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Copy pathprotocol.py
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1240 lines (960 loc) · 37.9 KB
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# Copyright 2013-2016 DataStax, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import absolute_import # to enable import io from stdlib
from collections import namedtuple
import logging
import socket
from uuid import UUID
import six
from six.moves import range
import io
from cassandra import type_codes
from cassandra import (Unavailable, WriteTimeout, ReadTimeout,
WriteFailure, ReadFailure, FunctionFailure,
AlreadyExists, InvalidRequest, Unauthorized,
UnsupportedOperation, UserFunctionDescriptor,
UserAggregateDescriptor, SchemaTargetType)
from cassandra.marshal import (int32_pack, int32_unpack, uint16_pack, uint16_unpack,
int8_pack, int8_unpack, uint64_pack, header_pack,
v3_header_pack)
from cassandra.cqltypes import (AsciiType, BytesType, BooleanType,
CounterColumnType, DateType, DecimalType,
DoubleType, FloatType, Int32Type,
InetAddressType, IntegerType, ListType,
LongType, MapType, SetType, TimeUUIDType,
UTF8Type, VarcharType, UUIDType, UserType,
TupleType, lookup_casstype, SimpleDateType,
TimeType, ByteType, ShortType)
from cassandra.policies import WriteType
from cassandra.cython_deps import HAVE_CYTHON, HAVE_NUMPY
from cassandra import util
log = logging.getLogger(__name__)
class NotSupportedError(Exception):
pass
class InternalError(Exception):
pass
ColumnMetadata = namedtuple("ColumnMetadata", ['keyspace_name', 'table_name', 'name', 'type'])
MIN_SUPPORTED_VERSION = 1
MAX_SUPPORTED_VERSION = 4
HEADER_DIRECTION_TO_CLIENT = 0x80
HEADER_DIRECTION_MASK = 0x80
COMPRESSED_FLAG = 0x01
TRACING_FLAG = 0x02
CUSTOM_PAYLOAD_FLAG = 0x04
WARNING_FLAG = 0x08
_message_types_by_opcode = {}
_UNSET_VALUE = object()
def register_class(cls):
_message_types_by_opcode[cls.opcode] = cls
def get_registered_classes():
return _message_types_by_opcode.copy()
class _RegisterMessageType(type):
def __init__(cls, name, bases, dct):
if not name.startswith('_'):
register_class(cls)
@six.add_metaclass(_RegisterMessageType)
class _MessageType(object):
tracing = False
custom_payload = None
warnings = None
def update_custom_payload(self, other):
if other:
if not self.custom_payload:
self.custom_payload = {}
self.custom_payload.update(other)
if len(self.custom_payload) > 65535:
raise ValueError("Custom payload map exceeds max count allowed by protocol (65535)")
def __repr__(self):
return '<%s(%s)>' % (self.__class__.__name__, ', '.join('%s=%r' % i for i in _get_params(self)))
def _get_params(message_obj):
base_attrs = dir(_MessageType)
return (
(n, a) for n, a in message_obj.__dict__.items()
if n not in base_attrs and not n.startswith('_') and not callable(a)
)
error_classes = {}
class ErrorMessage(_MessageType, Exception):
opcode = 0x00
name = 'ERROR'
summary = 'Unknown'
def __init__(self, code, message, info):
self.code = code
self.message = message
self.info = info
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
code = read_int(f)
msg = read_string(f)
subcls = error_classes.get(code, cls)
extra_info = subcls.recv_error_info(f)
return subcls(code=code, message=msg, info=extra_info)
def summary_msg(self):
msg = 'code=%04x [%s] message="%s"' \
% (self.code, self.summary, self.message)
return msg
def __str__(self):
return '<ErrorMessage %s>' % self.summary_msg()
__repr__ = __str__
@staticmethod
def recv_error_info(f):
pass
def to_exception(self):
return self
class ErrorMessageSubclass(_RegisterMessageType):
def __init__(cls, name, bases, dct):
if cls.error_code is not None: # Server has an error code of 0.
