简介

canal，阿里开源工具，主要用途是基于 MySQL 数据库增量日志解析，提供增量数据订阅和消费

应用场景

  • 数据库实时备份
  • 业务cache刷新
  • 索引构建和实时维护，例：将商品数据推送到es中构建倒排索引
  • 带业务逻辑的增量数据处理，例：增量数据推送到第三方平台

官网

https://github.com/alibaba/canal

原理

  1. MySQL master将数据写入binlog
  2. canal 向master发送dump协议
  3. master 收到dump请求，推送binlog给canal
  4. canal 解析binlog，可讲数据投递到MQ系统中，目前支持kafka、RocketMQ

安装

配置mysql

建议的mysql版本是5.7.x
mysql8.0.x见官方说明https://github.com/alibaba/ca...

修改mysql配置文件my.cnf

[mysqld]log-bin=mysql-bin # 开启 binlogbinlog-format=ROW # 选择 ROW 模式server_id=1

新增用户并授权，测试的话可以直接使用root用户

CREATE USER canal IDENTIFIED BY 'canal';  GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO '123456'@'%';-- GRANT ALL PRIVILEGES ON *.* TO 'canal'@'%' ;FLUSH PRIVILEGES;

配置canal

查看是否安装java

➜  canal-admin java -versionjava version "1.8.0_251"Java(TM) SE Runtime Environment (build 1.8.0_251-b08)Java HotSpot(TM) 64-Bit Server VM (build 25.251-b08, mixed mode)

若没有安装，去oracle官网下载1.8版本（切勿选择高版本），选择适合自己系统的版本安装即可，mac系统下载的dmg，直接点击安装，不再累述image.png

访问release页面，下载最新稳定版1.14
wget https://github.com/alibaba/canal/releases/download/canal-1.1.4/canal.deployer-1.1.4.tar.gz

解压到指定目录

mkdir /tmp/canaltar zxvf canal.deployer-1.1.4.tar.gz  -C /tmp/canal

进入到canal目录，查看文件

  • bin目录：运行命令
  • conf目录：配置文件目录
  • logs目录：记录运行log
  • lib目录：jar包
➜  ll                                  total 0drwxr-xr-x   7 jiao  staff   224B  6  3 17:17 bindrwxr-xr-x   9 jiao  staff   288B  6  3 20:12 confdrwxr-xr-x  83 jiao  staff   2.6K  6  1 17:54 libdrwxr-xr-x   7 jiao  staff   224B  6  3 17:05 logsdrwxr-xr-x   7 jiao  staff   224B  5 29 17:43 pierced

修改instance配置文件

vi conf/example/instance.properties

配置参数详解：https://github.com/alibaba/ca...

我这里修改了数据连接地址，用户和密码，以及同步规则：只同步test数据库的sc_user表

## mysql serverIdcanal.instance.mysql.slaveId = 1234#position info，需要改成自己的数据库信息canal.instance.master.address = 127.0.0.1:3306 canal.instance.dbUsername = canal  canal.instance.dbPassword = 123456#主库binlog文件路径#canal.instance.standby.journal.name =#主库binlog偏移量#canal.instance.standby.position =canal.instance.filter.regex = test\\.sc_user

