コード例 #1
0
ファイル: connection.py プロジェクト: twneale/vertica-python
class Connection(object):
    def __init__(self, options=None):
        self.reset_values()

        options = options or {}
        self.options = dict((key, value) for key, value in options.items() if value is not None)

        # we only support one cursor per connection
        self.options.setdefault("unicode_error", None)
        self._cursor = Cursor(self, None, unicode_error=self.options["unicode_error"])
        self.options.setdefault("port", 5433)
        self.options.setdefault("read_timeout", 600)
        self.startup_connection()

    def __enter__(self):
        return self

    def __exit__(self, type_, value, traceback):
        try:
            # if there's no outstanding transaction, we can simply close the connection
            if self.transaction_status in (None, "in_transaction"):
                return

            if type_ is not None:
                self.rollback()
            else:
                self.commit()
        finally:
            self.close()

    #
    # dbApi methods
    #

    def close(self):
        try:
            self.write(messages.Terminate())
        finally:
            self.close_socket()

    def commit(self):
        if self.closed():
            raise errors.ConnectionError("Connection is closed")

        cur = self.cursor()
        cur.execute("COMMIT;")

    def rollback(self):
        if self.closed():
            raise errors.ConnectionError("Connection is closed")

        cur = self.cursor()
        cur.execute("ROLLBACK;")

    def cursor(self, cursor_type=None):
        if self.closed():
            raise errors.ConnectionError("Connection is closed")

        if self._cursor.closed():
            self._cursor._closed = False

        # let user change type if they want?
        self._cursor.cursor_type = cursor_type
        return self._cursor

    #
    # Internal
    #
    def reset_values(self):
        self.parameters = {}
        self.session_id = None
        self.backend_pid = None
        self.backend_key = None
        self.transaction_status = None
        self.socket = None

    def _socket(self):
        if self.socket is not None:
            return self.socket

        host = self.options.get("host")
        port = self.options.get("port")
        raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        raw_socket.connect((host, port))

        ssl_options = self.options.get("ssl")
        if ssl_options is not None and ssl_options is not False:
            from ssl import CertificateError, SSLError

            raw_socket.sendall(messages.SslRequest().to_bytes())
            response = raw_socket.recv(1)
            if response in ("S", b"S"):
                try:
                    if isinstance(ssl_options, ssl.SSLContext):
                        raw_socket = ssl_options.wrap_socket(raw_socket, server_hostname=host)
                    else:
                        raw_socket = ssl.wrap_socket(raw_socket)
                except CertificateError as e:
                    raise errors.ConnectionError("SSL: " + e.message)
                except SSLError as e:
                    raise errors.ConnectionError("SSL: " + e.reason)
            else:
                raise SSLNotSupported("SSL requested but not supported by server")

        self.socket = raw_socket
        return self.socket

    def ssl(self):
        return self.socket is not None and isinstance(ssl.SSLSocket, self.socket)

    def opened(self):
        return self.socket is not None and self.backend_pid is not None and self.transaction_status is not None

    def closed(self):
        return not self.opened()

    def write(self, message):

        is_stream = hasattr(message, "read_bytes")

        if (
            hasattr(message, "to_bytes") is False
            or isinstance(getattr(message, "to_bytes"), collections.Callable) is False
        ) and not is_stream:
            raise TypeError("invalid message: ({0})".format(message))

        logger.debug("=> %s", message)
        try:

            if not is_stream:
                self._socket().sendall(message.to_bytes())
            else:
                # read to end in chunks
                while True:
                    data = message.read_bytes()
                    if len(data) == 0:
                        break

                    self._socket().sendall(data)

        except Exception as e:
            self.close_socket()
            if str(e) == "unsupported authentication method: 9":
                raise errors.ConnectionError("Error during authentication. Your password might be expired.")
            else:
                raise errors.ConnectionError(str(e))

    def close_socket(self):
        try:
            if self.socket is not None:
                self._socket().close()
        finally:
            self.reset_values()

    def reset_connection(self):
        self.close()
        self.startup_connection()

