使用paramiko的Python交互式ssh客户端

Question

I'm not a programmer, but would like to use Python for automation of some Administrative purposes. The first application after "Hello world" I tried to create is interactive ssh client. I've read some documentation and articles and decided it would be the easiest way to use paramiko module, but unfortunately I'm facing a problem: My applications asks you to enter some neccessary information such as server ip, username, password. After this it establishes connection with defined server and provide you with cli on your screen. For emulating the process of entering command I use while loop. Unfortunately my application works well only with the first command you enter. While trying to type the second command an error appears:

Traceback (most recent call last):
  File "C:\Python27\Tests\ssh_client.py", line 53, in <module>
    client.execute_command(command)
  File "C:\Python27\Tests\ssh_client.py", line 26, in execute_command
    stdin,stdout,stderr = self.connection.exec_command(command)
  File "C:\Python27\lib\site-packages\paramiko\client.py", line 343, in exec_command
    chan.exec_command(command)
AttributeError: 'NoneType' object has no attribute 'exec_command'

Code of the programm (Windows 7):

import paramiko

SERVER = raw_input('Please enter an ip address of remote host: ')
USER = raw_input('Please enter your username: ')
PASSWORD = raw_input('Please enter your password: ')

class MYSSHClient():

    def __init__(self, server=SERVER, username=USER, password=PASSWORD):
        self.server = server
        self.username = username
        self.password = password
        self.connection = None
        self.result =  ''
        self.is_error = False


    def do_connect(self):
        self.connection = paramiko.SSHClient()
        self.connection.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        self.connection.connect(self.server, username=self.username, password=self.password)

    def execute_command(self, command):
        if command:
            print command            
            stdin,stdout,stderr = self.connection.exec_command(command)
            stdin.close()
            error = str(stderr.read())
            if error:
                self.is_error = True
                self.result = error
                print 'error'
            else:
                self.is_error = False
                self.result = str(stdout.read())
                print 'no error'

            print self.result


        else:
            print "no command was entered"

    def do_close(self):
        self.connection.close()

if __name__ == '__main__':
    client = MYSSHClient()
    client.do_connect()
    while 1:
        command = raw_input('cli: ')
        if command == 'q': break
        client.execute_command(command)
    client.do_close()

I tried to delete while loop and just call commands one by one right in the code, but have the same problem (when typing the second command see the same error). It looks like I don't understand fully how paramiko module works. I tried to find information on web but unfortunately didn't find any solution.

I'd be very appreciated if somebody could tell me what I do wrong or give me a link on the similar issue where I can find a solution.

Thanks in advance for any help.

Answer 1

Please use for pxssh module this is very useful for your application if work for windows Python: How can remote from my local pc to remoteA to remoteb to remote c using Paramiko this example very helpful for you Python - Pxssh - Getting an password refused error when trying to login to a remote server

i think u check for your server settings in remote host machine

Answer 2

Not a real answer to your problem but more of a suggestion.

I would recommend you to have a look at fabric, which does exactly what you want: Automate tasks on local or remote hosts. Might be a bit easier since you don't have to implement the logic for the connection and execution of commands.

Fabric documentation: http://docs.fabfile.org/en/1.6/

Answer 3

Unfortunately I didn't find the way to resolve my issue using paramiko module, but I've found such a module as Exscript. The simple code is below:

from Exscript.util.interact import read_login
from Exscript.protocols import SSH2


account = read_login()
conn = SSH2()                       
conn.connect('192.168.1.1')     
conn.login(account)  


while True:
    command = raw_input('cli: ')
    if command == 'q': break
    conn.execute(command)
    print conn.response



conn.send('quit\r')               
conn.close()