brewpi/tasks/sud.py

import asyncio
from tasks import ATask
from ws.message import MsgIo
from utils.value import ChangedFloat
from components import APid, AStirrer
from components.plant import APlant
from components.sud import Sud, SudState


class SudTask(ATask):
	def __init__(self, sud: Sud, tc: APid, stirrer: AStirrer, pot: APlant, dt, interval, msg_handler: MsgIo,
			forecast_estimator=None):
		ATask.__init__(self, interval)
		self.sud = sud
		self.tc = tc
		self.stirrer = stirrer
		self.pot = pot
		# Simulated seconds per tick, vs. interval's wall-clock seconds per
		# tick - same dt/interval split Pot/TempController/Stirrer already
		# use internally. Their warp-induced speedup falls out naturally
		# from ticking real physics at simulated dt; Sud has no physics of
		# its own, so hold_remaining must be ticked by dt explicitly to get
		# the same speedup instead of running in real time.
		self.dt = dt
		self.msg_handler = msg_handler
		# Predicts a schedule's actual duration by simulating it with the
		# same plant/controller machinery this server uses for real - see
		# components/sud_forecast.py. Optional only so tests/demos that
		# build a SudTask without one still work; the server always passes
		# one.
		self.forecast_estimator = forecast_estimator
		# Accumulated forecast across all piecewise segments computed so
		# far (see send_forecast()/_continue_forecast_after_confirm()) -
		# T in simulated seconds, Theta in degrees, parallel lists, both
		# growing monotonically as segments get appended; never re-walked
		# from scratch once a run is in progress, except for the one
		# genuinely unforecastable case (a real user confirmation).
		self.forecast_t = []
		self.forecast_theta = []
		# Whether the most recently computed segment stopped at a step
		# requiring user confirmation rather than reaching the
		# schedule's actual end - see _continue_forecast_after_confirm().
		self.forecast_waiting_for_confirm = False
		msg_handler.set_recv_handler(self.recv)

	def apply_plant_params(self, step):
		"""Keeps the real plant's and the controller's internal model's
		lumped (M, C) in sync with the step's grain_mass/water_mass, since
		those vary over the course of a brew (malt going in, water boiling
		off) - mirrors demo_sud.py's apply_plant_params()."""
		params = self.sud.derive_plant_params(step.get('grain_mass', 0), step.get('water_mass', 0))
		self.pot.set_thermal_params(params['M'], params['C'])
		if hasattr(self.tc, 'set_model_params'):
			self.tc.set_model_params(params['M'], params['C'])

	def apply_stirrer(self, phase):
		stirrer_cfg = phase.get('stirrer', {})
		speed = stirrer_cfg.get('speed', 0)
		interval_time = stirrer_cfg.get('interval_time', 0)
		on_ratio = stirrer_cfg.get('on_ratio', 1.0)
		if interval_time > 0:
			self.stirrer.set_cycle_time(interval_time)
			self.stirrer.set_duty_cycle(on_ratio)
		else:
			self.stirrer.set_cycle_time(1.0)
			self.stirrer.set_duty_cycle(1.0 if speed > 0 else 0.0)
		self.stirrer.set_speed(speed)

	def on_step_changed(self, step):
		ramp = step.get('ramp') if step else None
		hold = step.get('hold') if step else None
		# Every step ramps to 'temperature' first, then optionally holds -
		# self.sud.state tells us which phase is currently active; it's
		# already up to date by the time this callback fires, both on a
		# full step transition and on the ramp->hold phase switch within
		# one step (components/sud.py's temp_reached()).
		ramping = self.sud.state == SudState.RAMPING
		phase = ramp if ramping else hold

		if step is not None:
			self.apply_plant_params(step)
			if ramping and step['temperature'] is not None:
				self.tc.set_theta_soll(step['temperature'])
				self.tc.set_heatrate_soll(ramp['rate'])
			self.apply_stirrer(phase)

		asyncio.create_task(self.send({'Step': {
			'Index': self.sud.index,
			'Type': 'ramp' if ramping else 'hold' if hold is not None else None,
			'Descr': step.get('descr') if step else None,
			'Temp': step.get('temperature') if step else None,
			'Rate': ramp.get('rate') if ramp else None,
			'Duration': hold.get('duration') if (hold is not None and not ramping) else None,
			'WaitForUser': step.get('user_wait_for_continue', False) if step else None,
		}}))

	def on_state_changed(self, value):
		asyncio.create_task(self.send({'State': str(value)}))

		if value in (SudState.DONE, SudState.IDLE):
			self.stirrer.set_duty_cycle(1.0)
			self.stirrer.set_speed(0)
			# A finished/stopped run no longer owns the controller - hand
			# control back to manual mode (off by default there too).
			self.tc.set_enabled(False)
		else:
			# Any other state (RAMPING/HOLDING/WAIT_USER/PAUSED) means a
			# run is in progress and needs the controller actively driving
			# the heater.
			self.tc.set_enabled(True)

	def on_user_message_changed(self, value):
		asyncio.create_task(self.send({'UserMessage': value}))

	def on_hold_remaining_changed(self, value):
		asyncio.create_task(self.send({'HoldRemaining': value}))

	def on_elapsed_changed(self, value):
		asyncio.create_task(self.send({'Elapsed': value}))

