cassandra - Exceptions and Enums¶

cassandra.__version_info__¶

The version of the driver in a tuple format

cassandra.__version__¶

The version of the driver in a string format

class cassandra.ConsistencyLevel¶

Spcifies how many replicas must respond for an operation to be considered a success. By default, ONE is used for all operations.

ANY = 0¶

Only requires that one replica receives the write or the coordinator stores a hint to replay later. Valid only for writes.

ONE = 1¶

Only one replica needs to respond to consider the operation a success

TWO = 2¶

Two replicas must respond to consider the operation a success

THREE = 3¶

Three replicas must respond to consider the operation a success

QUORUM = 4¶

ceil(RF/2) + 1 replicas must respond to consider the operation a success

ALL = 5¶

All replicas must respond to consider the operation a success

LOCAL_QUORUM = 6¶

Requires a quorum of replicas in the local datacenter

EACH_QUORUM = 7¶

Requires a quorum of replicas in each datacenter

SERIAL = 8¶

For conditional inserts/updates that utilize Cassandra’s lightweight transactions, this requires consensus among all replicas for the modified data.

LOCAL_SERIAL = 9¶

Like SERIAL, but only requires consensus among replicas in the local datacenter.

LOCAL_ONE = 10¶

Sends a request only to replicas in the local datacenter and waits for one response.

class cassandra.ProtocolVersion¶

Defines native protocol versions supported by this driver.

V1 = 1¶

v1, supported in Cassandra 1.2–>2.2

V2 = 2¶

v2, supported in Cassandra 2.0–>2.2; added support for lightweight transactions, batch operations, and automatic query paging.

V3 = 3¶

v3, supported in Cassandra 2.1–>3.x+; added support for protocol-level client-side timestamps (see Session.use_client_timestamp), serial consistency levels for BatchStatement, and an improved connection pool.

V4 = 4¶

v4, supported in Cassandra 2.2–>3.x+; added a number of new types, server warnings, new failure messages, and custom payloads. Details in the project docs

V5 = 5¶

v5, in beta from 3.x+. Finalised in 4.0-beta5

V6 = 6¶

v6, in beta from 4.0-beta5

DSE_V1 = 65¶

DSE private protocol v1, supported in DSE 5.1+

DSE_V2 = 66¶

DSE private protocol v2, supported in DSE 6.0+

SUPPORTED_VERSIONS = (66, 65, 6, 5, 4, 3, 2, 1)¶

A tuple of all supported protocol versions

BETA_VERSIONS = (6,)¶

A tuple of all beta protocol versions

MIN_SUPPORTED = 1¶

Minimum protocol version supported by this driver.

MAX_SUPPORTED = 66¶

Maximum protocol version supported by this driver.

classmethod get_lower_supported(previous_version)¶

Return the lower supported protocol version. Beta versions are omitted.

class cassandra.UserFunctionDescriptor(name, argument_types)¶

Describes a User function by name and argument signature

name = None¶

name of the function

argument_types = None¶

Ordered list of CQL argument type names comprising the type signature

property signature¶

function signature string in the form ‘name([type0[,type1[…]]])’

can be used to uniquely identify overloaded function names within a keyspace

class cassandra.UserAggregateDescriptor(name, argument_types)¶

Describes a User aggregate function by name and argument signature

name = None¶

name of the aggregate

argument_types = None¶

Ordered list of CQL argument type names comprising the type signature

property signature¶

function signature string in the form ‘name([type0[,type1[…]]])’

can be used to uniquely identify overloaded function names within a keyspace

exception cassandra.DriverException¶

Base for all exceptions explicitly raised by the driver.

exception cassandra.RequestExecutionException¶

Base for request execution exceptions returned from the server.

exception cassandra.Unavailable¶

There were not enough live replicas to satisfy the requested consistency level, so the coordinator node immediately failed the request without forwarding it to any replicas.

consistency = None¶

The requested ConsistencyLevel

required_replicas = None¶

The number of replicas that needed to be live to complete the operation

alive_replicas = None¶

The number of replicas that were actually alive

exception cassandra.Timeout¶

Replicas failed to respond to the coordinator node before timing out.

consistency = None¶

The requested ConsistencyLevel

required_responses = None¶

The number of required replica responses

received_responses = None¶

The number of replicas that responded before the coordinator timed out the operation

exception cassandra.ReadTimeout¶

A subclass of Timeout for read operations.

This indicates that the replicas failed to respond to the coordinator node before the configured timeout. This timeout is configured in cassandra.yaml with the read_request_timeout_in_ms and range_request_timeout_in_ms options.

data_retrieved = None¶

A boolean indicating whether the requested data was retrieved by the coordinator from any replicas before it timed out the operation

exception cassandra.WriteTimeout¶

A subclass of Timeout for write operations.

This indicates that the replicas failed to respond to the coordinator node before the configured timeout. This timeout is configured in cassandra.yaml with the write_request_timeout_in_ms option.

write_type = None¶

The type of write operation, enum on WriteType

exception cassandra.CoordinationFailure¶

Replicas sent a failure to the coordinator.

consistency = None¶

The requested ConsistencyLevel

required_responses = None¶

The number of required replica responses

received_responses = None¶

The number of replicas that responded before the coordinator timed out the operation

failures = None¶

The number of replicas that sent a failure message

error_code_map = None¶

A map of inet addresses to error codes representing replicas that sent a failure message. Only set when protocol_version is 5 or higher.

exception cassandra.ReadFailure¶

A subclass of CoordinationFailure for read operations.

This indicates that the replicas sent a failure message to the coordinator.

data_retrieved = None¶

A boolean indicating whether the requested data was retrieved by the coordinator from any replicas before it timed out the operation

exception cassandra.WriteFailure¶

A subclass of CoordinationFailure for write operations.

This indicates that the replicas sent a failure message to the coordinator.

write_type = None¶

The type of write operation, enum on WriteType

exception cassandra.FunctionFailure¶

User Defined Function failed during execution

keyspace = None¶

Keyspace of the function

function = None¶

Name of the function

arg_types = None¶

List of argument type names of the function

exception cassandra.RequestValidationException¶

Server request validation failed

exception cassandra.ConfigurationException¶

Server indicated request errro due to current configuration

exception cassandra.AlreadyExists¶

An attempt was made to create a keyspace or table that already exists.

keyspace = None¶

The name of the keyspace that already exists, or, if an attempt was made to create a new table, the keyspace that the table is in.

table = None¶

The name of the table that already exists, or, if an attempt was make to create a keyspace, None.

exception cassandra.InvalidRequest¶

A query was made that was invalid for some reason, such as trying to set the keyspace for a connection to a nonexistent keyspace.

exception cassandra.Unauthorized¶

The current user is not authorized to perform the requested operation.

exception cassandra.AuthenticationFailed¶

Failed to authenticate.

exception cassandra.OperationTimedOut¶

The operation took longer than the specified (client-side) timeout to complete. This is not an error generated by Cassandra, only the driver.

errors = None¶

A dict of errors keyed by the Host against which they occurred.

last_host = None¶

The last Host this operation was attempted against.