The Canal source connector pulls messages from MySQL to Pulsar topics.

Configuration

The configuration of Canal source connector has the following properties.

Property

Example

Before using the Canal connector, you can create a configuration file through one of the following methods.

• JSON

  {
      "zkServers": "127.0.0.1:2181",
      "batchSize": "5120",
      "destination": "example",
      "username": "",
      "password": "",
      "cluster": false,
      "singleHostname": "127.0.0.1",
      "singlePort": "11111",
  }
  

• YAML

  You can create a YAML file and copy the contents below to your YAML file.

  configs:
      zkServers: "127.0.0.1:2181"
      batchSize: 5120
      destination: "example"
      username: ""
      password: ""
      cluster: false
      singleHostname: "127.0.0.1"
      singlePort: 11111
  

Usage

Here is an example of storing MySQL data using the configuration file as above.

1. Start a MySQL server.

   $ docker pull mysql:5.7
   $ docker run -d -it --rm --name pulsar-mysql -p 3306:3306 -e MYSQL_ROOT_PASSWORD=canal -e MYSQL_USER=mysqluser -e MYSQL_PASSWORD=mysqlpw mysql:5.7
   

2. Create a configuration file mysqld.cnf.

   [mysqld]
   pid-file    = /var/run/mysqld/mysqld.pid
   socket      = /var/run/mysqld/mysqld.sock
   datadir     = /var/lib/mysql
   #log-error  = /var/log/mysql/error.log
   # By default we only accept connections from localhost
   #bind-address   = 127.0.0.1
   # Disabling symbolic-links is recommended to prevent assorted security risks
   symbolic-links=0
   log-bin=mysql-bin
   binlog-format=ROW
   server_id=1
   

3. Copy the configuration file mysqld.cnf to MySQL server.

   $ docker cp mysqld.cnf pulsar-mysql:/etc/mysql/mysql.conf.d/
   

4. Restart the MySQL server.

   $ docker restart pulsar-mysql
   

5. Create a test database in MySQL server.

   $ docker exec -it pulsar-mysql /bin/bash
   $ mysql -h 127.0.0.1 -uroot -pcanal -e 'create database test;'
   

6. Start a Canal server and connect to MySQL server.

   $ docker pull canal/canal-server:v1.1.2
   $ docker run -d -it --link pulsar-mysql -e canal.auto.scan=false -e canal.destinations=test -e canal.instance.master.address=pulsar-mysql:3306 -e canal.instance.dbUsername=root -e canal.instance.dbPassword=canal -e canal.instance.connectionCharset=UTF-8 -e canal.instance.tsdb.enable=true -e canal.instance.gtidon=false --name=pulsar-canal-server -p 8000:8000 -p 2222:2222 -p 11111:11111 -p 11112:11112 -m 4096m canal/canal-server:v1.1.2
   

7. Start Pulsar standalone.

   $ docker pull apachepulsar/pulsar:2.3.0
   $ docker run -d -it --link pulsar-canal-server -p 6650:6650 -p 8080:8080 -v $PWD/data:/pulsar/data --name pulsar-standalone apachepulsar/pulsar:2.3.0 bin/pulsar standalone
   

8. Modify the configuration file canal-mysql-source-config.yaml.

   configs:
       zkServers: ""
       batchSize: "5120"
       destination: "test"
       username: ""
       password: ""
       cluster: false
       singleHostname: "pulsar-canal-server"
       singlePort: "11111"
   

9. Create a consumer file pulsar-client.py.

   import pulsar
   
   client = pulsar.Client('pulsar://localhost:6650')
   consumer = client.subscribe('my-topic',
                               subscription_name='my-sub')
   
   while True:
       msg = consumer.receive()
       print("Received message: '%s'" % msg.data())
       consumer.acknowledge(msg)
   
   client.close()
   

10. Copy the configuration file canal-mysql-source-config.yaml and the consumer file pulsar-client.py to Pulsar server.

    $ docker cp canal-mysql-source-config.yaml pulsar-standalone:/pulsar/conf/
    $ docker cp pulsar-client.py pulsar-standalone:/pulsar/
    

11. Download a Canal connector and start it.

    $ docker exec -it pulsar-standalone /bin/bash
    $ wget https://archive.apache.org/dist/pulsar/pulsar-2.3.0/connectors/pulsar-io-canal-2.3.0.nar -P connectors
    $ ./bin/pulsar-admin source localrun \
    --archive ./connectors/pulsar-io-canal-2.3.0.nar \
    --classname org.apache.pulsar.io.canal.CanalStringSource \
    --tenant public \
    --namespace default \
    --name canal \
    --destination-topic-name my-topic \
    --source-config-file /pulsar/conf/canal-mysql-source-config.yaml \
    --parallelism 1
    

12. Consume data from MySQL.

    $ docker exec -it pulsar-standalone /bin/bash
    $ python pulsar-client.py
    

13. Open another window to log in MySQL server.

    $ docker exec -it pulsar-mysql /bin/bash
    $ mysql -h 127.0.0.1 -uroot -pcanal
    

14. Create a table, and insert, delete, and update data in MySQL server.

    mysql> use test;
    mysql> show tables;
    mysql> CREATE TABLE IF NOT EXISTS `test_table`(`test_id` INT UNSIGNED AUTO_INCREMENT,`test_title` VARCHAR(100) NOT NULL,
    `test_author` VARCHAR(40) NOT NULL,
    `test_date` DATE,PRIMARY KEY ( `test_id` ))ENGINE=InnoDB DEFAULT CHARSET=utf8;
    mysql> INSERT INTO test_table (test_title, test_author, test_date) VALUES("a", "b", NOW());
    mysql> UPDATE test_table SET test_title='c' WHERE test_title='a';
    mysql> DELETE FROM test_table WHERE test_title='c';