修改Server配置文件
vim conf/canal.properties

#tcp bind ip，设置投递到tcp时需设置canal.ip = 192.168.101.47#register ip to zookeepercanal.register.ip = 192.168.101.47canal.port = 11111canal.metrics.pull.port = 11112#canal instance user/passwd#canal.user = canal#canal.passwd = E3619321C1A937C46A0D8BD1DAC39F93B27D4458#canal-admin需设置，先不设置 #canal.admin.manager = 127.0.0.1:8089canal.admin.port = 11110canal.admin.user = admincanal.admin.passwd = 4ACFE3202A5FF5CF467898FC58AAB1D615029441#zk设置，单机的canal可不设置canal.zkServers = 127.0.0.1:2181,127.0.0.1:2182,127.0.0.1:2183#flush data to zkcanal.zookeeper.flush.period = 1000canal.withoutNetty = false#tcp, kafka, RocketMQ，投递到哪canal.serverMode = RocketMQ#flush meta cursor/parse position to filecanal.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 1kbcanal.instance.memory.buffer.memunit = 1024 ##meory store gets mode used MEMSIZE or ITEMSIZEcanal.instance.memory.batch.mode = MEMSIZEcanal.instance.memory.rawEntry = true##detecing configcanal.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 1canal.instance.detecting.interval.time = 3canal.instance.detecting.retry.threshold = 3canal.instance.detecting.heartbeatHaEnable = false#support maximum transaction size, more than the size of the transaction will be cut into multiple transactions deliverycanal.instance.transaction.size =  1024#mysql fallback connected to new master should fallback timescanal.instance.fallbackIntervalInSeconds = 60#network configcanal.instance.network.receiveBufferSize = 16384canal.instance.network.sendBufferSize = 16384canal.instance.network.soTimeout = 30#binlog filter configcanal.instance.filter.druid.ddl = truecanal.instance.filter.query.dcl = falsecanal.instance.filter.query.dml = falsecanal.instance.filter.query.ddl = falsecanal.instance.filter.table.error = falsecanal.instance.filter.rows = falsecanal.instance.filter.transaction.entry = false#binlog format/image checkcanal.instance.binlog.format = ROW,STATEMENT,MIXED canal.instance.binlog.image = FULL,MINIMAL,NOBLOB#binlog ddl isolationcanal.instance.get.ddl.isolation = false#parallel parser configcanal.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 2canal.instance.parser.parallelBufferSize = 256#table meta tsdb infocanal.instance.tsdb.enable = truecanal.instance.tsdb.dir = ${canal.file.data.dir:../conf}/${canal.instance.destination:}canal.instance.tsdb.url = jdbc:h2:${canal.instance.tsdb.dir}/h2;CACHE_SIZE=1000;MODE=MYSQL;canal.instance.tsdb.dbUsername = canalcanal.instance.tsdb.dbPassword = canal#dump snapshot interval, default 24 hourcanal.instance.tsdb.snapshot.interval = 24#purge snapshot expire , default 360 hour(15 days)canal.instance.tsdb.snapshot.expire = 360#aliyun ak/sk , support rds/mqcanal.aliyun.accessKey =canal.aliyun.secretKey =##########################################################         destinations        ###############################################################使用的instance，可设置上面定义的examplecanal.destinations = example#conf root dircanal.conf.dir = ../conf#auto scan instance dir add/remove and start/stop instancecanal.auto.scan = truecanal.auto.scan.interval = 5canal.instance.tsdb.spring.xml = classpath:spring/tsdb/h2-tsdb.xml#canal.instance.tsdb.spring.xml = classpath:spring/tsdb/mysql-tsdb.xmlcanal.instance.global.mode = managercanal.instance.global.lazy = falsecanal.instance.global.manager.address = ${canal.admin.manager}#canal.instance.global.spring.xml = classpath:spring/memory-instance.xmlcanal.instance.global.spring.xml = classpath:spring/file-instance.xml#canal.instance.global.spring.xml = classpath:spring/default-instance.xml###########################################################              MQ              ################################################################rocketmq地址设置canal.mq.servers = 192.168.101.47:9876canal.mq.retries = 0canal.mq.batchSize = 16384canal.mq.maxRequestSize = 1048576canal.mq.lingerMs = 100canal.mq.bufferMemory = 33554432canal.mq.canalBatchSize = 50canal.mq.canalGetTimeout = 100canal.mq.flatMessage = truecanal.mq.compressionType = nonecanal.mq.acks = all#canal.mq.properties. =canal.mq.producerGroup = test#Set this value to "cloud", if you want open message trace feature in aliyun.canal.mq.accessChannel = local#aliyun mq namespace#canal.mq.namespace =###########################################################     Kafka Kerberos Info    ###############################################################canal.mq.kafka.kerberos.enable = falsecanal.mq.kafka.kerberos.krb5FilePath = "../conf/kerberos/krb5.conf"canal.mq.kafka.kerberos.jaasFilePath = "../conf/kerberos/jaas.conf"

