    async def startup(self):
        """Start up the scheduler.

        Starting up includes setting up attributes and
        running tasks that have ``on_startup`` as ``True``."""
        #self.setup_listener()
        self.logger.info("Starting up...", extra={"action": "setup"})
        hooker = _Hooker(self.session.hooks.scheduler_startup)
        hooker.prerun(scheduler=self)

        self.n_cycles = 0
        self.startup_time = self.session._get_datetime_now()

        self.logger.debug("Beginning startup sequence...")
        for task in self.tasks:
            try:
                task.set_cached()
            except TaskLoggingError:
                self.logger.exception(f"Failed setting cache for task '{task.name}'")
                if not self.session.config.silence_task_logging:
                    raise
            
            if task.on_startup:
                if isinstance(task.start_cond, AlwaysFalse) and not task.disabled:
                    # Make sure the tasks run if start_cond not set
                    task.run()

                if self.is_task_runnable(task):
                    await self.run_task(task)

        hooker.postrun()
        self.logger.info("Startup complete.")
Start up the scheduler.

Starting up includes setting up attributes and
running tasks that have ``on_startup`` as ``True``.
rocketry/core/schedule.py