error_classes[cls.error_code] = cls
@six.add_metaclass(ErrorMessageSubclass)
class ErrorMessageSub(ErrorMessage):
error_code = None
class RequestExecutionException(ErrorMessageSub):
pass
class RequestValidationException(ErrorMessageSub):
pass
class ServerError(ErrorMessageSub):
summary = 'Server error'
error_code = 0x0000
class ProtocolException(ErrorMessageSub):
summary = 'Protocol error'
error_code = 0x000A
class BadCredentials(ErrorMessageSub):
summary = 'Bad credentials'
error_code = 0x0100
class UnavailableErrorMessage(RequestExecutionException):
summary = 'Unavailable exception'
error_code = 0x1000
@staticmethod
def recv_error_info(f):
return {
'consistency': read_consistency_level(f),
'required_replicas': read_int(f),
'alive_replicas': read_int(f),
}
def to_exception(self):
return Unavailable(self.summary_msg(), **self.info)
class OverloadedErrorMessage(RequestExecutionException):
summary = 'Coordinator node overloaded'
error_code = 0x1001
class IsBootstrappingErrorMessage(RequestExecutionException):
summary = 'Coordinator node is bootstrapping'
error_code = 0x1002
class TruncateError(RequestExecutionException):
summary = 'Error during truncate'
error_code = 0x1003
class WriteTimeoutErrorMessage(RequestExecutionException):
summary = "Coordinator node timed out waiting for replica nodes' responses"
error_code = 0x1100
@staticmethod
def recv_error_info(f):
return {
'consistency': read_consistency_level(f),
'received_responses': read_int(f),
'required_responses': read_int(f),
'write_type': WriteType.name_to_value[read_string(f)],
}
def to_exception(self):
return WriteTimeout(self.summary_msg(), **self.info)
class ReadTimeoutErrorMessage(RequestExecutionException):
summary = "Coordinator node timed out waiting for replica nodes' responses"
error_code = 0x1200
@staticmethod
def recv_error_info(f):
return {
'consistency': read_consistency_level(f),
'received_responses': read_int(f),
'required_responses': read_int(f),
'data_retrieved': bool(read_byte(f)),
}
def to_exception(self):
return ReadTimeout(self.summary_msg(), **self.info)
class ReadFailureMessage(RequestExecutionException):
summary = "Replica(s) failed to execute read"
error_code = 0x1300
@staticmethod
def recv_error_info(f):
return {
'consistency': read_consistency_level(f),
'received_responses': read_int(f),
'required_responses': read_int(f),
'failures': read_int(f),
'data_retrieved': bool(read_byte(f)),
}
def to_exception(self):
return ReadFailure(self.summary_msg(), **self.info)
class FunctionFailureMessage(RequestExecutionException):
summary = "User Defined Function failure"
error_code = 0x1400
@staticmethod
def recv_error_info(f):
return {
'keyspace': read_string(f),
'function': read_string(f),
'arg_types': [read_string(f) for _ in range(read_short(f))],
}
def to_exception(self):
return FunctionFailure(self.summary_msg(), **self.info)
class WriteFailureMessage(RequestExecutionException):
summary = "Replica(s) failed to execute write"
error_code = 0x1500
@staticmethod
def recv_error_info(f):
return {
'consistency': read_consistency_level(f),
'received_responses': read_int(f),
'required_responses': read_int(f),
'failures': read_int(f),
'write_type': WriteType.name_to_value[read_string(f)],
}
def to_exception(self):
return WriteFailure(self.summary_msg(), **self.info)
class SyntaxException(RequestValidationException):
summary = 'Syntax error in CQL query'
error_code = 0x2000
class UnauthorizedErrorMessage(RequestValidationException):
summary = 'Unauthorized'
error_code = 0x2100
def to_exception(self):
return Unauthorized(self.summary_msg())
class InvalidRequestException(RequestValidationException):
summary = 'Invalid query'
error_code = 0x2200
def to_exception(self):
return InvalidRequest(self.summary_msg())
class ConfigurationException(RequestValidationException):
summary = 'Query invalid because of configuration issue'
error_code = 0x2300
class PreparedQueryNotFound(RequestValidationException):
summary = 'Matching prepared statement not found on this node'
error_code = 0x2500
