Page 5: User-Defined Functions (UDFs) and Security

5. User-Defined Functions (UDFs) and Security

Trino provides a wide range of built-in functions, but you can extend its functionality by creating User-Defined Functions (UDFs) for specific business logic or complex calculations. Additionally, configuring security settings to protect data access is crucial.

5.1. Creating User-Defined Functions (UDFs)

Trino UDFs are written in Java and deployed as plugins to the Trino server. Let's look at a simple UDF example.

Here is an example UDF that converts an input string to uppercase. (Actual implementation requires a build and deployment process.)

import io.trino.spi.function.Description;
import io.trino.spi.function.ScalarFunction;
import io.trino.spi.function.SqlType;
import io.trino.spi.type.StandardTypes;
import io.airlift.slice.Slice;
import io.airlift.slice.Slices;

public class MyStringFunctions
{
    @Description("Converts a string to uppercase")
    @ScalarFunction("my_upper")
    @SqlType(StandardTypes.VARCHAR)
    public static Slice myUpper(@SqlType(StandardTypes.VARCHAR) Slice input)
    {
        return Slices.utf8Slice(input.toStringUtf8().toUpperCase());
    }
}

Once this UDF is deployed, you can use it in Trino queries like SELECT my_upper(\'hello\');.

5.2. Trino Security Configuration

Key security features for protecting your Trino environment include:

• Authentication: Verifies the identity of users connecting to the Trino server. Supports LDAP, Kerberos, JWT (JSON Web Token), etc. Configured in the config.properties file.
• Authorization: Defines what actions authenticated users can perform on specific catalogs, schemas, tables, or columns. It follows the SQL standard authorization model and is configured in the etc/access-control.properties file.
• TLS/SSL: Encrypts all communication between clients and the Trino server to prevent data interception. Configure http-server.https.enabled=true and certificate paths in config.properties.
• Audit Logging: Records all queries and user activities for security auditing and monitoring.

If you have completed all five steps, you are now ready to build and leverage a powerful and secure Trino-based data querying environment.