1 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 对象(原始为 byte 流)

优点： 可以完全和业务代码解耦，增量日志订阅。

缺点：实时性不高，订阅mysql日志，DB中数据事务成功后，开始同步至canal。

2 canal实现MySQL与Elasticsearch7数据同步

下面介绍下利用canal ，canal adapter实现MySQL与ES7数据同步

2.1 Mysql配置修改

在MySQL中需要创建一个用户，并授权：

-- 使用命令登录：mysql -u root -p 
-- 创建用户 用户名：canal  
create user 'canal'@'%' identified by 'canal'; 
-- 授权 .表示所有库 
grant SELECT, REPLICATION SLAVE, REPLICATION CLIENT on . to 'canal'@'%' identified by 'canal';

下一步在MySQL配置文件my.cnf设置如下信息：

[mysqld] 
# 开启binlog 
log-bin=mysql-bin 
# 选择ROW(行)模式 
binlog-format=ROW 
# 配置MySQL replaction需要定义，不要和canal的slaveId重复 
server_id=1

改了配置文件之后，重启MySQL

2.2 下载Canal

下载最新的cana1.1.5并解压，1.1.5 才支持Elasticsearch7
下载地址:
canal.adapter-1.1.5-SNAPSHOT.tar.gz(适配器)
canal.deployer-1.1.5-SNAPSHOT.tar.gz(服务端)

canal.adapter为适配端,canal.deployer为服务端

2.3 启动Canal服务端

2.3.1 修改数据库配置

进入conf/example目录下，修改instance.properties为数据库配置

2.3.2 启动服务端

进入bin目录，双击starup.bat启动，出现下面界面，表明启动成功


服务端启动成功， 接下来进入客户端测试

2.4 启动Canal客户端

2.4.1 修改配置

进入adapter目录，修改application.yml

yml内容：

server:port: 8081
spring:jackson:date-format: yyyy-MM-dd HH:mm:sstime-zone: GMT+8default-property-inclusion: non_nullcanal.conf:mode: rocketMQ #tcp kafka rocketMQ rabbitMQflatMessage: truezookeeperHosts:syncBatchSize: 1000retries: 0timeout:accessKey:secretKey:consumerProperties:# canal tcp consumercanal.tcp.server.host: 127.0.0.1:11111canal.tcp.zookeeper.hosts:canal.tcp.batch.size: 500canal.tcp.username:canal.tcp.password:# kafka consumerkafka.bootstrap.servers: 127.0.0.1:9092kafka.enable.auto.commit: falsekafka.auto.commit.interval.ms: 1000kafka.auto.offset.reset: latestkafka.request.timeout.ms: 40000kafka.session.timeout.ms: 30000kafka.isolation.level: read_committedkafka.max.poll.records: 1000# rocketMQ consumerrocketmq.namespace:rocketmq.namesrv.addr: 127.0.0.1:9876rocketmq.batch.size: 1000rocketmq.enable.message.trace: falserocketmq.customized.trace.topic:rocketmq.access.channel:rocketmq.subscribe.filter:# rabbitMQ consumerrabbitmq.host:rabbitmq.virtual.host:rabbitmq.username:rabbitmq.password:rabbitmq.resource.ownerId:#  srcDataSources:
#    defaultDS:
#      url: jdbc:mysql://127.0.0.1:3306/mytest?useUnicode=true
#      username: root
#      password: 121212canalAdapters:- instance: example # canal instance Name or mq topic namegroups:- groupId: g1outerAdapters:- name: logger
#      - name: rdb
#        key: mysql1
#        properties:
#          jdbc.driverClassName: com.mysql.jdbc.Driver
#          jdbc.url: jdbc:mysql://127.0.0.1:3306/mytest2?useUnicode=true
#          jdbc.username: root
#          jdbc.password: 121212
#      - name: rdb
#        key: oracle1
#        properties:
#          jdbc.driverClassName: oracle.jdbc.OracleDriver
#          jdbc.url: jdbc:oracle:thin:@localhost:49161:XE
#          jdbc.username: mytest
#          jdbc.password: m121212
#      - name: rdb
#        key: postgres1
#        properties:
#          jdbc.driverClassName: org.postgresql.Driver
#          jdbc.url: jdbc:postgresql://localhost:5432/postgres
#          jdbc.username: postgres
#          jdbc.password: 121212
#          threads: 1
#          commitSize: 3000
#      - name: hbase
#        properties:
#          hbase.zookeeper.quorum: 127.0.0.1
#          hbase.zookeeper.property.clientPort: 2181
#          zookeeper.znode.parent: /hbase
#      - name: es
#        hosts: 127.0.0.1:9300 # 127.0.0.1:9200 for rest mode
#        properties:
#          mode: transport # or rest
#          # security.auth: test:123456 #  only used for rest mode
#          cluster.name: elasticsearch
#        - name: kudu
#          key: kudu
#          properties:
#            kudu.master.address: 127.0.0.1 # ',' split multi address

