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Canal-监听数据库表的变化

1. 简介

Canal是阿里巴巴旗下的一款开源项目，纯Java开发。基于数据库增量日志解析，提供增量数据订阅&消费功能。

工作原理

Mysql主备复制原理

Canal-监听数据库表的变化-LMLPHP

  • MySQL master 将数据变更写入二进制日志( binary log, 其中记录叫做二进制日志事件binary log events，可以通过 show binlog events 进行查看)
  • MySQL slave 将 master 的 binary log events 拷贝到它的中继日志(relay log)
  • MySQL slave 重放 relay log 中事件，将数据变更反映它自己的数据

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)

mysql的binlog

它记录了所有的DDL和DML(除了数据查询语句)语句，以事件形式记录，还包含语句所执行的消耗的时间。主要用来备份和数据同步。

binlog有三种模式：STATEMENT、ROW、MIXED

  1. STATEMENT 记录的是执行的sql语句
  2. ROW 记录的是真实的行数据记录
  3. MIXED 记录的是1+2，优先按照1的模式记录

比如：

update user set age = 33

对应STATEMENT模式只是记录了当前执行的sql，而对应ROW模式则有可能有成千上万条记录（当然这取决于你user表的记录数）

2. 可以干什么

基于日志增量订阅和消费的业务包括

  • 数据库镜像
  • 数据库实时备份
  • 索引构建和实时维护(拆分异构索引、倒排索引等)
  • 业务 cache 刷新
  • 带业务逻辑的增量数据处理

当前的 canal 支持源端 MySQL 版本包括 5.1.x , 5.5.x , 5.6.x , 5.7.x , 8.0.x

3. 安装

原生安装请参考：https://github.com/alibaba/canal/wiki/QuickStart

3.1 docker-compose安装

3.1.1 创建同步用户

CREATE USER canal IDENTIFIED BY 'canal';
GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'canal'@'%';
-- GRANT ALL PRIVILEGES ON *.* TO 'canal'@'%' ;
FLUSH PRIVILEGES;

3.1.2 修改配置文件

首先启动一个零时的容器用于 将容器中的配置文件信息copy到宿主机

# run 零时容器
docker run --name canal-temp -d --rm canal/canal-server:v1.1.6
# 执行copy操作  copy配置文件到当前目录中
docker cp canal-temp:/home/admin/canal-server/conf ./canal-server/conf

canal-server/conf配置文件目录结构如下


canal-server/conf
├── canal.properties # canal server 的配置文件参数信息 例如：服务的端口/集群参数/server 模式（# tcp, kafka, rocketMQ, rabbitMQ, pulsarMQ）等
├── canal_local.properties
├── example # canal 实例相关配置信息，如果想要监听多个mysql server 可以copy此文件进行配置，当然也要在canal.properties的 canal.destinations 中添加对应的文件夹名称
│   ├── h2.mv.db
│   ├── instance.properties
│   └── meta.dat
├── logback.xml
...

修改配置文件信息

canal.properties我们使用默认的配置信息 即：canal.serverMode = tcp

example/instance.properties中配置mysql server连接信息 如下：

# position info
# mysql url 我这里直接使用的是 mysql容器name
canal.instance.master.address=my_mysql:3306
# 监听的binlog 文件名称 例：mysql-bin.000007
canal.instance.master.journal.name=
# 日志文件的Offset
canal.instance.master.position=

# username/password
canal.instance.dbUsername=canal
canal.instance.dbPassword=canal
canal.instance.connectionCharset = UTF-8

# table regex
# 默认配置是同步所有的库和表
#canal.instance.filter.regex=.*\\..*
# 配置只监听test库的user表，如果需要读取多个表可以使用正则表达式或者用逗号隔开
canal.instance.filter.regex=test.user

