关于canal

canal官网

  • 安装mysql
    MySQL5.7安装与配置
    添加配置

    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，建议配置binlog模式为row

vim /etc/my.cof

[mysqld]
log-bin=mysql-bin 
binlog-format=ROW
server_id=1
添加权限，canal的原理是模拟自己为mysql slave，所以这里一定需要做为mysql slave的相关权限.
# 该步骤如果有问题 可以直接刷新，使用：FLUSH PRIVILEGES;
1、CREATE USER canal IDENTIFIED BY 'canal';  
2、GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'canal'@'%';
-- GRANT ALL PRIVILEGES ON *.* TO 'canal'@'%' ;
3、FLUSH PRIVILEGES;

  • canal 安装和配置
    canal下载

    进入/opt/canal，创建 canal目录 进入该目录
    [root@localhost canal]#wget https://github.com/alibaba/canal/releases/download/canal-1.1.3/canal.adapter-1.1.3.tar.gz
[root@localhost canal]# ls
bin  conf  lib  logs
[root@localhost canal]#
    配置 vi conf/example/instance.properties
     canal.instance.dbUsername=数据库用户
 canal.instance.dbPassword=密码
 canal.instance.defaultDatabaseName=数据库名称
    运行&关闭
    [root@localhost canal]# bin/startup.sh 
[root@localhost canal]# bin/stop.sh
    查看日志
    [root@localhost canal]# tail -f logs/canal/canal.log 
2019-06-11 01:13:10.143 [main] INFO  com.alibaba.otter.canal.deployer.CanalController - ## start the canal server[172.17.0.1:11111]
2019-06-11 01:13:11.240 [main] WARN  o.s.beans.GenericTypeAwarePropertyDescriptor - Invalid JavaBean property 'connectionCharset' being accessed! Ambiguous write methods found next to actually used [public void com.alibaba.otter.canal.parse.inbound.mysql.AbstractMysqlEventParser.setConnectionCharset(java.nio.charset.Charset)]: [public void com.alibaba.otter.canal.parse.inbound.mysql.AbstractMysqlEventParser.setConnectionCharset(java.lang.String)]
2019-06-11 01:13:11.597 [main] ERROR com.alibaba.druid.pool.DruidDataSource - testWhileIdle is true, validationQuery not set
2019-06-11 01:13:11.996 [main] WARN  c.a.o.canal.parse.inbound.mysql.dbsync.LogEventConvert - --> init table filter : ^.*\..*$
2019-06-11 01:13:11.996 [main] WARN  c.a.o.canal.parse.inbound.mysql.dbsync.LogEventConvert - --> init table black filter : 
2019-06-11 01:13:12.252 [destination = example , address = /127.0.0.1:3306 , EventParser] WARN  c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - ---> begin to find start position, it will be long time for reset or first position
2019-06-11 01:13:12.274 [destination = example , address = /127.0.0.1:3306 , EventParser] WARN  c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - prepare to find start position just last position
 {"identity":{"slaveId":-1,"sourceAddress":{"address":"localhost","port":3306}},"postion":{"gtid":"","included":false,"journalName":"mysql-bin.000023","position":6421,"serverId":223344,"timestamp":1560240096000}}
2019-06-11 01:13:12.357 [main] INFO  com.alibaba.otter.canal.deployer.CanalStater - ## the canal server is running now ......
2019-06-11 01:13:12.787 [destination = example , address = /127.0.0.1:3306 , EventParser] WARN  c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - ---> find start position successfully, EntryPosition[included=false,journalName=mysql-bin.000023,position=6421,serverId=223344,gtid=,timestamp=1560240096000] cost : 507ms , the next step is binlog dump

  • 客户端，创建maven项目，可以直接使用springboot
    下官网示例

    pom添加依赖包
    <dependency>
  <groupId>com.alibaba.otter</groupId>
  <artifactId>canal.client</artifactId>
  <version>1.1.0</version>
</dependency>
    java 代码
    package com.elastic.search;

import java.net.InetSocketAddress;
import java.util.List;

import com.alibaba.otter.canal.client.CanalConnector;
import com.alibaba.otter.canal.client.CanalConnectors;
import com.alibaba.otter.canal.protocol.CanalEntry.Column;
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.RowChange;
import com.alibaba.otter.canal.protocol.CanalEntry.RowData;
import com.alibaba.otter.canal.protocol.Message;

public class TestCanal {

  public static void main(String args[]) {
      // 创建链接
      CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("192.168.177.128", 11111),
              "example", "", "");
      int batchSize = 1000;
      int emptyCount = 0;
      try {
          connector.connect();
          connector.subscribe(".*\\..*");
          connector.rollback();
          int totalEmtryCount = 2500;
          while (emptyCount < totalEmtryCount) {
              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) {
                      e.printStackTrace();
                  }
              } 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<Entry> entrys) {
      for (Entry entry : entrys) {
          if (entry.getEntryType() == EntryType.TRANSACTIONBEGIN
                  || entry.getEntryType() == EntryType.TRANSACTIONEND) {
              continue;
          }

          RowChange rowChage = null;
          try {
              rowChage = RowChange.parseFrom(entry.getStoreValue());
          } catch (Exception e) {
              throw new RuntimeException("ERROR ## parser of eromanga-event has an error , data:" + entry.toString(),e);
          }

          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 (RowData rowData : rowChage.getRowDatasList()) {
              if (eventType == EventType.DELETE) {
                  printColumn(rowData.getBeforeColumnsList());
              } else if (eventType == 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<Column> columns) {
      for (Column column : columns) {
          System.out.println(column.getName() + " : " + column.getValue() + "    update=" + column.getUpdated());
      }
  }
}
    直接运行，在数据库触发新增，修改，删除 操作，你可以看到打印信息

reference

官方文档
阿里Canal安装和代码示例
不错的springboot导入ES的封装

个人站点

最后修改：2020 年 02 月 13 日
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