aboutsummaryrefslogtreecommitdiffstats
path: root/mediagoblin/db/open.py
blob: 9922cc1053aaaa46f2d906fe53ee53c015cb2f89 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
# 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

import six
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

if not DISABLE_GLOBALS:
    from mediagoblin.db.base import Session

    class DatabaseMaster(object):
        def __init__(self, engine):
            self.engine = engine

            for k, v in six.iteritems(Base._decl_class_registry):
                setattr(self, k, v)

        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()

else:
    from sqlalchemy.orm import sessionmaker

    class DatabaseManager(object):
        def __init__(self, engine):
            self.engine = engine
            self.Session = sessionmaker(bind=engine)

        @contextmanager
        def session_scope(self):
            session = self.Session()

            #####################################
            # Functions to emulate DatabaseMaster
            #####################################
            def commit():
                session.commit()

            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.commit = commit
            session.save = save
            session.check_session_clean = check_session_clean
            session.reset_after_request = reset_after_request
            #####################################

            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 {0}.models: {1}".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):
    engine = create_engine(app_config['sql_engine'])

    # 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