3.1.3 启动canal

docker-compose.yaml 如下

version: '3'
services:
    canal:
        image: canal/canal-server:v1.1.6
        hostname: canal
        container_name: canal
        restart: "no"
        ports:
            - "11111:11111"
        volumes:
            - "./canal-server/conf:/home/admin/canal-server/conf"
            - "./canal-server/logs:/home/admin/canal-server/logs"
        networks:
            - mysql_mysql
networks:
  mysql_mysql:
    external: true

4. springboot 测试

4.1 添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <optional>true</optional>
</dependency>

<!-- https://mvnrepository.com/artifact/top.javatool/canal-spring-boot-starter -->
<dependency>
    <groupId>top.javatool</groupId>
    <artifactId>canal-spring-boot-starter</artifactId>
    <version>1.2.1-RELEASE</version>
</dependency>

4.2 添加配置

canal:
  server: localhost:11111
  destination: example

logging:
  level:
    top.javatool.canal.client.client: OFF

4.3 监听canal数据

package com.ldx.canaldemo.handler;

import com.ldx.canaldemo.domain.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import top.javatool.canal.client.annotation.CanalTable;
import top.javatool.canal.client.handler.EntryHandler;

@Slf4j
@Component
// 监听user表
@CanalTable(value = "user")
public class UserHandler implements EntryHandler<User> {

    @Override
    public void insert(User user) {
        log.info("insert info {}", user);
    }

    @Override
    public void update(User before, User after) {
        log.info("update before {} ", before);
        log.info("update after {}", after);
    }

    @Override
    public void delete(User user) {
        log.info("delete {}", user);
    }
}

package com.ldx.canaldemo.domain;

import lombok.Data;

import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import java.io.Serializable;

@Data
@Table(name = "user")
public class User implements Serializable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Integer id;

    @Column(name = "username")
    private String username;

    @Column(name = "password")
    private String password;

    @Column(name = "sex")
    private Integer sex;
}

4.4 测试

user表信息如下

CREATE TABLE `user` (
  `id` int(11) NOT NULL,
  `username` varchar(255) COLLATE utf8mb4_bin DEFAULT NULL,
  `password` varchar(255) COLLATE utf8mb4_bin DEFAULT NULL,
  `age` int(1) DEFAULT NULL,
  `sex` int(1) COLLATE utf8mb4_bin DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;

测试新增

INSERT INTO `test`.`user`(`id`, `username`, `password`, `age`, `sex`) VALUES (5, 'zhangtieniu', '123456', 28, 1);

查看控制台输出如下

2022-06-14 13:50:38.144  INFO 71053 --- [xecute-thread-1] com.ldx.canaldemo.handler.UserHandler    : insert info User(id=5, username=zhangtieniu, password=123456, age=28, sex=1)

测试修改

UPDATE `test`.`user` SET `username` = 'zhangsan', age = 23 WHERE id = 5;

查看控制台输出如下

2022-06-14 13:54:55.997  INFO 71053 --- [xecute-thread-2] com.ldx.canaldemo.handler.UserHandler    : update before User(id=null, username=zhangtieniu, password=null, age=28, sex=null)
2022-06-14 13:54:55.997  INFO 71053 --- [xecute-thread-2] com.ldx.canaldemo.handler.UserHandler    : update after User(id=5, username=zhangsan, password=123456, age=23, sex=1)

测试删除

DELETE FROM `test`.`user` WHERE id = 5;

查看控制台输出如下

2022-06-14 13:56:46.359  INFO 71053 --- [xecute-thread-3] com.ldx.canaldemo.handler.UserHandler    : delete User(id=5, username=zhangsan, password=123456, age=23, sex=1)

5. rabbit mq 测试

5.1 修改canal配置

canal.properties 修改如下

# 将serverMode 修改成rabbitMQ
canal.serverMode = rabbitMQ

# 添加rabbitmq 配置信息
rabbitmq.host = rabbitmq:5672
rabbitmq.virtual.host = /
rabbitmq.exchange = canal.exchange
rabbitmq.username = admin
rabbitmq.password = admin123

example/instance.properties 添加路由规则

canal.mq.topic=canal_routing_key

5.2 springboot consumer

5.2.1 添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-amqp</artifactId>
</dependency>

