60、Flink CDC 入门介绍及Streaming ELT示例(同步Mysql数据库数据到Elasticsearch)-CDC Connector介绍及示例 (1)

Flink 系列文章

一、Flink 专栏

Flink 专栏系统介绍某一知识点,并辅以具体的示例进行说明。

  • 1、Flink 部署系列

    本部分介绍Flink的部署、配置相关基础内容。

  • 2、Flink基础系列

    本部分介绍Flink 的基础部分,比如术语、架构、编程模型、编程指南、基本的datastream api用法、四大基石等内容。

  • 3、Flik Table API和SQL基础系列

    本部分介绍Flink Table Api和SQL的基本用法,比如Table API和SQL创建库、表用法、查询、窗口函数、catalog等等内容。

  • 4、Flik Table API和SQL提高与应用系列

    本部分是table api 和sql的应用部分,和实际的生产应用联系更为密切,以及有一定开发难度的内容。

  • 5、Flink 监控系列

    本部分和实际的运维、监控工作相关。

二、Flink 示例专栏

Flink 示例专栏是 Flink 专栏的辅助说明,一般不会介绍知识点的信息,更多的是提供一个一个可以具体使用的示例。本专栏不再分目录,通过链接即可看出介绍的内容。

两专栏的所有文章入口点击:Flink 系列文章汇总索引


文章目录

  • Flink 系列文章
  • 一、Flink CDC Connectors介绍
    • 1、CDC Connectors介绍及架构图
    • 2、支持的连接
    • 3、Flink CDC与 Flink 版本关系
    • 4、特性介绍
    • 5、flink sql client集成flink cdc
      • 1)、集成步骤
      • 2)、示例:捕获mysql的user表数据变化情况
    • 6、flink datastream API集成flink cdc
      • 1)、maven依赖
      • 2)、代码实现
      • 3)、验证
      • 4)、debezium数据格式介绍

本文详细的介绍了Flink CDC的应用,并且提供2个示例进行说明如何使用,即使用Flink sql client的观察数据同步的情况、通过DataStream API 捕获数据变化情况及验证。

如果需要了解更多内容,可以在本人Flink 专栏中了解更新系统的内容。

本文除了maven依赖外,本文依赖Flink 集群环境、mysql。

本专题分为以下几篇文章:

60、Flink CDC 入门介绍及Streaming ELT示例(同步Mysql数据库数据到Elasticsearch)-CDC Connector介绍及示例 (1)

60、Flink CDC 入门介绍及Streaming ELT示例(同步Mysql数据库数据到Elasticsearch)-Streaming ELT介绍及示例(2)

60、Flink CDC 入门介绍及Streaming ELT示例(同步Mysql数据库数据到Elasticsearch)-完整版

一、Flink CDC Connectors介绍

本文介绍的CDC是基于2.4版本,当前版本已经发布至3.0,本Flink 专栏介绍是基于Flink 1.17版本,CDC 2.4版本支持到1.17版本。

1、CDC Connectors介绍及架构图

Apache Flink®的CDC连接器是用于Apache Flnk®的一组源连接器,使用更改数据捕获(CDC)接收来自不同数据库的更改。Apache Flink®的CDC连接器将Debezium集成为捕获数据更改的引擎。因此,它可以充分利用Debezium的能力。

了解更多关于Debezium的信息。

或者参考:37、Flink 的CDC 格式:debezium部署以及mysql示例

在这里插入图片描述

2、支持的连接

在这里插入图片描述

3、Flink CDC与 Flink 版本关系

在这里插入图片描述

4、特性介绍

  • 支持读取数据库快照,并在处理失败后立即继续读取binlog。
  • CDC连接器用于DataStream API,用户可以在一个作业中使用多个数据库和表的更改,而无需部署Debezium和Kafka。
  • 用于Table/SQL API的CDC连接器,用户可以使用SQL DDL创建CDC源以监视单个表上的更改。

下表显示了连接器的当前功能:

在这里插入图片描述

5、flink sql client集成flink cdc

1)、集成步骤

1、需要有一个flink的集群环境

具体搭建参考:2、Flink1.13.5二种部署方式(Standalone、Standalone HA )、四种提交任务方式(前两种及session和per-job)验证详细步骤

