rattail-tutorial/rattail_tutorial/db/alembic/env.py

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# -*- coding: utf-8; mode: python; -*-
"""
Alembic environment script
"""
from __future__ import unicode_literals, absolute_import
from alembic import context
from sqlalchemy.orm import configure_mappers
from rattail.config import make_config
from rattail.db.util import get_default_engine
from rattail.db.continuum import configure_versioning
# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
alembic_config = context.config
# use same config file for Rattail
rattail_config = make_config(alembic_config.config_file_name, usedb=False, versioning=False)
# configure Continuum..this is trickier than we want but it works..
configure_versioning(rattail_config, force=True)
from rattail_tutorial.db import model
configure_mappers()
# needed for 'autogenerate' support
target_metadata = model.Base.metadata
def run_migrations_offline():
"""Run migrations in 'offline' mode.
This configures the context with just a URL
and not an Engine, though an Engine is acceptable
here as well. By skipping the Engine creation
we don't even need a DBAPI to be available.
Calls to context.execute() here emit the given string to the
script output.
"""
engine = get_default_engine(rattail_config)
context.configure(
url=engine.url,
target_metadata=target_metadata)
with context.begin_transaction():
context.run_migrations()
def run_migrations_online():
"""Run migrations in 'online' mode.
In this scenario we need to create an Engine
and associate a connection with the context.
"""
engine = get_default_engine(rattail_config)
connection = engine.connect()
context.configure(
connection=connection,
target_metadata=target_metadata)
try:
with context.begin_transaction():
context.run_migrations()
finally:
connection.close()
if context.is_offline_mode():
run_migrations_offline()
else:
run_migrations_online()