connection.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Copyright (c) 2012-2019 Snowflake Computing Inc. All right reserved.
#
import logging
import os
import re
import sys
import uuid
from io import StringIO
from logging import getLogger
from threading import Lock
from time import strptime

from .incident import IncidentAPI
from . import errors
from . import proxy
from .auth import Auth
from .auth_default import AuthByDefault
from .auth_keypair import AuthByKeyPair
from .auth_oauth import AuthByOAuth
from .auth_okta import AuthByOkta
from .auth_webbrowser import AuthByWebBrowser
from .chunk_downloader import (
    SnowflakeChunkDownloader,
    DEFAULT_CLIENT_PREFETCH_THREADS,
    MAX_CLIENT_PREFETCH_THREADS)
from .compat import (
    TO_UNICODE, IS_OLD_PYTHON, urlencode, PY2, PY_ISSUE_23517, IS_WINDOWS)
from .constants import (
    PARAMETER_AUTOCOMMIT,
    PARAMETER_CLIENT_SESSION_KEEP_ALIVE_HEARTBEAT_FREQUENCY,
    PARAMETER_CLIENT_SESSION_KEEP_ALIVE,
    PARAMETER_CLIENT_TELEMETRY_ENABLED,
    PARAMETER_CLIENT_TELEMETRY_OOB_ENABLED,
    PARAMETER_TIMEZONE,
    PARAMETER_SERVICE_NAME,
    PARAMETER_CLIENT_STORE_TEMPORARY_CREDENTIAL,
    PARAMETER_CLIENT_PREFETCH_THREADS,
    PARAMETER_CLIENT_VALIDATE_DEFAULT_PARAMETERS,
    OCSPMode
)
from .cursor import SnowflakeCursor, LOG_MAX_QUERY_LENGTH
from .description import (
    SNOWFLAKE_CONNECTOR_VERSION,
    PYTHON_VERSION,
    PLATFORM,
    CLIENT_NAME,
    CLIENT_VERSION
)
from .errorcode import (ER_CONNECTION_IS_CLOSED,
                        ER_NO_ACCOUNT_NAME, ER_OLD_PYTHON, ER_NO_USER,
                        ER_NO_PASSWORD, ER_INVALID_VALUE,
                        ER_FAILED_PROCESSING_PYFORMAT,
                        ER_NOT_IMPLICITY_SNOWFLAKE_DATATYPE)
from .errors import (Error, ProgrammingError, InterfaceError,
                     DatabaseError)
from .network import (
    DEFAULT_AUTHENTICATOR,
    EXTERNAL_BROWSER_AUTHENTICATOR,
    KEY_PAIR_AUTHENTICATOR,
    OAUTH_AUTHENTICATOR,
    REQUEST_ID,
    SnowflakeRestful,
)
from .sqlstate import (SQLSTATE_CONNECTION_NOT_EXISTS,
                       SQLSTATE_FEATURE_NOT_SUPPORTED)
from .telemetry import (TelemetryClient)
from .telemetry_oob import TelemetryService
from .time_util import (
    DEFAULT_MASTER_VALIDITY_IN_SECONDS,
    HeartBeatTimer, get_time_millis)
from .util_text import split_statements, construct_hostname, parse_account


def DefaultConverterClass():
    if PY_ISSUE_23517 or IS_WINDOWS:
        from .converter_issue23517 import SnowflakeConverterIssue23517
        return SnowflakeConverterIssue23517
    else:
        from .converter import SnowflakeConverter
        return SnowflakeConverter


SUPPORTED_PARAMSTYLES = {
    u"qmark",
    u'numeric',
    u'format',
    u'pyformat',
}
# default configs
DEFAULT_CONFIGURATION = {
    u'dsn': None,  # standard
    u'user': u'',  # standard
    u'password': u'',  # standard
    u'host': u'127.0.0.1',  # standard
    u'port': 8080,  # standard
    u'database': None,  # standard
    u'proxy_host': None,  # snowflake
    u'proxy_port': None,  # snowflake
    u'proxy_user': None,  # snowflake
    u'proxy_password': None,  # snowflake
    u'protocol': u'http',  # snowflake
    u'warehouse': None,  # snowflake
    u'region': None,  # snowflake
    u'account': None,  # snowflake
    u'schema': None,  # snowflake
    u'role': None,  # snowflake
    u'session_id': None,  # snowflake
    u'login_timeout': 120,  # login timeout
    u'network_timeout': None,  # network timeout (infinite by default)
    u'passcode_in_password': False,  # Snowflake MFA
    u'passcode': None,  # Snowflake MFA
    u'private_key': None,
    u'token': None,  # OAuth or JWT Token
    u'authenticator': DEFAULT_AUTHENTICATOR,
    u'mfa_callback': None,
    u'password_callback': None,
    u'application': CLIENT_NAME,
    u'internal_application_name': CLIENT_NAME,
    u'internal_application_version': CLIENT_VERSION,