    def read_message(self):
        try:
            type_ = self.read_bytes(1)
            size = unpack("!I", self.read_bytes(4))[0]

            if size < 4:
                raise errors.MessageError("Bad message size: {0}".format(size))
            message = BackendMessage.factory(type_, self.read_bytes(size - 4))
            logger.debug("<= %s", message)
            return message
        except (SystemError, IOError) as e:
            self.close_socket()
            raise errors.ConnectionError(str(e))

    def process_message(self, message):
        if isinstance(message, messages.ErrorResponse):
            raise errors.ConnectionError(message.error_message())
        elif isinstance(message, messages.NoticeResponse):
            if getattr(self, "notice_handler", None) is not None:
                self.notice_handler(message)
        elif isinstance(message, messages.BackendKeyData):
            self.backend_pid = message.pid
            self.backend_key = message.key
        elif isinstance(message, messages.ParameterStatus):
            self.parameters[message.name] = message.value
        elif isinstance(message, messages.ReadyForQuery):
            self.transaction_status = message.transaction_status
        elif isinstance(message, messages.CommandComplete):
            # TODO: im not ever seeing this actually returned by vertica...
            # if vertica returns a row count, set the rowcount attribute in cursor
            # if hasattr(message, 'rows'):
            #    self.cursor.rowcount = message.rows
            pass
        elif isinstance(message, messages.CopyInResponse):
            pass
        else:
            raise errors.MessageError("Unhandled message: {0}".format(message))

        # set last message
        self._cursor._message = message

    def __str__(self):
        safe_options = dict((key, value) for key, value in self.options.items() if key != "password")
        s1 = "<Vertica.Connection:{0} parameters={1} backend_pid={2}, ".format(
            id(self), self.parameters, self.backend_pid
        )
        s2 = "backend_key={0}, transaction_status={1}, socket={2}, options={3}>".format(
            self.backend_key, self.transaction_status, self.socket, safe_options
        )
        return s1 + s2

    def read_bytes(self, n):
        results = bytes()
        while len(results) < n:
            bytes_ = self._socket().recv(n - len(results))
            if not bytes_:
                raise errors.ConnectionError("Connection closed by Vertica")
            results = results + bytes_
        return results

    def startup_connection(self):
        # This doesn't handle Unicode usernames or passwords
        user = self.options["user"].encode("ascii")
        database = self.options["database"].encode("ascii")
        password = self.options["password"].encode("ascii")

        self.write(messages.Startup(user, database))

        while True:
            message = self.read_message()

            if isinstance(message, messages.Authentication):
                # Password message isn't right format ("incomplete message from client")
                if message.code != messages.Authentication.OK:
                    self.write(
                        messages.Password(
                            password, message.code, {"user": user, "salt": getattr(message, "salt", None)}
                        )
                    )
            else:
                self.process_message(message)

            if isinstance(message, messages.ReadyForQuery):
                break
コード例 #2
0
ファイル: connection.py プロジェクト: jkim/vertica-python
class Connection(object):
    def __init__(self, options=None):
        self.reset_values()

        options = options or {}
        self.options = dict((key, value) for key, value in options.items()
                            if value is not None)

        # we only support one cursor per connection
        self.options.setdefault('unicode_error', None)
        self._cursor = Cursor(self,
                              None,
                              unicode_error=self.options['unicode_error'])
        self.options.setdefault('port', 5433)
        self.options.setdefault('read_timeout', 600)
        self.startup_connection()

    def __enter__(self):
        return self

    def __exit__(self, type_, value, traceback):
        try:
            # if there's no outstanding transaction, we can simply close the connection
            if self.transaction_status in (None, 'in_transaction'):
                return

            if type_ is not None:
                self.rollback()
            else:
                self.commit()
        finally:
            self.close()

    #
    # dbApi methods
    #

    def close(self):
        try:
            self.write(messages.Terminate())
        finally:
            self.close_socket()

    def commit(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('COMMIT;')

    def rollback(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('ROLLBACK;')

    def cursor(self, cursor_type=None):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        if self._cursor.closed():
            self._cursor._closed = False

