def openSession()

in thriftserver/server/src/main/scala/org/apache/livy/thriftserver/LivyThriftSessionManager.scala [235:292]
58 lines of code
4 McCabe index (conditional complexity)

  def openSession(
      protocol: TProtocolVersion,
      username: String,
      password: String,
      ipAddress: String,
      sessionConf: JMap[String, String],
      withImpersonation: Boolean,
      delegationToken: String): SessionHandle = {
    val sessionHandle = new SessionHandle(protocol)
    incrementConnections(username, ipAddress, SessionInfo.getForwardedAddresses)
    sessionInfo.put(sessionHandle,
      new SessionInfo(username, ipAddress, SessionInfo.getForwardedAddresses, protocol))
    val (initStatements, createInteractiveRequest, sessionId) =
      LivyThriftSessionManager.processSessionConf(sessionConf, supportUseDatabase)
    val createLivySession = () => {
      createInteractiveRequest.kind = Spark
      val newSession = InteractiveSession.create(
        server.livySessionManager.nextId(),
        createInteractiveRequest.name,
        username,
        None,
        server.livyConf,
        server.accessManager,
        createInteractiveRequest,
        server.sessionStore,
        None,
        None)
      onLivySessionOpened(newSession)
      newSession
    }
    val futureLivySession = Future {
      val livyServiceUGI = UserGroupInformation.getCurrentUser
      var livySession: InteractiveSession = null
      try {
        livyServiceUGI.doAs(new PrivilegedExceptionAction[InteractiveSession] {
          override def run(): InteractiveSession = {
            livySession =
              getOrCreateLivySession(sessionHandle, sessionId, createInteractiveRequest.name,
                username, createLivySession)
            synchronized {
              managedLivySessionActiveUsers.get(livySession.id).foreach { numUsers =>
                managedLivySessionActiveUsers(livySession.id) = numUsers + 1
              }
            }
            initSession(sessionHandle, livySession, initStatements)
            livySession
          }
        })
      } catch {
        case e: UndeclaredThrowableException =>
          throw new ThriftSessionCreationException(Option(livySession), e.getCause)
        case e: Throwable =>
          throw new ThriftSessionCreationException(Option(livySession), e)
      }
    }
    sessionHandleToLivySession.put(sessionHandle, futureLivySession)
    sessionHandle
  }