2、下载flink cdc的jar并放在FLINK_HOME/lib/目录下面

下载地址:https://github.com/ververica/flink-cdc-connectors/releases

3、重启flink集群

2)、示例:捕获mysql的user表数据变化情况

本示例的前提是设置好了binlog,具体设置方式可以参考文章:

37、Flink 的CDC 格式:debezium部署以及mysql示例

Flink SQL> CREATE TABLE mysql_binlog_user (
>  id INT NOT NULL,
>  name STRING,
>  age INT,
>  PRIMARY KEY(id) NOT ENFORCED
> ) WITH (
>  'connector' = 'mysql-cdc',
>  'hostname' = '192.168.10.44',
>  'port' = '3306',
>  'username' = 'root',
>  'password' = '123456',
>  'database-name' = 'cdctest',
>  'table-name' = 'user'
> );
[INFO] Execute statement succeed.

Flink SQL> select * from mysql_binlog_user;
+----+-------------+--------------------------------+-------------+
| op |          id |                           name |         age |
+----+-------------+--------------------------------+-------------+
| +I |           4 |                        test456 |        8888 |
| +I |           2 |                       alanchan |          20 |
| +I |           3 |                    alanchanchn |          33 |
| +I |           1 |                           alan |          18 |
| -U |           4 |                        test456 |        8888 |
| +U |           4 |                        test123 |        8888 |
| -U |           4 |                        test123 |        8888 |
| +U |           4 |                        test123 |       66666 |
| -D |           4 |                        test123 |       66666 |
| +I |           4 |                   alanchanchn2 |         100 |

Flink SQL> select name ,sum(age) from mysql_binlog_user group by name;
+----+--------------------------------+-------------+
| op |                           name |      EXPR$1 |
+----+--------------------------------+-------------+
| +I |                   alanchanchn2 |         100 |
| +I |                       alanchan |          20 |
| +I |                    alanchanchn |          33 |
| +I |                           alan |          18 |


6、flink datastream API集成flink cdc

本示例是捕获mysql cdctest库的user表数据变化情况。

1)、maven依赖

使用flink cdc添加如下依赖即可,但flink本身的运行环境相关依赖需要添加。



	com.ververica
	flink-sql-connector-mysql-cdc
	2.4.0
	provided

2)、代码实现

import com.ververica.cdc.connectors.mysql.source.MySqlSource;
import com.ververica.cdc.debezium.JsonDebeziumDeserializationSchema;

import org.apache.flink.api.common.eventtime.WatermarkStrategy;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;

import lombok.extern.slf4j.Slf4j;

/*
 * @Author: alanchan
 * @LastEditors: alanchan
 * @Description: 
 */
@Slf4j
public class TestFlinkCDCFromMysqlDemo {
	public static void main(String[] args) throws Exception {
		StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
		env.enableCheckpointing(3000);

		MySqlSource mySqlSource = MySqlSource.builder()
				.hostname("192.168.10.44")
				.port(3306)
				.databaseList("cdctest") // 设置捕获的数据库, 如果需要同步整个数据库,请将 tableList 设置为 ".*".
				.tableList("cdctest.user") // 设置捕获的表
				.username("root")
				.password("123456")
				.deserializer(new JsonDebeziumDeserializationSchema()) // 将 SourceRecord 转换为 JSON 字符串
				.build();

		DataStream result = env.fromSource(mySqlSource, WatermarkStrategy.noWatermarks(), "MySQL Source");
		log.info(result.toString());
		result.map(new MapFunction() {

			@Override
			public String map(String value) throws Exception {
				log.info("value ======={}",value);
				return value;
			}
			