    u'insecure_mode': False,  # Error security fix requirement
    u'ocsp_fail_open': True,  # fail open on ocsp issues, default true
    u'inject_client_pause': 0,  # snowflake internal
    u'session_parameters': None,  # snowflake session parameters
    u'autocommit': None,  # snowflake
    u'client_session_keep_alive': False,  # snowflake
    u'client_session_keep_alive_heartbeat_frequency': None,  # snowflake
    u'client_prefetch_threads': 4,  # snowflake
    u'numpy': False,  # snowflake
    u'ocsp_response_cache_filename': None,  # snowflake internal
    u'converter_class': DefaultConverterClass(),
    u'chunk_downloader_class': SnowflakeChunkDownloader,  # snowflake internal
    u'validate_default_parameters': False,  # snowflake
    u'probe_connection': False,  # snowflake
    u'paramstyle': None,  # standard/snowflake
    u'timezone': None,  # snowflake
    u'consent_cache_id_token': True,  # snowflake
    u'service_name': None,  # snowflake,
    u'support_negative_year': True,  # snowflake
    u'log_max_query_length': LOG_MAX_QUERY_LENGTH,  # snowflake
    u'disable_request_pooling': False,  # snowflake
}

APPLICATION_RE = re.compile(r'[\w\d_]+')

# adding the exception class to Connection class
for m in [method for method in dir(errors) if
          callable(getattr(errors, method))]:
    setattr(sys.modules[__name__], m, getattr(errors, m))

# Workaround for https://bugs.python.org/issue7980
strptime('20150102030405', '%Y%m%d%H%M%S')

logger = getLogger(__name__)


class SnowflakeConnection(object):
    u"""
    Implementation of the connection object for the Snowflake Database. Use
    connect(..) to get the object.
    """

    OCSP_ENV_LOCK = Lock()

    def __init__(self, **kwargs):
        self._lock_sequence_counter = Lock()
        self.sequence_counter = 0
        self._errorhandler = Error.default_errorhandler
        self._lock_converter = Lock()
        self.messages = []
        logger.info(
            u"Snowflake Connector for Python Version: %s, "
            u"Python Version: %s, Platform: %s",
            SNOWFLAKE_CONNECTOR_VERSION,
            PYTHON_VERSION, PLATFORM)

        self._rest = None
        for name, value in DEFAULT_CONFIGURATION.items():
            setattr(self, u'_' + name, value)

        self.heartbeat_thread = None

        self.converter = None
        self.connect(**kwargs)
        self._telemetry = TelemetryClient(self._rest)
        self.telemetry_enabled = False
        self.incident = IncidentAPI(self._rest)

    def __del__(self):
        try:
            self.close()
        except:
            pass

    @property
    def insecure_mode(self):
        u"""
        insecure mode. It validates the TLS certificate but doesn't check
        a revocation status.
        :return:
        """
        return self._insecure_mode

    @property
    def ocsp_fail_open(self):
        u"""
        fail open mode. TLS cerificates continue to be validated. Revoked
        certificates are blocked. Any other exceptions are disregarded.
        :return:
        """
        return self._ocsp_fail_open

    def _ocsp_mode(self):
        """
        OCSP mode. INSECURE, FAIL_OPEN or FAIL_CLOSED
        :return:
        """
        if self.insecure_mode:
            return OCSPMode.INSECURE
        return OCSPMode.FAIL_OPEN \
            if self.ocsp_fail_open else OCSPMode.FAIL_CLOSED

    @property
    def session_id(self):
        u"""
        session id
        """
        return self._session_id

    @property
    def user(self):
        u"""
        User name
        """
        return self._user

    @property
    def host(self):
        u"""
        Host name
        """
        return self._host

    @property
    def port(self):
        u"""
        Port number
        """
        return self._port

    @property
    def region(self):
        u"""
        Region name if not the default Snowflake Database deployment
        """
        return self._region

    @property
    def proxy_host(self):
        u"""
        Proxy host name
        """
        return self._proxy_host

    @property
    def proxy_port(self):
        u"""
        Proxy port number
        """
        return self._proxy_port

    @property
    def proxy_user(self):
        u"""
        Proxy user name
        """
        return self._proxy_user

    @property
    def proxy_password(self):
        u"""
        Proxy password
        """
        return self._proxy_password

    @property
    def account(self):
        u"""
        Account name
        """
        return self._account

