Configure the CData JDBC Driver for Kafka in a Connection Pool in Tomcat

The CData JDBC Drivers support standard JDBC interfaces to integrate with Web applications running on the JVM. This article details how to connect to Kafka data from a connection pool in Tomcat.

Connect to Kafka Data through a Connection Pool in Tomcat

1. Copy the CData JAR and CData .lic file to $CATALINA_HOME/lib. The CData JAR is located in the lib subfolder of the installation directory.
2. Add a definition of the resource to the context. Specify the JDBC URL here.

   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.

   👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)
   

   You can see the JDBC URL specified in the resource definition below.

   <Resource name="jdbc/apachekafka" auth="Container" type="javax.sql.DataSource" driverClassName="cdata.jdbc.apachekafka.ApacheKafkaDriver" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" url="jdbc:apachekafka:User=admin;Password=pass;BootStrapServers=https://localhost:9091;Topic=MyTopic;" maxActive="20" maxIdle="10" maxWait="-1" />
   

   To allow a single application to access Kafka data, add the code above to the context.xml in the application's META-INF directory.

   For a shared resource configuration, add the code above to the context.xml located in $CATALINA_BASE/conf. A shared resource configuration provides connectivity to Kafka for all applications.

3. Add a reference to the resource to the web.xml for the application.

    Kafka data JSP
    jdbc/ApacheKafka
    javax.sql.DataSource
    Container
   
   

4. Initialize connections from the connection pool:

   Context initContext = new InitialContext();
   Context envContext = (Context)initContext.lookup("java:/comp/env");
   DataSource ds = (DataSource)envContext.lookup("jdbc/ApacheKafka");
   Connection conn = ds.getConnection();
    

More Tomcat Integration

The steps above show how to connect to Kafka data in a simple connection pooling scenario. For more use cases and information, see the JNDI Datasource How-To in the Tomcat documentation.