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使用Apache Kafka進行流連接示例？

[英]Stream join example with Apache Kafka?

 原文  2019-05-22 06:53:52  8   3    java/ elasticsearch/ apache-kafka/ apache-kafka-streams/ ksql

問題描述

我正在尋找一個使用Kafka Streams如何做這種事情的例子，即將客戶表與地址表連接並將數據匯入ES： -

顧客 

+------+------------+----------------+-----------------------+
| id   | first_name | last_name      | email                 |
+------+------------+----------------+-----------------------+
| 1001 | Sally      | Thomas         | sally.thomas@acme.com |
| 1002 | George     | Bailey         | gbailey@foobar.com    |
| 1003 | Edward     | Davidson       | ed@walker.com         |
| 1004 | Anne       | Kim            | annek@noanswer.org    |
+------+------------+----------------+-----------------------+

地址 

+----+-------------+---------------------------+------------+--------------+-------+----------+
| id | customer_id | street                    | city       | state        | zip   | type     |
+----+-------------+---------------------------+------------+--------------+-------+----------+
| 10 |        1001 | 3183 Moore Avenue         | Euless     | Texas        | 76036 | SHIPPING |
| 11 |        1001 | 2389 Hidden Valley Road   | Harrisburg | Pennsylvania | 17116 | BILLING  |
| 12 |        1002 | 281 Riverside Drive       | Augusta    | Georgia      | 30901 | BILLING  |
| 13 |        1003 | 3787 Brownton Road        | Columbus   | Mississippi  | 39701 | SHIPPING |
| 14 |        1003 | 2458 Lost Creek Road      | Bethlehem  | Pennsylvania | 18018 | SHIPPING |
| 15 |        1003 | 4800 Simpson Square       | Hillsdale  | Oklahoma     | 73743 | BILLING  |
| 16 |        1004 | 1289 University Hill Road | Canehill   | Arkansas     | 72717 | LIVING   |
+----+-------------+---------------------------+------------+--------------+-------+----------+

輸出Elasticsearch索引 

"hits": [
  {
    "_index": "customers_with_addresses",
    "_type": "_doc",
    "_id": "1",
    "_score": 1.3278645,
    "_source": {
      "first_name": "Sally",
      "last_name": "Thomas",
      "email": "sally.thomas@acme.com",
      "addresses": [{
        "street": "3183 Moore Avenue",
        "city": "Euless",
        "state": "Texas",
        "zip": "76036",
        "type": "SHIPPING"
      }, {
        "street": "2389 Hidden Valley Road",
        "city": "Harrisburg",
        "state": "Pennsylvania",
        "zip": "17116",
        "type": "BILLING"
      }],
    }
  }, ….

表數據來自Debezium主題，我是否正確認為我需要一些中間的Java加入流，將其輸出到一個新主題，然后將其匯入ES？

有人會有任何示例代碼嗎？

謝謝。

3 個解決方案

解決方案1
 5 已采納  2019-05-22 10:45:42

根據您在一個客戶節點中嵌套多個地址的要​​求的嚴格程度，您可以在KSQL（基於Kafka Streams構建）之上執行此操作。

將一些測試數據填充到Kafka中（在您的情況下已經通過Debezium完成）： 

$ curl -s "https://api.mockaroo.com/api/ffa9ff20?count=10&key=ff7856d0" | kafkacat -b localhost:9092 -t addresses -P

$ curl -s "https://api.mockaroo.com/api/9b868890?count=4&key=ff7856d0" | kafkacat -b localhost:9092 -t customers -P

啟動KSQL並開始只檢查數據： 

ksql> PRINT 'addresses' FROM BEGINNING ;
Format:JSON
{"ROWTIME":1558519823351,"ROWKEY":"null","id":1,"customer_id":1004,"street":"8 Moulton Center","city":"Bronx","state":"New York","zip":"10474","type":"BILLING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":2,"customer_id":1001,"street":"5 Hollow Ridge Alley","city":"Washington","state":"District of Columbia","zip":"20016","type":"LIVING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":3,"customer_id":1000,"street":"58 Maryland Point","city":"Greensboro","state":"North Carolina","zip":"27404","type":"LIVING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":4,"customer_id":1002,"street":"55795 Derek Avenue","city":"Temple","state":"Texas","zip":"76505","type":"LIVING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":5,"customer_id":1002,"street":"164 Continental Plaza","city":"Modesto","state":"California","zip":"95354","type":"SHIPPING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":6,"customer_id":1004,"street":"6 Miller Road","city":"Louisville","state":"Kentucky","zip":"40205","type":"BILLING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":7,"customer_id":1003,"street":"97 Shasta Place","city":"Pittsburgh","state":"Pennsylvania","zip":"15286","type":"BILLING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":8,"customer_id":1000,"street":"36 Warbler Circle","city":"Memphis","state":"Tennessee","zip":"38109","type":"SHIPPING"}
{"ROWTIME":1558519823351,"ROWKEY":"null","id":9,"customer_id":1001,"street":"890 Eagan Circle","city":"Saint Paul","state":"Minnesota","zip":"55103","type":"SHIPPING"}
{"ROWTIME":1558519823354,"ROWKEY":"null","id":10,"customer_id":1000,"street":"8 Judy Terrace","city":"Washington","state":"District of Columbia","zip":"20456","type":"SHIPPING"}
^C
Topic printing ceased

