CLI Services

/**
 * Core CLI service implementation with Spark SQL integration
 * @param hiveServer The parent HiveServer2 instance
 * @param sqlContext The Spark SQL context for query execution
 */
class SparkSQLCLIService(hiveServer: HiveServer2, sqlContext: SQLContext) extends CLIService(hiveServer) {
  /**
   * Initialize the CLI service with Hive configuration
   * @param hiveConf Hive configuration object containing server settings
   */
  def init(hiveConf: HiveConf): Unit
  
  /**
   * Start the CLI service and all composite services
   */
  def start(): Unit
  
  /**
   * Get server information for a given session
   * @param sessionHandle Handle identifying the client session
   * @param getInfoType Type of information to retrieve
   * @return GetInfoValue containing the requested information
   */
  def getInfo(sessionHandle: SessionHandle, getInfoType: GetInfoType): GetInfoValue
}

import org.apache.spark.sql.hive.thriftserver.SparkSQLCLIService
import org.apache.hadoop.hive.conf.HiveConf
import org.apache.hive.service.server.HiveServer2

// Create and initialize the CLI service
val hiveServer = new HiveServer2()
val cliService = new SparkSQLCLIService(hiveServer, SparkSQLEnv.sqlContext)

// Initialize with configuration
val hiveConf = new HiveConf()
cliService.init(hiveConf)

// Start the service
cliService.start()

// Information types supported by getInfo()
import org.apache.hive.service.cli.GetInfoType

// Spark SQL specific information
GetInfoType.CLI_SERVER_NAME    // Returns "Spark SQL"
GetInfoType.CLI_DBMS_NAME      // Returns "Spark SQL" 
GetInfoType.CLI_DBMS_VER       // Returns Spark version
GetInfoType.CLI_ODBC_KEYWORDS  // Returns SQL keywords supported by Spark

import org.apache.hive.service.cli.{GetInfoType, SessionHandle}

// Get server information
val serverName = cliService.getInfo(sessionHandle, GetInfoType.CLI_SERVER_NAME)
println(s"Server: ${serverName.getStringValue()}")  // "Spark SQL"

val version = cliService.getInfo(sessionHandle, GetInfoType.CLI_DBMS_VER)
println(s"Version: ${version.getStringValue()}")    // "3.5.6"

val keywords = cliService.getInfo(sessionHandle, GetInfoType.CLI_ODBC_KEYWORDS)
println(s"Keywords: ${keywords.getStringValue()}")  // "SELECT,FROM,WHERE,..."

// Authentication configuration in init()
// Kerberos authentication
hive.server2.authentication = "KERBEROS"
hive.server2.authentication.kerberos.principal = "spark/_HOST@REALM"
hive.server2.authentication.kerberos.keytab = "/etc/spark/spark.keytab"

// SPNEGO for HTTP transport
hive.server2.authentication.spnego.principal = "HTTP/_HOST@REALM"  
hive.server2.authentication.spnego.keytab = "/etc/spark/spnego.keytab"

// Custom authentication providers
hive.server2.authentication = "CUSTOM"
hive.server2.custom.authentication.class = "com.example.MyAuthProvider"

/**
 * Trait providing composite service functionality via reflection
 * Used to maintain compatibility with HiveServer2 internal APIs
 */
trait ReflectedCompositeService { this: AbstractService =>
  /**
   * Initialize all composite services with the given configuration
   * @param hiveConf Hive configuration object
   */
  def initCompositeService(hiveConf: HiveConf): Unit
  
  /**
   * Start all composite services in order
   */
  def startCompositeService(): Unit
}

/**
 * Core CLI service interface defining all thrift server operations
 */
public interface ICLIService {
  /**
   * Open a new client session
   * @param username Client username
   * @param password Client password  
   * @param configuration Session configuration parameters
   * @return SessionHandle identifying the new session
   */
  SessionHandle openSession(String username, String password, Map<String, String> configuration) throws HiveSQLException;
  
  /**
   * Open a session with user impersonation
   * @param username Client username
   * @param password Client password
   * @param configuration Session configuration parameters
   * @param delegationToken Delegation token for authentication
   * @return SessionHandle identifying the new session
   */
  SessionHandle openSessionWithImpersonation(String username, String password, Map<String, String> configuration, String delegationToken) throws HiveSQLException;
  
  /**
   * Close an existing session
   * @param sessionHandle Handle identifying the session to close
   */
  void closeSession(SessionHandle sessionHandle) throws HiveSQLException;
  
  /**
   * Get server or session information
   * @param sessionHandle Session handle
   * @param infoType Type of information to retrieve
   * @return GetInfoValue containing the requested information
   */
  GetInfoValue getInfo(SessionHandle sessionHandle, GetInfoType infoType) throws HiveSQLException;
  
  /**
   * Execute a SQL statement synchronously
   * @param sessionHandle Session handle
   * @param statement SQL statement to execute
   * @param confOverlay Configuration overrides for this statement
   * @return OperationHandle for the execution operation
   */
  OperationHandle executeStatement(SessionHandle sessionHandle, String statement, Map<String, String> confOverlay) throws HiveSQLException;
  
  /**
   * Execute a SQL statement asynchronously
   * @param sessionHandle Session handle
   * @param statement SQL statement to execute  
   * @param confOverlay Configuration overrides for this statement
   * @return OperationHandle for the execution operation
   */
  OperationHandle executeStatementAsync(SessionHandle sessionHandle, String statement, Map<String, String> confOverlay) throws HiveSQLException;
}

// Service states (from Apache Hive Service interface)
enum SERVICE_STATE {
  NOTINITED,    // Service not initialized
  INITED,       // Service initialized but not started  
  STARTED,      // Service started and running
  STOPPED       // Service stopped
}

// Service lifecycle methods
abstract class AbstractService {
  def init(conf: Configuration): Unit
  def start(): Unit  
  def stop(): Unit
  def getServiceState(): SERVICE_STATE
}

// Check service state
val state = cliService.getServiceState()
state match {
  case SERVICE_STATE.STARTED => println("Service is running")
  case SERVICE_STATE.STOPPED => println("Service is stopped")
  case _ => println(s"Service state: $state")
}

// Proper service shutdown
try {
  if (cliService.getServiceState() == SERVICE_STATE.STARTED) {
    cliService.stop()
  }
} catch {
  case e: Exception => 
    println(s"Error stopping CLI service: ${e.getMessage}")
}

/**
 * Base exception for all CLI service errors
 */
class HiveSQLException extends SQLException {
  public HiveSQLException(String reason, String sqlState, int vendorCode, Throwable cause)
  public String getSqlState()
  public int getVendorCode()
}

/**
 * Service-level exceptions
 */
class ServiceException extends Exception {
  public ServiceException(String message)
  public ServiceException(String message, Throwable cause)
}

import org.apache.hive.service.cli.HiveSQLException

try {
  val sessionHandle = cliService.openSession("user", "pass", Map.empty.asJava)
  // Use session...
} catch {
  case e: HiveSQLException =>
    println(s"SQL Error: ${e.getMessage}, State: ${e.getSqlState}")
  case e: ServiceException =>
    println(s"Service Error: ${e.getMessage}")
}