5.2.2 添加配置

spring:
  rabbitmq:
    host: localhost
    port: 5672
    # rabbit 默认的虚拟主机
    virtual-host: /
    # rabbit 用户名密码
    username: admin
    password: admin123
    listener:
      simple:
        # manual 手动确认
        acknowledge-mode: manual

5.2.3 添加 consumer

package com.ldx.canaldemo.rabbitmq;

import com.rabbitmq.client.Channel;
import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageProperties;
import org.springframework.amqp.rabbit.annotation.Exchange;
import org.springframework.amqp.rabbit.annotation.Queue;
import org.springframework.amqp.rabbit.annotation.QueueBinding;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

import java.io.IOException;

/**
 * @author ludangxin
 * @date 2022/6/14
 */
@Slf4j
@Component
public class RabbitMQConsumer {
   @RabbitListener(bindings =
         {@QueueBinding(
               value = @Queue(value = MqConstant.CANAL_QUEUE, durable = "true"),
               exchange = @Exchange(value = MqConstant.CANAL_EXCHANGE),
               key = MqConstant.CANAL_ROUTING_KEY)
         })
   public void helloRabbitMq(Message message, Channel channel) throws IOException {
      MessageProperties messageProperties = message.getMessageProperties();
      try {
         log.info(message.toString());
         log.info(new String(message.getBody()));
         channel.basicAck(messageProperties.getDeliveryTag(), false);
      } catch(Exception e) {
         // 当前的消息是否重新投递的消息,也就是该消息是重新回到队列里的消息
         if(messageProperties.getRedelivered()) {
            log.info("消息已重复处理失败,拒绝再次接收...");
            // 拒绝消息Ò
            channel.basicReject(messageProperties.getDeliveryTag(), false);
         }
         else {
            log.info("消息即将再次返回队列处理...");
            channel.basicNack(messageProperties.getDeliveryTag(), false, true);
         }
      }
   }
}

package com.ldx.canaldemo.rabbitmq;

/**
 * @author ludangxin
 * @date 2022/6/14
 */
public interface MqConstant {
    String CANAL_EXCHANGE = "canal.exchange";
    String CANAL_QUEUE = "canal_queue";
    String CANAL_ROUTING_KEY = "canal_routing_key";
}

5.3 启动测试

先启动项目让程序自动建立所需mq中的交换机和队列

Canal-监听数据库表的变化-LMLPHP

测试新增

INSERT INTO `test`.`user`(`id`, `username`, `password`, `age`, `sex`) VALUES (8, 'zhangtieniu', '123456', 28, 1);

查看控制台输出如下

2022-06-14 14:42:04.818  INFO 73549 --- [ntContainer#0-1] c.l.canaldemo.rabbitmq.RabbitMQConsumer  : (Body:'[B@189a76a(byte[414])' MessageProperties [headers={}, contentLength=0, redelivered=false, receivedExchange=canal.exchange, receivedRoutingKey=canal_routing_key, deliveryTag=4, consumerTag=amq.ctag-KXSHZ8D0wMQo7z2_L2LKsg, consumerQueue=canal_queue])
2022-06-14 14:42:04.818  INFO 73549 --- [ntContainer#0-1] c.l.canaldemo.rabbitmq.RabbitMQConsumer  : {"data":[{"id":"8","username":"zhangtieniu","password":"123456","age":"28","sex":"1"}],"database":"test","es":1655188924000,"id":6,"isDdl":false,"mysqlType":{"id":"int(11)","username":"varchar(255)","password":"varchar(255)","age":"int(11)","sex":"varchar(255)"},"old":null,"pkNames":["id"],"sql":"","sqlType":{"id":4,"username":12,"password":12,"age":4,"sex":12},"table":"user","ts":1655188924822,"type":"INSERT"}