ksql>
ksql> PRINT 'customers' FROM BEGINNING;
Format:JSON
{"ROWTIME":1558519852363,"ROWKEY":"null","id":1001,"first_name":"Jolee","last_name":"Handasyde","email":"jhandasyde0@nhs.uk"}
{"ROWTIME":1558519852363,"ROWKEY":"null","id":1002,"first_name":"Rebeca","last_name":"Kerrod","email":"rkerrod1@sourceforge.net"}
{"ROWTIME":1558519852363,"ROWKEY":"null","id":1003,"first_name":"Bobette","last_name":"Brumble","email":"bbrumble2@cdc.gov"}
{"ROWTIME":1558519852368,"ROWKEY":"null","id":1004,"first_name":"Royal","last_name":"De Biaggi","email":"rdebiaggi3@opera.com"}

現在我們在數據上聲明一個STREAM （Kafka主題+模式），以便我們可以進一步操作它： 

ksql> CREATE STREAM addresses_RAW (ID INT, CUSTOMER_ID INT, STREET VARCHAR, CITY VARCHAR, STATE VARCHAR, ZIP VARCHAR, TYPE VARCHAR) WITH (KAFKA_TOPIC='addresses', VALUE_FORMAT='JSON');

 Message
----------------
 Stream created
----------------

ksql> CREATE STREAM customers_RAW (ID INT, FIRST_NAME VARCHAR, LAST_NAME VARCHAR, EMAIL VARCHAR) WITH (KAFKA_TOPIC='customers', VALUE_FORMAT='JSON');

 Message
----------------
 Stream created
----------------

我們將把customers建模為一個TABLE ，為此，需要正確鍵入Kafka消息（以及它們具有空鍵的時刻，從"ROWKEY":"null"可以看出"ROWKEY":"null" PRINT輸出中的"ROWKEY":"null"以上）。 您可以配置Debezium來設置消息密鑰，因此在KSQL中可能不需要此步驟： 

ksql> CREATE STREAM CUSTOMERS_KEYED WITH (PARTITIONS=1) AS SELECT * FROM CUSTOMERS_RAW PARTITION BY ID;

 Message
----------------------------
 Stream created and running
----------------------------

現在我們聲明一個TABLE （給定鍵的狀態 ，從Kafka主題+模式實例化）： 

ksql> CREATE TABLE CUSTOMER (ID INT, FIRST_NAME VARCHAR, LAST_NAME VARCHAR, EMAIL VARCHAR) WITH (KAFKA_TOPIC='CUSTOMERS_KEYED', VALUE_FORMAT='JSON', KEY='ID');

 Message
---------------
 Table created
---------------

現在我們可以加入數據： 


ksql> CREATE STREAM customers_with_addresses AS 
      SELECT CUSTOMER_ID, 
             FIRST_NAME + ' ' + LAST_NAME AS FULL_NAME, 
             FIRST_NAME, 
             LAST_NAME, 
             TYPE AS ADDRESS_TYPE, 
             STREET, 
             CITY, 
             STATE, 
             ZIP 
        FROM ADDRESSES_RAW A 
             INNER JOIN CUSTOMER C 
             ON A.CUSTOMER_ID = C.ID;

 Message
----------------------------
 Stream created and running
----------------------------

這將創建一個新的KSQL STREAM，它反過來填充一個新的Kafka主題。 

ksql> SHOW STREAMS;

 Stream Name                              | Kafka Topic                          | Format
------------------------------------------------------------------------------------------
 CUSTOMERS_KEYED                          | CUSTOMERS_KEYED                      | JSON
 ADDRESSES_RAW                            | addresses                            | JSON
 CUSTOMERS_RAW                            | customers                            | JSON
 CUSTOMERS_WITH_ADDRESSES                 | CUSTOMERS_WITH_ADDRESSES             | JSON

該流有一個架構： 

ksql> DESCRIBE CUSTOMERS_WITH_ADDRESSES;

Name                 : CUSTOMERS_WITH_ADDRESSES
 Field        | Type
------------------------------------------
 ROWTIME      | BIGINT           (system)
 ROWKEY       | VARCHAR(STRING)  (system)
 CUSTOMER_ID  | INTEGER          (key)
 FULL_NAME    | VARCHAR(STRING)
 FIRST_NAME   | VARCHAR(STRING)
 ADDRESS_TYPE | VARCHAR(STRING)
 LAST_NAME    | VARCHAR(STRING)
 STREET       | VARCHAR(STRING)
 CITY         | VARCHAR(STRING)
 STATE        | VARCHAR(STRING)
 ZIP          | VARCHAR(STRING)
------------------------------------------
For runtime statistics and query details run: DESCRIBE EXTENDED <Stream,Table>;

