什么是canal
canal是纯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
![史上最全的分布式数据同步中间间canal 之入门篇]
如上图：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
canal 搭建
搭建mysql环境
- 对于自建 MySQL , 需要先开启 Binlog 写入功能，配置 binlog-format 为 ROW 模式，my.cnf 中配置如下
[mysqld]
log-bin=mysql-bin # 开启 binlog
binlog-format=ROW # 选择 ROW 模式
server_id=1 # 配置 MySQL replaction 需要定义，不要和 canal 的 slaveId 重复
- 授权 canal 链接 MySQL 账号具有作为 MySQL slave 的权限, 如果已有账户可直接 grant
CREATE USER canal IDENTIFIED BY 'canal';
GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON . TO 'canal'@'%';
-- GRANT ALL PRIVILEGES ON . TO 'canal'@'%' ;
FLUSH PRIVILEGES;
这个第一步还是蛮简单的，就是要自己搭建一个mysql，修改一下mysql的配置,这个配置一般是再/etc/my.cnf中，还是得要点小基础的哈，至少mysql得会搭
搭建canal环境
- 下载 canal, 访问 release 页面 , 选择需要的包下载, 如以 1.0.17 版本为例
wget https://github.com/alibaba/canal/releases/download/canal-1.0.17/canal.deployer-1.0.17.tar.gz
- 解压缩
mkdir /tmp/canal
tar zxvf canal.deployer-$version.tar.gz -C /tmp/canal
解压完成后，进入 /tmp/canal 目录，可以看到如下结构
- 配置修改
vi conf/example/instance.properties
#################################################mysql serverId , v1.0.26+ will autoGen
canal.instance.mysql.slaveId=8
enable gtid use true/false
canal.instance.gtidon=false
position info 需要改成自己的数据库信息
canal.instance.master.address=10.0.98.186:3306
canal.instance.master.journal.name=
canal.instance.master.position=
canal.instance.master.timestamp=
canal.instance.master.gtid=rds oss binlog
canal.instance.rds.accesskey=
canal.instance.rds.secretkey=
canal.instance.rds.instanceId=table meta tsdb info
canal.instance.tsdb.enable=true
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 =
canal.instance.standby.gtid=
username/password 需要改成自己的数据库信息
canal.instance.dbUsername=root
canal.instance.dbPassword=root
canal.instance.connectionCharset=UTF-8
canal.instance.defaultDatabaseName=expert-online-schooltable regex
canal.instance.filter.regex=.\..
table black regex
canal.instance.filter.black.regex=
#################################################
注意： canal.instance.connectionCharset 代表数据库的编码方式对应到 java 中的编码类型，比如 UTF-8，GBK , ISO-8859-1 如果系统是1个 cpu，需要将 canal.instance.parser.parallel 设置为 false
- 启动
sh bin/startup.sh
到目前为止 canal的服务端我们已经搭建好了 但是到目前 我们只是把数据库的binlog 拉到canal中，我们还得把数据用otter去消费
写个简单的Demo 去监听mysql 数据的变动
Jar包
com.alibaba.otter
canal.client
1.1.3
测试代码
package com.hq.eos.sync.client;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 CanalTest {
public static void main(String[] args) throws Exception {
CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("10.0.98.186", 11111), "expert", "root", "root");
connector.connect();
connector.subscribe(".\..");
connector.rollback();while (true) {
Message message = connector.getWithoutAck(100); // 获取指定数量的数据
long batchId = message.getId();
if (batchId == -1 || message.getEntries().isEmpty()) {
Thread.sleep(1000);
continue;
}
// System.out.println(message.getEntries());
printEntries(message.getEntries());
connector.ack(batchId);// 提交确认，消费成功，通知server删除数据
// connector.rollback(batchId);// 处理失败, 回滚数据，后续重新获取数据
}
}private static void printEntries(List
entries) throws Exception {
for (Entry entry : entries) {
if (entry.getEntryType() != EntryType.ROWDATA) {
continue;
}RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
EventType eventType = rowChange.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 : rowChange.getRowDatasList()) {
switch (rowChange.getEventType()) {
case INSERT:
System.out.println("INSERT ");
printColumns(rowData.getAfterColumnsList());
break;
case UPDATE:
System.out.println("UPDATE ");
printColumns(rowData.getAfterColumnsList());
break;
case DELETE:
System.out.println("DELETE ");
printColumns(rowData.getBeforeColumnsList());
break;default:
break;
}
}
}
}private static void printColumns(List
columns) {
for(Column column : columns) {
System.out.println(column.getName() + " : " + column.getValue() + " update=" + column.getUpdated());
}
}
}
测试结果
================> binlog[mysql-bin.000017:240485980] , name[xxl_job,xxl_job_registry] , eventType : UPDATE
UPDATE
id : 402 update=false
registry_group : EXECUTOR update=false
registry_key : hq-eos-crawler update=false
registry_value : 172.27.0.1:15674 update=false