2.4.2 创建索引， 根据同步sql数据至Elasticsearch中

调用http://127.0.0.1:9200/product(PUT请求)创建索引,product为索引名字

{"mappings" : {"properties" : {"attrs" : {"type" : "nested","properties" : {"attrId" : {"type" : "long"},"attrName" : {"type" : "keyword"},"attrValueId" : {"type" : "long"},"attrValueName" : {"type" : "keyword"}}},"tags" : {"type" : "nested","properties" : {"tagId" : {"type" : "long"},"seq" : {"type" : "integer"}}},"brandId" : {"type" : "long"},"brandImg" : {"type" : "keyword"},"brandName" : {"type" : "keyword"},"code" : {"type" : "text","fields" : {"keyword" : {"type" : "keyword","ignore_above" : 256}}},"commentNum" : {"type" : "integer"},"createTime" : {"type" : "date"},"hasStock" : {"type" : "boolean"},"imgUrls" : {"type" : "keyword","index" : false,"doc_values" : false},"mainImgUrl" : {"type" : "text","fields" : {"keyword" : {"type" : "keyword","ignore_above" : 256}}},"marketPriceFee" : {"type" : "long"},"priceFee" : {"type" : "long"},"saleNum" : {"type" : "integer"},"sellingPoint" : {"type" : "text","analyzer" : "ik_max_word","search_analyzer" : "ik_smart"},"shopId" : {"type" : "long"},"shopImg" : {"type" : "keyword","index" : false,"doc_values" : false},"shopName" : {"type" : "text","analyzer" : "ik_max_word","search_analyzer" : "ik_smart"},"shopType" : {"type" : "integer"},"shopPrimaryCategoryId" : {"type" : "long"},"shopPrimaryCategoryName" : {"type" : "keyword"},"shopSecondaryCategoryId" : {"type" : "long"},"shopSecondaryCategoryName" : {"type" : "keyword"},"primaryCategoryId" : {"type" : "long"},"primaryCategoryName" : {"type" : "keyword"},"secondaryCategoryId" : {"type" : "long"},"secondaryCategoryName" : {"type" : "keyword"},"categoryId" : {"type" : "long"},"categoryName" : {"type" : "keyword"},"spuId" : {"type" : "long"},"spuName" : {"type" : "text","analyzer" : "ik_max_word","search_analyzer" : "ik_smart"},"spuStatus" : {"type" : "integer"},"success" : {"type" : "boolean"}}}
}

2.4.3 启动客户端

进入\canal.adapter-1.1.5-SNAPSHOT\bin 双击startup.bat 出现下面界面，表明启动成功

3 注意事项

3.1 使用队列

2.4.1中客户端配置需要配置队列,我使用的rocketmq,大家可以根据自己需要选择队列,根据选择的队列,需改配置

3.2 启动顺序

需要优先启动Mysql和Elasticsearch,然后启动Canal服务端,最后启动客户端

4 验证

当你在操作界面添加一个商品时,那么此时Elasticsearch也会同步这条数据,具体不展开来了