Canal 同步 Mysql
1. Canal 介绍
Canal是阿里巴巴的数据同步工具，最初主要为了应对杭州和美国的双机房部署问题，目前也是国内互联网企业经常使用的数据增量同步解决方案。
工作原理：
- canal将自己伪装为MySQL的slave，向master发送dump协议
- master收到dump协议，数据发生修改后推送binary log给canal
- canal解析binary log对象，转换为增量数据，同步到ES、Redis等
2. Mysql 配置
-- 查看mysql是否启动binlog，log_bin为ON表示启动，为OFF则未启动，需要修改mysql配置文件启动log_bin
SHOW VARIABLES LIKE '%log_bin%';
windows配置文件是MySQL安装目录的 my.ini ，如： C:\ProgramData\MySQL\MySQL Server 8.0
linux在 /etc/my.cnf
修改：
[mysqld]
log-bin="DESKTOP-425G2B9-bin"
binlog-format=ROW
server_id=1
show master status;
账号需要拥有全局的
REPLICATION权限 ,MySQL Replication（主从复制）权限
SELECT * FROM mysql.user WHERE user='onnoa';
CREATE USER canal IDENTIFIED BY 'canal';
GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'canal'@'%';
-- GRANT ALL PRIVILEGES ON *.* TO 'canal'@'%' ;
FLUSH PRIVILEGES;
3. Canal 的下载、安装与配置
版本 v.1.1.5
将下载好的 .tar.gz 上传到 linux 服务器的 /usr/local/soft 目录下
cd /usr/local/soft
mkdir canal
tar -vxf canal.deployer-1.1.4.tar.gz -C canal
配置Canal
vi conf/example/instance.properties
canal.instance.mysql.slaveId=0
canal.instance.gtidon=false
# 数据库地址
canal.instance.master.address=127.0.0.1:3306
# binlog日志名称
canal.instance.master.journal.name=mysql-bin.000001
# mysql主库链接时起始的binlog偏移量
canal.instance.master.position=154
# mysql主库链接时起始的binlog的时间戳
canal.instance.master.timestamp=
canal.instance.master.gtid=
# username/password
# 在MySQL服务器授权的账号密码
canal.instance.dbUsername=canal
canal.instance.dbPassword=canal
canal.instance.connectionCharset = UTF-8
# table regex .*\\..*表示监听所有表 也可以写具体的表名，用，隔开
canal.instance.filter.regex=.*\\..*
# table black regex mysql 数据解析表的黑名单，多个表用，隔开
canal.instance.filter.black.regex=mysql\\.slave_.*
canal.properties vi /usr/local/soft/canal/conf/canal.properties单机这个配置暂时无变动
canal.id = 1 #canal服务id，目前没有实际意义
canal.ip =
canal.port = 11111 #canal服务socket监听端口，代码中连接canal-server时，使用此段口连接
canal.metrics.pull.port = 11112
- 启动 Canal
# 进入 bin 目录，并启动 Canal
./startup.sh
# 关闭服务
./stop.sh
# 查看启动日志文件
cat /usr/local/canal/logs/example/example.log
cat /usr/local/canal/logs/canal/canal.log
启动成功
-- example.log
root@ubuntu:/usr/local/soft/canal/logs# cd canal/
root@ubuntu:/usr/local/soft/canal/logs/canal# tail -f canal.log
2022-04-25 14:52:40.593 [main] INFO com.alibaba.otter.canal.deployer.CanalLauncher - ## set default uncaught exception handler
2022-04-25 14:52:40.644 [main] INFO com.alibaba.otter.canal.deployer.CanalLauncher - ## load canal configurations
2022-04-25 14:52:40.660 [main] INFO com.alibaba.otter.canal.deployer.CanalStarter - ## start the canal server.
2022-04-25 14:52:40.738 [main] INFO com.alibaba.otter.canal.deployer.CanalController - ## start the canal server[172.19.0.1(172.19.0.1):11111]
2022-04-25 14:52:42.904 [main] INFO com.alibaba.otter.canal.deployer.CanalStarter - ## the canal server is running now ......
--------------------------------------------------------
-- canal.log
2022-04-25 16:36:06.714 [Thread-6] INFO c.a.otter.canal.instance.core.AbstractCanalInstance - stop CannalInstance for null-example
2022-04-25 16:36:07.905 [Thread-6] INFO c.a.otter.canal.instance.core.AbstractCanalInstance - stop successful....
2022-04-25 16:36:23.687 [main] INFO c.a.otter.canal.instance.spring.CanalInstanceWithSpring - start CannalInstance for 1-example
2022-04-25 16:36:23.699 [main] WARN c.a.o.canal.parse.inbound.mysql.dbsync.LogEventConvert - --> init table filter : ^.*\..*$
2022-04-25 16:36:23.699 [main] WARN c.a.o.canal.parse.inbound.mysql.dbsync.LogEventConvert - --> init table black filter : ^mysql\.slave_
2022-04-25 16:36:23.790 [main] INFO c.a.otter.canal.instance.core.AbstractCanalInstance - subscribe filter change to .*\..*
2022-04-25 16:36:23.791 [main] WARN c.a.o.canal.parse.inbound.mysql.dbsync.LogEventConvert - --> init table filter : ^.*\..*$
2022-04-25 16:36:23.791 [main] INFO c.a.otter.canal.instance.core.AbstractCanalInstance - start successful....
