Usage

To use oslo.db in a project:

Session Handling

from oslo.config import cfg
from oslo.db.sqlalchemy import session as db_session

_FACADE = None

def _create_facade_lazily():
    global _FACADE
    if _FACADE is None:
        _FACADE = db_session.EngineFacade.from_config(cfg.CONF)
    return _FACADE

def get_engine():
    facade = _create_facade_lazily()
    return facade.get_engine()

def get_session(**kwargs):
    facade = _create_facade_lazily()
    return facade.get_session(**kwargs)

Base class for models usage

from oslo.db import models


class ProjectSomething(models.TimestampMixin,
                       models.ModelBase):
    id = Column(Integer, primary_key=True)
    ...

DB API backend support

from oslo.config import cfg
from oslo.db import api as db_api


_BACKEND_MAPPING = {'sqlalchemy': 'project.db.sqlalchemy.api'}

IMPL = db_api.DBAPI.from_config(cfg.CONF, backend_mapping=_BACKEND_MAPPING)

def get_engine():
    return IMPL.get_engine()

def get_session():
    return IMPL.get_session()

# DB-API method
def do_something(somethind_id):
    return IMPL.do_something(somethind_id)