		});

		env.execute();
	}
}

3)、验证

在程序运行起来后,对cdctest.user表的数据进行添加、修改、删除操作,观察程序控制台日志输出情况

08:50:26.819 [Source: MySQL Source -> Map (4/16)#0] INFO com.win.TestFlinkCDCFromMysqlDemo  - value ======={"before":null,"after":{"id":2,"name":"alanchan","age":20},"source":{"version":"1.9.7.Final","connector":"mysql","name":"mysql_binlog_source","ts_ms":0,"snapshot":"false","db":"cdctest","sequence":null,"table":"user","server_id":0,"gtid":null,"file":"","pos":0,"row":0,"thread":null,"query":null},"op":"r","ts_ms":1705884626222,"transaction":null}
08:50:26.821 [Source: MySQL Source -> Map (4/16)#0] INFO com.win.TestFlinkCDCFromMysqlDemo  - value ======={"before":null,"after":{"id":3,"name":"alanchanchn","age":33},"source":{"version":"1.9.7.Final","connector":"mysql","name":"mysql_binlog_source","ts_ms":0,"snapshot":"false","db":"cdctest","sequence":null,"table":"user","server_id":0,"gtid":null,"file":"","pos":0,"row":0,"thread":null,"query":null},"op":"r","ts_ms":1705884626223,"transaction":null}
08:50:26.821 [Source: MySQL Source -> Map (4/16)#0] INFO com.win.TestFlinkCDCFromMysqlDemo  - value ======={"before":null,"after":{"id":1,"name":"alan","age":18},"source":{"version":"1.9.7.Final","connector":"mysql","name":"mysql_binlog_source","ts_ms":0,"snapshot":"false","db":"cdctest","sequence":null,"table":"user","server_id":0,"gtid":null,"file":"","pos":0,"row":0,"thread":null,"query":null},"op":"r","ts_ms":1705884626221,"transaction":null}
08:50:26.822 [Source: MySQL Source -> Map (4/16)#0] INFO com.win.TestFlinkCDCFromMysqlDemo  - value ======={"before":null,"after":{"id":4,"name":"test456","age":999000},"source":{"version":"1.9.7.Final","connector":"mysql","name":"mysql_binlog_source","ts_ms":0,"snapshot":"false","db":"cdctest","sequence":null,"table":"user","server_id":0,"gtid":null,"file":"","pos":0,"row":0,"thread":null,"query":null},"op":"r","ts_ms":1705884626223,"transaction":null}
一月 22, 2024 8:50:27 上午 com.github.shyiko.mysql.binlog.BinaryLogClient connect信息: 
Connected to 192.168.10.44:3306 at alan_master_logbin.000004/10816 (sid:6116, cid:565)
08:50:56.030 [Source: MySQL Source -> Map (1/16)#0] INFO com.win.TestFlinkCDCFromMysqlDemo  - value ======={"before":{"id":4,"name":"test456","age":999000},"after":{"id":4,"name":"test456","age":8888},"source":{"version":"1.9.7.Final","connector":"mysql","name":"mysql_binlog_source","ts_ms":1705884032000,"snapshot":"false","db":"cdctest","sequence":null,"table":"user","server_id":1,"gtid":null,"file":"alan_master_logbin.000004","pos":11010,"row":0,"thread":557,"query":null},"op":"u","ts_ms":1705884655747,"transaction":null}

4)、debezium数据格式介绍

关于debezium更多的信息可以参考:37、Flink 的CDC 格式:debezium部署以及mysql示例

在flink cdc的版本中,不需要特别对debezium数据格式进行处理,默认的形如下面的内容,也即不带schema的,解析方式参考上例。

{

	"before": {
		"name": "alan_test",
		"scores": 666.0
	},
	"after": {
		"name": "alan_test",
		"scores": 888.0
	},
	"source": {
		"version": "1.7.2.Final",
		"connector": "mysql",
		"name": "ALAN",
		"ts_ms": 1705717298000,
		"snapshot": "false",
		"db": "cdctest",
		"sequence": null,
		"table": "userscoressink",
		"server_id": 1,
		"gtid": null,
		"file": "alan_master_logbin.000004",
		"pos": 4931,
		"row": 0,
		"thread": null,
		"query": null
	},
	"op": "u",
	"ts_ms": 1705717772785,
	"transaction": null

}

在某些情况下可能需要带schema的,形如下例,

如果需要解析则需要将JsonDebeziumDeserializationSchema()改成JsonDebeziumDeserializationSchema(true)