    @property
    def database(self):
        u"""
        Database name
        """
        return self._database

    @property
    def schema(self):
        u"""
        Schema name
        """
        return self._schema

    @property
    def warehouse(self):
        u"""
        Schema name
        """
        return self._warehouse

    @property
    def role(self):
        u"""
        Role name
        """
        return self._role

    @property
    def login_timeout(self):
        """
        Login timeout. Used in authentication
        """
        return int(self._login_timeout) if self._login_timeout is not None \
            else None

    @property
    def network_timeout(self):
        """
        Network timeout. Used for general purpose
        """
        return int(self._network_timeout) if self._network_timeout is not \
                                             None else None

    @property
    def client_session_keep_alive(self):
        u"""
        Keep connection alive by issuing a heartbeat.
        """
        return self._client_session_keep_alive

    @client_session_keep_alive.setter
    def client_session_keep_alive(self, value):
        u"""
        Keep connection alive by issuing a heartbeat.
        """
        self._client_session_keep_alive = True if value else False

    @property
    def client_session_keep_alive_heartbeat_frequency(self):
        u"""
        Heartbeat frequency to keep connection alive in seconds.
        """
        return self._client_session_keep_alive_heartbeat_frequency if \
            self._client_session_keep_alive_heartbeat_frequency else \
            DEFAULT_MASTER_VALIDITY_IN_SECONDS / 16

    @client_session_keep_alive_heartbeat_frequency.setter
    def client_session_keep_alive_heartbeat_frequency(self, value):
        u"""
        Specify the heartbeat frequency to keep connection alive in seconds.
        """
        self._client_session_keep_alive_heartbeat_frequency = value
        self._validate_client_session_keep_alive_heartbeat_frequency()

    @property
    def client_prefetch_threads(self):
        u"""
        Number of threads to download the result set
        """
        return self._client_prefetch_threads if \
            self._client_prefetch_threads else DEFAULT_CLIENT_PREFETCH_THREADS

    @client_prefetch_threads.setter
    def client_prefetch_threads(self, value):
        """
        Number of threads to download the result set
        """
        self._client_prefetch_threads = value
        self._validate_client_prefetch_threads()

    @property
    def rest(self):
        u"""
        Snowflake REST API object. Internal use only. Maybe removed in the
        later release
        """
        return self._rest

    @property
    def application(self):
        u"""
        Application name. By default, PythonConnector.
        Set this for Snowflake to identify the application by name
        """
        return self._application

    @property
    def errorhandler(self):
        u"""
        Error handler. By default, an exception is raised on error.
        """
        return self._errorhandler

    @errorhandler.setter
    def errorhandler(self, value):
        if value is None:
            raise ProgrammingError(u'None errorhandler is specified')
        self._errorhandler = value

    @property
    def converter_class(self):
        """
        Converter Class
        """
        return self._converter_class

    @property
    def validate_default_parameters(self):
        """
        Validate default database, schema, role and warehouse?
        """
        return self._validate_default_parameters

    @property
    def is_pyformat(self):
        """
        Is binding parameter style pyformat or format?

        The default value should be True.
        """
        return self._paramstyle in (u'pyformat', u'format')

    @property
    def consent_cache_id_token(self):
        """
        Consented cache ID token
        """
        return self._consent_cache_id_token

    @property
    def telemetry_enabled(self):
        return self._telemetry_enabled

    @telemetry_enabled.setter
    def telemetry_enabled(self, value):
        self._telemetry_enabled = True if value else False

    @property
    def service_name(self):
        return self._service_name

    @service_name.setter
    def service_name(self, value):
        self._service_name = value

    @property
    def log_max_query_length(self):
        return self._log_max_query_length

    @property
    def disable_request_pooling(self):
        return self._disable_request_pooling

    @disable_request_pooling.setter
    def disable_request_pooling(self, value):
        self._disable_request_pooling = True if value else False

    def connect(self, **kwargs):
        u"""
        Connects to the database
        """
        logger.debug(u'connect')
        if len(kwargs) > 0:
            self.__config(**kwargs)
            TelemetryService.get_instance().update_context(kwargs)

        self.__set_error_attributes()
        self.__open_connection()

    def close(self):
        u"""
        Closes the connection.
        """
        try:
            if not self.rest:
                return

            # will hang if the application doesn't close the connection and
            # CLIENT_SESSION_KEEP_ALIVE is set, because the heartbeat runs on
            # a separate thread.
            self._cancel_heartbeat()