        # let user change type if they want?
        self._cursor.cursor_type = cursor_type
        return self._cursor

    #
    # Internal
    #
    def reset_values(self):
        self.parameters = {}
        self.session_id = None
        self.backend_pid = None
        self.backend_key = None
        self.transaction_status = None
        self.socket = None

    def _socket(self):
        if self.socket is not None:
            return self.socket

        host = self.options.get('host')
        port = self.options.get('port')
        connection_timeout = self.options.get('connection_timeout')
        raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        raw_socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
        if connection_timeout is not None:
            raw_socket.settimeout(connection_timeout)
        raw_socket.connect((host, port))

        ssl_options = self.options.get('ssl')
        if ssl_options is not None and ssl_options is not False:
            from ssl import CertificateError, SSLError
            raw_socket.sendall(messages.SslRequest().to_bytes())
            response = raw_socket.recv(1)
            if response in ('S', b'S'):
                try:
                    if isinstance(ssl_options, ssl.SSLContext):
                        raw_socket = ssl_options.wrap_socket(
                            raw_socket, server_hostname=host)
                    else:
                        raw_socket = ssl.wrap_socket(raw_socket)
                except CertificateError as e:
                    raise errors.ConnectionError('SSL: ' + e.message)
                except SSLError as e:
                    raise errors.ConnectionError('SSL: ' + e.reason)
            else:
                raise SSLNotSupported(
                    "SSL requested but not supported by server")

        self.socket = raw_socket
        return self.socket

    def ssl(self):
        return self.socket is not None and isinstance(self.socket,
                                                      ssl.SSLSocket)

    def opened(self):
        return (self.socket is not None and self.backend_pid is not None
                and self.transaction_status is not None)

    def closed(self):
        return not self.opened()

    def write(self, message):

        is_stream = hasattr(message, "read_bytes")

        if (hasattr(message, 'to_bytes') is False or
                isinstance(getattr(message, 'to_bytes'),
                           collections.Callable) is False) and not is_stream:
            raise TypeError("invalid message: ({0})".format(message))

        logger.debug('=> %s', message)
        try:

            if not is_stream:
                self._socket().sendall(message.to_bytes())
            else:
                # read to end in chunks
                while True:
                    data = message.read_bytes()
                    if len(data) == 0:
                        break

                    self._socket().sendall(data)

        except Exception as e:
            self.close_socket()
            if str(e) == 'unsupported authentication method: 9':
                raise errors.ConnectionError(
                    'Error during authentication. Your password might be expired.'
                )
            else:
                raise errors.ConnectionError(str(e))

    def close_socket(self):
        try:
            if self.socket is not None:
                self._socket().close()
        finally:
            self.reset_values()

    def reset_connection(self):
        self.close()
        self.startup_connection()

    def read_message(self):
        try:
            type_ = self.read_bytes(1)
            size = unpack('!I', self.read_bytes(4))[0]

            if size < 4:
                raise errors.MessageError("Bad message size: {0}".format(size))
            message = BackendMessage.factory(type_, self.read_bytes(size - 4))
            logger.debug('<= %s', message)
            return message
        except (SystemError, IOError) as e:
            self.close_socket()
            raise errors.ConnectionError(str(e))

    def process_message(self, message):
        if isinstance(message, messages.ErrorResponse):
            raise errors.ConnectionError(message.error_message())
        elif isinstance(message, messages.NoticeResponse):
            if getattr(self, 'notice_handler', None) is not None:
                self.notice_handler(message)
        elif isinstance(message, messages.BackendKeyData):
            self.backend_pid = message.pid
            self.backend_key = message.key
        elif isinstance(message, messages.ParameterStatus):
            self.parameters[message.name] = message.value
        elif isinstance(message, messages.ReadyForQuery):
            self.transaction_status = message.transaction_status
        elif isinstance(message, messages.CommandComplete):
            # TODO: im not ever seeing this actually returned by vertica...
            # if vertica returns a row count, set the rowcount attribute in cursor
            #if hasattr(message, 'rows'):
            #    self.cursor.rowcount = message.rows
            pass
        elif isinstance(message, messages.EmptyQueryResponse):
            pass
        elif isinstance(message, messages.CopyInResponse):
            pass
        else:
            raise errors.MessageError("Unhandled message: {0}".format(message))

