pexpect调用ssh的报错：'NoneType' object has no attribute 'expect'

[Steel_Victor]

本人初学python，是菜鸟中的菜鸟。今天跑了一个脚本，调用pexpect连接ssh到远端服务器运行命令并返回结果。python版本是2.5.
遇到报错，无法解决。望DX赐教。谢谢！

错误信息（斜体字部分是脚本中定义的部分信息）：
ERROR! 1
SSH could not login. Here is what SSH said:
Password: <class 'pexpect.TIMEOUT'>
'NoneType' object has no attribute 'expect'

这个报错是说对象未定义类型？错误应该是发生在第一个if i==0处，但是child已经是由pexpect.spawn生成的对象了，为什么要报错说NoneType？



完整脚本：（来源： http://www.oschina.net/question/12_7583 ）

#!/usr/bin/env python
import pexpect
import getpass, os

def ssh_command(user, host, password, command):
ssh_newkey="Are you sure you want to continue connecting"
child = pexpect.spawn ('ssh -l %s %s %s'%(user, host, command))
i=child.expect([pexpect.TIMEOUT, ssh_newkey, 'passowrd: '])
if i==0:
print 'ERROR! 1'
print 'SSH could not login. Here is what SSH said:'
print child.before, child.after
return None
if i==1:
child.sendline('yes')
child.expect('password: ')
i=child.expect([pexpect.TIMEOUT, 'password: '])
if i==0:
print 'ERROR! 2'
print 'SSH could not login. here is what SSH said:'
print child.before, child.after
return None
child.sendline(password)
return child

def main():
host = raw_input('Hostname: ')
user = raw_input('User: ')
password = getpass.getpass()
command = raw_input('Enter the command: ')
child = ssh_command(user, host, password, command)
child.expect(pexpect.EOF)
print child.before

if __name__ == '__main__':
try:
main()
except Exception, e:
print str(e)
# traceback.print_exc()
os._exit(1)

[livesguan]

#!/usr/bin/env python
#-*- encoding: utf-8 -*-

import pexpect
import getpass, os

def ssh_command(user, host, password, command):
    ssh_newkey="Are you sure you want to continue connecting"
    child = pexpect.spawn ('ssh -l %s %s %s'%(user, host, command))
    i=child.expect([pexpect.TIMEOUT, ssh_newkey, 'passowrd: '])
    if i==0:
        print 'ERROR! 1'
        print 'SSH could not login. Here is what SSH said:'
        print child.before, child.after
        # 程序执行到这，返回None
        return None        

def main():
    host = raw_input('Hostname: ')
    user = raw_input('User: ')
    password = getpass.getpass()
    command = raw_input('Enter the command: ')
    # 此时child为None值
    child = ssh_command(user, host, password, command)
    # 抛出异常
    child.expect(pexpect.EOF)
    print child.before

if __name__ == '__main__':
    try:
        main()
    except Exception, e:
        print str(e)
        # traceback.print_exc()
       os._exit(1)

希望对楼主有所帮助．．．

建议楼主，插入代码一定要记得缩进．．

[荷兰人号]

child = pexpect.spawn ('ssh -l %s %s %s'%(user, host, command))
i=child.expect([pexpect.TIMEOUT, ssh_newkey, 'passowrd: '])

从错误来看，是ssh超时了，导致child是none的
直接用none的expect函数报了下面的错误'NoneType' object has no attribute 'expect'

所以，先确认下是否ssh能连上
，第二加个try

[Steel_Victor]

谢谢大侠！不过我直接用ssh -l user host command测试那台host，是可以的。用这个脚本就会报错。很奇怪。
这是什么原因？

[Steel_Victor]

[Quote=引用 1 楼 userguanguan 的回复:]

Python code

#!/usr/bin/env python
#-*- encoding: utf-8 -*-

import pexpect
import getpass, os

def ssh_command(user, host, password, command):
ssh_newkey="Are you sure you want to continue conn……
[/Quote]
谢谢大侠！ 请帮忙看一下我刚才的回复。为什么直接运行ssh -l命令结果是正常的，但用这个脚本就是不行？

[Steel_Victor]

我补充一下，我用这个脚本对一台安装了ssh服务的windows服务器做操作，是正常。但对另外一台负载均和设备就会失败。直接用ssh命令连接，又是正常。
有点头大。。。

[hentianxu]

加个超时参数就行，默认30S超时，估计你的网络不太好吧。 i=child.expect([pexpect.TIMEOUT, ssh_newkey, 'passowrd: '],timeout=180)