update_time : 2019-12-03 17:54:42 update=true
================> binlog[mysql-bin.000017:240486374] , name[xxl_job,xxl_job_registry] , eventType : UPDATE
UPDATE
id : 82 update=false
registry_group : EXECUTOR update=false
registry_key : hq-eos-inf-config update=false
registry_value : 172.18.0.1:15672 update=false
update_time : 2019-12-03 17:54:42 update=true
================> binlog[mysql-bin.000017:240486774] , name[xxl_job,xxl_job_registry] , eventType : UPDATE
注意一下
CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("10.0.98.186", 11111), "expert", "root", "root");
复制代码
这里的配置来自于 canal.properties 我把这个配置也贴出来吧
canal.id= 8
canal.ip=
canal.port=11111
canal.metrics.pull.port=11112
canal.zkServers=10.0.14.36:2181,10.0.14.39:2181,10.0.14.49:2181flush data to zk
canal.zookeeper.flush.period = 1000
canal.withoutNetty = falseflush meta cursor/parse position to file
canal.file.data.dir = ${canal.conf.dir}
canal.file.flush.period = 1000memory store RingBuffer size, should be Math.pow(2,n)
canal.instance.memory.buffer.size = 16384
memory store RingBuffer used memory unit size , default 1kb
canal.instance.memory.buffer.memunit = 1024
meory store gets mode used MEMSIZE or ITEMSIZE
canal.instance.memory.batch.mode = MEMSIZE
detecing config
canal.instance.detecting.enable = false
canal.instance.detecting.sql = insert into retl.xdual values(1,now()) on duplicate key update x=now()
canal.instance.detecting.sql = select 1
canal.instance.detecting.interval.time = 3
canal.instance.detecting.retry.threshold = 3
canal.instance.detecting.heartbeatHaEnable = falsesupport maximum transaction size, more than the size of the transaction will be cut into multiple transactions delivery
canal.instance.transaction.size = 1024
mysql fallback connected to new master should fallback times
canal.instance.fallbackIntervalInSeconds = 60
network config
canal.instance.network.receiveBufferSize = 16384
canal.instance.network.sendBufferSize = 16384
canal.instance.network.soTimeout = 30binlog filter config
canal.instance.filter.druid.ddl = true
canal.instance.filter.query.dcl = false
canal.instance.filter.query.dml = false
canal.instance.filter.query.ddl = false
canal.instance.filter.table.error = false
canal.instance.filter.rows = false
canal.instance.filter.transaction.entry = falsebinlog format/image check
canal.instance.binlog.format = ROW,STATEMENT,MIXED
canal.instance.binlog.image = FULL,MINIMAL,NOBLOBbinlog ddl isolation
canal.instance.get.ddl.isolation = false
parallel parser config
canal.instance.parser.parallel = true
concurrent thread number, default 60% available processors, suggest not to exceed Runtime.getRuntime().availableProcessors()
canal.instance.parser.parallelThreadSize = 16
disruptor ringbuffer size, must be power of 2
canal.instance.parser.parallelBufferSize = 256
table meta tsdb info
canal.instance.tsdb.enable=true
canal.instance.tsdb.dir={canal.instance.destination:}
canal.instance.tsdb.url=jdbc:h2:${canal.instance.tsdb.dir}/h2;CACHE_SIZE=1000;MODE=MYSQL;
canal.instance.tsdb.dbUsername=root
canal.instance.tsdb.dbPassword=rootrds oss binlog account
canal.instance.rds.accesskey =
canal.instance.rds.secretkey =#################################################
######### destinations #############
#################################################
canal.destinations= expertconf root dir
canal.conf.dir = ../conf
auto scan instance dir add/remove and start/stop instance
canal.auto.scan = true
canal.auto.scan.interval = 5canal.instance.tsdb.spring.xml=classpath:spring/tsdb/h2-tsdb.xml
canal.instance.tsdb.spring.xml=classpath:spring/tsdb/mysql-tsdb.xml
canal.instance.global.mode = spring
canal.instance.global.lazy = falsecanal.instance.global.manager.address = 127.0.0.1:1099
canal.instance.global.spring.xml = classpath:spring/memory-instance.xml
canal.instance.global.spring.xml = classpath:spring/file-instance.xml
canal.instance.global.spring.xml = classpath:spring/default-instance.xml
这上面很多配置这边就不一一说明了 zookeeper的话是做instance 集群的时候用的
结尾
canal入门写完，谢谢大家的支持，大家如果想学后面一篇文章，一定要把这个照着做一遍。
因为博主也是一个开发萌新 我也是一边学一边写 我有个目标就是一周 二到三篇 希望能坚持个一年吧 希望各位大佬多提意见，让我多学习，一起进步。