def tmpdb():
"""Get a handle to an empty temporary database that is wiped on
teardown."""
from brainscopypaste.conf import settings
engine = create_engine(
'postgresql+psycopg2://{user}:{pw}@localhost:5432/{db}'
.format(user=settings.DB_USER, pw=settings.DB_PASSWORD,
db=settings.DB_NAME_TEST),
client_encoding='utf8')
Session.configure(bind=engine)
Base.metadata.drop_all(engine)
Base.metadata.create_all(engine)
yield
Base.metadata.drop_all(engine)
def session_scope():
"""Provide an SQLAlchemy transactional scope around a series of
operations.
Wrap your SQLAlchemy operations (queries, insertions, modifications, etc.)
in a ``with session_scope() as session`` block to deal with sessions
easily. Changes are committed when the block finishes. If an exception
occurrs in the block, the session is rolled back and the exception
propagated.
"""
from brainscopypaste.db import Session
session = Session()
logger.debug('Opened session %s', session)
try:
yield session
logger.debug('Committing session %s', session)
session.commit()
except:
logger.debug('Rolling back session %s', session)
session.rollback()
raise
finally:
logger.debug('Closing session %s', session)
session.close()
def init_db(echo_sql=False):
"""Connect to the database and bind :mod:`.db`'s `Session` object to it.
Uses the :data:`~.settings.DB_USER` and :data:`~.settings.DB_PASSWORD`
credentials to connect to PostgreSQL database :data:`~.settings.DB_NAME`.
It binds the `Session` object in :mod:`.db` to this engine, and returns the
engine object. Note that once this is done, you can directly use
:func:`session_scope` since it uses the right `Session` object.
Parameters
----------
echo_sql : bool, optional
If `True`, print to stdout all SQL commands sent to the engine;
defaults to `False`.
Returns
-------
:class:`sqlalchemy.engine.Engine`
The engine connected to the database.
"""
from brainscopypaste.db import Base, Session
from brainscopypaste.conf import settings
logger.info('Initializing database connection')
engine = create_engine(
'postgresql+psycopg2://{user}:{pw}@localhost:5432/{db}'
.format(user=settings.DB_USER, pw=settings.DB_PASSWORD,
db=settings.DB_NAME),
client_encoding='utf8', echo=echo_sql)
Session.configure(bind=engine)
logger.info('Database connected')
logger.debug('Checking tables to create')
Base.metadata.create_all(engine)
return engine