            # close telemetry first, since it needs rest to send remaining data
            logger.info('closed')
            self._telemetry.close()
            self.rest.delete_session()
            self.rest.close()
            self._rest = None
            del self.messages[:]
        except:
            pass

    def is_closed(self):
        u"""
        Is closed?
        """
        return self.rest is None

    def autocommit(self, mode):
        u"""
        Sets autocommit mode. True/False. Default: True
        """
        if not self.rest:
            Error.errorhandler_wrapper(
                self, None, DatabaseError,
                {
                    u'msg': u"Connection is closed",
                    u'errno': ER_CONNECTION_IS_CLOSED,
                    u'sqlstate': SQLSTATE_CONNECTION_NOT_EXISTS,
                })
        if not isinstance(mode, bool):
            Error.errorhandler_wrapper(
                self, None, ProgrammingError,
                {
                    u'msg': u'Invalid parameter: {0}'.format(mode),
                    u'errno': ER_INVALID_VALUE,
                }
            )
        try:
            self.cursor().execute(
                "ALTER SESSION SET autocommit={0}".format(mode))
        except Error as e:
            if e.sqlstate == SQLSTATE_FEATURE_NOT_SUPPORTED:
                logger.debug(u"Autocommit feature is not enabled for this "
                             u"connection. Ignored")
            else:
                raise e

    def commit(self):
        u"""Commits the current transaction.
        """
        self.cursor().execute("COMMIT")

    def rollback(self):
        u"""Rollbacks the current transaction.
        """
        self.cursor().execute("ROLLBACK")

    def cursor(self, cursor_class=SnowflakeCursor):
        u"""Creates a cursor object. Each statement should create a new cursor
        object.
        """
        logger.debug(u'cursor')
        if not self.rest:
            Error.errorhandler_wrapper(
                self, None, DatabaseError,
                {
                    u'msg': u"Connection is closed",
                    u'errno': ER_CONNECTION_IS_CLOSED,
                    u'sqlstate': SQLSTATE_CONNECTION_NOT_EXISTS,

                })
        return cursor_class(self)

    def execute_string(self, sql_text,
                       remove_comments=False,
                       return_cursors=True,
                       **kwargs):
        """
        Executes a SQL text including multiple statements.
        This is a non-standard convenient method.
        """
        ret = []
        if PY2:
            stream = StringIO(sql_text.decode('utf-8') if isinstance(
                sql_text, str) else sql_text)
        else:
            stream = StringIO(sql_text)
        for sql, is_put_or_get in split_statements(
                stream, remove_comments=remove_comments):
            cur = self.cursor()
            if return_cursors:
                ret.append(cur)
            cur.execute(sql, _is_put_get=is_put_or_get, **kwargs)
        return ret

    def execute_stream(self, stream,
                       remove_comments=False):
        """
        Executes a stream of SQL statements.
        This is a non-standard convenient method.
        """
        for sql, is_put_or_get in split_statements(
                stream, remove_comments=remove_comments):
            cur = self.cursor()
            cur.execute(sql, _is_put_get=is_put_or_get)
            yield cur

    def __set_error_attributes(self):
        for m in [method for method in dir(errors) if
                  callable(getattr(errors, method))]:
            setattr(self, m, getattr(errors, m))

    @staticmethod
    def setup_ocsp_privatelink(app, hostname):
        SnowflakeConnection.OCSP_ENV_LOCK.acquire()
        ocsp_cache_server = \
            u'http://ocsp.{}/ocsp_response_cache.json'.format(
                hostname)
        os.environ[
            'SF_OCSP_RESPONSE_CACHE_SERVER_URL'] = ocsp_cache_server
        logger.debug(u"OCSP Cache Server is updated: %s", ocsp_cache_server)
        SnowflakeConnection.OCSP_ENV_LOCK.release()

    def __open_connection(self):
        u"""
        Opens a new network connection
        """
        self.converter = self._converter_class(
            use_numpy=self._numpy,
            support_negative_year=self._support_negative_year)

        proxy.set_proxies(
            self.proxy_host, self.proxy_port, self.proxy_user,
            self.proxy_password)

        self._rest = SnowflakeRestful(
            host=self.host,
            port=self.port,
            protocol=self._protocol,
            inject_client_pause=self._inject_client_pause,
            connection=self)
        logger.debug(u'REST API object was created: %s:%s',
                     self.host,
                     self.port)

        if 'SF_OCSP_RESPONSE_CACHE_SERVER_URL' in os.environ:
            logger.debug(
                u"Custom OCSP Cache Server URL found in environment - %s",
                os.environ['SF_OCSP_RESPONSE_CACHE_SERVER_URL'])