我們可以查詢流： 

ksql> SELECT * FROM CUSTOMERS_WITH_ADDRESSES WHERE CUSTOMER_ID=1002;
1558519823351 | 1002 | 1002 | Rebeca Kerrod | Rebeca | LIVING | Kerrod | 55795 Derek Avenue | Temple | Texas | 76505
1558519823351 | 1002 | 1002 | Rebeca Kerrod | Rebeca | SHIPPING | Kerrod | 164 Continental Plaza | Modesto | California | 95354

我們還可以使用Kafka Connect將其流式傳輸到Elasticsearch： 

curl -i -X POST -H "Accept:application/json" \
    -H  "Content-Type:application/json" http://localhost:8083/connectors/ \
    -d '{
      "name": "sink-elastic-customers_with_addresses-00",
      "config": {
        "connector.class": "io.confluent.connect.elasticsearch.ElasticsearchSinkConnector",
        "topics": "CUSTOMERS_WITH_ADDRESSES",
        "connection.url": "http://elasticsearch:9200",
        "type.name": "type.name=kafkaconnect",
        "key.ignore": "true",
        "schema.ignore": "true",
        "key.converter": "org.apache.kafka.connect.storage.StringConverter",
        "value.converter": "org.apache.kafka.connect.json.JsonConverter",
        "value.converter.schemas.enable": "false"
      }
    }'

結果： 

$ curl -s http://localhost:9200/customers_with_addresses/_search | jq '.hits.hits[0]'
{
  "_index": "customers_with_addresses",
  "_type": "type.name=kafkaconnect",
  "_id": "CUSTOMERS_WITH_ADDRESSES+0+2",
  "_score": 1,
  "_source": {
    "ZIP": "76505",
    "CITY": "Temple",
    "ADDRESS_TYPE": "LIVING",
    "CUSTOMER_ID": 1002,
    "FULL_NAME": "Rebeca Kerrod",
    "STATE": "Texas",
    "STREET": "55795 Derek Avenue",
    "LAST_NAME": "Kerrod",
    "FIRST_NAME": "Rebeca"
  }
}

解決方案2
 2  2019-05-22 07:57:17

是的，您可以通過以下方式在Java中使用Kafka流API實現解決方案。

  1. 將主題作為流消費。
  2. 使用客戶ID在列表中聚合地址流，並將流轉換為表。
  3. 使用地址表加入客戶流

下面是示例（考慮以json格式使用數據）： 

KStream<String,JsonNode> customers = builder.stream("customer", Consumed.with(stringSerde, jsonNodeSerde));
KStream<String,JsonNode> addresses = builder.stream("address", Consumed.with(stringSerde, jsonNodeSerde));

// Select the customer ID as key in order to join with address. 
KStream<String,JsonNode> customerRekeyed = customers.selectKey(value-> value.get("id").asText());

ObjectMapper mapper = new ObjectMapper();    
// Select Customer_id as key to aggregate the addresses and join with customer
KTable<String,JsonNode> addressTable = addresses
        .selectKey(value-> value.get("customer_id").asText())
        .groupByKey()
        .aggregate(() ->mapper::createObjectNode,  //initializer
                   (key,value,aggregate) -> aggregate.add(value),
                 Materialized.with(stringSerde, jsonNodeSerde)
         );  //adder

// Join Customer Stream with Address Table
KStream<String,JsonNode> customerAddressStream = customerRekeyed.leftJoin(addressTable,
               (left,right) -> {
                      ObjectNode finalNode = mapper.createObjectNode();
                      ArrayList addressList = new ArrayList<JsonNode>();
                      // Considering the address is arrayNode
                      ((ArrayNode)right).elements().forEachRemaining(addressList ::add);
                      left.putArray("addresses").allAll(addressList);              
                      return left;
               },Joined.keySerde(stringSerde).withValueSerde(jsonNodeSerde));

您可以在此處參考所有類型的連接的詳細信息：

https://docs.confluent.io/current/streams/developer-guide/dsl-api.html#joining

解決方案3
 1  2019-05-23 19:02:05

我們不久前在Debezium博客上建立了一個關於這個用例（流式聚合到Elasticsearch）的演示和博客文章 。

要記住的一個問題是這個解決方案（基於Kafka Streams，但我認為它對KSQL來說是相同的）很容易暴露中間連接結果。 假設您在一次交易中插入一個客戶和10個地址。 流連接方法可能首先生成客戶及其前五個地址的聚合，然后很快生成具有所有10個地址的完整聚合。 對於您的特定用例，這可能是也可能不合適。 我還記得處理刪除並不簡單（例如，如果你刪除10個地址中的一個，那么你將不得不再次生成聚合，其余的9個地址可能沒有被觸及）。

另一種考慮方法可以是發件箱模式 ，您實際上會在應用程序本身內使用預先計算的聚合生成顯式事件。 即它需要一些應用程序的幫助，但它避免了事后產生連接結果的微妙之處。

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