【Canal】之 搭建環境 和 用戶端運作

前言

在搭建時候，發現幾個易錯點（坑點），并一一填過

1. mysql 版本盡量5.7以下（官方有支援的版本）

2. canal運作方式

一、準備

平台：Ubuntu 16.04

MySQL： 5.7.22

MySQL 安裝（指定版本）

# 指定版本：apt-get install mysql-client-core-* （* 為 版本号）
apt-get install mysql-client-core-
apt-get install mysql-client-
apt-get install mysql-server-
           

MySQL 相關指令

# 服務開啟
service mysql start

# 服務關閉
service mysql stop

# 登入
mysql -uxxx -pyyy （xxx 為賬号， yyy為密碼）
           

MySQL 對應目錄

• 資料庫目錄：

  /var/lib/mysql

• 配置檔案:

  /usr/share/mysql

  ,

  /etc/mysql

• 相關指令:

  /usr/bin

  ,

  /usr/sbin

• 啟動腳本:

  etc/init.d/mysql

二、配置MySQL

（1）在

/etc/mysql/my.cnf

中添加

[mysqld]  
log-bin=mysql-bin #添加這一行就ok  
binlog-format=ROW #選擇row模式  
server_id= #配置mysql replaction需要定義，不能和canal的slaveId重複  
           

（2）在mysql中配置canal資料庫管理使用者，配置相應權限

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

三、搭建Canal

（1）下載下傳

wget https://github.com/alibaba/canal/releases/download/canal-1.0.17/canal.deployer-1.0.24.tar.gz

（2）解壓

在

/tmp

目錄下的檔案在重新開機後會被自動删除

mkdir /tmp/canal
tar zxvf canal.deployer-$version.tar.gz  -C /tmp/canal
           

（3）修改配置

sudo vi /tmp/canal/conf/example/instance.properties

（4）啟動

./bin/startup.sh

（5）檢視日志

vi /tmp/canal/logs/canal/canal.log

vi /tmp/canal/logs/example/example.log

（6）關閉

./bin/stop.sh

四、搭建canal-client

Maven 配置

<dependency>
    <groupId>com.alibaba.otter</groupId>
    <artifactId>canal.client</artifactId>
    <version>1.0.12</version>
</dependency>
           

CanalDemo.java

package com.donaldy.platform.canalyoung.demo;

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

import com.alibaba.otter.canal.client.CanalConnectors;
import com.alibaba.otter.canal.common.utils.AddressUtils;
import com.alibaba.otter.canal.client.CanalConnector;
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 CanalDemo {

    public static void main(String args[]) {
        // 建立連結
        CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress(AddressUtils.getHostIp(),
                ), "example", "", "");
        int batchSize = ;
        int emptyCount = ;
        try {
            connector.connect();
            connector.subscribe(".*\\..*");
            connector.rollback();
            int totalEmptyCount = ;
            while (emptyCount < totalEmptyCount) {
                Message message = connector.getWithoutAck(batchSize); // 擷取指定數量的資料
                long batchId = message.getId();
                int size = message.getEntries().size();
                if (batchId == - || size == ) {
                    emptyCount++;
                    System.out.println("empty count : " + emptyCount);
                    try {
                        Thread.sleep();
                    } catch (InterruptedException e) {
                    }
                } else {
                    emptyCount = ;
                    // System.out.printf("message[batchId=%s,size=%s] \n", batchId, size);
                    printEntry(message.getEntries());
                }

                connector.ack(batchId); // 送出确認
                // connector.rollback(batchId); // 處理失敗, 復原資料
            }

            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("================&gt; 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("-------&gt; before");
                    printColumn(rowData.getBeforeColumnsList());
                    System.out.println("-------&gt; 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());
        }
    }
}
           

運作

首先啟動Canal Server，即之前的

./bin/startup.sh

建立資料庫，表，插入記錄

# 建立資料庫
create database test;

use test;

# 建立表
create table test (  
uid int () primary key not null auto_increment,  
name varchar() not null);  

# 插入記錄
insert into test (name) values('10');  
           

五、參考資料

https://github.com/alibaba/canal/wiki/QuickStart

https://github.com/alibaba/canal/wiki/ClientExample

https://blog.csdn.net/hackerwin7/article/details/37923607

https://blog.csdn.net/zjerryj/article/details/77152226