Stream Avro Data into Apache Kafka Topics

Apache Kafka is an open-source stream processing platform that is primarily used for building real-time data pipelines and event-driven applications. When paired with the CData JDBC Driver for Avro, Kafka can work with live Avro data. This article describes how to connect, access and stream Avro data into Apache Kafka Topics and to start Confluent Control Center to help users secure, manage, and monitor the Avro data received using Kafka infrastructure in the Confluent Platform.

With built-in optimized data processing, the CData JDBC Driver offers unmatched performance for interacting with live Avro data. When you issue complex SQL queries to Avro, the driver pushes supported SQL operations, like filters and aggregations, directly to Avro and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations). Its built-in dynamic metadata querying allows you to work with and analyze Avro data using native data types.

Prerequisites

Before connecting the CData JDBC Driver for streaming Avro data in Apache Kafka Topics, install and configure the following in the client Linux-based system.

1. Confluent Platform for Apache Kafka
2. Confluent Hub CLI Installation
3. Self-Managed Kafka JDBC Source Connector for Confluent Platform

Define a New JDBC Connection to Avro data

1. Download CData JDBC Driver for Avro on a Linux-based system
2. Follow the given instructions to create a new directory extract all the driver contents into it:
   1. Create a new directory named Avro mkdir Avro
   2. Move the downloaded driver file (.zip) into this new directory mv AvroJDBCDriver.zip Avro/
   3. Unzip the CData AvroJDBCDriver contents into this new directory unzip AvroJDBCDriver.zip
3. Open the Avro directory and navigate to the lib folder ls cd lib/
4. Copy the contents of the lib folder of Avro into the lib folder of Kafka Connect JDBC. Check the Kafka Connect JDBC folder contents to confirm that the cdata.jdbc.avro.jar file is successfully copied into the lib folder cp * ../../confluent-7.5.0/share/confluent-hub-components/confluentinc-kafka-connect-jdbc/lib/ cd ../../confluent-7.5.0/share/confluent-hub-components/confluentinc-kafka-connect-jdbc/lib/
5. Install the CData Avro JDBC driver license using the given command, followed by your Name and Email ID java -jar cdata.jdbc.avro.jar -l
6. Enter the product key or "TRIAL" (In the scenarios of license expiry, please contact our CData Support team)
7. Start the Confluent local services using the command: confluent local services start

   This starts all the Confluent Services like Zookeeper, Kafka, Schema Registry, Kafka REST, Kafka CONNECT, ksqlDB and Control Center. You are now ready to use the CData JDBC driver for Avro to stream messages using Kafka Connect Driver into Kafka Topics on ksqlDB.

8. Create the Kafka topics manually using a POST HTTP API Request: curl --location 'server_address:8083/connectors' --header 'Content-Type: application/json' --data '{ "name": "jdbc_source_cdata_avro_01", "config": { "connector.class": "io.confluent.connect.jdbc.JdbcSourceConnector", "connection.url": "jdbc:avro:URI=C:/folder/table.avro; InitiateOAuth=GETANDREFRESH", "topic.prefix": "avro-01-", "mode": "bulk" } }'

   Let us understand the fields used in the HTTP POST body (shown above):

   • connector.class: Specifies the Java class of the Kafka Connect connector to be used.
   • connection.url: The JDBC connection URL to connect with Avro data.

     Built-in Connection String Designer

     For assistance in constructing the JDBC URL, use the connection string designer built into the Avro JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

     java -jar cdata.jdbc.avro.jar

     Fill in the connection properties and copy the connection string to the clipboard.

     Connect to your local Avro file(s) by setting the URI connection property to the location of the Avro file.

   • topic.prefix: A prefix that will be added to the Kafka topics created by the connector. It's set to "avro-01-".
   • mode: Specifies the mode in which the connector operates. In this case, it's set to "bulk", which suggests that the connector is configured to perform bulk data transfer.

   This request adds all the tables/contents from Avro as Kafka Topics.

   Note: The IP Address (server) to POST the request (shown above) is the Linux Network IP Address.

9. Run ksqlDB and list the topics. Use the commands: ksql list topics;
10. To view the data inside the topics, type the SQL Statement: PRINT topic FROM BEGINNING;

Connecting with the Confluent Control Center

To access the Confluent Control Center user interface, ensure to run the "confluent local services" as described in the above section and type http://<server address>:9021/clusters/ on your local browser.

Get Started Today

Download a free, 30-day trial of the CData JDBC Driver for Avro and start streaming Avro data into Apache Kafka. Reach out to our Support Team if you have any questions.