@staticmethod
def recv_error_info(f):
# return the query ID
return read_binary_string(f)
class AlreadyExistsException(ConfigurationException):
summary = 'Item already exists'
error_code = 0x2400
@staticmethod
def recv_error_info(f):
return {
'keyspace': read_string(f),
'table': read_string(f),
}
def to_exception(self):
return AlreadyExists(**self.info)
class StartupMessage(_MessageType):
opcode = 0x01
name = 'STARTUP'
KNOWN_OPTION_KEYS = set((
'CQL_VERSION',
'COMPRESSION',
))
def __init__(self, cqlversion, options):
self.cqlversion = cqlversion
self.options = options
def send_body(self, f, protocol_version):
optmap = self.options.copy()
optmap['CQL_VERSION'] = self.cqlversion
write_stringmap(f, optmap)
class ReadyMessage(_MessageType):
opcode = 0x02
name = 'READY'
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
return cls()
class AuthenticateMessage(_MessageType):
opcode = 0x03
name = 'AUTHENTICATE'
def __init__(self, authenticator):
self.authenticator = authenticator
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
authname = read_string(f)
return cls(authenticator=authname)
class CredentialsMessage(_MessageType):
opcode = 0x04
name = 'CREDENTIALS'
def __init__(self, creds):
self.creds = creds
def send_body(self, f, protocol_version):
if protocol_version > 1:
raise UnsupportedOperation(
"Credentials-based authentication is not supported with "
"protocol version 2 or higher. Use the SASL authentication "
"mechanism instead.")
write_short(f, len(self.creds))
for credkey, credval in self.creds.items():
write_string(f, credkey)
write_string(f, credval)
class AuthChallengeMessage(_MessageType):
opcode = 0x0E
name = 'AUTH_CHALLENGE'
def __init__(self, challenge):
self.challenge = challenge
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
return cls(read_binary_longstring(f))
class AuthResponseMessage(_MessageType):
opcode = 0x0F
name = 'AUTH_RESPONSE'
def __init__(self, response):
self.response = response
def send_body(self, f, protocol_version):
write_longstring(f, self.response)
class AuthSuccessMessage(_MessageType):
opcode = 0x10
name = 'AUTH_SUCCESS'
def __init__(self, token):
self.token = token
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
return cls(read_longstring(f))
class OptionsMessage(_MessageType):
opcode = 0x05
name = 'OPTIONS'
def send_body(self, f, protocol_version):
pass
class SupportedMessage(_MessageType):
opcode = 0x06
name = 'SUPPORTED'
def __init__(self, cql_versions, options):
self.cql_versions = cql_versions
self.options = options
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
options = read_stringmultimap(f)
cql_versions = options.pop('CQL_VERSION')
return cls(cql_versions=cql_versions, options=options)
# used for QueryMessage and ExecuteMessage
_VALUES_FLAG = 0x01
_SKIP_METADATA_FLAG = 0x01
_PAGE_SIZE_FLAG = 0x04
_WITH_PAGING_STATE_FLAG = 0x08
_WITH_SERIAL_CONSISTENCY_FLAG = 0x10
_PROTOCOL_TIMESTAMP = 0x20
class QueryMessage(_MessageType):
opcode = 0x07
name = 'QUERY'
def __init__(self, query, consistency_level, serial_consistency_level=None,
fetch_size=None, paging_state=None, timestamp=None):
self.query = query
self.consistency_level = consistency_level
self.serial_consistency_level = serial_consistency_level
self.fetch_size = fetch_size
self.paging_state = paging_state
self.timestamp = timestamp
self._query_params = None # only used internally. May be set to a list of native-encoded values to have them sent with the request.
def send_body(self, f, protocol_version):
write_longstring(f, self.query)
write_consistency_level(f, self.consistency_level)
flags = 0x00
if self._query_params is not None:
flags |= _VALUES_FLAG # also v2+, but we're only setting params internally right now
if self.serial_consistency_level:
if protocol_version >= 2:
flags |= _WITH_SERIAL_CONSISTENCY_FLAG
else:
raise UnsupportedOperation(
"Serial consistency levels require the use of protocol version "
"2 or higher. Consider setting Cluster.protocol_version to 2 "
"to support serial consistency levels.")