一般推荐使用系统默认的,不带schema的数据格式。

{
	"schema": {
		"type": "struct",
		"fields": [{
			"type": "struct",
			"fields": [{
				"type": "string",
				"optional": true,
				"field": "name"
			}, {
				"type": "double",
				"optional": true,
				"field": "scores"
			}],
			"optional": true,
			"name": "ALAN.cdctest.userscoressink.Value",
			"field": "before"
		}, {
			"type": "struct",
			"fields": [{
				"type": "string",
				"optional": true,
				"field": "name"
			}, {
				"type": "double",
				"optional": true,
				"field": "scores"
			}],
			"optional": true,
			"name": "ALAN.cdctest.userscoressink.Value",
			"field": "after"
		}, {
			"type": "struct",
			"fields": [{
				"type": "string",
				"optional": false,
				"field": "version"
			}, {
				"type": "string",
				"optional": false,
				"field": "connector"
			}, {
				"type": "string",
				"optional": false,
				"field": "name"
			}, {
				"type": "int64",
				"optional": false,
				"field": "ts_ms"
			}, {
				"type": "string",
				"optional": true,
				"name": "io.debezium.data.Enum",
				"version": 1,
				"parameters": {
					"allowed": "true,last,false"
				},
				"default": "false",
				"field": "snapshot"
			}, {
				"type": "string",
				"optional": false,
				"field": "db"
			}, {
				"type": "string",
				"optional": true,
				"field": "sequence"
			}, {
				"type": "string",
				"optional": true,
				"field": "table"
			}, {
				"type": "int64",
				"optional": false,
				"field": "server_id"
			}, {
				"type": "string",
				"optional": true,
				"field": "gtid"
			}, {
				"type": "string",
				"optional": false,
				"field": "file"
			}, {
				"type": "int64",
				"optional": false,
				"field": "pos"
			}, {
				"type": "int32",
				"optional": false,
				"field": "row"
			}, {
				"type": "int64",
				"optional": true,
				"field": "thread"
			}, {
				"type": "string",
				"optional": true,
				"field": "query"
			}],
			"optional": false,
			"name": "io.debezium.connector.mysql.Source",
			"field": "source"
		}, {
			"type": "string",
			"optional": false,
			"field": "op"
		}, {
			"type": "int64",
			"optional": true,
			"field": "ts_ms"
		}, {
			"type": "struct",
			"fields": [{
				"type": "string",
				"optional": false,
				"field": "id"
			}, {
				"type": "int64",
				"optional": false,
				"field": "total_order"
			}, {
				"type": "int64",
				"optional": false,
				"field": "data_collection_order"
			}],
			"optional": true,
			"field": "transaction"
		}],
		"optional": false,
		"name": "ALAN.cdctest.userscoressink.Envelope"
	},
	"payload": {
		"before": {
			"name": "alan_test",
			"scores": 666.0
		},
		"after": {
			"name": "alan_test",
			"scores": 888.0
		},
		"source": {
			"version": "1.7.2.Final",
			"connector": "mysql",
			"name": "ALAN",
			"ts_ms": 1705717298000,
			"snapshot": "false",
			"db": "cdctest",
			"sequence": null,
			"table": "userscoressink",
			"server_id": 1,
			"gtid": null,
			"file": "alan_master_logbin.000004",
			"pos": 4931,
			"row": 0,
			"thread": null,
			"query": null
		},
		"op": "u",
		"ts_ms": 1705717772785,
		"transaction": null
	}
}

以上,本文详细的介绍了Flink CDC的应用,并且提供2个示例进行说明如何使用,即使用Flink sql client的观察数据同步的情况、通过DataStream API 捕获数据变化情况及验证。

本专题分为以下几篇文章:

60、Flink CDC 入门介绍及Streaming ELT示例(同步Mysql数据库数据到Elasticsearch)-CDC Connector介绍及示例 (1)

60、Flink CDC 入门介绍及Streaming ELT示例(同步Mysql数据库数据到Elasticsearch)-Streaming ELT介绍及示例(2)

60、Flink CDC 入门介绍及Streaming ELT示例(同步Mysql数据库数据到Elasticsearch)-完整版

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