        # set last message
        self._cursor._message = message

    def __str__(self):
        safe_options = dict((key, value)
                            for key, value in self.options.items()
                            if key != 'password')
        s1 = "<Vertica.Connection:{0} parameters={1} backend_pid={2}, ".format(
            id(self), self.parameters, self.backend_pid)
        s2 = "backend_key={0}, transaction_status={1}, socket={2}, options={3}>".format(
            self.backend_key,
            self.transaction_status,
            self.socket,
            safe_options,
        )
        return s1 + s2

    def read_bytes(self, n):
        results = bytes()
        while len(results) < n:
            bytes_ = self._socket().recv(n - len(results))
            if not bytes_:
                raise errors.ConnectionError("Connection closed by Vertica")
            results = results + bytes_
        return results

    def startup_connection(self):
        # This doesn't handle Unicode usernames or passwords
        user = self.options['user'].encode('ascii')
        database = self.options['database'].encode('ascii')
        password = self.options['password'].encode('ascii')

        self.write(messages.Startup(user, database))

        while True:
            message = self.read_message()

            if isinstance(message, messages.Authentication):
                # Password message isn't right format ("incomplete message from client")
                if message.code != messages.Authentication.OK:
                    self.write(
                        messages.Password(
                            password, message.code, {
                                'user': user,
                                'salt': getattr(message, 'salt', None)
                            }))
            else:
                self.process_message(message)

            if isinstance(message, messages.ReadyForQuery):
                break
コード例 #3
0
ファイル: connection.py プロジェクト: jrowan/vertica-python
class Connection(object):
    def __init__(self, options=None):
        self.reset_values()

        options = options or {}
        self.options = dict(
            (key, value) for key, value in options.iteritems() if value is not None
        )

        # we only support one cursor per connection
        self._cursor = Cursor(self, None)
        self.options.setdefault('port', 5433)
        self.options.setdefault('read_timeout', 600)
        self.boot_connection()

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        try:
            # if there's no outstanding transaction, we can simply close the connection
            if self.transaction_status in (None, 'in_transaction'):
                return

            if type is not None:
                self.rollback()
            else:
                self.commit()
        finally:
            self.close()

    #
    # dbApi methods
    #

    def close(self):
        try:
            self.write(messages.Terminate())
        finally:
            self.close_socket()

    def commit(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('COMMIT;')

    def rollback(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('ROLLBACK;')

    def cursor(self, cursor_type=None):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        if self._cursor.closed():
            self._cursor._closed = False

        # let user change type if they want?
        self._cursor.cursor_type = cursor_type
        return self._cursor

    #
    # Internal
    #
    def reset_values(self):
        self.parameters = {}
        self.session_id = None
        self.backend_pid = None
        self.backend_key = None
        self.transaction_status = None
        self.socket = None

    def _socket(self):
        if self.socket is not None:
            return self.socket

        if self.options.get('ssl'):
            # SSL
            raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            raw_socket.connect((self.options['host'], self.options['port']))
            raw_socket.sendall(messages.SslRequest().to_bytes())
            response = raw_socket.recv(1)
            if response == 'S':
                # May want to add certs to this
                raw_socket = ssl.wrap_socket(raw_socket)
            else:
                raise SSLNotSupported("SSL requested but not supported by server")
        else:
            # Non-SSL
            raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            raw_socket.connect((self.options['host'], self.options['port']))

        self.socket = raw_socket
        return raw_socket

    def ssl(self):
        return self.socket is not None and isinstance(ssl.SSLSocket, self.socket)

    def opened(self):
        return (self.socket is not None
                and self.backend_pid is not None
                and self.transaction_status is not None)

    def closed(self):
        return not self.opened()

    def write(self, message):

        is_stream = hasattr(message, "read_bytes")

