Canal 入门教程：MySQL Binlog、Server 启动与客户端订阅

服务端

服务端ip：192.168.1.101

1. 下载canal 到/opt/softwares

   wget https://github.com/alibaba/canal/releases/download/canal-1.0.26-preview-2/canal.deployer-1.0.26-SNAPSHOT.tar.gz

Canal 通过模拟 MySQL 从库协议读取 binlog，适合缓存更新、搜索索引同步和异构数据复制。搭建时需要同时检查 MySQL 日志格式、复制权限、位点和下游消费幂等性。

2. 解压缩

   mkdir /opt/canal && tar -zxvf canal.deployer-1.0.26-SNAPSHOT.tar.gz -C /opt/canal/

3. 配置mysql

   vim /etc/my.cnf
   
   [mysqld]
   log-bin=mysql-bin
   binlog-format=ROW
   server_id=1

4. 创建用户

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

5. 创建数据库

   CREATE DATABASE IF NOT EXISTS canal_tsdb default charset utf8 COLLATE utf8_general_ci;

6. 配置canal

   cp /opt/canal/conf/example/instance.properties /opt/canal/conf/example/instance.properties.bak

   vim /opt/canal/conf/example/instance.properties
   
   #################################################
   ## mysql serverId
   canal.instance.mysql.slaveId=0
   # position info
   canal.instance.master.address=127.0.0.1:3306
   canal.instance.master.journal.name=mysql-bin.000001
   canal.instance.master.position=12172
   canal.instance.master.timestamp=
   
   
   # table meta tsdb info
   canal.instance.tsdb.enable=true
   #canal.instance.tsdb.dir=${canal.file.data.dir:../conf}/${canal.instance.destination:}
   #canal.instance.tsdb.url=jdbc:h2:${canal.instance.tsdb.dir}/h2;CACHE_SIZE=1000;MODE=MYSQL;
   canal.instance.tsdb.url=jdbc:mysql://127.0.0.1:3306/canal_tsdb
   canal.instance.tsdb.dbUsername=canal
   canal.instance.tsdb.dbPassword=canal
   
   
   #canal.instance.standby.address =
   #canal.instance.standby.journal.name =
   #canal.instance.standby.position = 
   #canal.instance.standby.timestamp = 
   # username/password
   canal.instance.dbUsername=canal
   canal.instance.dbPassword=canal
   canal.instance.defaultDatabaseName=test
   canal.instance.connectionCharset=UTF-8
   # table regex
   canal.instance.filter.regex=.*\\..*
   # table black regex
   canal.instance.filter.black.regex=
   #################################################

   修改canal.properties

   vim /opt/canal/conf/canal.properties
   
   #canal.instance.tsdb.spring.xml=classpath:spring/tsdb/h2-tsdb.xml
   canal.instance.tsdb.spring.xml=classpath:spring/tsdb/mysql-tsdb.xml
   
   # 找到tsdb的配置，注释上面的配置，启用下面的配置

   ​

7. 启动canal

   sh /opt/canal/bin/startup.sh

客户端

1. 引入依赖

   <dependency>
   	<groupId>com.alibaba.otter</groupId>
   	<artifactId>canal.client</artifactId>
   	<version>1.0.23</version>
   </dependency>

2. 客户端启动类

   package canal.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.Message;
   
   import java.net.InetSocketAddress;
   import java.util.List;
   
   /**
    * @author tt
    */
   public class SimpleCanalClientExample {
   
       public static void main(String[] args) {
           // 创建链接
           CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("192.168.1.101",
                   11111), "example", "", "");
           int batchSize = 1000;
           int emptyCount = 0;
           try {
               connector.connect();
               connector.subscribe(".*\\..*");
               connector.rollback();
               int totalEmptyCount = 120;
               boolean flag = true;
               while (flag || emptyCount < totalEmptyCount) {
                   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) {
                       emptyCount++;
                       System.out.println("empty count : " + emptyCount);
                       try {
                           Thread.sleep(1000);
                       } catch (InterruptedException e) {
                       }
                   } else {
                       emptyCount = 0;
                       // System.out.printf("message[batchId=%s,size=%s] \n", batchId, size);
                       printEntry(message.getEntries());
                   }
   
                   connector.ack(batchId); // 提交确认
                   // connector.rollback(batchId); // 处理失败, 回滚数据
               }
   
               System.out.println("empty too many times, exit");
           } finally {
               connector.disconnect();
           }
       }
   
       private static 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 static void printColumn(List<CanalEntry.Column> columns) {
           for (CanalEntry.Column column : columns) {
               System.out.println(column.getName() + " : " + column.getValue() + "    update=" + column.getUpdated());
           }
       }
   
   }

快速开始到这里就结束了。