Cassandra in Django

db_routers.py

from django_cassandra_engine.models import DjangoCassandraModel

class CassandraRouter(object):
    """
    A router to control all database operations on models in the
    auth application.
    """
    def db_for_read(self, model, **hints):
        """
        Attempts to read auth models go to auth_db.
        """
        if issubclass(model, DjangoCassandraModel):
            return 'cassandra'
        return None

    def db_for_write(self, model, **hints):
        """
        Attempts to write auth models go to auth_db.
        """
        if issubclass(model, DjangoCassandraModel):
            return 'cassandra'
        return None

    def allow_relation(self, obj1, obj2, **hints):
        """
        Allow relations if a model in the auth app is involved.
        """
        if issubclass(obj1.__class__, DjangoCassandraModel) or issubclass(obj2.__class__, DjangoCassandraModel):
           return issubclass(obj1.__class__, DjangoCassandraModel) == issubclass(obj2.__class__, DjangoCassandraModel)
        return None

    def allow_migrate(self, db, app_label, model_name=None, **hints):
        """
        Make sure the auth app only appears in the 'auth_db'
        database.
        """
        return None

DJANGO_CASSANDRA.md

./manage.py sync_cassandra

models.py

class ExampleModel(DjangoCassandraModel):
    example_id    = columns.UUID(primary_key=True, default=uuid.uuid4)
    example_type  = columns.Integer(index=True)
    created_at    = columns.DateTime()
    description   = columns.Text(required=False)

settings.py

INSTALLED_APPS = [
    ...,
    'django_cassandra_engine',
]

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'mydb',
        'USER': 'postgres',
        'PASSWORD': '123',
        'HOST': 'localhost',
        'PORT': '5432',
    },

    'cassandra': {
        'ENGINE': 'django_cassandra_engine',
        'NAME': 'db',
        'TEST_NAME': 'test_db',
        'HOST': 'localhost',
        'OPTIONS': {
            'replication': {
                'strategy_class': 'SimpleStrategy',
                'replication_factor': 1
            }
        }
    },
}

DATABASE_ROUTERS = ['db_routers.CassandraRouter']

CASSANDRA_FALLBACK_ORDER_BY_PYTHON = True