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

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Configuration

The configuration of Canal source connector has the following properties.

​
Property

NameRequiredSensitiveDefaultDescription
usernametruetrueNoneCanal server account (not MySQL).
passwordtruetrueNoneCanal server password (not MySQL).
destinationtruefalseNoneSource destination that Canal source connector connects to.
singleHostnamefalsefalseNoneCanal server address.
singlePortfalsefalseNoneCanal server port.
clustertruefalsefalseWhether to enable cluster mode based on Canal server configuration or not.

  • true: cluster mode.
    If set to true, it talks to zkServers to figure out the actual database host.

  • false: standalone mode.
    If set to false, it connects to the database specified by singleHostname and singlePort.
    • zkServerstruefalseNoneAddress and port of the Zookeeper that Canal source connector talks to figure out the actual database host.
    batchSizefalsefalse1000Batch size to fetch from Canal.

    ​
    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';