为了方便起见,我编写了一个小包装类来登录远程主机,执行命令,结束检索数据:
def MySSHClient:
def connect(self, remoteHost, remotePort, userName, password):
self.__s = paramiko.SSHClient()
self.__s.load_system_host_keys()
self.__s.connect(remoteHost, remotePort, userName, password)
def exec_command(self, command):
bufsize = -1
chan = self.__s.get_transport().open_session()
chan.exec_command(command)
stdin = chan.makefile('wb', bufsize)
stdout = chan.makefile('r', bufsize)
stderr = chan.makefile_stderr('r', bufsize)
stdin.close()
exitcode = chan.recv_exit_status()
r = MySSHCommandResult(command, stdin, stdout, stderr, exitcode)
chan.close()
return r
def close(self):
self.__s.close()
该代码改编自原始的 paramiko python 实现。我刚刚添加了最后 5 行。
(仅供参考:MySSHCommandResult 在构造期间从 stdout 和 stderr 读取所有数据并将其存储以供进一步使用。)
MySSHClient 类在一个简单的 python 程序中使用:
....
exitCode = 0
s = None
try:
....
exitCode = 3
s = MySSHClient()
s.connect(host, port, login, password)
exitCode = 4
result = s.exec_command(myCommand)
exitCode = 5
if not result.isSuccess():
raise Exception("Failed to execute command!")
result.dump() # for current debugging purposes
exitCode = 0
except:
pass
if s is not None:
s.close()
sys.exit(exitCode)
(通过这些退出代码,Python 程序告诉调用者一切是否成功。如您所见,使用了各种退出代码,以便在失败时进行一些错误诊断。)
到目前为止,一切都很好。基本上这是有效的。但我不明白的是,有时我的 python 程序会提供如下额外的输出:
Exception ignored in: <bound method BufferedFile.__del__ of <paramiko.ChannelFile from <paramiko.Channel 0 (closed) -> <paramiko.Transport at 0x74300588 (unconnected)>>>>
Traceback (most recent call last):
File "/usr/local/lib/python3.5/dist-packages/paramiko/file.py", line 61, in __del__
File "/usr/local/lib/python3.5/dist-packages/paramiko/file.py", line 79, in close
File "/usr/local/lib/python3.5/dist-packages/paramiko/file.py", line 88, in flush
TypeError: 'NoneType' object is not callable
或者像这样:
Exception ignored in: <object repr() failed>
Traceback (most recent call last):
File "/usr/local/lib/python3.5/dist-packages/paramiko/file.py", line 61, in __del__
File "/usr/local/lib/python3.5/dist-packages/paramiko/file.py", line 79, in close
File "/usr/local/lib/python3.5/dist-packages/paramiko/file.py", line 88, in flush
TypeError: 'NoneType' object is not callable
一切都一直工作正常,但大约有 10% 到 20% 的时间我会看到这些错误消息。有谁知道为什么有时清理会在程序终止时失败?我怎样才能避免这些错误消息?