数据同步工具Canal

目录

  • Canal数据同步工具
    • 一、Canal介绍
    • 二、使用

Canal数据同步工具

一、Canal介绍

1、应用场景
在前面的统计分析功能中,我们采取了服务调用获取统计数据,这样耦合度高,效率相对较低,目前我采取另一种实现方式,通过实时同步数据库表的方式实现,例如我们要统计每天注册与登录人数,我们只需把会员表同步到统计库中,实现本地统计就可以了,这样效率更高,耦合度更低,Canal就是一个很好的数据库同步工具。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,目前主要支持了MySQL。

2、Canal环境搭建
canal的原理是基于mysql binlog技术,所以这里一定需要开启mysql的binlog写入功能
开启mysql服务:

 service mysql start

(1)检查binlog功能是否有开启

mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin       | OFF    |
+---------------+-------+
1 row in set (0.00 sec)

(2)如果显示状态为OFF表示该功能未开启,开启binlog功能

1,修改 mysql 的配置文件 my.cnf
vi /etc/my.cnf 
追加内容:
log-bin=mysql-bin     #binlog文件名
binlog_format=ROW     #选择row模式
server_id=1           #mysql实例id,不能和canal的slaveId重复
​
2,重启 mysql:
service mysql restart   
​
3,登录 mysql 客户端,查看 log_bin 变量
mysql> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin       | ON|
+---------------+-------+
1 row in set (0.00 sec)
————————————————
如果显示状态为ON表示该功能已开启

(3)在mysql里面添加以下的相关用户和权限

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

3、下载安装Canal服务
下载地址: https://github.com/alibaba/canal/releases
(1)下载之后,放到目录中,解压文件
cd /usr/local/canal
canal.deployer-1.1.4.tar.gz
tar zxvf canal.deployer-1.1.4.tar.gz
(2)修改配置文件
vi conf/example/instance.properties

#需要改成自己的数据库信息
canal.instance.master.address=192.168.44.132:3306

#需要改成自己的数据库用户名与密码

canal.instance.dbUsername=canal
canal.instance.dbPassword=canal

#需要改成同步的数据库表规则,例如只是同步一下表
#canal.instance.filter.regex=.*\\..*
canal.instance.filter.regex=guli_ucenter.ucenter_member

注:
mysql 数据解析关注的表,Perl正则表达式.
多个正则之间以逗号(,)分隔,转义符需要双斜杠(\)
常见例子:

  1. 所有表:.* or .\…
  2. canal schema下所有表: canal\…*
  3. canal下的以canal打头的表:canal\.canal.*
  4. canal schema下的一张表:canal.test1
  5. 多个规则组合使用:canal\…*,mysql.test1,mysql.test2 (逗号分隔)
    注意:此过滤条件只针对row模式的数据有效(ps. mixed/statement因为不解析sql,所以无法准确提取tableName进行过滤)

(3)进入bin目录下启动

sh bin/startup.sh

二、使用

创建springboot项目,引入相关依赖


    
        org.springframework.boot
        spring-boot-starter-web
    
    
        mysql
        mysql-connector-java
    
        commons-dbutils
        commons-dbutils
    
        org.springframework.boot
        spring-boot-starter-jdbc
    
        com.alibaba.otter
        canal.client
    

3、创建application.properties配置文件

# 服务端口
server.port=10000
# 服务名
spring.application.name=canal-client
​
# 环境设置:dev、test、prod
spring.profiles.active=dev
​
# mysql数据库连接
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/demo_db?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=root

