canal demo搭建全記錄

1、環境介紹

canal是阿里開源的中間件，主要用於同步mysql數據庫變動。具體參見：https://github.com/alibaba/canal/releases

搭建環境：

vmware centos7 部署mysql和canal

windows開發canal client，自動捕獲mysql數據庫變動

2、Centos安裝Mysql

一、嘗試用yum安裝mysql

wget http://repo.mysql.com/mysql57-community-release-el7-10.noarch.rpm

返回：2018-07-13 16:04:42 (63.9 KB/s) - ‘mysql57-community-release-el7-10.noarch.rpm’ saved [25548/25548]

sudo rpm -Uvh mysql57-community-release-el7-10.noarch.rpm
sudo yum install -y mysql-community-server

若是執行順利，安裝mysql server 成功。

2.改用阿里源安裝

但是官方的yum源在國內訪問效果不佳，我下載mysql server的速度太慢了，決定改用阿里源

#下載wget
yum install wget -y

#備份當前的yum源
mv /etc/yum.repos.d /etc/yum.repos.d.backup4comex

#新建空的yum源設置目錄
mkdir /etc/yum.repos.d

#下載阿里雲的yum源配置
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

#最後重建緩存
yum clean all
yum makecache

 

3.安裝MariaDB

MariaDB數據庫管理系統是MySQL的一個分支，主要由開源社區在維護，採用GPL受權許可。開發這個分支的緣由之一是：甲骨文公司收購了MySQL後，有將MySQL閉源的潛在風險，所以社區採用分支的方式來避開這個風險。MariaDB的目的是徹底兼容MySQL，包括API和命令行，使之能輕鬆成爲MySQL的代替品。

安裝mariadb，大小59 M。

[root@yl-web yl]# yum install mariadb-server mariadb

其它幾條經常使用的mariadb命令：

systemctl start mariadb  #啓動MariaDB

systemctl stop mariadb  #中止MariaDB

systemctl restart mariadb  #重啓MariaDB

systemctl enable mariadb  #設置開機啓動

運行systemctl start mariadb，而後就能夠正常使用mysql了

4.設置數據庫密碼：

set password for 'root'@'localhost' =password('root');

5.遇到的幾個問題

①從windows訪問centos mysql失敗

解決方案：設置mysql容許遠程鏈接

mysql -u root;
//賦予任何主機訪問數據的權限
mysql>GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;

//使修改生效
mysql>FLUSH PRIVILEGES;

②進行上述操做以後，發現仍然鏈接失敗，返回錯誤

Can't connect to MySQL server on '10.168.12.43' (10060)

解決方案：從windows鏈接vmware裏面的mysql失敗，關閉windows防火牆後成功。

3、部署canal server

（參考：https://github.com/alibaba/canal/wiki/QuickStart）

1.下載canal server

https://github.com/alibaba/canal/releases

我下載的是canal.exaple-1.0.24.gar.gz，下載完成後解壓縮：

mkdir /tmp/canal
tar zxvf canal.deployer-1.0.24.tar.gz  -C /tmp/canal

 

2.查看binlog相關數據庫命令：

是否啓用了日誌
mysql>show variables like 'log_bin';

怎樣知道當前的日誌
mysql> show master status;

查看mysql binlog模式
show variables like 'binlog_format';

獲取binlog文件列表
show binary logs;

查看當前正在寫入的binlog文件
show master status\G

查看指定binlog文件的內容
show binlog events in 'mysql-bin.000002';

3.開啓binlog

若是log_bin關閉，須要在etc下面找到my.cnf，開啓binlog：

server-id=1
log-bin=/var/lib/mysql/mysql-bin

而後重啓mysql服務。

4.添加canal mysql數據庫帳號

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

GRANT ALL PRIVILEGES ON *.* TO 'canal'@'%' ;

FLUSH PRIVILEGES;

5.配置canal實例，設置本地數據庫信息

vi conf/example/instance.properties

## mysql serverId
canal.instance.mysql.slaveId = 1234
# position info
canal.instance.master.address = 10.168.12.43:3306
canal.instance.master.journal.name =mysql-bin.000003
canal.instance.master.position =
canal.instance.master.timestamp =

……

canal.instance.dbUsername = canal
canal.instance.dbPassword = canal
canal.instance.defaultDatabaseName =testcanal
canal.instance.connectionCharset = UTF-8

# table regex
canal.instance.filter.regex = .*\\..*

6.啓動canal

sh bin/startup.sh

7.查看日誌

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

4、canal lient demo

1.引入pom依賴

<dependency>
<groupId>com.alibaba.otter</groupId>
<artifactId>canal.client</artifactId>
<version>1.0.24</version>
</dependency>

 

2.客戶端代碼

public class ClientTest {
    public static void main(String args[]) {
        // 建立連接
        CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("10.168.12.43",
                11111), "example", "", "");
        int batchSize = 1000;
        int emptyCount = 0;
        try {
            connector.connect();
            connector.subscribe(".*\\..*");
            connector.rollback();
            int totalEmptyCount = 120;
            while (emptyCount < totalEmptyCount) {
                Message message = connector.getWithoutAck(batchSize); // 獲取指定數量的數據
                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;
                    printEntry(message.getEntries());
                }

                connector.ack(batchId); // 提交確認
            }

            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());
        }
    }
}

 

3.創建數據庫鏈接，進行insert，delete等數據庫操做

5、遇到的問題

1.canal創建鏈接失敗

解決方案：用telnet命令測試創建鏈接仍然失敗，關閉linux防火牆。

systemctl stop firewalld.service

其餘centos7防火牆相關命令：

firewall-cmd --list-ports#查看已經開放的端口：

firewall-cmd --reload #重啓firewall

systemctl stop firewalld.service #中止firewall

systemctl disable firewalld.service #禁止firewall開機啓動

firewall-cmd --state #查看默認防火牆狀態（關閉後顯示notrunning，開啓後顯示running）