这是我当前的代码,主要问题是我使用Semphore来控制两个过程的输出,但是似乎Semphore不会改变全球,即当过程"生产者"更改时SEMPHORE到2该过程"消费者"仍然认为流孔为零,这会导致它永远等待。
from multiprocessing import Process, Semaphore, Queue
import time
from random import random
buffer = Queue(10)
empty = Semaphore(2)
full = Semaphore(0)
class Consumer(Process):
def run(self):
global buffer, empty, full
while True:
time.sleep(4)
print(full)
full.acquire()
buffer.get()
print('Consumer get')
time.sleep(1)
empty.release()
class Producer(Process):
def run(self):
global buffer, empty, full
while True:
empty.acquire()
print ('Producer put ')
time.sleep(1)
full.release()
buffer.put(1)
print(full)
if __name__ == '__main__':
p = Producer()
c = Consumer()
p.daemon = c.daemon = True
p.start()
c.start()
p.join()
c.join()
print ('Ended!')
,输出为
Producer put
<Semaphore(value=1)>
Producer put
<Semaphore(value=2)>
<Semaphore(value=0)>
我不知道该怎么做才能让"消费者"过程检测变化。
您的两个过程都有两个信号量的副本,因为每个过程在实例化时都在脚本中运行整个代码。
您必须将信号量和队列定义移动到if __name__ == '__main__':
中,然后将信号量的实例传递到Producer
和Consumer
构造函数,以便它们两个使用三个对象的相同实例。
from multiprocessing import Process, Semaphore, Lock, Queue
import time
from random import random
class Consumer(Process):
def __init__(self, empty, full, buffer):
super(Consumer, self).__init__()
self.empty = empty
self.full = full
self.buffer = buffer
def run(self):
while True:
time.sleep(4)
print("Consumer: {}".format(self.full), flush=True)
print("Consumer: buf {}".format(self.buffer.qsize()), flush=True)
self.full.acquire()
self.buffer.get()
print('Consumer get', flush=True)
time.sleep(1)
self.empty.release()
class Producer(Process):
def __init__(self, empty, full, buffer):
super(Process, self).__init__()
self.empty = empty
self.full = full
self.buffer = buffer
def run(self):
while True:
self.empty.acquire()
print ('Producer put ', flush=True)
self.buffer.put('a') #<<<<<<<<<<< you forgot this in your code. If the queue is empty, get() will block on the consumer
time.sleep(1)
self.full.release()
print(self.full, flush=True)
if __name__ == '__main__':
buffer = Queue(10)
empty = Semaphore(2)
full = Semaphore(0)
p = Producer(empty, full, buffer)
c = Consumer(empty, full, buffer)
p.daemon = c.daemon = True
p.start()
c.start()
p.join()
c.join()
print ('Ended!')