        if self.host.endswith(u".privatelink.snowflakecomputing.com"):
            SnowflakeConnection.setup_ocsp_privatelink(self.application, self.host)
        else:
            if 'SF_OCSP_RESPONSE_CACHE_SERVER_URL' in os.environ:
                del os.environ['SF_OCSP_RESPONSE_CACHE_SERVER_URL']

        if self._authenticator == DEFAULT_AUTHENTICATOR:
            auth_instance = AuthByDefault(self._password)
        elif self._authenticator == EXTERNAL_BROWSER_AUTHENTICATOR:
            auth_instance = AuthByWebBrowser(
                self.rest, self.application, protocol=self._protocol,
                host=self.host, port=self.port)
        elif self._authenticator == KEY_PAIR_AUTHENTICATOR:
            auth_instance = AuthByKeyPair(self._private_key)
        elif self._authenticator == OAUTH_AUTHENTICATOR:
            auth_instance = AuthByOAuth(self._token)
        else:
            # okta URL, e.g., https://<account>.okta.com/
            auth_instance = AuthByOkta(self.rest, self.application)

        if self._session_parameters is None:
            self._session_parameters = {}
        if self._autocommit is not None:
            self._session_parameters[PARAMETER_AUTOCOMMIT] = self._autocommit

        if self._timezone is not None:
            self._session_parameters[PARAMETER_TIMEZONE] = self._timezone

        if self._validate_default_parameters:
            # Snowflake will validate the requested database, schema, and warehouse
            self._session_parameters[PARAMETER_CLIENT_VALIDATE_DEFAULT_PARAMETERS] = True

        if self.client_session_keep_alive:
            self._session_parameters[PARAMETER_CLIENT_SESSION_KEEP_ALIVE] = True

        if self.client_session_keep_alive_heartbeat_frequency:
            self._session_parameters[
                PARAMETER_CLIENT_SESSION_KEEP_ALIVE_HEARTBEAT_FREQUENCY] = \
                self._validate_client_session_keep_alive_heartbeat_frequency()

        if self.client_prefetch_threads:
            self._session_parameters[PARAMETER_CLIENT_PREFETCH_THREADS] = \
                self._validate_client_prefetch_threads()

        if self._authenticator == EXTERNAL_BROWSER_AUTHENTICATOR:
            # enable storing temporary credential in a file
            self._session_parameters[
                PARAMETER_CLIENT_STORE_TEMPORARY_CREDENTIAL] = True

        auth = Auth(self.rest)
        if not auth.read_temporary_credential(
                self.account, self.user, self._session_parameters):
            self.__authenticate(auth_instance)
        else:
            # set the current objects as the session is derived from the id
            # token, and the current objects may be different.
            self._set_current_objects()

        self._password = None  # ensure password won't persist

        if self.client_session_keep_alive:
            self._add_heartbeat()

    def __config(self, **kwargs):
        u"""
        Sets the parameters
        """
        logger.debug(u'__config')
        for name, value in kwargs.items():
            if name == u'sequence_counter':
                self.sequence_counter = value
            elif name == u'application':
                if not APPLICATION_RE.match(value):
                    msg = u'Invalid application name: {0}'.format(value)
                    raise ProgrammingError(
                        msg=msg,
                        errno=0
                    )
                else:
                    setattr(self, u'_' + name, value)
            else:
                setattr(self, u'_' + name, value)

        if self._paramstyle is None:
            import snowflake.connector
            self._paramstyle = snowflake.connector.paramstyle
        elif self._paramstyle not in SUPPORTED_PARAMSTYLES:
            raise ProgrammingError(
                msg=u'Invalid paramstyle is specified',
                errno=ER_INVALID_VALUE
            )

        if u'account' in kwargs:
            if u'host' not in kwargs:
                setattr(self, u'_host',
                        construct_hostname(
                            kwargs.get(u'region'), self._account))
            if u'port' not in kwargs:
                setattr(self, u'_port', u'443')
            if u'protocol' not in kwargs:
                setattr(self, u'_protocol', u'https')

        if not self.user and self._authenticator != OAUTH_AUTHENTICATOR:
            # OAuth Authentication does not require a username
            Error.errorhandler_wrapper(
                self, None, ProgrammingError,
                {
                    u'msg': u"User is empty",
                    u'errno': ER_NO_USER
                })

        if self._private_key:
            self._authenticator = KEY_PAIR_AUTHENTICATOR

        if self._authenticator:
            self._authenticator = self._authenticator.upper()

        if self._authenticator != EXTERNAL_BROWSER_AUTHENTICATOR and \
                self._authenticator != OAUTH_AUTHENTICATOR and \
                self._authenticator != KEY_PAIR_AUTHENTICATOR:
            # authentication is done by the browser if the authenticator
            # is externalbrowser
            if not self._password:
                Error.errorhandler_wrapper(
                    self, None, ProgrammingError,
                    {
                        u'msg': u"Password is empty",
                        u'errno': ER_NO_PASSWORD
                    })

