'file_count': column_property(
sql.select(
[sql.func.count(media_files.c.id)],
storage.c.id == media_files.c.storage_id,
).label('file_count'),
deferred=True,
),
'file_size_sum': column_property(
sql.select(
[sql.func.sum(media_files.c.size)],
storage.c.id == media_files.c.storage_id,
).label('file_size_sum'),
deferred=True,
),
},
)
def add_engine_type(engine_cls):
"""Register this storage engine with the ORM."""
log.debug('Registering engine %r: %r', engine_cls.engine_type, engine_cls)
mapper(engine_cls,
inherits=storage_mapper,
polymorphic_identity=engine_cls.engine_type)
# Add our built-in storage engines to the polymorphic ORM mapping.
for engine in StorageEngine:
add_engine_type(engine)
# Automatically add new engines as they're registered by plugins.
StorageEngine.add_register_observer(add_engine_type)
