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# GNU MediaGoblin -- federated, autonomous media hosting
# Copyright (C) 2011, 2012 MediaGoblin contributors. See AUTHORS.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
from contextlib import contextmanager
import logging
from sqlalchemy import create_engine, event
from mediagoblin import mg_globals
from mediagoblin.db.base import Base
_log = logging.getLogger(__name__)
from mediagoblin.tools.transition import DISABLE_GLOBALS
def set_models_as_attributes(obj):
"""
Set all models as attributes on this object, for convenience
TODO: This should eventually be deprecated.
"""
for k, v in Base._decl_class_registry.items():
setattr(obj, k, v)
if not DISABLE_GLOBALS:
from mediagoblin.db.base import Session
class DatabaseMaster:
def __init__(self, engine):
self.engine = engine
set_models_as_attributes(self)
def commit(self):
Session.commit()
def save(self, obj):
Session.add(obj)
Session.flush()
def check_session_clean(self):
for dummy in Session():
_log.warn("STRANGE: There are elements in the sql session. "
"Please report this and help us track this down.")
break
def reset_after_request(self):
Session.rollback()
Session.remove()
@property
def query(self):
return Session.query
else:
from sqlalchemy.orm import sessionmaker
class DatabaseManager:
"""
Manage database connections.
The main method here is session_scope which can be used with a
"with" statement to get a session that is properly torn down
by the end of execution.
"""
def __init__(self, engine):
self.engine = engine
self.Session = sessionmaker(bind=engine)
set_models_as_attributes(self)
@contextmanager
def session_scope(self):
"""
This is a context manager, use like::
with dbmanager.session_scope() as request.db:
some_view(request)
"""
session = self.Session()
#####################################
# Functions to emulate DatabaseMaster
#####################################
def save(obj):
session.add(obj)
session.flush()
def check_session_clean():
# Is this implemented right?
for dummy in session:
_log.warn("STRANGE: There are elements in the sql session. "
"Please report this and help us track this down.")
break
def reset_after_request():
session.rollback()
session.remove()
# now attach
session.save = save
session.check_session_clean = check_session_clean
session.reset_after_request = reset_after_request
set_models_as_attributes(session)
#####################################
try:
yield session
finally:
session.rollback()
session.close()
def load_models(app_config):
import mediagoblin.db.models
for plugin in mg_globals.global_config.get('plugins', {}).keys():
_log.debug("Loading %s.models", plugin)
try:
__import__(plugin + ".models")
except ImportError as exc:
_log.debug("Could not load {}.models: {}".format(
plugin,
exc))
def _sqlite_fk_pragma_on_connect(dbapi_con, con_record):
"""Enable foreign key checking on each new sqlite connection"""
dbapi_con.execute('pragma foreign_keys=on')
def _sqlite_disable_fk_pragma_on_connect(dbapi_con, con_record):
"""
Disable foreign key checking on each new sqlite connection
(Good for migrations!)
"""
dbapi_con.execute('pragma foreign_keys=off')
def setup_connection_and_db_from_config(app_config, migrations=False, app=None):
engine = create_engine(app_config['sql_engine'])
# @@: Maybe make a weak-ref so an engine can get garbage
# collected? Not that we expect to make a lot of MediaGoblinApp
# instances in a single process...
engine.app = app
# Enable foreign key checking for sqlite
if app_config['sql_engine'].startswith('sqlite://'):
if migrations:
event.listen(engine, 'connect',
_sqlite_disable_fk_pragma_on_connect)
else:
event.listen(engine, 'connect', _sqlite_fk_pragma_on_connect)
# logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)
if DISABLE_GLOBALS:
return DatabaseManager(engine)
else:
Session.configure(bind=engine)
return DatabaseMaster(engine)
def check_db_migrations_current(db):
pass
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