I have a SQLAlchemy model that represents a file and thus contains the path to an actual file. Since deletion of the database row and file should go along (so no orphaned files are left and no rows point to deleted files) I added a delete() method to my model class:
def delete(self):
if os.path.exists(self.path):
os.remove(self.path)
db.session.delete(self)
This works fine but has one huge disadvantage: The file is deleted immediately before the transaction containing the database deletion is committed.
One option would be committing in the delete() method - but I don't want to do this since I might not be finished with the current transaction. So I'm looking for a way to delay the deletion of the physical file until the transaction deleting the row is actually committed.
SQLAlchemy has an after_delete event but according to the docs this is triggered when the SQL is emitted (i.e. on flush) which is too early. It also has an after_commit event but at this point everything deleted in the transaction has probably been deleted from SA.