使用Paramiko在python中通过ssh实现交互式shell?

问题描述

我想编写一个程序(在Windows 7的Python 3.x中)，通过ssh在远程shell上执行多个命令.看了paramikos的exec_command()函数之后，我意识到它不适合我的用例(因为在执行命令后通道被关闭了)，因为命令取决于环境变量(由先前的命令设置)，并且不能连接到一个exec_command()调用中，因为它们将在程序中的不同时间执行.

因此，我想在同一通道中执行命令.我研究的下一个选项是使用paramikos的invoke_shell()函数实现交互式shell:

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(host, username=user, password=psw, port=22)

channel = ssh.invoke_shell()

out = channel.recv(9999)

channel.send('cd mivne_final\n')
channel.send('ls\n')

while not channel.recv_ready():
    time.sleep(3)

out = channel.recv(9999)
print(out.decode("ascii"))

channel.send('cd ..\n')
channel.send('cd or_fail\n')
channel.send('ls\n')

while not channel.recv_ready():
    time.sleep(3)

out = channel.recv(9999)
print(out.decode("ascii"))

channel.send('cd ..\n')
channel.send('cd simulator\n')
channel.send('ls\n')

while not channel.recv_ready():
    time.sleep(3)

out = channel.recv(9999)
print(out.decode("ascii"))

ssh.close() 

此代码存在一些问题:

1. 第一个print并不总是打印ls输出(有时仅打印在第二个print上).
2. 第一个cd和ls命令始终出现在输出中(我通过recv命令获得它们，作为输出的一部分)，而随后的所有cd和ls命令都是有时打印，有时不打印.
3. 第二个和第三个cd和ls命令(在打印时)始终出现在第一个ls输出之前.

我对这种不确定性"感到困惑，非常感谢您的帮助.

推荐答案

import paramiko
import re


class ShellHandler:

    def __init__(self, host, user, psw):
        self.ssh = paramiko.SSHClient()
        self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        self.ssh.connect(host, username=user, password=psw, port=22)

        channel = self.ssh.invoke_shell()
        self.stdin = channel.makefile('wb')
        self.stdout = channel.makefile('r')

    def __del__(self):
        self.ssh.close()

    def execute(self, cmd):
        """

        :param cmd: the command to be executed on the remote computer
        :examples:  execute('ls')
                    execute('finger')
                    execute('cd folder_name')
        """
        cmd = cmd.strip('\n')
        self.stdin.write(cmd + '\n')
        finish = 'end of stdOUT buffer. finished with exit status'
        echo_cmd = 'echo {} $?'.format(finish)
        self.stdin.write(echo_cmd + '\n')
        shin = self.stdin
        self.stdin.flush()

        shout = []
        sherr = []
        exit_status = 0
        for line in self.stdout:
            if str(line).startswith(cmd) or str(line).startswith(echo_cmd):
                # up for now filled with shell junk from stdin
                shout = []
            elif str(line).startswith(finish):
                # our finish command ends with the exit status
                exit_status = int(str(line).rsplit(maxsplit=1)[1])
                if exit_status:
                    # stderr is combined with stdout.
                    # thus, swap sherr with shout in a case of failure.
                    sherr = shout
                    shout = []
                break
            else:
                # get rid of 'coloring and formatting' special characters
                shout.append(re.compile(r'(\x9B|\x1B\[)[0-?]*[ -/]*[@-~]').sub('', line).
                             replace('\b', '').replace('\r', ''))

        # first and last lines of shout/sherr contain a prompt
        if shout and echo_cmd in shout[-1]:
            shout.pop()
        if shout and cmd in shout[0]:
            shout.pop(0)
        if sherr and echo_cmd in sherr[-1]:
            sherr.pop()
        if sherr and cmd in sherr[0]:
            sherr.pop(0)

        return shin, shout, sherr