mediagoblin/db/open.py

   1 # GNU MediaGoblin -- federated, autonomous media hosting
   2 # Copyright (C) 2011, 2012 MediaGoblin contributors.  See AUTHORS.
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU Affero General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU Affero General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Affero General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 from sqlalchemy import create_engine, event
  19 import logging
  20
  21 from mediagoblin.db.base import Base, Session
  22 from mediagoblin import mg_globals
  23
  24 _log = logging.getLogger(__name__)
  25
  26
  27 class DatabaseMaster(object):
  28     def __init__(self, engine):
  29         self.engine = engine
  30
  31         for k, v in Base._decl_class_registry.iteritems():
  32             setattr(self, k, v)
  33
  34     def commit(self):
  35         Session.commit()
  36
  37     def save(self, obj):
  38         Session.add(obj)
  39         Session.flush()
  40
  41     def check_session_clean(self):
  42         for dummy in Session():
  43             _log.warn("STRANGE: There are elements in the sql session. "
  44                       "Please report this and help us track this down.")
  45             break
  46
  47     def reset_after_request(self):
  48         Session.rollback()
  49         Session.remove()
  50
  51
  52 def load_models(app_config):
  53     import mediagoblin.db.models
  54
  55     for plugin in mg_globals.global_config.get('plugins', {}).keys():
  56         _log.debug("Loading %s.models", plugin)
  57         try:
  58             __import__(plugin + ".models")
  59         except ImportError as exc:
  60             _log.debug("Could not load {0}.models: {1}".format(
  61                 plugin,
  62                 exc))
  63
  64
  65 def _sqlite_fk_pragma_on_connect(dbapi_con, con_record):
  66     """Enable foreign key checking on each new sqlite connection"""
  67     dbapi_con.execute('pragma foreign_keys=on')
  68
  69
  70 def _sqlite_disable_fk_pragma_on_connect(dbapi_con, con_record):
  71     """
  72     Disable foreign key checking on each new sqlite connection
  73     (Good for migrations!)
  74     """
  75     dbapi_con.execute('pragma foreign_keys=off')
  76
  77
  78 def setup_connection_and_db_from_config(app_config, migrations=False):
  79     engine = create_engine(app_config['sql_engine'])
  80
  81     # Enable foreign key checking for sqlite
  82     if app_config['sql_engine'].startswith('sqlite://'):
  83         if migrations:
  84             event.listen(engine, 'connect',
  85                          _sqlite_disable_fk_pragma_on_connect)
  86         else:
  87             event.listen(engine, 'connect', _sqlite_fk_pragma_on_connect)
  88
  89     # logging.getLogger('sqlalchemy.engine').setLevel(logging.INFO)
  90
  91     Session.configure(bind=engine)
  92
  93     return DatabaseMaster(engine)
  94
  95
  96 def check_db_migrations_current(db):
  97     pass