models.py 文件源码

def get_singleton(cls):
        """Return (and create if missing) the single Portal document"""
        try:
            portal = cls.objects.get()
            log.debug("Loaded portal info from db.")
        except me.DoesNotExist:
            log.info("No portal info found in db, will try to initialize.")
            try:
                portal = cls()
                portal.save()
                log.info("Initialized portal info.")
            except me.NotUniqueError:
                log.warning("Probable race condition while initializing "
                            "portal info, will try to reload.")
                portal = cls.objects.get()
                log.debug("Loaded portal info from db.")
        except me.MultipleObjectsReturned:
            log.error("Multiple Portal info found in database.")
            portal = cls.objects.first()
        return portal