What is the right approach to migrating QueryOptions to the new Cassandra Java driver v4.14?

I am migrating from Datastax Cassandra Driver 1.9 to 4.14.x

I would be interested how to migrate this code:

Builder builder =
        Cluster.builder()
            .withQueryOptions(new QueryOptions().setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM));

Is that the right approach and the equivalent to the code above?

DriverConfigLoader driverConfigLoader = DriverConfigLoader.programmaticBuilder()
        .withString(DefaultDriverOption.REQUEST_CONSISTENCY, "LOCAL_QUORUM")
        .build();
    final CqlSessionBuilder cqlSessionBuilder =
        CqlSession.builder()
            .withConfigLoader(driverConfigLoader);

Thanks in advance!

With the drivers 4.x keys configuration keys be defined in application.conf. As long as the file is in the classpath it will load properties and it is the best way to setup your application without having to change your code. documentation

Knowing this, if you still want to do configuration programmatically you indeed have the correct approach:

 DriverConfigLoader loader = DriverConfigLoader.programmaticBuilder()
        .withStringList(DefaultDriverOption.CONTACT_POINTS, Arrays.asList("127.0.0.1:9042"))
        .withString(DefaultDriverOption.REQUEST_CONSISTENCY, "LOCAL_QUORUM")
        .withString(DefaultDriverOption.LOAD_BALANCING_LOCAL_DATACENTER, "datacenter1")
        .withString(DefaultDriverOption.SESSION_KEYSPACE, KEYSPACE_NAME)
        .withDuration(DefaultDriverOption.REQUEST_TIMEOUT, Duration.ofSeconds(5))
        
        // If you want to override with an execution profile
        .startProfile("slow")
        .withDuration(DefaultDriverOption.REQUEST_TIMEOUT, Duration.ofSeconds(30))
        .endProfile()
        .build();
    // Use it to create the session
    try (CqlSession cqlSession = CqlSession.builder().withConfigLoader(loader).build()) {
        
        // Use session
        LOGGER.info("[OK] Connected to Keyspace {}", cqlSession.getKeyspace().get());
    }

A lot of 4.x code can be found here and used as reference.

The Cassandra Java driver was completely refactored from the ground up in version 4.0 so it does mean that it is not binary-compatible with earlier versions so the previous APIs and classes like QueryOptions have been replaced.

There are several ways to configure the driver including the programmaticBuilder() in your example which allows you to programmatically specify configuration options.

There is also a configuration API which allows you to use dynamic profiles or load configuration options at runtime.

Your example code is a direct translation of the programmatic builder in previous releases and it will work. However, our opinion is that in most cases, developers should configure the driver using an application configuration properties file (application.conf or its variations) placed in the application classpath. With this option, the driver configuration is de-coupled from your application.

The obvious advantage of this method is that you can easily reconfigure the driver without having to recompile your application.

There is a reference configuration file (reference.conf) available that has tons of in-line comments for developers. For details, see Configuring the Cassandra Java driver. Cheers!