        if not self._account:
            Error.errorhandler_wrapper(
                self, None, ProgrammingError,
                {
                    u'msg': u"Account must be specified",
                    u'errno': ER_NO_ACCOUNT_NAME
                })
        if u'.' in self._account:
            self._account = parse_account(self._account)

        if self.ocsp_fail_open:
            logger.info(
                u'This connection is in OCSP Fail Open Mode. '
                u'TLS Certificates would be checked for validity '
                u'and revocation status. Any other Certificate '
                u'Revocation related exceptions or OCSP Responder '
                u'failures would be disregarded in favor of '
                u'connectivity.')

        if self.insecure_mode:
            logger.info(
                u'THIS CONNECTION IS IN INSECURE MODE. IT '
                u'MEANS THE CERTIFICATE WILL BE VALIDATED BUT THE '
                u'CERTIFICATE REVOCATION STATUS WILL NOT BE '
                u'CHECKED.')

        elif self._protocol == u'https':
            if IS_OLD_PYTHON():
                msg = (u"ERROR: The ssl package installed with your Python "
                       u"- version {0} - does not have the security fix. "
                       u"Upgrade to Python 2.7.9/3.4.3 or higher.\n").format(
                    PYTHON_VERSION)
                raise InterfaceError(
                    msg=msg,
                    errno=ER_OLD_PYTHON)

    def cmd_query(self, sql, sequence_counter, request_id,
                  binding_params=None,
                  is_file_transfer=False, statement_params=None,
                  is_internal=False, _no_results=False,
                  _update_current_object=True):
        u"""
        Executes a query with a sequence counter.
        """
        logger.debug(u'_cmd_query')
        data = {
            u'sqlText': sql,
            u'asyncExec': _no_results,
            u'sequenceId': sequence_counter,
            u'querySubmissionTime': get_time_millis(),
        }
        if statement_params is not None:
            data[u'parameters'] = statement_params
        if is_internal:
            data[u'isInternal'] = is_internal
        if binding_params is not None:
            # binding parameters. This is for qmarks paramstyle.
            data[u'bindings'] = binding_params

        client = u'sfsql_file_transfer' if is_file_transfer else u'sfsql'

        if logger.getEffectiveLevel() <= logging.DEBUG:
            logger.debug(
                u'sql=[%s], sequence_id=[%s], is_file_transfer=[%s]',
                self._format_query_for_log(data[u'sqlText']),
                data[u'sequenceId'],
                is_file_transfer
            )

        url_parameters = {REQUEST_ID: request_id}

        ret = self.rest.request(
            u'/queries/v1/query-request?' + urlencode(url_parameters),
            data, client=client, _no_results=_no_results,
            _include_retry_params=True)

        if ret is None:
            ret = {u'data': {}}
        if ret.get(u'data') is None:
            ret[u'data'] = {}
        if _update_current_object:
            data = ret['data']
            if u'finalDatabaseName' in data:
                self._database = data[u'finalDatabaseName']
            if u'finalSchemaName' in data:
                self._schema = data[u'finalSchemaName']
            if u'finalWarehouseName' in data:
                self._warehouse = data[u'finalWarehouseName']
            if u'finalRoleName' in data:
                self._role = data[u'finalRoleName']

        return ret

    def _set_current_objects(self):
        """
        Sets the current objects to the specified ones. This is mainly used
        when a session token is derived from an id token.
        """

        def cmd(sql, params, _update_current_object=False):
            processed_params = self._process_params_qmarks(params)
            sequence_counter = self._next_sequence_counter()
            request_id = uuid.uuid4()
            self.cmd_query(
                sql,
                sequence_counter,
                request_id,
                binding_params=processed_params,
                is_internal=True,
                _update_current_object=_update_current_object)

        if self._role:
            cmd(u"USE ROLE IDENTIFIER(?)", (self._role,))
        if self._warehouse:
            cmd(u"USE WAREHOUSE IDENTIFIER(?)", (self._warehouse,))
        if self._database:
            cmd(u"USE DATABASE IDENTIFIER(?)", (self._database,))
        if self._schema:
            cmd(u'USE SCHEMA IDENTIFIER(?)', (self._schema,))
        cmd(u"SELECT 1", (), _update_current_object=True)

    def _reauthenticate_by_webbrowser(self):
        auth_instance = AuthByWebBrowser(
            self.rest, self.application, protocol=self._protocol,
            host=self.host, port=self.port)
        self.__authenticate(auth_instance)
        self._set_current_objects()
        return {u'success': True}

