使用Python实现生产者消费者问题
浏览数：27 /
时间：2015年06月08日
之前用C++写过一篇生产者消费者的实现。
生产者和消费者主要是处理互斥和同步的问题：
队列作为缓冲区，需要互斥操作
队列中没有产品，消费者需要等待，直到生产者放入产品并通知它。队列慢的情况类似。
这里我使用list模拟Python标准库的Queue，这里我设置一个大小限制为5：
SyncQueue.py
from threading import Lock from threading import Condition class Queue(): def __init__(self): self.mutex = Lock() self.full = Condition(self.mutex) self.empty = Condition(self.mutex) self.data = [] def push(self, element): self.mutex.acquire() while len(self.data) >= 5: self.empty.wait() self.data.append(element) self.full.notify() self.mutex.release() def pop(self): self.mutex.acquire() while len(self.data) == 0: self.full.wait() data = self.data[0] self.data.pop(0) self.empty.notify() self.mutex.release() return data if __name__ == ‘__main__‘: q = Queue() q.push(10) q.push(2) q.push(13) print q.pop() print q.pop() print q.pop()
这是最核心的代码，注意里面判断条件要使用while循环。
接下来是生产者进程，producer.py
from threading import Thread from random import randrange from time import sleep from SyncQueue import Queue class ProducerThread(Thread): def __init__(self, queue): Thread.__init__(self) self.queue = queue def run(self): while True: data = randrange(0, 100) self.queue.push(data) print ‘push %d‘ % (data) sleep(1) if __name__ == ‘__main__‘: q = Queue() t = ProducerThread(q) t.start() t.join()
消费者,Condumer.py
from threading import Thread from time import sleep from SyncQueue import Queue class ConsumerThread(Thread): def __init__(self, queue): Thread.__init__(self) self.queue = queue def run(self): while True: data = self.queue.pop() print ‘pop %d‘ % (data) sleep(1) if __name__ == ‘__main__‘: q = Queue() t = ConsumerThread(q) t.start() t.join()
最后我们写一个车间类,可以指定线程数量:
from SyncQueue import Queue from Producer import ProducerThread from Consumer import ConsumerThread class WorkShop(): def __init__(self, producerNums, consumerNums): self.producers = [] self.consumers = [] self.queue = Queue() self.producerNums = producerNums self.consumerNums = consumerNums def start(self): for i in range(self.producerNums): self.producers.append(ProducerThread(self.queue)) for i in range(self.consumerNums): self.consumers.append(ConsumerThread(self.queue)) for i in range(len(self.producers)): self.producers[i].start() for i in range(len(self.consumers)): self.consumers[i].start() for i in range(len(self.producers)): self.producers[i].join() for i in range(len(self.consumers)): self.consumers[i].join() if __name__ == ‘__main__‘: w = WorkShop(3, 4) w.start()
最后写一个main模块:
from WorkShop import WorkShop if __name__ == ‘__main__‘: w = WorkShop(2, 3) w.start()
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