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Canal GitHub：https://github.com/alibaba/canal#readme
实时采集工具canal：利用mysql主从复制的原理，slave定期读取master的binarylog对binarylog进行解析。
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对像（原始为bye流）
官网配置：https://github.com/alibaba/canal/wiki/QuickStart
1.在mysql中开启binlog日志功能
mysql上配置
linux>vi /etc/my.cnf
server-id=1
log-bin=mysql-bin
binlog_format=row
binlog-do-db=testdb //指定数据库
2.重启mysql服务
linux>systemctl restart mysqld
3.查看binlog是否生效：
linux>ls /var/lib/mysql
4.解压canal压缩包
linux>tar -zxvf canal-* -C canal
5.数据库设置
登陆mysql
mysql>GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'canal'@'%' IDENTIFIED BY 'canal';
mysql>flush privileges;
6.配置文件
1.修改canal.properties配置文件
linux>vi conf/canal.properties
canal.instance.parser.parallelThreadSize = 1
2.修改instance.properties配置文件
linux>vi conf/example/instance.properties
canal.instance.mysql.slaveId=21
canal.instance.master.address=192.168.58.203:3306
7.启动服务并查看进程
linux>bin/startup.shlinux>jpsxxxx CanalLauncher
查看日志
linux>cat /opt/install/canal/logs/canal/canal.log
idea客户端
pom.xml
<dependency><groupId>com.alibaba.otter</groupId><artifactId>canal.client</artifactId><version>1.1.2</version></dependency><dependency><groupId>org.apache.kafka</groupId><artifactId>kafka-clients</artifactId><version>2.4.1</version></dependency>
import java.net.InetSocketAddress;
import java.util.List;
import com.alibaba.otter.canal.client.CanalConnectors;
import com.alibaba.otter.canal.client.CanalConnector;
import com.alibaba.otter.canal.common.utils.AddressUtils;
import com.alibaba.otter.canal.protocol.CanalEntry;
import com.alibaba.otter.canal.protocol.Message;
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;public class CanalClientDemo {public static void main(String args[]) {// 创建链接CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("192.168.58.203）",11111), "example", "", "");int batchSize = 1000;int emptyCount = 0;try {//testdb库中的所有表connector.connect();connector.subscribe("testdb.*");connector.rollback();int totalEmptyCount = 120;while (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 (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());}}
}
注意：canal只能在java8中运行，如果canal进程CanalLauncher起不来，检查本地java环境
CanalClientDemo运行提示拒绝连接，检查脚本中的连接地址是不是运行canal的主机 CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress(“192.168.58.203（canal））”,
xxxx");
Canal kafka github 配置官网：github.com/alibaba/canal/wiki/Canal-Kafka-RocketMQ-QuickStart
使用canal将数据同步到kafka上
#重新解压一个canal到nodefour上进行配置
1.修改canal.properties配置文件
linux>vi canal.propertiescanal.serverMode = kafka
canal.instance.parser.parallel = false
canal.mq.servers = 192.168.58.201:9092,192.168.58.202:9092,192.168.58.203:9092
2.修改instance.properties配置文件
linux>vi instance.propertiescanal.instance.mysql.slaveId=21
canal.instance.master.address=192.168.58.203:3306
canal.mq.topic=example
3.可以创建topic，也可以不创建
在kafka上启动一个消费者
bin/kafka-console-consumer.sh --topic example --from-beginning --bootstrap-server 192.168.58.201:9092,192.168.58.202:9092,192.168.58.203:9092
启动 canal
linux>bin/startup.sh
结果：