测试tcp

下载canal php客户端: https://github.com/xingwenge/canal-php

修改src/sample/client.php文件

<?phpnamespace xingwenge\canal_php\sample;use xingwenge\canal_php\CanalClient;use xingwenge\canal_php\CanalConnectorFactory;use xingwenge\canal_php\Fmt;require_once __DIR__ . '/../../vendor/autoload.php';ini_set('display_errors', 'On');error_reporting(E_ALL);try {    $host   = '192.168.101.47';//canal server地址    $client = CanalConnectorFactory::createClient(CanalClient::TYPE_SOCKET);    # $client = CanalConnectorFactory::createClient(CanalClient::TYPE_SWOOLE);    $client->connect($host, 11111);    $client->checkValid('canal','E3619321C1A937C46A0D8BD1DAC39F93B27D4458');//认证信息，对于canal.properties配置的canal.user 和canal.passwd//    $client->subscribe("1001", "example", ".*\\..*");    $client->subscribe("1001", "example", "test.sc_user"); # 设置过滤规则    while (true) {        $message = $client->get(100);        if ($entries = $message->getEntries()) {            foreach ($entries as $entry) {                Fmt::println($entry);            }        }        sleep(1);    }    $client->disConnect();} catch (\Exception $e) {    echo $e->getMessage(), PHP_EOL;}

运行canal
sh bin/startup.sh
查看log是否有错误信息
tail -n 50 -f logs/example/example.log
输出一下内容说明canal已正常启动，canal已成功连接mysql准备发送dump指令同步数据

2020-06-03 19:30:47.625 [destination = example , address = /127.0.0.1:3307 , EventParser] WARN  c.a.o.c.p.inbound.mysql.rds.RdsBinlogEventParserProxy - ---> find start position successfully, EntryPosition[included=false,journalName=mysql-bin.000001,position=303179,serverId=1,gtid=,timestamp=1591183839000] cost : 5ms , the next step is binlog dump

运行php client.php，并在数据库sc_user表中修改一条数据，可以看到client输出了数据库修改的内容
`================> binlog[mysql-bin.000001 : 208118],name[wcc-scm-service,sc_status_history], eventType: 2

-------> before
status_history_id : 2543 update= false
record_id : 662 update= false
status_type : 151 update= false
old_status : 158 update= false
new_status : 153 update= false
opt_type : SELLER_REVOKE update= false
user_id : 282 update= false
user_name : 加工厂1 update= false
remark : update= false
created : 2020-05-28 18:40:02 update= false
-------> after
status_history_id : 2543 update= false
record_id : 662 update= false
status_type : 151 update= false
old_status : 158 update= false
new_status : 153 update= false
opt_type : SELLER_REVOKE update= false
user_id : 282 update= false
user_name : 加工厂12 update= true
remark : update= false
created : 2020-05-28 18:40:02 update= false
TSocket: Could not read 4 bytes from 192.168.101.47:11111`

测试RocketMQ

安装RocketMQ

这里直接在docker里安装

1.安装server
docker run -d -p 9876:9876 --name rocketmq-server -e "MAX\_POSSIBLE\_HEAP=100000000" rocketmqinc/rocketmq sh mqnamesrv
2.新增配置文件
echo "brokerIP1=192.168.101.47" > broker.properties
3.安装broker将/path/broker.properties替换成第2步文件路径
docker run -d -p 10911:10911 -p 10909:10909 -v /path/broker.properties:/opt/rocketmq-4.4.0/bin/broker.properties --name rocketmq-broker --link rocketmq-server -e "NAMESRV\_ADDR=rocketmq-server:9876" -e "MAX\_POSSIBLE\_HEAP=200000000" rocketmqinc/rocketmq sh mqbroker -c broker.properties
4.安装RocketMQ Web
docker run -e "JAVA\_OPTS=-Drocketmq.namesrv.addr=192.168.101.47:9876 -Dcom.rocketmq.sendMessageWithVIPChannel=false" -p 8080:8080 -t styletang/rocketmq-console-ng -d

访问Rocket管理页面
http://localhost:8080/

修改配置文件

修改canal.properties
投递到tcp修改成投递到RocketMQ
`canal.serverMode = RocketMQ
canal.mq.servers = 192.168.101.47:9876`

运行canal

sh bin/startup.sh
查看log文件，排查是否有错误
tail -n 50 -f logs/canal/canal.log
tail -n 50 -f logs/example/example.log

顺利的话，在RocketMQ中可以查看到，新增的Topic和Message，RocketMQ可以在manage页面直接查看messge内容

后记

在安装和使用canal的时候还是遇到了一些坑，比如java高版本报错，投递到消息队列失败等，需要耐心排查log日志，分析原因，canal也用到了很多技术栈[zookeeper、kafka、RocketMQ]，后续将会进一步去深入研究。