    def __authenticate(self, auth_instance):
        auth_instance.authenticate(
            authenticator=self._authenticator,
            service_name=self.service_name,
            account=self.account,
            user=self.user,
            password=self._password,
        )
        self._consent_cache_id_token = getattr(
            auth_instance, 'consent_cache_id_token', True)

        auth = Auth(self.rest)
        self._session_parameters = auth.authenticate(
            auth_instance=auth_instance,
            account=self.account,
            user=self.user,
            database=self.database,
            schema=self.schema,
            warehouse=self.warehouse,
            role=self.role,
            passcode=self._passcode,
            passcode_in_password=self._passcode_in_password,
            mfa_callback=self._mfa_callback,
            password_callback=self._password_callback,
            session_parameters=self._session_parameters,
        )

    def _process_params_qmarks(self, params, cursor=None):
        if not params:
            return None
        processed_params = {}
        if not isinstance(params, (list, tuple)):
            errorvalue = {
                u'msg': u"Binding parameters must be a list: {0}".format(
                    params
                ),
                u'errno': ER_FAILED_PROCESSING_PYFORMAT
            }
            Error.errorhandler_wrapper(self, cursor,
                                       ProgrammingError,
                                       errorvalue)
            return None
        for idx, v in enumerate(params):
            if isinstance(v, tuple):
                if len(v) != 2:
                    Error.errorhandler_wrapper(
                        self, cursor,
                        ProgrammingError,
                        {
                            u'msg': u"Binding parameters must be a list "
                                    u"where one element is a single value or "
                                    u"a pair of Snowflake datatype and a value",
                            u'errno': ER_FAILED_PROCESSING_PYFORMAT,
                        }
                    )
                    return None
                processed_params[TO_UNICODE(idx + 1)] = {
                    'type': v[0],
                    'value': self.converter.to_snowflake_bindings(
                        v[0], v[1])}
            else:
                snowflake_type = self.converter.snowflake_type(
                    v)
                if snowflake_type is None:
                    Error.errorhandler_wrapper(
                        self, cursor,
                        ProgrammingError,
                        {
                            u'msg': u"Python data type [{0}] cannot be "
                                    u"automatically mapped to Snowflake data "
                                    u"type. Specify the snowflake data type "
                                    u"explicitly.".format(
                                v.__class__.__name__.lower()),
                            u'errno': ER_NOT_IMPLICITY_SNOWFLAKE_DATATYPE
                        }
                    )
                    return None
                if isinstance(v, list):
                    vv = [
                        self.converter.to_snowflake_bindings(
                            self.converter.snowflake_type(v0), v0) for v0 in v]
                else:
                    vv = self.converter.to_snowflake_bindings(
                        snowflake_type, v)
                processed_params[TO_UNICODE(idx + 1)] = {
                    'type': snowflake_type,
                    'value': vv}
        if logger.getEffectiveLevel() <= logging.DEBUG:
            for k, v in processed_params.items():
                logger.debug("idx: %s, type: %s", k, v.get('type'))
        return processed_params

    def _process_params(self, params, cursor=None):
        if params is None:
            return {}
        if isinstance(params, dict):
            return self.__process_params_dict(params)

        if not isinstance(params, (tuple, list)):
            params = [params, ]

        try:
            res = params
            res = map(self.converter.to_snowflake, res)
            res = map(self.converter.escape, res)
            res = map(self.converter.quote, res)
            ret = tuple(res)
            logger.debug(u'parameters: %s', ret)
            return ret
        except Exception as e:
            errorvalue = {
                u'msg': u"Failed processing pyformat-parameters; {0}".format(
                    e),
                u'errno': ER_FAILED_PROCESSING_PYFORMAT}
            Error.errorhandler_wrapper(self, cursor,
                                       ProgrammingError,
                                       errorvalue)

    def __process_params_dict(self, params, cursor=None):
        try:
            to_snowflake = self.converter.to_snowflake
            escape = self.converter.escape
            quote = self.converter.quote
            res = {}
            for k, v in params.items():
                c = v
                c = to_snowflake(c)
                c = escape(c)
                c = quote(c)
                res[k] = c
            logger.debug(u'parameters: %s', res)
            return res
        except Exception as e:
            errorvalue = {
                u'msg': u"Failed processing pyformat-parameters; {0}".format(
                    e),
                u'errno': ER_FAILED_PROCESSING_PYFORMAT}
            Error.errorhandler_wrapper(
                self, cursor, ProgrammingError, errorvalue)

