canal
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1. canal 简介
canal 主要用途是基于 MySQL 数据库增量日志解析,提供增量数据订阅和消费。
canal 工作原理:
- canal 模拟 MySQL slave 的交互协议,伪装自己为 MySQL slave ,向 MySQL master 发送dump 协议
- MySQL master 收到 dump 请求,开始推送 binary log 给 slave (即 canal )
- canal 解析 binary log 对象(原始为 byte 流)
官网地址:https://github.com/alibaba/canal
2. canal 服务端
(1)修改 /etc/my.cnf 文件,增加以下配置(PS:改完后别忘了重启数据库 systemctl restart mysqld )
[mysqld]
log-bin=mysql-bin # 开启 binlog
binlog-format=ROW # 选择 ROW 模式
server_id=1 # 配置 MySQL replaction 需要定义,不要和 canal 的 slaveId 重复
备忘录
show variables like \'log_bin\';
show binary logs;
show master status;
select * from mysql.`user`;
(2)授权 canal 链接 MySQL 账号具有作为 MySQL slave 的权限, 如果已有账户可直接 grant
CREATE USER canal IDENTIFIED BY \'Canal@123456\';
GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO \'canal\'@\'%\';
-- GRANT ALL PRIVILEGES ON *.* TO \'canal\'@\'%\' ;
FLUSH PRIVILEGES;
(3)下载canal,并解压缩
https://github.com/alibaba/canal/releases
(4)修改配置
vim conf/example/instance.properties
启动
sh bin/startup.sh
查看日志
# 查看 server 日志
vi logs/canal/canal.log
# 查看 instance 的日志
vi logs/example/example.log
# 关闭
sh bin/stop.sh
3. canal 客户端
依赖
<dependency>
<groupId>com.alibaba.otter</groupId>
<artifactId>canal.client</artifactId>
<version>1.1.5</version>
</dependency>
<dependency>
<groupId>com.alibaba.otter</groupId>
<artifactId>canal.protocol</artifactId>
<version>1.1.5</version>
</dependency>
配置
canal.server.host=192.168.28.32
canal.server.port=11111
canal.server.destination=example
canal.server.username=canal
canal.server.password=canal
spring.kafka.bootstrap-servers=192.168.28.32:9092
logback.xml
<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" scanPeriod="30 seconds" debug="false">
<property name="log.charset" value="utf-8" />
<property name="log.pattern" value="%dyyyy-MM-dd HH:mm:ss [%thread] %-5level %logger36 - %msg%n" />
<property name="log.dir" value="./logs" />
<!--输出到控制台-->
<appender name="console" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>$log.pattern</pattern>
<charset>$log.charset</charset>
</encoder>
</appender>
<appender name="file" class="ch.qos.logback.core.rolling.RollingFileAppender">
<file>$log.dir/my-canal-client.log</file>
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
<fileNamePattern>$log.dir/my-canal-client.%dyyyy-MM-dd.log</fileNamePattern>
<maxHistory>30</maxHistory>
<totalSizeCap>3GB</totalSizeCap>
</rollingPolicy>
<encoder>
<pattern>$log.pattern</pattern>
</encoder>
</appender>
<root level="info">
<appender-ref ref="console" />
<appender-ref ref="file" />
</root>
</configuration>
测试代码
package com.my.component.canal;
import com.alibaba.otter.canal.client.CanalConnector;
import com.alibaba.otter.canal.protocol.CanalEntry;
import com.alibaba.otter.canal.protocol.Message;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.Assert;
import java.util.List;
/**
* @Author ChengJianSheng
* @Date 2022/1/13
*/
@Slf4j
public class Demo
private volatile boolean running = false;
private CanalConnector connector;
private Thread thread = null;
public Demo(CanalConnector connector)
this.connector = connector;
public void start()
Assert.notNull(connector, "connector is null");
thread = new Thread(this::process);
running = true;
thread.start();
public void stop()
if (!running)
return;
running = false;
if (thread != null)
try
thread.join();
catch (InterruptedException e)
// ignore
private void process()
int batchSize = 5 * 1024;
while (running)
try
connector.connect();
connector.subscribe(".*\\\\..*");
while (running)
Message message = connector.getWithoutAck(batchSize); // 获取指定数量的数据
long batchId = message.getId();
int size = message.getEntries().size();
if (batchId == -1 || size == 0)
// try
// Thread.sleep(1000);
// catch (InterruptedException e)
//
else
printEntry(message.getEntries());
if (batchId != -1)
connector.ack(batchId); // 提交确认
catch (Throwable e)
log.error("process error!", e);
try
Thread.sleep(1000L);
catch (InterruptedException e1)
// ignore
connector.rollback(); // 处理失败, 回滚数据
finally
connector.disconnect();
private void printEntry(List<CanalEntry.Entry> entrys)
for (CanalEntry.Entry entry : entrys)
if (entry.getEntryType() == CanalEntry.EntryType.TRANSACTIONBEGIN || entry.getEntryType() == CanalEntry.EntryType.TRANSACTIONEND)
continue;
CanalEntry.RowChange rowChage = null;
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);
CanalEntry.EventType eventType = rowChage.getEventType();
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));
for (CanalEntry.RowData rowData : rowChage.getRowDatasList())
if (eventType == CanalEntry.EventType.DELETE)
printColumn(rowData.getBeforeColumnsList());
else if (eventType == CanalEntry.EventType.INSERT)
printColumn(rowData.getAfterColumnsList());
else
System.out.println("-------> before");
printColumn(rowData.getBeforeColumnsList());
System.out.println("-------> after");
printColumn(rowData.getAfterColumnsList());
private void printColumn(List<CanalEntry.Column> columns)
for (CanalEntry.Column column : columns)
System.out.println(column.getName() + " : " + column.getValue() + " update=" + column.getUpdated());
启动
package com.my.component.canal;
import com.alibaba.otter.canal.client.CanalConnector;
import com.alibaba.otter.canal.client.CanalConnectors;
import com.alibaba.otter.canal.common.utils.AddressUtils;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.stereotype.Component;
import java.net.InetSocketAddress;
import java.net.SocketAddress;
/**
* @Author ChengJianSheng
* @Date 2022/1/4
*/
@Slf4j
@Component
public class MyCommandLineRunner implements CommandLineRunner
@Autowired
private CanalServerProperties canalServerProperties;
@Autowired
private KafkaTemplate<String, String> kafkaTemplate;
@Override
public void run(String... args) throws Exception
String destination = "example";
// String ip = AddressUtils.getHostIp();
// String ip = canalServerProperties.getHost();
String ip = "192.168.28.32";
SocketAddress address = new InetSocketAddress(ip, 11111);
CanalConnector connector = CanalConnectors.newSingleConnector(address, destination, "canal", "canal");
Demo demo = new Demo(connector);
demo.start();
Runtime.getRuntime().addShutdownHook(new Thread(() ->
try
log.info("## stop the canal client");
demo.stop();
catch (Throwable e)
log.warn("##something goes wrong when stopping canal:", e);
finally
log.info("## canal client is down.");
));
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