4、编写canal客户端类

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.Message;
import com.google.protobuf.InvalidProtocolBufferException;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.springframework.stereotype.Component;
​
import javax.annotation.Resource;
import javax.sql.DataSource;
import java.net.InetSocketAddress;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
​
@Component
public class CanalClient {
​
    //sql队列
    private Queue SQL_QUEUE = new ConcurrentLinkedQueue<>();
​
    @Resource
    private DataSource dataSource;
​
    /**
     * canal入库方法
     */
    public void run() {
​
        CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("192.168.44.132",
                11111), "example", "", "");
        int batchSize = 1000;
        try {
            connector.connect();
            connector.subscribe(".*\\..*");
            connector.rollback();
            try {
                while (true) {
                    //尝试从master那边拉去数据batchSize条记录,有多少取多少
                    Message message = connector.getWithoutAck(batchSize);
                    long batchId = message.getId();
                    int size = message.getEntries().size();
                    if (batchId == -1 || size == 0) {
                        Thread.sleep(1000);
                    } else {
                        dataHandle(message.getEntries());
                    }
                    connector.ack(batchId);
​
                    //当队列里面堆积的sql大于一定数值的时候就模拟执行
                    if (SQL_QUEUE.size() >= 1) {
                        executeQueueSql();
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (InvalidProtocolBufferException e) {
                e.printStackTrace();
            }
        } finally {
            connector.disconnect();
        }
    }
​
    /**
     * 模拟执行队列里面的sql语句
     */
    public void executeQueueSql() {
        int size = SQL_QUEUE.size();
        for (int i = 0; i < size; i++) {
            String sql = SQL_QUEUE.poll();
            System.out.println("[sql]----> " + sql);
​
            this.execute(sql.toString());
        }
    }
​
    /**
     * 数据处理
     *
     * @param entrys
     */
    private void dataHandle(List entrys) throws InvalidProtocolBufferException {
        for (Entry entry : entrys) {
            if (EntryType.ROWDATA == entry.getEntryType()) {
                RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
                EventType eventType = rowChange.getEventType();
                if (eventType == EventType.DELETE) {
                    saveDeleteSql(entry);
                } else if (eventType == EventType.UPDATE) {
                    saveUpdateSql(entry);
                } else if (eventType == EventType.INSERT) {
                    saveInsertSql(entry);
                }
            }
        }
    }
​
    /**
     * 保存更新语句
     *
     * @param entry
     */
    private void saveUpdateSql(Entry entry) {
        try {
            RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
            List rowDatasList = rowChange.getRowDatasList();
            for (RowData rowData : rowDatasList) {
                List newColumnList = rowData.getAfterColumnsList();
                StringBuffer sql = new StringBuffer("update " + entry.getHeader().getTableName() + " set ");
                for (int i = 0; i < newColumnList.size(); i++) {
                    sql.append(" " + newColumnList.get(i).getName()
                            + " = '" + newColumnList.get(i).getValue() + "'");
                    if (i != newColumnList.size() - 1) {
                        sql.append(",");
                    }
                }
                sql.append(" where ");
                List oldColumnList = rowData.getBeforeColumnsList();
                for (Column column : oldColumnList) {
                    if (column.getIsKey()) {
                        //暂时只支持单一主键
                        sql.append(column.getName() + "=" + column.getValue());
                        break;
                    }
                }
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }
​
    /**
     * 保存删除语句
     *
     * @param entry
     */
    private void saveDeleteSql(Entry entry) {
        try {
            RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
            List rowDatasList = rowChange.getRowDatasList();
            for (RowData rowData : rowDatasList) {
                List columnList = rowData.getBeforeColumnsList();
                StringBuffer sql = new StringBuffer("delete from " + entry.getHeader().getTableName() + " where ");
                for (Column column : columnList) {
                    if (column.getIsKey()) {
                        //暂时只支持单一主键
                        sql.append(column.getName() + "=" + column.getValue());
                        break;
                    }
                }
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }
​
    /**
     * 保存插入语句
     *
     * @param entry
     */
    private void saveInsertSql(Entry entry) {
        try {
            RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
            List rowDatasList = rowChange.getRowDatasList();
            for (RowData rowData : rowDatasList) {
                List columnList = rowData.getAfterColumnsList();
                StringBuffer sql = new StringBuffer("insert into " + entry.getHeader().getTableName() + " (");
                for (int i = 0; i < columnList.size(); i++) {
                    sql.append(columnList.get(i).getName());
                    if (i != columnList.size() - 1) {
                        sql.append(",");
                    }
                }
                sql.append(") VALUES (");
                for (int i = 0; i < columnList.size(); i++) {
                    sql.append("'" + columnList.get(i).getValue() + "'");
                    if (i != columnList.size() - 1) {
                        sql.append(",");
                    }
                }
                sql.append(")");
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }
​
    /**
     * 入库
     * @param sql
     */
    public void execute(String sql) {
        Connection con = null;
        try {
            if(null == sql) return;
            con = dataSource.getConnection();
            QueryRunner qr = new QueryRunner();
            int row = qr.execute(con, sql);
            System.out.println("update: "+ row);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DbUtils.closeQuietly(con);
        }
    }
}

5、创建启动类

@SpringBootApplication
public class CanalApplication implements CommandLineRunner {
    @Resource
    private CanalClient canalClient;
​
    public static void main(String[] args) {
        SpringApplication.run(CanalApplication.class, args);
    }
​
    @Override
    public void run(String... strings) throws Exception {
        //项目启动,执行canal客户端监听
        canalClient.run();
    }
}

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