    def _cancel_query(self, sql, request_id):
        u"""
        Cancels the query by the query and requestId
        """
        logger.debug(u'_cancel_query sql=[%s], request_id=[%s]', sql,
                     request_id)
        url_parameters = {REQUEST_ID: TO_UNICODE(uuid.uuid4())}

        return self.rest.request(
            u'/queries/v1/abort-request?' + urlencode(url_parameters), {
                u'sqlText': sql,
                REQUEST_ID: TO_UNICODE(request_id),
            })

    def _next_sequence_counter(self):
        u"""Gets next sequence counter. Used internally.
        """
        with self._lock_sequence_counter:
            self.sequence_counter += 1
            logger.debug(u'sequence counter: %s', self.sequence_counter)
            return self.sequence_counter

    def _log_telemetry(self, telemetry_data):
        u"""
        Logs data to telemetry
        """
        if self.telemetry_enabled:
            self._telemetry.try_add_log_to_batch(telemetry_data)

    def _add_heartbeat(self):
        """Add an hourly heartbeat query in order to keep connection alive."""
        if not self.heartbeat_thread:
            self._validate_client_session_keep_alive_heartbeat_frequency()
            self.heartbeat_thread = HeartBeatTimer(
                self.client_session_keep_alive_heartbeat_frequency,
                self._heartbeat_tick)
            self.heartbeat_thread.start()
            logger.debug("started heartbeat")

    def _cancel_heartbeat(self):
        """Cancel a heartbeat thread."""
        if self.heartbeat_thread:
            self.heartbeat_thread.cancel()
            self.heartbeat_thread.join()
            self.heartbeat_thread = None
            logger.debug("stopped heartbeat")

    def _heartbeat_tick(self):
        """Execute a hearbeat if connection isn't closed yet."""
        if not self.is_closed():
            logger.debug("heartbeating!")
            self.rest._heartbeat()

    def _validate_client_session_keep_alive_heartbeat_frequency(self):
        """Validate and return heartbeat frequency in seconds"""
        real_max = int(self.rest.master_validity_in_seconds / 4)
        real_min = int(real_max / 4)
        if self.client_session_keep_alive_heartbeat_frequency > real_max:
            self._client_session_keep_alive_heartbeat_frequency = real_max
        elif self.client_session_keep_alive_heartbeat_frequency < real_min:
            self._client_session_keep_alive_heartbeat_frequency = real_min

        # ensure the type is integer
        self._client_session_keep_alive_heartbeat_frequency = int(
            self.client_session_keep_alive_heartbeat_frequency)
        return self.client_session_keep_alive_heartbeat_frequency

    def _validate_client_prefetch_threads(self):
        if self.client_prefetch_threads <= 0:
            self._client_prefetch_threads = 1
        elif self.client_prefetch_threads > MAX_CLIENT_PREFETCH_THREADS:
            self._client_prefetch_threads = MAX_CLIENT_PREFETCH_THREADS
        self._client_prefetch_threads = int(
            self.client_prefetch_threads)
        return self.client_prefetch_threads

    def _set_parameters(self, ret, session_parameters):
        """
        Set session parameters
        """
        if u'parameters' not in ret[u'data']:
            return
        parameters = ret[u'data'][u'parameters']
        with self._lock_converter:
            self.converter.set_parameters(parameters)
        for kv in parameters:
            name = kv['name']
            value = kv['value']
            session_parameters[name] = value
            if PARAMETER_CLIENT_TELEMETRY_ENABLED == name:
                self.telemetry_enabled = value
            elif PARAMETER_CLIENT_TELEMETRY_OOB_ENABLED == name:
                if value:
                    TelemetryService.get_instance().enable()
                else:
                    TelemetryService.get_instance().disable()
            elif PARAMETER_CLIENT_SESSION_KEEP_ALIVE == name:
                self.client_session_keep_alive = value
            elif PARAMETER_CLIENT_SESSION_KEEP_ALIVE_HEARTBEAT_FREQUENCY == \
                    name:
                self.client_session_keep_alive_heartbeat_frequency = value
            elif PARAMETER_SERVICE_NAME == name:
                self.service_name = value
            elif PARAMETER_CLIENT_PREFETCH_THREADS == name:
                self.client_prefetch_threads = value

    def _format_query_for_log(self, query):
        ret = u' '.join(line.strip() for line in query.split(u'\n'))
        return (ret if len(ret) < self.log_max_query_length
                else ret[0:self.log_max_query_length] + '...')

    def __enter__(self):
        u"""
        context manager
        """
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        u"""
        context manager with commit or rollback
        """
        if exc_tb is None:
            self.commit()
        else:
            self.rollback()
        self.close()