Files
deb-python-cassandra-driver/cqlengine/connection.py
2014-06-26 17:42:14 -07:00

93 lines
2.5 KiB
Python

#http://pypi.python.org/pypi/cql/1.0.4
#http://code.google.com/a/apache-extras.org/p/cassandra-dbapi2 /
#http://cassandra.apache.org/doc/cql/CQL.html
from collections import namedtuple
from cassandra.cluster import Cluster
from cassandra.query import SimpleStatement, Statement
try:
import Queue as queue
except ImportError:
# python 3
import queue
import logging
from cqlengine.exceptions import CQLEngineException
from cassandra import ConsistencyLevel
from cqlengine.statements import BaseCQLStatement
from cassandra.query import dict_factory
LOG = logging.getLogger('cqlengine.cql')
class CQLConnectionError(CQLEngineException): pass
Host = namedtuple('Host', ['name', 'port'])
cluster = None
session = None
default_consistency_level = None
def setup(
hosts,
default_keyspace,
consistency=ConsistencyLevel.ONE,
**kwargs):
"""
Records the hosts and connects to one of them
:param hosts: list of hosts, see http://datastax.github.io/python-driver/api/cassandra/cluster.html
:type hosts: list
:param default_keyspace: The default keyspace to use
:type default_keyspace: str
:param consistency: The global consistency level
:type consistency: int
"""
global cluster, session, default_consistency_level
if 'username' in kwargs or 'password' in kwargs:
raise CQLEngineException("Username & Password are now handled by using the native driver's auth_provider")
if default_keyspace:
from cqlengine import models
models.DEFAULT_KEYSPACE = default_keyspace
default_consistency_level = consistency
cluster = Cluster(hosts, **kwargs)
session = cluster.connect()
session.row_factory = dict_factory
def execute(query, params=None, consistency_level=None):
if not session:
raise CQLEngineException("It is required to setup() cqlengine before executing queries")
if consistency_level is None:
consistency_level = default_consistency_level
if isinstance(query, Statement):
pass
elif isinstance(query, BaseCQLStatement):
params = query.get_context()
query = str(query)
query = SimpleStatement(query, consistency_level=consistency_level)
elif isinstance(query, basestring):
query = SimpleStatement(query, consistency_level=consistency_level)
params = params or {}
result = session.execute(query, params)
return result
def get_session():
return session
def get_cluster():
return cluster