def consumer(): r = '' while True: n = yield r if not n: return print('[CONSUMER] Consuming %s...' % n) r = '200 OK' def produce(c): c.send(None) n = 0 while n < 5: n = n + 1 print('[PRODUCER] Producing %s...' % n) r = c.send(n) print('[PRODUCER] Consumer return: %s' % r) c.close() c = consumer() produce(c)
# 执行结果为
[PRODUCER] Producing 1... [CONSUMER] Consuming 1... [PRODUCER] Consumer return: 200 OK [PRODUCER] Producing 2... [CONSUMER] Consuming 2... [PRODUCER] Consumer return: 200 OK [PRODUCER] Producing 3... [CONSUMER] Consuming 3... [PRODUCER] Consumer return: 200 OK [PRODUCER] Producing 4... [CONSUMER] Consuming 4... [PRODUCER] Consumer return: 200 OK [PRODUCER] Producing 5... [CONSUMER] Consuming 5... [PRODUCER] Consumer return: 200 OK
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首先调用
c.send(None)
启动生成器; -
然后,一旦生产了东西,通过
c.send(n)
切换到consumer
执行; -
consumer
通过yield
拿到消息,处理,又通过yield
把结果传回; -
produce
拿到consumer
处理的结果,继续生产下一条消息; -
produce
决定不生产了,通过c.close()
关闭consumer
,整个过程结束。
整个流程无锁,由一个线程执行,produce
和consumer
协作完成任务,所以称为“协程”,而非线程的抢占式多任务。