测试修改

UPDATE `test`.`user` SET `username` = 'zhangsan', age = 23 WHERE id = 8;

查看控制台输出如下

2022-06-14 14:56:23.471  INFO 73549 --- [ntContainer#0-1] c.l.canaldemo.rabbitmq.RabbitMQConsumer  : (Body:'[B@6a3a1f0(byte[446])' MessageProperties [headers={}, contentLength=0, redelivered=false, receivedExchange=canal.exchange, receivedRoutingKey=canal_routing_key, deliveryTag=5, consumerTag=amq.ctag-KXSHZ8D0wMQo7z2_L2LKsg, consumerQueue=canal_queue])
2022-06-14 14:56:23.471  INFO 73549 --- [ntContainer#0-1] c.l.canaldemo.rabbitmq.RabbitMQConsumer  : {"data":[{"id":"8","username":"zhangsan","password":"123456","age":"23","sex":"1"}],"database":"test","es":1655189783000,"id":7,"isDdl":false,"mysqlType":{"id":"int(11)","username":"varchar(255)","password":"varchar(255)","age":"int(11)","sex":"varchar(255)"},"old":[{"username":"zhangtieniu","age":"28"}],"pkNames":["id"],"sql":"","sqlType":{"id":4,"username":12,"password":12,"age":4,"sex":12},"table":"user","ts":1655189783493,"type":"UPDATE"}

测试删除

DELETE FROM `test`.`user` WHERE id = 8;

查看控制台输出如下

2022-06-14 14:57:06.407  INFO 73549 --- [ntContainer#0-1] c.l.canaldemo.rabbitmq.RabbitMQConsumer  : (Body:'[B@628caa50(byte[411])' MessageProperties [headers={}, contentLength=0, redelivered=false, receivedExchange=canal.exchange, receivedRoutingKey=canal_routing_key, deliveryTag=6, consumerTag=amq.ctag-KXSHZ8D0wMQo7z2_L2LKsg, consumerQueue=canal_queue])
2022-06-14 14:57:06.408  INFO 73549 --- [ntContainer#0-1] c.l.canaldemo.rabbitmq.RabbitMQConsumer  : {"data":[{"id":"8","username":"zhangsan","password":"123456","age":"23","sex":"1"}],"database":"test","es":1655189826000,"id":8,"isDdl":false,"mysqlType":{"id":"int(11)","username":"varchar(255)","password":"varchar(255)","age":"int(11)","sex":"varchar(255)"},"old":null,"pkNames":["id"],"sql":"","sqlType":{"id":4,"username":12,"password":12,"age":4,"sex":12},"table":"user","ts":1655189826419,"type":"DELETE"}

6. canal admin管理canal

  1. 创建canal admin 数据库 canal_manager

  2. 运行初始化sqlLiunx/canal/canal_admin/canal_manager.sql

    文件内容如下：

    CREATE DATABASE /*!32312 IF NOT EXISTS*/ `canal_manager` /*!40100 DEFAULT CHARACTER SET utf8 COLLATE utf8_bin */;

USE `canal_manager`;

