentRequest.numberOfActions();
            setErrors(numberOfErrors);
        }
        if (makeNew) {
            // currentRequest = client.prepareBulk();
            try {
                client.bulk(currentRequest, RequestOptions.DEFAULT);
            } catch (IOException e1) {
                rejectAllRows(e1.getLocalizedMessage());
                String msg = BaseMessages.getString(PKG,
                        "ElasticSearchBulk.Log.Exception",
                        e1.getLocalizedMessage());
                logError(msg);
                throw new KettleStepException(msg, e1);
            }
            data.nextBufferRowIdx = 0;
            data.inputRowBuffer = new Object[batchSize][];
        } else {
            currentRequest = null;
            data.inputRowBuffer = null;
        }
        return responseOk;
    }

无论服务端是那个版本的Elasticsearch集群，客户端必须具有与服务端群集中的节点相同的主要版本（例如6.x或7.x）

四、ElasticSearch Bulk Insert使用说明

4.1、General参数

①Index：动态索引字段，索引前缀+动态日期
②Type：默认_doc
③Test Index：在线检查索引是否存在
④Batch Size：批次大小
⑤Stop on error：遇到错误是否终止
⑥Batch Timeout：批次写入超时时间，单位秒
⑦Id Field：即文档ID，doc_id
⑧Overwrite if exists：存在是否覆盖
⑨Output Rows：输出行

4.2、Servers参数

①Address：Elasticsearch集群地址列表
②Port：匹配端口号

4.3、Fields输出字段

①Name：数据流字段
②Target Name：Elasticsearch集群对应index，目标mapping字段

4.4、Settings参数

①cluster.name：集群名称
②es.user：es鉴权认证用户名，自定义参数名
③es.password：es鉴权认证密码，自定义参数名

五、总结

如果你需要源码或者了解更多自定义插件及集成方式，抑或有开发过程或者使用过程中的任何疑问或建议，请关注小编公众号"游走在数据之间"，回复2查看源代码，回复3获取入门视频。加入Kettle交流群"话说Kettle"。

数据库 elasticsearch

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