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) 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.

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.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 perfom 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.