alexandra is a thin abstraction over pycassa to interact with Cassandra from Django.
Requires Django and pycassa 0.20 or greater:
pip install -e git+http://github.com/dziegler/alexandra.git#egg=alexandra add CASSANDRA_CLUSTER and CASSANDRA_KEYSPACE to settings.py :
CASSANDRA_CLUSTER = ['localhost:9160']
CASSANDRA_KEYSPACE = 'my_keyspace'Syntax for model definition is similar to Django's, but because rows can have as many columns as you want, there's no need to define them. :
import pycassa
from alexandra import cass
class EventManager(cass.Manager):
def get_for_uuid(self, uuid):
return self.get(uuid)
class Event(cass.ColumnFamily):
"""
Event = {
"89c23f26377e439a8e52fadec8f6bf19" = {
"uuid": "804e39e29a6148039633e5a69f0c0870",
"action": "landing:home"
"ip_address": "127.0.0.1",
"gender": "1",
}
...
}
"""
objects = EventManager()
class Meta:
# defaults to pycassa.ConsistencyLevel.ONE
read_consistency_level = pycassa.ConsistencyLevel.ONE
# defaults to pycassa.ConsistencyLevel.ONE
write_consistency_level = pycassa.ConsistencyLevel.QUORUM
# defaults to settings.CASSANDRA_KEYSPACE
keyspace = 'another_keyspace'
# defaults to False. Set to True if this is a super column family
super_cf = False
def save(self, *args, **kwargs):
super(Event, self).save(*args, **kwargs)
TrackingUUID.objects.add_event(self['uuid'], self.pk)Queries use the pycassa query api, along with whatever other methods you want to define in your manager. :
import uuid
event = Event()
event['uuid'] = "804e39e29a6148039633e5a69f0c0870"
event['action'] = 'landing: home'
event['gender'] = "1"
event.pk = uuid.uuid4().hex
event.save()
# or you could do this
event = Event(uuid="804e39e29a6148039633e5a69f0c0870", action='landing: home', gender='1')
Event.objects.insert(uuid.uuid4().hex, event)