        if (hasattr(message, 'to_bytes') is False or callable(getattr(message, 'to_bytes')) is False) and not is_stream:
            raise TypeError("invalid message: ({0})".format(message))

        logger.debug('=> %s', message)
        try:

            if not is_stream:
                self._socket().sendall(message.to_bytes())
            else:
                # read to end in chunks
                while True:
                    data = message.read_bytes()
                    if len(data) == 0:
                        break

                    self._socket().sendall(data)

        except Exception, e:
            self.close_socket()
            raise errors.ConnectionError(e.message)
コード例 #4
0
class Connection(object):
    def __init__(self, options=None):
        self.reset_values()

        options = options or {}
        self.options = dict((key, value) for key, value in options.iteritems()
                            if value is not None)

        # we only support one cursor per connection
        self._cursor = Cursor(self, None)
        self.options.setdefault('port', 5433)
        self.options.setdefault('read_timeout', 600)
        self.boot_connection()

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        try:
            # if there's no outstanding transaction, we can simply close the connection
            if self.transaction_status in (None, 'in_transaction'):
                return

            if type is not None:
                self.rollback()
            else:
                self.commit()
        finally:
            self.close()

    #
    # dbApi methods
    #

    def close(self):
        try:
            self.write(messages.Terminate())
        finally:
            self.close_socket()

    def commit(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('COMMIT;')

    def rollback(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('ROLLBACK;')

    def cursor(self, cursor_type=None):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        if self._cursor.closed():
            self._cursor._closed = False

        # let user change type if they want?
        self._cursor.cursor_type = cursor_type
        return self._cursor

    #
    # Internal
    #
    def reset_values(self):
        self.parameters = {}
        self.session_id = None
        self.backend_pid = None
        self.backend_key = None
        self.transaction_status = None
        self.socket = None

    def _socket(self):
        if self.socket is not None:
            return self.socket

        if self.options.get('ssl'):
            # SSL
            raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            raw_socket.connect((self.options['host'], self.options['port']))
            raw_socket.sendall(messages.SslRequest().to_bytes())
            response = raw_socket.recv(1)
            if response == 'S':
                # May want to add certs to this
                raw_socket = ssl.wrap_socket(raw_socket)
            else:
                raise SSLNotSupported(
                    "SSL requested but not supported by server")
        else:
            # Non-SSL
            raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            raw_socket.connect((self.options['host'], self.options['port']))

        self.socket = raw_socket
        return raw_socket

    def ssl(self):
        return self.socket is not None and isinstance(ssl.SSLSocket,
                                                      self.socket)

    def opened(self):
        return (self.socket is not None and self.backend_pid is not None
                and self.transaction_status is not None)

    def closed(self):
        return not self.opened()

    def write(self, message):

        is_stream = hasattr(message, "read_bytes")

        if (hasattr(message, 'to_bytes') is False or callable(
                getattr(message, 'to_bytes')) is False) and not is_stream:
            raise TypeError("invalid message: ({0})".format(message))

        logger.debug('=> %s', message)
        try:

            if not is_stream:
                self._socket().sendall(message.to_bytes())
            else:
                # read to end in chunks
                while True:
                    data = message.read_bytes()
                    if len(data) == 0:
                        break

                    self._socket().sendall(data)

        except Exception, e:
            self.close_socket()
            if e.message == 'unsupported authentication method: 9':
                raise errors.ConnectionError(
                    'Error during authentication. Your password might be expired.'
                )
            else:
                raise errors.ConnectionError(e.message)
コード例 #5
0
ファイル: connection.py プロジェクト: nicktrav/vertica-python
class Connection(object):
    def __init__(self, options=None):
        self.reset_values()

        options = options or {}
        self.options = dict((key, value) for key, value in options.iteritems() if value is not None)

        # we only support one cursor per connection
        self.options.setdefault("unicode_error", None)
        self._cursor = Cursor(self, None, unicode_error=self.options["unicode_error"])
        self.options.setdefault("port", 5433)
        self.options.setdefault("read_timeout", 600)
        self.startup_connection()

