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使用Paramiko在Python上用ssh实现交互式shell?

运维开发网 https://www.qedev.com 2020-07-11 08:07 出处:网络 作者:运维开发网整理
我想编写一个程序(在 Windows 7上的 Python 3.x中),它通过ssh在远程shell上执行多个命令.在查看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),因为命令依赖于环境变
我想编写一个程序(在 Windows 7上的 Python 3.x中),它通过ssh在远程shell上执行多个命令.在查看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),因为命令依赖于环境变量(由先前的命令设置)并且不能连接到一个exec_command()调用,因为它们将在程序中的不同时间执行.

因此,我想在同一个通道中执行命令.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()

这段代码存在一些问题:

>第一次打印并不总是打印ls输出(有时它只打印在第二次打印时).

>第一个cd和ls命令始终存在于输出中(我通过recv命令获取它们,作为输出的一部分),而有时会打印以下所有cd和ls命令,有时它们不会.

>第二个和第三个cd和ls命令(打印时)总是出现在第一个ls输出之前.

我对这种“非决定论”感到困惑,非常感谢你的帮助.

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
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