SET NAMES utf8;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for canal_adapter_config
-- ----------------------------
DROP TABLE IF EXISTS `canal_adapter_config`;
CREATE TABLE `canal_adapter_config` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `category` varchar(45) NOT NULL,
  `name` varchar(45) NOT NULL,
  `status` varchar(45) DEFAULT NULL,
  `content` text NOT NULL,
  `modified_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Table structure for canal_cluster
-- ----------------------------
DROP TABLE IF EXISTS `canal_cluster`;
CREATE TABLE `canal_cluster` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(63) NOT NULL,
  `zk_hosts` varchar(255) NOT NULL,
  `modified_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Table structure for canal_config
-- ----------------------------
DROP TABLE IF EXISTS `canal_config`;
CREATE TABLE `canal_config` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `cluster_id` bigint(20) DEFAULT NULL,
  `server_id` bigint(20) DEFAULT NULL,
  `name` varchar(45) NOT NULL,
  `status` varchar(45) DEFAULT NULL,
  `content` text NOT NULL,
  `content_md5` varchar(128) NOT NULL,
  `modified_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `sid_UNIQUE` (`server_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Table structure for canal_instance_config
-- ----------------------------
DROP TABLE IF EXISTS `canal_instance_config`;
CREATE TABLE `canal_instance_config` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `cluster_id` bigint(20) DEFAULT NULL,
  `server_id` bigint(20) DEFAULT NULL,
  `name` varchar(45) NOT NULL,
  `status` varchar(45) DEFAULT NULL,
  `content` text NOT NULL,
  `content_md5` varchar(128) DEFAULT NULL,
  `modified_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `name_UNIQUE` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Table structure for canal_node_server
-- ----------------------------
DROP TABLE IF EXISTS `canal_node_server`;
CREATE TABLE `canal_node_server` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `cluster_id` bigint(20) DEFAULT NULL,
  `name` varchar(63) NOT NULL,
  `ip` varchar(63) NOT NULL,
  `admin_port` int(11) DEFAULT NULL,
  `tcp_port` int(11) DEFAULT NULL,
  `metric_port` int(11) DEFAULT NULL,
  `status` varchar(45) DEFAULT NULL,
  `modified_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

-- ----------------------------
-- Table structure for canal_user
-- ----------------------------
DROP TABLE IF EXISTS `canal_user`;
CREATE TABLE `canal_user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `username` varchar(31) NOT NULL,
  `password` varchar(128) NOT NULL,
  `name` varchar(31) NOT NULL,
  `roles` varchar(31) NOT NULL,
  `introduction` varchar(255) DEFAULT NULL,
  `avatar` varchar(255) DEFAULT NULL,
  `creation_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

SET FOREIGN_KEY_CHECKS = 1;

-- ----------------------------
-- Records of canal_user
-- ----------------------------
BEGIN;
INSERT INTO `canal_user` VALUES (1, 'admin', '6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9', 'Canal Manager', 'admin', NULL, NULL, '2019-07-14 00:05:28');
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

  3. docker-compose.yaml如下

    version: '3'
services:
  canal_admin:
    image: canal/canal-admin:v1.1.6
    container_name: canal_admin
    restart: unless-stopped
    volumes:
      - "./canal/canal-admin/logs:/home/admin/canal-admin/logs"
    environment:
      TZ: Asia/Shanghai
      LANG: en_US.UTF-8
      canal.adminUser: admin
      canal.adminPasswd: 123456
      spring.datasource.address: my_mysql:3306
      spring.datasource.database: canal_manager
      spring.datasource.username: root
      spring.datasource.password: 123456
    ports:
      - "8089:8089"
    networks:
      - canal
      - mysql_mysql
  canal_server:
    image: canal/canal-server:v1.1.6
    container_name: canal_server
    restart: unless-stopped
    volumes:
      - "./canal/canal-server/logs:/home/admin/canal-server/logs"
    environment:
      TZ: Asia/Shanghai
      LANG: en_US.UTF-8
      canal.admin.manager: canal_admin:8089
      canal.admin.port: 11110
      canal.admin.user: admin
      canal.admin.passwd: 6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9
    ports:
      - "11110:11110"
      - "11111:11111"
      - "11112:11112"
    depends_on:
      - canal_admin
    links:
      - canal_admin
    networks:
      - canal
      - mysql_mysql
networks:
  canal:
  mysql_mysql:
    external: true

  4. 启动服务/访问http://localhost:8089/#/canalServer/nodeServers

    Canal-监听数据库表的变化-LMLPHP

06-15 09:51
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