def test_pool_cancel(env):
pool = Pool(env)
event_cancel = pool.get(2)
event_cancel.cancel()
event_full = pool.when_full()
event_full.cancel()
event_any = pool.when_any()
event_any.cancel()
event_new = pool.when_new()
event_new.cancel()
env.run()
assert pool.level == 0
assert not event_cancel.triggered
assert not event_full.triggered
assert not event_any.triggered
assert not event_new.triggered
class TankerTruck(Component):
"""Tanker trucks carry fuel to gas stations.
Each tanker truck has a queue of gas stations it must visit. When the
truck's tank becomes empty, it must go refill itself.
"""
base_name = 'truck'
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.pump_rate = self.env.config.get('tanker.pump_rate', 10)
self.avg_travel = self.env.config.get('tanker.travel_time', 600)
tank_capacity = self.env.config.get('tanker.capacity', 200)
self.tank = Pool(self.env, tank_capacity)
# This auto_probe() call uses the self.tank Pool get/put hooks so that
# whenever it's level changes, the new level is noted in the log.
self.auto_probe('tank', log={})
# The parent TankerCompany enqueues instructions to this queue.
self._instructions = Queue(self.env)
# Declare a persistant process to be started at simulation-time.
self.add_process(self._dispatch_loop)
def dispatch(self, gas_station, done_event):
"""Append dispatch instructions to the truck's queue."""
return self._instructions.put((gas_station, done_event))
def _dispatch_loop(self):
"""This is the tanker truck's main behavior. Travel, pump, refill..."""
while True:
if not self.tank.level:
self.info('going for refill')
# Desmod simulation environments come equipped with a
# random.Random() instance seeded based on the 'sim.seed'
# configuration key.
travel_time = self.env.rand.expovariate(1 / self.avg_travel)
yield self.env.timeout(travel_time)
self.info('refilling')
pump_time = self.tank.capacity / self.pump_rate
yield self.env.timeout(pump_time)
yield self.tank.put(self.tank.capacity)
self.info(
f'refilled {self.tank.capacity}L in {pump_time:.0f}s')
gas_station, done_event = yield self._instructions.get()
self.info(f'traveling to {gas_station.name}')
travel_time = self.env.rand.expovariate(1 / self.avg_travel)
yield self.env.timeout(travel_time)
self.info(f'arrived at {gas_station.name}')
while self.tank.level and (gas_station.reservoir.level <
gas_station.reservoir.capacity):
yield self.env.timeout(1 / self.pump_rate)
yield gas_station.reservoir.put(1)
yield self.tank.get(1)
self.info('done pumping')
done_event.succeed()
class TankerTruck(Component):
"""Tanker trucks carry fuel to gas stations.
Each tanker truck has a queue of gas stations it must visit. When the
truck's tank becomes empty, it must go refill itself.
"""
base_name = 'truck'
def __init__(self, *args, **kwargs):
super(TankerTruck, self).__init__(*args, **kwargs)
self.pump_rate = self.env.config.get('tanker.pump_rate', 10)
self.avg_travel = self.env.config.get('tanker.travel_time', 600)
tank_capacity = self.env.config.get('tanker.capacity', 200)
self.tank = Pool(self.env, tank_capacity)
# This auto_probe() call uses the self.tank Pool get/put hooks so that
# whenever it's level changes, the new level is noted in the log.
self.auto_probe('tank', log={})
# The parent TankerCompany enqueues instructions to this queue.
self._instructions = Queue(self.env)
# Declare a persistant process to be started at simulation-time.
self.add_process(self._dispatch_loop)
def dispatch(self, gas_station, done_event):
"""Append dispatch instructions to the truck's queue."""
return self._instructions.put((gas_station, done_event))
def _dispatch_loop(self):
"""This is the tanker truck's main behavior. Travel, pump, refill..."""
while True:
if not self.tank.level:
self.info('going for refill')
# Desmod simulation environments come equipped with a
# random.Random() instance seeded based on the 'sim.seed'
# configuration key.
travel_time = self.env.rand.expovariate(1 / self.avg_travel)
yield self.env.timeout(travel_time)
self.info('refilling')
pump_time = self.tank.capacity / self.pump_rate
yield self.env.timeout(pump_time)
yield self.tank.put(self.tank.capacity)
self.info('refilled {}L in {:.0f}s'.format(
self.tank.capacity, pump_time))
gas_station, done_event = yield self._instructions.get()
self.info('traveling to {}'.format(gas_station.name))
travel_time = self.env.rand.expovariate(1 / self.avg_travel)
yield self.env.timeout(travel_time)
self.info('arrived at {}'.format(gas_station.name))
while self.tank.level and (gas_station.reservoir.level <
gas_station.reservoir.capacity):
yield self.env.timeout(1 / self.pump_rate)
yield gas_station.reservoir.put(1)
yield self.tank.get(1)
self.info('done pumping')
done_event.succeed()
class GasStation(Component):
"""A gas station has a fuel reservoir shared among several fuel pumps.
The gas station has a traffic generator process that causes cars to arrive
to fill up their tanks.
