Access Kafka Data in Mule Applications Using the CData JDBC Driver

The CData JDBC Driver for Apache Kafka connects Kafka data to Mule applications enabling read , write, update, and delete functionality with familiar SQL queries. The JDBC Driver allows users to easily create Mule applications to backup, transform, report, and analyze Kafka data.

This article demonstrates how to use the CData JDBC Driver for Apache Kafka inside of a Mule project to create a Web interface for Kafka data. The application created allows you to request Kafka data using an HTTP request and have the results returned as JSON. The exact same procedure outlined below can be used with any CData JDBC Driver to create a Web interface for the hundreds of available data sources.

1. Create a new Mule Project in Anypoint Studio.
2. Add an HTTP Connector to the Message Flow.
3. Configure the address for the HTTP Connector. 👁 Add and Configure the HTTP Connector
   
4. Add a Database Select Connector to the same flow, after the HTTP Connector.
5. Create a new Connection (or edit an existing one) and configure the properties.
   • Set Connection to "Generic Connection"
   • Select the CData JDBC Driver JAR file in the Required Libraries section (e.g. cdata.jdbc.apachekafka.jar). 👁 Adding the JAR file (Salesforce is shown).
     
   • Set the URL to the connection string for Kafka

     Set BootstrapServers and the Topic properties to specify the address of your Apache Kafka server, as well as the topic you would like to interact with.

     Authorization Mechanisms

     • SASL Plain: The User and Password properties should be specified. AuthScheme should be set to 'Plain'.
     • SASL SSL: The User and Password properties should be specified. AuthScheme should be set to 'Scram'. UseSSL should be set to true.
     • SSL: The SSLCert and SSLCertPassword properties should be specified. UseSSL should be set to true.
     • Kerberos: The User and Password properties should be specified. AuthScheme should be set to 'Kerberos'.

     You may be required to trust the server certificate. In such cases, specify the TrustStorePath and the TrustStorePassword if necessary.

     Built-in Connection String Designer

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

     		java -jar cdata.jdbc.apachekafka.jar
     		

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

   • Set the Driver class name to cdata.jdbc.apachekafka.ApacheKafkaDriver. 👁 A configured Database Connection (Salesforce is shown).
     
   • Click Test Connection.
6. Set the SQL Query Text to a SQL query to request Kafka data. For example:

   SELECT Id, Column1 FROM SampleTable_1 WHERE Column2 = '100'

   👁 Configure the Select object (Salesforce is Shown)
   
7. Add a Transform Message Component to the flow.
8. Set the Output script to the following to convert the payload to JSON:

   %dw 2.0
   output application/json
   ---
   payload
    

   👁 Add the Transform Message Component to the Flow
   
9. To view your Kafka data, navigate to the address you configured for the HTTP Connector (localhost:8081 by default): http://localhost:8081. The Kafka data is available as JSON in your Web browser and any other tools capable of consuming JSON endpoints.

At this point, you have a simple Web interface for working with Kafka data (as JSON data) in custom apps and a wide variety of BI, reporting, and ETL tools. Download a free, 30 day trial of the JDBC Driver for Kafka and see the CData difference in your Mule Applications today.