if self.fetch_size:
if protocol_version >= 2:
flags |= _PAGE_SIZE_FLAG
else:
raise UnsupportedOperation(
"Automatic query paging may only be used with protocol version "
"2 or higher. Consider setting Cluster.protocol_version to 2.")
if self.paging_state:
if protocol_version >= 2:
flags |= _WITH_PAGING_STATE_FLAG
else:
raise UnsupportedOperation(
"Automatic query paging may only be used with protocol version "
"2 or higher. Consider setting Cluster.protocol_version to 2.")
if self.timestamp is not None:
flags |= _PROTOCOL_TIMESTAMP
write_byte(f, flags)
if self._query_params is not None:
write_short(f, len(self._query_params))
for param in self._query_params:
write_value(f, param)
if self.fetch_size:
write_int(f, self.fetch_size)
if self.paging_state:
write_longstring(f, self.paging_state)
if self.serial_consistency_level:
write_consistency_level(f, self.serial_consistency_level)
if self.timestamp is not None:
write_long(f, self.timestamp)
CUSTOM_TYPE = object()
RESULT_KIND_VOID = 0x0001
RESULT_KIND_ROWS = 0x0002
RESULT_KIND_SET_KEYSPACE = 0x0003
RESULT_KIND_PREPARED = 0x0004
RESULT_KIND_SCHEMA_CHANGE = 0x0005
class ResultMessage(_MessageType):
opcode = 0x08
name = 'RESULT'
kind = None
results = None
paging_state = None
# Names match type name in module scope. Most are imported from cassandra.cqltypes (except CUSTOM_TYPE)
type_codes = _cqltypes_by_code = dict((v, globals()[k]) for k, v in type_codes.__dict__.items() if not k.startswith('_'))
_FLAGS_GLOBAL_TABLES_SPEC = 0x0001
_HAS_MORE_PAGES_FLAG = 0x0002
_NO_METADATA_FLAG = 0x0004
def __init__(self, kind, results, paging_state=None):
self.kind = kind
self.results = results
self.paging_state = paging_state
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
kind = read_int(f)
paging_state = None
if kind == RESULT_KIND_VOID:
results = None
elif kind == RESULT_KIND_ROWS:
paging_state, results = cls.recv_results_rows(
f, protocol_version, user_type_map)
elif kind == RESULT_KIND_SET_KEYSPACE:
ksname = read_string(f)
results = ksname
elif kind == RESULT_KIND_PREPARED:
results = cls.recv_results_prepared(f, protocol_version, user_type_map)
elif kind == RESULT_KIND_SCHEMA_CHANGE:
results = cls.recv_results_schema_change(f, protocol_version)
else:
raise Exception("Unknown RESULT kind: %d" % kind)
return cls(kind, results, paging_state)
@classmethod
def recv_results_rows(cls, f, protocol_version, user_type_map):
paging_state, column_metadata = cls.recv_results_metadata(f, user_type_map)
rowcount = read_int(f)
rows = [cls.recv_row(f, len(column_metadata)) for _ in range(rowcount)]
colnames = [c[2] for c in column_metadata]
coltypes = [c[3] for c in column_metadata]
parsed_rows = [
tuple(ctype.from_binary(val, protocol_version)
for ctype, val in zip(coltypes, row))
for row in rows]
return (paging_state, (colnames, parsed_rows))
@classmethod
def recv_results_prepared(cls, f, protocol_version, user_type_map):
query_id = read_binary_string(f)
column_metadata, pk_indexes = cls.recv_prepared_metadata(f, protocol_version, user_type_map)
return (query_id, column_metadata, pk_indexes)
@classmethod
def recv_results_metadata(cls, f, user_type_map):
flags = read_int(f)
glob_tblspec = bool(flags & cls._FLAGS_GLOBAL_TABLES_SPEC)
colcount = read_int(f)
if flags & cls._HAS_MORE_PAGES_FLAG:
paging_state = read_binary_longstring(f)
else:
paging_state = None
if glob_tblspec:
ksname = read_string(f)
cfname = read_string(f)
column_metadata = []
for _ in range(colcount):
if glob_tblspec:
colksname = ksname
colcfname = cfname
else:
colksname = read_string(f)
