如何使用 pexcept 发送本地和远程命令

Question

我有一个简单的类，允许我发送大量本地 CLI 命令。允许我测试某些命令行功能。该机制运行良好，但需要扩展。我对如何更改此机制以处理本地或远程命令感到困惑。

from pexpect import *
class Expect( ):
    def Do( self, cmd, program: list = [], timeout = 20 ):
        result = run( cmd, events=program, timeout=timeout).decode() 
        return result

cmd  = 'login'
prog = [('username \\(.+\\):', 'yourUN\n'), ('password:', 'yourPW\n')]
res  = Expect().Do( cmd, prog )    # Returns everything
print( 'res: ' + res )
# use results to verify functionality

返回类似：

username (root):yourUN
password:*****
Logged in user yourUN

我目前有超过 1250 个测试运行大约 5000 个 cli 本地命令。唯一的问题是我需要这个类来支持本地命令以及远程 SSH 命令。

我已将我的测试机器设置为允许远程 SSH 而无需用户 SSH 登录。

Answer 1

如果我理解了这个问题，并且根据我的测试，您将需要两个函数或方法。

1. 第一个函数使用 Pexpect 运行本地命令。您也可以使用第一个函数运行 ssh 命令，但前提是 IP 地址存在于 known_hosts 文件中：

pexpect.run("ssh yourUN@192.168.x.x 'whoami'")

否则，您将遇到"The authenticity of host '192.168.x.x (192.168.x.x)' can't be established." 错误。

2.为避免该错误，我建议使用 Paramiko 的 ssh 命令使用第二个函数。

完整代码如下：

注意 - 使用 Python 3.9 在 Linux 5.14.16 上测试。远程机器是 Ubuntu 8.04。

from getpass import getpass

import paramiko
import pexpect


def run_cli_commands(list_of_commands, password=None):
    for c in list_of_commands:
        print("Command:", c)
        command_output, exitstatus = pexpect.run(
            c,
            events={"(?i)password": password if password is not None else getpass()},
            withexitstatus=True)
        print("Output:\n", command_output.decode())


def run_ssh_commands(list_of_commands, ip_address, username, password):
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.connect(ip_address, username=username, password=password)
    for c in list_of_commands:
        print("Command:", c)
        stdin, stdout, stderr = ssh.exec_command(c)
        print("Output:\n", stdout.read().decode())


run_cli_commands(["which ssh",
                  "systemctl status ssh",
                  "systemctl start ssh",
                  "systemctl status ssh", ], password="**********")
run_ssh_commands(["whoami",
                  "date", ], "192.168.x.x", "yourUN", "**********")
run_cli_commands(["systemctl stop ssh", ], password="**********")
print("Script complete. Have a nice day.")

输出：

Local command: which ssh
Output:
 /usr/bin/ssh

Local command: systemctl status ssh
Output:
 ○ ssh.service - OpenBSD Secure Shell server
     Loaded: loaded (/lib/systemd/system/ssh.service; disabled; vendor preset: disabled)
     Active: inactive (dead)
       Docs: man:sshd(8)
             man:sshd_config(5)

Local command: systemctl start ssh
Output:
 
Local command: systemctl status ssh
Output:
 ● ssh.service - OpenBSD Secure Shell server
     Loaded: loaded (/lib/systemd/system/ssh.service; disabled; vendor preset: disabled)
     Active: active (running) since Thu 2021-12-09 23:13:05 EST; 174ms ago
       Docs: man:sshd(8)
             man:sshd_config(5)
    Process: 4565 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
   Main PID: 4566 (sshd)
      Tasks: 1 (limit: 2275)
     Memory: 2.3M
        CPU: 18ms
     CGroup: /system.slice/ssh.service
             └─4566 "sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups"

SSH command: whoami
Output:
 yourUN

SSH command: date
Output:
 Thu Dec  9 23:13:04 EST 2021

Local command: systemctl stop ssh
Output:
 
Script complete. Have a nice day.