Pexpect：异步期望与几个连接

Question

我正在尝试编写脚本从网络设备使用Pexpect异步期望（python 3.5.1和pexpect从github）收集一些信息，并得到一些奇怪的事情：所有工作正常几个设备，并不能与更多的工作（通常> 5-6）。我写了这个简单的脚本来进行测试：

@asyncio.coroutine 
def test_ssh_expect_async(num): 
    print('Task #{0} start'.format(num)) 
    p = pexpect.spawn('ssh localhost', encoding='utf8') 
    #p.logfile = sys.stdout 
    yield from p.expect('password', async=True) 
    p.sendline('***') 
    yield from p.expect(r'@self-VirtualBox\:', async=True) 
    p.sendline('uptime') 
    yield from p.expect(r'@self-VirtualBox\:', async=True) 
    p.sendline('uname -a') 
    yield from p.expect(r'@self-VirtualBox\:', async=True) 
    p.sendline('ll') 
    yield from p.expect(r'@self-VirtualBox\:', async=True) 
    print('Task #{0} end'.format(num)) 

@asyncio.coroutine 
def test_loop(): 
    tasks = [] 
    for i in range(1, 5): 
     tasks.append(test_ssh_expect_async(i)) 
    yield from asyncio.wait(tasks) 
    print('All Tasks done') 


print('--------------Async--------------------') 

loop = asyncio.get_event_loop() 
loop.run_until_complete(test_loop()) 

如果我尝试使用范围（1,3）为例子，我得到这样的：

self@self-VirtualBox:/media/sf_netdev$ python3 simple-test.py 
--------------Async-------------------- 
Task #3 running 
Task #1 running 
Task #2 running 
Task #3 closed 
Task #1 closed 
Task #2 closed 
All Tasks done 

但是，如果我增加上限，我得到了一些错误：

self@self-VirtualBox:/media/sf_netdev$ python3 simple-test.py 
--------------Async-------------------- 
Task #3 running 
Task #1 running 
Task #4 running 
Task #2 running 
Exception in callback BaseSelectorEventLoop.add_reader(11, <bound method...d=11 polling>>) 
handle: <Handle BaseSelectorEventLoop.add_reader(11, <bound method...d=11 polling>>)> 
Traceback (most recent call last): 
    File "/usr/lib/python3.5/asyncio/selector_events.py", line 234, in add_reader 
    key = self._selector.get_key(fd) 
    File "/usr/lib/python3.5/selectors.py", line 191, in get_key 
    raise KeyError("{!r} is not registered".format(fileobj)) from None 
KeyError: '11 is not registered' 

During handling of the above exception, another exception occurred: 
... 

为什么会发生？如何用异步pexpect编写工作脚本？

---------------回答------------

这是一个错误https://github.com/pexpect/pexpect/issues/347。现在pexpect命令修复了它。

Answer 1

这是一个错误https://github.com/pexpect/pexpect/issues/347。现在pexpect命令修复了它。