colcfname = read_string(f)
colname = read_string(f)
coltype = cls.read_type(f, user_type_map)
column_metadata.append((colksname, colcfname, colname, coltype))
return paging_state, column_metadata
@classmethod
def recv_prepared_metadata(cls, f, protocol_version, user_type_map):
flags = read_int(f)
glob_tblspec = bool(flags & cls._FLAGS_GLOBAL_TABLES_SPEC)
colcount = read_int(f)
pk_indexes = None
if protocol_version >= 4:
num_pk_indexes = read_int(f)
pk_indexes = [read_short(f) for _ in range(num_pk_indexes)]
if glob_tblspec:
ksname = read_string(f)
cfname = read_string(f)
column_metadata = []
for _ in range(colcount):
if glob_tblspec:
colksname = ksname
colcfname = cfname
else:
colksname = read_string(f)
colcfname = read_string(f)
colname = read_string(f)
coltype = cls.read_type(f, user_type_map)
column_metadata.append(ColumnMetadata(colksname, colcfname, colname, coltype))
return column_metadata, pk_indexes
@classmethod
def recv_results_schema_change(cls, f, protocol_version):
return EventMessage.recv_schema_change(f, protocol_version)
@classmethod
def read_type(cls, f, user_type_map):
optid = read_short(f)
try:
typeclass = cls.type_codes[optid]
except KeyError:
raise NotSupportedError("Unknown data type code 0x%04x. Have to skip"
" entire result set." % (optid,))
if typeclass in (ListType, SetType):
subtype = cls.read_type(f, user_type_map)
typeclass = typeclass.apply_parameters((subtype,))
elif typeclass == MapType:
keysubtype = cls.read_type(f, user_type_map)
valsubtype = cls.read_type(f, user_type_map)
typeclass = typeclass.apply_parameters((keysubtype, valsubtype))
elif typeclass == TupleType:
num_items = read_short(f)
types = tuple(cls.read_type(f, user_type_map) for _ in range(num_items))
typeclass = typeclass.apply_parameters(types)
elif typeclass == UserType:
ks = read_string(f)
udt_name = read_string(f)
num_fields = read_short(f)
names, types = zip(*((read_string(f), cls.read_type(f, user_type_map))
for _ in range(num_fields)))
specialized_type = typeclass.make_udt_class(ks, udt_name, names, types)
specialized_type.mapped_class = user_type_map.get(ks, {}).get(udt_name)
typeclass = specialized_type
elif typeclass == CUSTOM_TYPE:
classname = read_string(f)
typeclass = lookup_casstype(classname)
return typeclass
@staticmethod
def recv_row(f, colcount):
return [read_value(f) for _ in range(colcount)]
class PrepareMessage(_MessageType):
opcode = 0x09
name = 'PREPARE'
def __init__(self, query):
self.query = query
def send_body(self, f, protocol_version):
write_longstring(f, self.query)
class ExecuteMessage(_MessageType):
opcode = 0x0A
name = 'EXECUTE'
def __init__(self, query_id, query_params, consistency_level,
serial_consistency_level=None, fetch_size=None,
paging_state=None, timestamp=None):
self.query_id = query_id
self.query_params = query_params
self.consistency_level = consistency_level
self.serial_consistency_level = serial_consistency_level
self.fetch_size = fetch_size
self.paging_state = paging_state
self.timestamp = timestamp
def send_body(self, f, protocol_version):
write_string(f, self.query_id)
if protocol_version == 1:
if self.serial_consistency_level:
raise UnsupportedOperation(
"Serial consistency levels require the use of protocol version "
"2 or higher. Consider setting Cluster.protocol_version to 2 "
"to support serial consistency levels.")
if self.fetch_size or self.paging_state:
raise UnsupportedOperation(
"Automatic query paging may only be used with protocol version "
"2 or higher. Consider setting Cluster.protocol_version to 2.")
