Big ol' start of the SQL migrations system.

Things definitely don't work yet, but should be heading in the right direction.

mediagoblin/gmg_commands/dbupdate.py

@@ -0,0 +1,84 @@
+# GNU MediaGoblin -- federated, autonomous media hosting
+# Copyright (C) 2011 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 mediagoblin.db.sql.open import setup_connection_and_db_from_config
+from mediagoblin.db.sql.util import (
+    MigrationManager, assure_migrations_table_setup)
+from mediagoblin.init import setup_global_and_app_config
+from mediagoblin.tools.common import import_component
+
+
+class DatabaseData(object):
+    def __init__(self, name, models, migrations):
+        self.name = name
+        self.models = models
+        self.migrations = migrations
+
+    def make_migration_manager(self, db):
+        return MigrationManager(
+            self.name, self.models, self.migrations, db)
+
+
+def gather_database_data(self, media_types):
+    """
+    Gather all database data relevant to the extensions we have
+    installed so we can do migrations and table initialization.
+
+    Returns a list of DatabaseData objects.
+    """
+    managed_dbdata = []
+
+    # Add main first
+    from mediagoblin.db.sql.models import MODELS as MAIN_MODELS
+    from mediagoblin.db.sql.migrations import MIGRATIONS as MAIN_MIGRATIONS
+
+    managed_dbdata.append(
+        DatabaseData(
+            '__main__', MAIN_MODELS, MAIN_MIGRATIONS))
+
+    # Then get all registered media managers (eventually, plugins)
+    for media_type in media_types:
+        models = import_component('%s.models:MODELS' % media_type)
+        migrations = import_component('%s.migrations:MIGRATIONS' % media_type)
+        managed_dbdata.append(
+            DatabaseData(media_type, models, migrations))
+
+    return managed_dbdata
+
+
+def dbupdate(args):
+    """
+    Initialize or migrate the database as specified by the config file.
+
+    Will also initialize or migrate all extensions (media types, and
+    in the future, plugins)
+    """
+    globa_config, app_config = setup_global_and_app_config(args.conf_file)
+
+    # Gather information from all media managers / projects
+    dbdatas = gather_database_data(app_config['media_types'])
+
+    # Set up the database
+    connection, db = setup_connection_and_db_from_config(app_config)
+
+    # If migrations table not made, make it!
+    assure_migrations_table_setup(db)
+
+    # Setup media managers for all dbdata, run init/migrate and print info
+    # For each component, create/migrate tables
+    for dbdata in dbdatas:
+        migration_manager = dbdata.make_migration_manager(db)
+        migration_manager.init_or_migrate()