主要问题总结：
异常信息 authentication error，数据库账号和密码配置错误 异常信息 can’t find position，检查配置的文件名和位置，再删除conf/example/meta.dat 重启 客户端版本兼容问题，canal的版本和客户端的版本要一致
4. 客户端代码编写
4.1. 项目结构
4.2. 客户端代码
依赖
<dependency>
<groupId>com.alibaba.otter</groupId>
<artifactId>canal.client</artifactId>
<version>1.1.4</version>
</dependency>
测试代码
package com.onnoa.canal.sync.test;
import com.alibaba.otter.canal.client.CanalConnector;
import com.alibaba.otter.canal.client.CanalConnectors;
import com.alibaba.otter.canal.protocol.CanalEntry;
import com.alibaba.otter.canal.protocol.CanalEntry.Entry;
import com.alibaba.otter.canal.protocol.CanalEntry.EntryType;
import com.alibaba.otter.canal.protocol.CanalEntry.EventType;
import com.alibaba.otter.canal.protocol.CanalEntry.RowData;
import com.alibaba.otter.canal.protocol.Message;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.stereotype.Component;
import java.net.InetSocketAddress;
import java.util.List;
/**
* @Classname CannalClient
* @Description 阿里 Canal 数据同步客户端测试类
* @Date 2022/4/25 23:48
* @Author onnoA
*/
@Component
public class CannalClient implements InitializingBean {
private final static int BATCH_SIZE = 1000;
@Override
public void afterPropertiesSet() throws Exception {
// 创建链接
CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("192.168.40.129",
11111), "example", "root", "123456");
try {
//打开连接
connector.connect();
//订阅数据库表,全部表
connector.subscribe(".*\\..*");
//回滚到未进行ack的地方，下次fetch的时候，可以从最后一个没有ack的地方开始拿
connector.rollback();
while (true) {
// 获取指定数量的数据
Message message = connector.getWithoutAck(BATCH_SIZE);
//获取批量ID
long batchId = message.getId();
//获取批量的数量
int size = message.getEntries().size();
//如果没有数据
if (batchId == -1 || size == 0) {
try {
//线程休眠2秒
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
} else {
//如果有数据,处理数据
printEntry(message.getEntries());
}
//进行 batch id 的确认。确认之后，小于等于此 batchId 的 Message 都会被确认。
connector.ack(batchId);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
connector.disconnect();
}
}
/**
* 打印canal server解析binlog获得的实体类信息
*/
private static void printEntry(List<Entry> entrys) {
for (Entry entry : entrys) {
if (entry.getEntryType() == EntryType.TRANSACTIONBEGIN || entry.getEntryType() == EntryType.TRANSACTIONEND) {
//开启/关闭事务的实体类型，跳过
continue;
}
//RowChange对象，包含了一行数据变化的所有特征
//比如isDdl 是否是ddl变更操作 sql 具体的ddl sql beforeColumns afterColumns 变更前后的数据字段等等
CanalEntry.RowChange rowChage;
try {
rowChage = CanalEntry.RowChange.parseFrom(entry.getStoreValue());
} catch (Exception e) {
throw new RuntimeException("ERROR ## parser of eromanga-event has an error , data:" + entry.toString(), e);
}
//获取操作类型：insert/update/delete类型
EventType eventType = rowChage.getEventType();
//打印Header信息
System.out.println(String.format("================》; binlog[%s:%s] , name[%s,%s] , eventType : %s",
entry.getHeader().getLogfileName(), entry.getHeader().getLogfileOffset(),
entry.getHeader().getSchemaName(), entry.getHeader().getTableName(),
eventType));
//判断是否是DDL语句
if (rowChage.getIsDdl()) {
System.out.println("================》;isDdl: true,sql:" + rowChage.getSql());
}
//获取RowChange对象里的每一行数据，打印出来
for (RowData rowData : rowChage.getRowDatasList()) {
//如果是删除语句
if (eventType == EventType.DELETE) {
printColumn(rowData.getBeforeColumnsList());
//如果是新增语句
} else if (eventType == EventType.INSERT) {
printColumn(rowData.getAfterColumnsList());
//如果是更新的语句
} else {
//变更前的数据
System.out.println("------->; before");
printColumn(rowData.getBeforeColumnsList());
//变更后的数据
System.out.println("------->; after");
printColumn(rowData.getAfterColumnsList());
}
}
}
}
private static void printColumn(List<CanalEntry.Column> columns) {
for (CanalEntry.Column column : columns) {
System.out.println(column.getName() + " : " + column.getValue() + " update=" + column.getUpdated());
}
}
}
当表插入或删除数据，客户端可以实时监控到变化。