write_short(f, len(self.query_params))
for param in self.query_params:
write_value(f, param)
write_consistency_level(f, self.consistency_level)
else:
write_consistency_level(f, self.consistency_level)
flags = _VALUES_FLAG
if self.serial_consistency_level:
flags |= _WITH_SERIAL_CONSISTENCY_FLAG
if self.fetch_size:
flags |= _PAGE_SIZE_FLAG
if self.paging_state:
flags |= _WITH_PAGING_STATE_FLAG
if self.timestamp is not None:
if protocol_version >= 3:
flags |= _PROTOCOL_TIMESTAMP
else:
raise UnsupportedOperation(
"Protocol-level timestamps may only be used with protocol version "
"3 or higher. Consider setting Cluster.protocol_version to 3.")
write_byte(f, flags)
write_short(f, len(self.query_params))
for param in self.query_params:
write_value(f, param)
if self.fetch_size:
write_int(f, self.fetch_size)
if self.paging_state:
write_longstring(f, self.paging_state)
if self.serial_consistency_level:
write_consistency_level(f, self.serial_consistency_level)
if self.timestamp is not None:
write_long(f, self.timestamp)
class BatchMessage(_MessageType):
opcode = 0x0D
name = 'BATCH'
def __init__(self, batch_type, queries, consistency_level,
serial_consistency_level=None, timestamp=None):
self.batch_type = batch_type
self.queries = queries
self.consistency_level = consistency_level
self.serial_consistency_level = serial_consistency_level
self.timestamp = timestamp
def send_body(self, f, protocol_version):
write_byte(f, self.batch_type.value)
write_short(f, len(self.queries))
for prepared, string_or_query_id, params in self.queries:
if not prepared:
write_byte(f, 0)
write_longstring(f, string_or_query_id)
else:
write_byte(f, 1)
write_short(f, len(string_or_query_id))
f.write(string_or_query_id)
write_short(f, len(params))
for param in params:
write_value(f, param)
write_consistency_level(f, self.consistency_level)
if protocol_version >= 3:
flags = 0
if self.serial_consistency_level:
flags |= _WITH_SERIAL_CONSISTENCY_FLAG
if self.timestamp is not None:
flags |= _PROTOCOL_TIMESTAMP
write_byte(f, flags)
if self.serial_consistency_level:
write_consistency_level(f, self.serial_consistency_level)
if self.timestamp is not None:
write_long(f, self.timestamp)
known_event_types = frozenset((
'TOPOLOGY_CHANGE',
'STATUS_CHANGE',
'SCHEMA_CHANGE'
))
class RegisterMessage(_MessageType):
opcode = 0x0B
name = 'REGISTER'
def __init__(self, event_list):
self.event_list = event_list
def send_body(self, f, protocol_version):
write_stringlist(f, self.event_list)
class EventMessage(_MessageType):
opcode = 0x0C
name = 'EVENT'
def __init__(self, event_type, event_args):
self.event_type = event_type
self.event_args = event_args
@classmethod
def recv_body(cls, f, protocol_version, user_type_map):
event_type = read_string(f).upper()
if event_type in known_event_types:
read_method = getattr(cls, 'recv_' + event_type.lower())
return cls(event_type=event_type, event_args=read_method(f, protocol_version))
raise NotSupportedError('Unknown event type %r' % event_type)
@classmethod
def recv_topology_change(cls, f, protocol_version):
# "NEW_NODE" or "REMOVED_NODE"
change_type = read_string(f)
address = read_inet(f)
return dict(change_type=change_type, address=address)
@classmethod
def recv_status_change(cls, f, protocol_version):
# "UP" or "DOWN"
change_type = read_string(f)
address = read_inet(f)
return dict(change_type=change_type, address=address)
@classmethod
def recv_schema_change(cls, f, protocol_version):
# "CREATED", "DROPPED", or "UPDATED"
change_type = read_string(f)
if protocol_version >= 3:
target = read_string(f)
keyspace = read_string(f)
event = {'target_type': target, 'change_type': change_type, 'keyspace': keyspace}
if target != SchemaTargetType.KEYSPACE:
target_name = read_string(f)
if target == SchemaTargetType.FUNCTION:
event['function'] = UserFunctionDescriptor(target_name, [read_string(f) for _ in range(read_short(f))])
elif target == SchemaTargetType.AGGREGATE:
event['aggregate'] = UserAggregateDescriptor(target_name, [read_string(f) for _ in range(read_short(f))])
else:
event[target.lower()] = target_name
else:
keyspace = read_string(f)
table = read_string(f)
if table:
event = {'target_type': SchemaTargetType.TABLE, 'change_type': change_type, 'keyspace': keyspace, 'table': table}
else:
event = {'target_type': SchemaTargetType.KEYSPACE, 'change_type': change_type, 'keyspace': keyspace}
return event
class ProtocolHandler(object):
"""
ProtocolHander handles encoding and decoding messages.