As the cars fill up, the reservoir's level goes down. When the level goes
below a critical threshold, the gas station makes a request to the tanker
company for a tanker truck to refill the reservoir.
"""
base_name = 'station'
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
config = self.env.config
self.add_connections('tanker_company')
self.arrival_interval = config.get('gas_station.arrival_interval', 60)
station_capacity = config.get('gas_station.capacity', 200)
self.reservoir = Pool(self.env,
capacity=station_capacity,
init=station_capacity)
self.auto_probe('reservoir', log={})
threshold_pct = config.get('gas_station.threshold_pct', 10)
self.reservoir_low_water = threshold_pct * station_capacity / 100
self.pump_rate = config.get('gas_station.pump_rate', 2)
num_pumps = config.get('gas_station.pumps', 2)
self.fuel_pumps = Resource(self.env, capacity=num_pumps)
self.auto_probe('fuel_pumps', log={})
self.car_capacity = config.get('car.capacity', 50)
self.car_level_range = config.get('car.level', [5, 25])
# A gas station has two persistent processes. One to monitor the
# reservoir level and one that models the arrival of cars at the
# station. Desmod starts these processes before simulation phase.
self.add_processes(self._monitor_reservoir, self._traffic_generator)
@property
def reservoir_pct(self):
return self.reservoir.level / self.reservoir.capacity * 100
def _monitor_reservoir(self):
"""Periodically monitor reservoir level.
The a request is made to the tanker company when the reservoir falls
below a critical threshold.
"""
while True:
yield self.reservoir.when_at_most(self.reservoir_low_water)
done_event = self.env.event()
yield self.tanker_company.request_truck(self, done_event)
yield done_event
def _traffic_generator(self):
"""Model the sporadic arrival of cars to the gas station."""
for i in count():
interval = self.env.rand.expovariate(1 / self.arrival_interval)
yield self.env.timeout(interval)
self.env.process(self._car(i))
def _car(self, i):
"""Model a car transacting fuel."""
with self.fuel_pumps.request() as pump_req:
self.info(f'car{i} awaiting pump')
yield pump_req
self.info(f'car{i} at pump')
car_level = self.env.rand.randint(*self.car_level_range)
amount = self.car_capacity - car_level
t0 = self.env.now
for _ in range(amount):
yield self.reservoir.get(1)
yield self.env.timeout(1 / self.pump_rate)
pump_time = self.env.now - t0
self.info(f'car{i} pumped {amount}L in {pump_time:.0f}s')
class GasStation(Component):
"""A gas station has a fuel reservoir shared among several fuel pumps.
The gas station has a traffic generator process that causes cars to arrive
to fill up their tanks.
As the cars fill up, the reservoir's level goes down. When the level goes
below a critical threshold, the gas station makes a request to the tanker
company for a tanker truck to refill the reservoir.
"""
base_name = 'station'
def __init__(self, *args, **kwargs):
super(GasStation, self).__init__(*args, **kwargs)
config = self.env.config
self.add_connections('tanker_company')
self.arrival_interval = config.get('gas_station.arrival_interval', 60)
station_capacity = config.get('gas_station.capacity', 200)
self.reservoir = Pool(
self.env, capacity=station_capacity, init=station_capacity
)
self.auto_probe('reservoir', log={})
threshold_pct = config.get('gas_station.threshold_pct', 10)
self.reservoir_low_water = threshold_pct * station_capacity / 100
self.pump_rate = config.get('gas_station.pump_rate', 2)
num_pumps = config.get('gas_station.pumps', 2)
self.fuel_pumps = Resource(self.env, capacity=num_pumps)
self.auto_probe('fuel_pumps', log={})
self.car_capacity = config.get('car.capacity', 50)
self.car_level_range = config.get('car.level', [5, 25])
# A gas station has two persistent processes. One to monitor the
# reservoir level and one that models the arrival of cars at the
# station. Desmod starts these processes before simulation phase.
self.add_processes(self._monitor_reservoir, self._traffic_generator)
@property
def reservoir_pct(self):
return self.reservoir.level / self.reservoir.capacity * 100
def _monitor_reservoir(self):
"""Periodically monitor reservoir level.
The a request is made to the tanker company when the reservoir falls
below a critical threshold.
"""
while True:
yield self.reservoir.when_at_most(self.reservoir_low_water)
done_event = self.env.event()
yield self.tanker_company.request_truck(self, done_event)
yield done_event
def _traffic_generator(self):
"""Model the sporadic arrival of cars to the gas station."""
for i in count():
interval = self.env.rand.expovariate(1 / self.arrival_interval)
yield self.env.timeout(interval)
self.env.process(self._car(i))
def _car(self, i):
"""Model a car transacting fuel."""
with self.fuel_pumps.request() as pump_req:
self.info('car{} awaiting pump'.format(i))
yield pump_req
self.info('car{} at pump'.format(i))
car_level = self.env.rand.randint(*self.car_level_range)
amount = self.car_capacity - car_level
t0 = self.env.now
for _ in range(amount):
yield self.reservoir.get(1)
yield self.env.timeout(1 / self.pump_rate)
pump_time = self.env.now - t0
self.info('car{} pumped {}L in {:.0f}s'.format(
i, amount, pump_time))