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        try:
            # if there's no outstanding transaction, we can simply close the connection
            if self.transaction_status in (None, "in_transaction"):
                return

            if type is not None:
                self.rollback()
            else:
                self.commit()
        finally:
            self.close()

    #
    # dbApi methods
    #

    def close(self):
        try:
            self.write(messages.Terminate())
        finally:
            self.close_socket()

    def commit(self):
        if self.closed():
            raise errors.ConnectionError("Connection is closed")

        cur = self.cursor()
        cur.execute("COMMIT;")

    def rollback(self):
        if self.closed():
            raise errors.ConnectionError("Connection is closed")

        cur = self.cursor()
        cur.execute("ROLLBACK;")

    def cursor(self, cursor_type=None):
        if self.closed():
            raise errors.ConnectionError("Connection is closed")

        if self._cursor.closed():
            self._cursor._closed = False

        # let user change type if they want?
        self._cursor.cursor_type = cursor_type
        return self._cursor

    #
    # Internal
    #
    def reset_values(self):
        self.parameters = {}
        self.session_id = None
        self.backend_pid = None
        self.backend_key = None
        self.transaction_status = None
        self.socket = None

    def _socket(self):
        if self.socket is not None:
            return self.socket

        host = self.options.get("host")
        port = self.options.get("port")
        raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        raw_socket.connect((host, port))

        ssl_options = self.options.get("ssl")
        if ssl_options is not None and not ssl_options:
            from ssl import CertificateError, SSLError

            raw_socket.sendall(messages.SslRequest().to_bytes())
            response = raw_socket.recv(1)
            if response == "S":
                try:
                    if isinstance(ssl_options, ssl.SSLContext):
                        raw_socket = ssl_options.wrap_socket(raw_socket, server_hostname=host)
                    else:
                        raw_socket = ssl.wrap_socket(raw_socket)
                except CertificateError, e:
                    raise errors.ConnectionError("SSL: " + e.message)
                except SSLError, e:
                    raise errors.ConnectionError("SSL: " + e.reason)
            else:
コード例 #6
0
class Connection(object):
    def __init__(self, options=None):
        self.reset_values()

        options = options or {}
        self.options = dict(
            (key, value) for key, value in list(options.items()) if value is not None
        )

        # we only support one cursor per connection
        self._cursor = Cursor(self, None)
        self.options.setdefault('port', 5433)
        self.options.setdefault('read_timeout', 600)
        self.boot_connection()

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        try:
            # if there's no outstanding transaction, we can simply close the connection
            if self.transaction_status in (None, 'in_transaction'):
                return

            if type is not None:
                self.rollback()
            else:
                self.commit()
        finally:
            self.close()

    #
    # dbApi methods
    #

    def close(self):
        try:
            self.write(messages.Terminate())
        finally:
            self.close_socket()

    def commit(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('COMMIT;')

    def rollback(self):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        cur = self.cursor()
        cur.execute('ROLLBACK;')

    def cursor(self, cursor_type=None):
        if self.closed():
            raise errors.ConnectionError('Connection is closed')

        if self._cursor.closed():
            self._cursor._closed = False

        # let user change type if they want?
        self._cursor.cursor_type = cursor_type
        return self._cursor

    #
    # Internal
    #
    def reset_values(self):
        self.parameters = {}
        self.session_id = None
        self.backend_pid = None
        self.backend_key = None
        self.transaction_status = None
        self.socket = None

    def _socket(self):
        if self.socket is not None:
            return self.socket

        if self.options.get('ssl'):
            # SSL
            raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            raw_socket.connect((self.options['host'], self.options['port']))
            raw_socket.sendall(messages.SslRequest().to_bytes())
            response = raw_socket.recv(1)
            if response == 'S':
                # May want to add certs to this
                raw_socket = ssl.wrap_socket(raw_socket)
            else:
                raise SSLNotSupported("SSL requested but not supported by server")
        else:
            # Non-SSL
            raw_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            raw_socket.connect((self.options['host'], self.options['port']))

