Token Provider

/**
 * Kafka delegation token provider for Apache Spark
 * Implements HadoopDelegationTokenProvider to integrate with Spark's security framework
 */
class KafkaDelegationTokenProvider extends HadoopDelegationTokenProvider with Logging {
  
  /**
   * Service name identifier for this token provider
   * @return "kafka"
   */
  def serviceName: String
  
  /**
   * Obtains delegation tokens for all configured Kafka clusters
   * @param hadoopConf Hadoop configuration
   * @param sparkConf Spark configuration containing cluster settings
   * @param creds Credentials object to store obtained tokens
   * @return Optional next renewal time (earliest across all clusters)
   */
  def obtainDelegationTokens(
    hadoopConf: Configuration,
    sparkConf: SparkConf,
    creds: Credentials
  ): Option[Long]
  
  /**
   * Checks if delegation tokens are required for any configured Kafka cluster
   * @param sparkConf Spark configuration
   * @param hadoopConf Hadoop configuration  
   * @return true if tokens are required, false otherwise
   */
  def delegationTokensRequired(
    sparkConf: SparkConf,
    hadoopConf: Configuration
  ): Boolean
}

import org.apache.spark.SparkConf
import org.apache.spark.kafka010.KafkaDelegationTokenProvider
import org.apache.hadoop.conf.Configuration
import org.apache.hadoop.security.Credentials

// Setup Spark configuration with Kafka cluster details
val sparkConf = new SparkConf()
  .set("spark.kafka.clusters.prod.auth.bootstrap.servers", "kafka1:9092,kafka2:9092")
  .set("spark.kafka.clusters.prod.security.protocol", "SASL_SSL")
  .set("spark.kafka.clusters.prod.sasl.kerberos.service.name", "kafka")
  .set("spark.kafka.clusters.prod.ssl.truststore.location", "/path/to/truststore.jks")
  .set("spark.kafka.clusters.prod.ssl.truststore.password", "password")

// Create provider and check requirements
val tokenProvider = new KafkaDelegationTokenProvider()
val hadoopConf = new Configuration()

// Check if tokens are needed
if (tokenProvider.delegationTokensRequired(sparkConf, hadoopConf)) {
  println("Delegation tokens are required for configured Kafka clusters")
  
  // Obtain tokens
  val credentials = new Credentials()
  val nextRenewal = tokenProvider.obtainDelegationTokens(hadoopConf, sparkConf, credentials)
  
  nextRenewal match {
    case Some(renewalTime) => 
      println(s"Tokens obtained successfully. Next renewal: $renewalTime")
    case None => 
      println("No tokens obtained or renewal not required")
  }
} else {
  println("No delegation tokens required")
}

// Configure multiple Kafka clusters
val sparkConf = new SparkConf()
  // Production cluster
  .set("spark.kafka.clusters.prod.auth.bootstrap.servers", "prod-kafka1:9092")
  .set("spark.kafka.clusters.prod.security.protocol", "SASL_SSL")
  .set("spark.kafka.clusters.prod.target.bootstrap.servers.regex", "prod-kafka.*:9092")
  
  // Development cluster  
  .set("spark.kafka.clusters.dev.auth.bootstrap.servers", "dev-kafka1:9092")
  .set("spark.kafka.clusters.dev.security.protocol", "SASL_PLAINTEXT")
  .set("spark.kafka.clusters.dev.target.bootstrap.servers.regex", "dev-kafka.*:9092")

val tokenProvider = new KafkaDelegationTokenProvider()
val credentials = new Credentials()

// This will obtain tokens for both clusters
tokenProvider.obtainDelegationTokens(new Configuration(), sparkConf, credentials)

/**
 * Service name identifier for this token provider
 * @return "kafka" - the service name used by Hadoop security framework
 */
def serviceName: String

/**
 * Checks if delegation tokens are required for any configured Kafka cluster
 * Returns true if any cluster requires delegation tokens based on:
 * - Security protocol (SASL_SSL, SASL_PLAINTEXT, SSL)
 * - Authentication method availability
 * - Current user credentials
 * 
 * @param sparkConf Spark configuration containing cluster settings
 * @param hadoopConf Hadoop configuration
 * @return true if delegation tokens are required, false otherwise
 */
def delegationTokensRequired(sparkConf: SparkConf, hadoopConf: Configuration): Boolean

/**
 * Obtains delegation tokens for all configured Kafka clusters
 * Processes each cluster configuration and:
 * - Validates security requirements
 * - Connects to Kafka cluster using admin client
 * - Requests delegation token with appropriate credentials
 * - Stores token in provided Credentials object
 * - Tracks renewal times across all clusters
 * 
 * @param hadoopConf Hadoop configuration
 * @param sparkConf Spark configuration containing cluster settings under spark.kafka.clusters.*
 * @param creds Credentials object to store obtained tokens
 * @return Optional next renewal time (earliest across all clusters), None if no tokens obtained
 */
def obtainDelegationTokens(
  hadoopConf: Configuration,
  sparkConf: SparkConf,
  creds: Credentials
): Option[Long]