Python Fabric 运行命令返回 "binascii.Error: 填充不正确

Question

我正在尝试通过下面的脚本使用fabric连接到亚马逊的EC2服务。但是我遇到了一个问题，不知道该怎么解决。

import os
from fabric.api import run, env, local, cd

WORK = os.getenv('HOME') + '/Work/myproject/'

env.user = 'ubuntu'
env.hosts = [
    '128.248.268.288'
]
env.key_filename = [
    '%s/aws/myproject.pem' % WORK
]

def deploy():
    print("Executing on %(host)s as %(user)s" % env)
    with cd('/sites/myproject.com/code/'):
        run('ls')

这是错误信息的追踪记录。我不太确定该如何解决这个问题。

Traceback (most recent call last):
  File "/Library/Python/2.6/site-packages/fabric/main.py", line 540, in main
    commands[name](*args, **kwargs)
  File "/Users/mickeyckm/Work/myproject/codes/giivee/fabfile.py", line 18, in deploy
    run('ls')
  File "/Library/Python/2.6/site-packages/fabric/network.py", line 391, in host_prompting_wrapper
    return func(*args, **kwargs)
  File "/Library/Python/2.6/site-packages/fabric/operations.py", line 422, in run
    channel = connections[env.host_string]._transport.open_session()
  File "/Library/Python/2.6/site-packages/fabric/network.py", line 65, in __getitem__
    self[real_key] = connect(user, host, port)
  File "/Library/Python/2.6/site-packages/fabric/network.py", line 140, in connect
    client.load_system_host_keys()
  File "/Library/Python/2.6/site-packages/paramiko/client.py", line 151, in load_system_host_keys
    self._system_host_keys.load(filename)
  File "/Library/Python/2.6/site-packages/paramiko/hostkeys.py", line 155, in load
    e = HostKeyEntry.from_line(line)
  File "/Library/Python/2.6/site-packages/paramiko/hostkeys.py", line 67, in from_line
    key = RSAKey(data=base64.decodestring(key))
  File "/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/base64.py", line 321, in decodestring
    return binascii.a2b_base64(s)
binascii.Error: Incorrect padding

如果有人能提供帮助或提示，我会非常感激。

谢谢，
Mickey

Answer 1

我遇到过类似的问题，后来发现是我的 .ssh/known_hosts 文件出了点问题。

所以我在我的 .bashrc 文件里加了一些内容：

alias deploy='mv ~/.ssh/known_hosts ~/.ssh/known_hosts.tmp; fab <myfabscript>; mv ~/.ssh/known_hosts.old ~/.ssh/known_hosts'

（当然要把正确的 fabric 脚本放在 <myfabscript> 的位置）现在我只要运行 "deploy"，一切就正常了！

Answer 2

看看你电脑上的 ~/.ssh/known_hosts 文件。这个文件里可能有重复的条目，或者以其他方式损坏了。

Answer 3

我看到有些地方提到“错误的填充”这个问题是由于binascii模块引起的，通常是在你传入的字符串中有多余的空格字符时出现的。

>>> import binascii
>>> binascii.a2b_base64('a')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
binascii.Error: Incorrect padding

在你的情况下，是你为env对象设置的各种属性。试着这样做，看看你的密钥文件位置是否能正常工作。

filelocation = os.path.join(WORK,'aws/myproject.pem')
env.key_filename = [filelocation]