python 2龙卷风非同步方法

使用龙卷风自己的 process.Subprocess 类,它是stdlib的包装器。 subprocess.Popen .

例子:

from tornado import process

@gen.coroutine
def longProcess():
    bashCommand = "sleep 5 && echo hi"

    proc = process.Subprocess(bashCommand.split(), stdout=subprocess.PIPE)

    yield proc.wait_for_exit() # `wait_for_exit` returns a future 
                               # which you can yield. Basically, it means
                               # you can wait for the process to complete
                               # without blocking the server

    return proc.stdout.read() # return the result of the process

    # for Python 2:
    # you can't return from a generator
    # instead use this:
    # raise gen.Return(proc.stdout.read())

你不需要 while 循环。您可以将代码移到其他的协同程序中,并生成列表。 futures . 这样地:

@gen.coroutine
def main():
    futures = [longProcess() for x in range(0, 5)]

    results = yield futures # this coroutine will not move further 
                            # until every future in the list 
                            # `futures` is resolved

    for result in results:
        print(result)

    print('All futures resolved')

作为补充说明,不要使用 time.sleep . 它会阻塞整个服务器。而是使用异步等效 gen.sleep - yield gen.sleep(1)