This class can be specialized to compose Handlers which implement alternative
result decoding or type deserialization. Class definitions are passed to :class:`cassandra.cluster.Cluster`
on initialization.
Contracted class methods are :meth:`ProtocolHandler.encode_message` and :meth:`ProtocolHandler.decode_message`.
"""
message_types_by_opcode = _message_types_by_opcode.copy()
"""
Default mapping of opcode to Message implementation. The default ``decode_message`` implementation uses
this to instantiate a message and populate using ``recv_body``. This mapping can be updated to inject specialized
result decoding implementations.
"""
@classmethod
def encode_message(cls, msg, stream_id, protocol_version, compressor):
"""
Encodes a message using the specified frame parameters, and compressor
:param msg: the message, typically of cassandra.protocol._MessageType, generated by the driver
:param stream_id: protocol stream id for the frame header
:param protocol_version: version for the frame header, and used encoding contents
:param compressor: optional compression function to be used on the body
"""
flags = 0
body = io.BytesIO()
if msg.custom_payload:
if protocol_version < 4:
raise UnsupportedOperation("Custom key/value payloads can only be used with protocol version 4 or higher")
flags |= CUSTOM_PAYLOAD_FLAG
write_bytesmap(body, msg.custom_payload)
msg.send_body(body, protocol_version)
body = body.getvalue()
if compressor and len(body) > 0:
body = compressor(body)
flags |= COMPRESSED_FLAG
if msg.tracing:
flags |= TRACING_FLAG
buff = io.BytesIO()
cls._write_header(buff, protocol_version, flags, stream_id, msg.opcode, len(body))
buff.write(body)
return buff.getvalue()
@staticmethod
def _write_header(f, version, flags, stream_id, opcode, length):
"""
Write a CQL protocol frame header.
"""
pack = v3_header_pack if version >= 3 else header_pack
f.write(pack(version, flags, stream_id, opcode))
write_int(f, length)
@classmethod
def decode_message(cls, protocol_version, user_type_map, stream_id, flags, opcode, body,
decompressor):
"""
Decodes a native protocol message body
:param protocol_version: version to use decoding contents
:param user_type_map: map[keyspace name] = map[type name] = custom type to instantiate when deserializing this type
:param stream_id: native protocol stream id from the frame header
:param flags: native protocol flags bitmap from the header
:param opcode: native protocol opcode from the header
:param body: frame body
:param decompressor: optional decompression function to inflate the body
:return: a message decoded from the body and frame attributes
"""
if flags & COMPRESSED_FLAG:
if decompressor is None:
raise Exception("No de-compressor available for compressed frame!")
body = decompressor(body)
flags ^= COMPRESSED_FLAG
body = io.BytesIO(body)
if flags & TRACING_FLAG:
trace_id = UUID(bytes=body.read(16))
flags ^= TRACING_FLAG
else:
trace_id = None
if flags & WARNING_FLAG:
warnings = read_stringlist(body)
flags ^= WARNING_FLAG
else:
warnings = None
if flags & CUSTOM_PAYLOAD_FLAG:
custom_payload = read_bytesmap(body)
flags ^= CUSTOM_PAYLOAD_FLAG
else:
custom_payload = None
if flags:
log.warning("Unknown protocol flags set: %02x. May cause problems.", flags)
msg_class = cls.message_types_by_opcode[opcode]
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