        self.socket = raw_socket
        return raw_socket

    def ssl(self):
        return self.socket is not None and isinstance(ssl.SSLSocket, self.socket)

    def opened(self):
        return (self.socket is not None
                and self.backend_pid is not None
                and self.transaction_status is not None)

    def closed(self):
        return not self.opened()

    def write(self, message):

        if hasattr(message, 'to_bytes') is False or isinstance(getattr(message, 'to_bytes'), collections.Callable) is False:
            raise TypeError("invalid message: ({0})".format(message))

        logger.debug('=> %s', message)
        try:
            self._socket().sendall(message.to_bytes())
        except Exception as e:
            self.close_socket()
            raise errors.ConnectionError(str(e))

    def close_socket(self):
        try:
            if self.socket is not None:
                self._socket().close()
        finally:
            self.reset_values()

    def reset_connection(self):
        self.close()
        self.boot_connection()

    def boot_connection(self):
        self.startup_connection()
        self.initialize_connection()

    def read_message(self):
        try:
            ready = select.select([self._socket()], [], [], self.options['read_timeout'])
            if len(ready[0]) > 0:
                type = self.read_bytes(1).decode('utf-8')
                size = unpack('!I', self.read_bytes(4))[0]

                if size < 4:
                    raise errors.MessageError(
                        "Bad message size: {0}".format(size)
                    )

                message = BackendMessage.factory(type, self.read_bytes(size - 4))
                logger.debug('<= %s', message)
                return message
            else:
                self.close()
                raise errors.TimedOutError("Connection timed out")
        except errors.TimedOutError:
            raise
        except Exception as e:
            self.close_socket()
            raise errors.ConnectionError(str(e))

    def process_message(self, message):
        if isinstance(message, messages.ErrorResponse):
            raise errors.ConnectionError(message.error_message())
        elif isinstance(message, messages.NoticeResponse):
            if getattr(self, 'notice_handler', None) is not None:
                self.notice_handler(message)
        elif isinstance(message, messages.BackendKeyData):
            self.backend_pid = message.pid
            self.backend_key = message.key
        elif isinstance(message, messages.ParameterStatus):
            self.parameters[message.name] = message.value
        elif isinstance(message, messages.ReadyForQuery):
            self.transaction_status = message.transaction_status
        elif isinstance(message, messages.CommandComplete):
            pass
        else:
            raise errors.MessageError("Unhandled message: {0}".format(message))

        # set last message
        self._cursor._message = message

    def __str__(self):
        safe_options = dict(
            (key, value) for key, value in list(self.options.items()) if key != 'password'
        )
        s1 = "<Vertica.Connection:{0} parameters={1} backend_pid={2}, ".format(
            id(self), self.parameters, self.backend_pid
        )
        s2 = "backend_key={0}, transaction_status={1}, socket={2}, options={3}>".format(
            self.backend_key, self.transaction_status, self.socket,
            safe_options,
        )
        return s1 + s2

    def read_bytes(self, n):
        results = b''
        while len(results) < n:
            bytes = self._socket().recv(n - len(results))
            if not bytes:
                raise errors.ConnectionError("Connection closed by Vertica")
            results = results + bytes
        return results

    def startup_connection(self):
        # This doesn't handle Unicode usernames or passwords
        user = self.options['user'].encode('utf-8')
        database = self.options['database'].encode('utf-8')
        password = self.options['password'].encode('utf-8')

        self.write(messages.Startup(user, database))

        while True:
            message = self.read_message()

            if isinstance(message, messages.Authentication):
                # Password message isn't right format ("incomplete message from client")
                if message.code != messages.Authentication.OK:
                    self.write(messages.Password(password, message.code, {
                        'user': user, 'salt': getattr(message, 'salt', None)
                    }))
            else:
                self.process_message(message)

            if isinstance(message, messages.ReadyForQuery):
                break

    def initialize_connection(self):
        if self.options.get('search_path') is not None:
            self.query("SET SEARCH_PATH TO {0}".format(self.options['search_path']))
        if self.options.get('role') is not None:
            self.query("SET ROLE {0}".format(self.options['role']))