	async def send_forecast(self, doc):
		"""Computes and sends the first piecewise segment of doc's
		forecast - from the very start, up to either the schedule's end
		or its first step requiring user confirmation (see
		components/sud_forecast.py's SudForecastEstimator.estimate()).
		Always a fresh start: resets any segments accumulated for
		whatever was loaded before."""
		if self.forecast_estimator is None:
			return
		# Runs the simulation in a worker thread - it's CPU-bound and can
		# take a couple hundred ms for a long schedule, which would
		# otherwise stall every other task (heater, sensor, ...) for that
		# whole window.
		loop = asyncio.get_event_loop()
		t, theta, final_state = await loop.run_in_executor(None, self.forecast_estimator.estimate, doc)
		self.forecast_t = t
		self.forecast_theta = theta
		self.forecast_waiting_for_confirm = (final_state == SudState.WAIT_USER)
		await self._send_forecast()

	async def _send_forecast(self):
		await self.send({'Forecast': {
			'T': self.forecast_t,
			'Theta': self.forecast_theta,
			'Finished': not self.forecast_waiting_for_confirm,
		}})

	async def _continue_forecast_after_confirm(self):
		"""Computes and appends the next piecewise segment once a real
		user confirmation has actually happened, rather than guessing at
		the delay - see SudForecastEstimator.estimate()'s docstring for
		why. Anchored at the real elapsed time (self.sud.elapsed), so the
		unforecastable wait shows up honestly as a gap in the forecast
		rather than as zero delay, and at the real current temperature
		(more trustworthy than whatever the now-superseded previous
		segment's simulation predicted it would be by now)."""
		if self.forecast_estimator is None or not self.forecast_waiting_for_confirm:
			return
		schedule = self.sud.schedule
		index = self.sud.index
		if not (0 <= index < len(schedule)):
			self.forecast_waiting_for_confirm = False
			return
		doc = {
			'Name': self.sud.name,
			'Description': self.sud.description,
			'pot_mass': self.sud.pot_mass,
			'pot_material': self.sud.pot_material,
			'steps': schedule[index:],
		}
		start_theta = self.tc.get_theta_ist()
		real_elapsed = self.sud.elapsed
		loop = asyncio.get_event_loop()
		t, theta, final_state = await loop.run_in_executor(None, self.forecast_estimator.estimate, doc, start_theta)
		# Bridge the gap between where the previous segment's own
		# simulated time left off and the real elapsed time the confirm
		# actually happened at, holding flat at its last temperature -
		# then append the new segment, offset to start exactly there.
		if self.forecast_t and self.forecast_t[-1] < real_elapsed:
			self.forecast_t.append(real_elapsed)
			self.forecast_theta.append(self.forecast_theta[-1])
		self.forecast_t.extend(real_elapsed + seconds for seconds in t)
		self.forecast_theta.extend(theta)
		self.forecast_waiting_for_confirm = (final_state == SudState.WAIT_USER)
		await self._send_forecast()

	async def recv(self, data):
		for pair in data.items():
			if 'Start' in pair[0]:
				self.sud.start()
			elif 'Confirm' in pair[0]:
				self.sud.confirm()
				asyncio.create_task(self._continue_forecast_after_confirm())
			elif 'Pause' in pair[0]:
				self.sud.pause()
			elif 'Stop' in pair[0]:
				self.sud.stop()
			elif 'Save' in pair[0]:
				doc = self.sud.save()
				await self.send({'Json': doc})
				await self.send_forecast(doc)
			elif 'Load' in pair[0]:
				if self.sud.load(pair[1]):
					await self.send({'Name': self.sud.name, 'Description': self.sud.description})
					await self.send({'Json': pair[1]})
					await self.send_forecast(pair[1])
				else:
					# Sud.load() refuses while a run is in progress (state
					# not IDLE/DONE) - tell the client why instead of
					# silently dropping the request. The client has no
					# business pre-emptively guessing this itself from its
					# own (replicated, laggy) view of the state.
					#
					# Immediately cleared back to None - unlike every other
					# field here, this is a one-shot event, not state. The
					# dispatcher has no concept of "don't persist this into
					# global_state" (see ws/user.py's update()), so without
					# clearing it, any client connecting later - even one
					# that never touched Load - would get this stale error
					# replayed on connect, with nothing it just did to
					# explain why.
					await self.send({'Error': 'Cannot load a new schedule while a run is in progress - stop it first.'})
					await self.send({'Error': None})

	async def send(self, data):
		await self.msg_handler.send(data)

	async def on_process(self):
		print("{}: Started with interval {} s".format(self.msg_handler.get_key(), self.interval))

		self.sud.set_on_changed('step', self.on_step_changed)
		self.sud.set_on_changed('state', self.on_state_changed)
		self.sud.set_on_changed('user_message', self.on_user_message_changed)
		self.sud.set_on_changed('hold_remaining', ChangedFloat(self.on_hold_remaining_changed, prec=0).set)
		self.sud.set_on_changed('elapsed', ChangedFloat(self.on_elapsed_changed, prec=1).set)

		asyncio.create_task(self.send({'Name': self.sud.name, 'Description': self.sud.description}))

		while True:
			if self.sud.state == SudState.RAMPING and self.tc.is_holding():
				self.sud.temp_reached()
			self.sud.tick(self.dt)
			await asyncio.sleep(self.interval)