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]

v2-da6d148ce9ad5297c4a8317ee8c492cf_hd_看图王.jpg

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

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">[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</pre>

• 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

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">CREATE USER canal IDENTIFIED BY 'canal';
GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON . TO 'canal'@'%';
-- GRANT ALL PRIVILEGES ON . TO 'canal'@'%' ;
FLUSH PRIVILEGES;</pre>

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

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">wget https://github.com/alibaba/canal/releases/download/canal-1.0.17/canal.deployer-1.0.17.tar.gz</pre>

• 解压缩

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">mkdir /tmp/canal
tar zxvf canal.deployer-$version.tar.gz -C /tmp/canal</pre>

解压完成后，进入 /tmp/canal 目录，可以看到如下结构

v2-c1756d30c8acd6f7bcf12f0e76ab53da_hd_看图王.jpg

• 配置修改

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">vi conf/example/instance.properties</pre>

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">#################################################

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-school

table regex

canal.instance.filter.regex=.\..

table black regex

canal.instance.filter.black.regex=
#################################################
</pre>

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

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">sh bin/startup.sh</pre>

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

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"><dependency>
<groupId>com.alibaba.otter</groupId>
<artifactId>canal.client</artifactId>
<version>1.1.3</version>
</dependency></pre>

测试代码

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">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<Entry> 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<Column> columns) {
for(Column column : columns) {
System.out.println(column.getName() + " : " + column.getValue() + " update=" + column.getUpdated());
}
}
}</pre>

测试结果

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">================> 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</pre>

注意一下

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"> CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("10.0.98.186", 11111), "expert", "root", "root");
复制代码</pre>

这里的配置来自于 canal.properties 我把这个配置也贴出来吧

<pre style="-webkit-tap-highlight-color: transparent; box-sizing: border-box; font-family: Consolas, Menlo, Courier, monospace; font-size: 16px; white-space: pre-wrap; position: relative; line-height: 1.5; color: rgb(153, 153, 153); margin: 1em 0px; padding: 12px 10px; background: rgb(244, 245, 246); border: 1px solid rgb(232, 232, 232); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">canal.id= 8
canal.ip=
canal.port=11111
canal.metrics.pull.port=11112
canal.zkServers=10.0.14.36:2181,10.0.14.39:2181,10.0.14.49:2181

flush data to zk

canal.zookeeper.flush.period = 1000
canal.withoutNetty = false

flush meta cursor/parse position to file

canal.file.data.dir = ${canal.conf.dir}
canal.file.flush.period = 1000

memory 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 = false

support 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 = 30

binlog 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 = false

binlog format/image check

canal.instance.binlog.format = ROW,STATEMENT,MIXED
canal.instance.binlog.image = FULL,MINIMAL,NOBLOB

binlog 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=root

rds oss binlog account

canal.instance.rds.accesskey =
canal.instance.rds.secretkey =

#################################################
######### destinations #############
#################################################
canal.destinations= expert

conf root dir

canal.conf.dir = ../conf

auto scan instance dir add/remove and start/stop instance

canal.auto.scan = true
canal.auto.scan.interval = 5

canal.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 = false

canal.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</pre>

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。