Python学习之paramiko模块的基础操作与排错

关于

python的ssh库操作需要引入一个远程控制的模块——paramiko，可用于对远程服务器进行命令或文件操作。

应用

登陆服务器，问题排查。可用于编写脚本，在服务器上做一些繁琐的重复操作。

安装

打开cmd，输入命令python -m pip install paramiko

示例

1.秘钥登陆

配置免密登录，linux上信任了windows的公钥，然后脚本在windows上跑，使用windows的私钥就可以直接不要密码登录linux

注意：提供秘钥的paramiko.RSAKey.from_private_key_file('文件')，这里面的"文件"是你本机上的秘钥，不是指你被控机上的公钥哦！

import paramiko

key = paramiko.RSAKey.from_private_key_file("C:\\Users\\liyansheng\\.ssh\\id_rsa")
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
print("connecting")
ssh.connect(hostname="192.168.220.128", username="root", pkey=key)
print("connected")
commands = "uname -a"
stdin, stdout, stderr = ssh.exec_command(commands)
stdin.close()
res, err = stdout.read(), stderr.read()
result = res if res else err
print(result)
ssh.close()

if __name__ == '__main__':
    print()

2.单个命令执行

1. 创建一个.py文件，引入 paramiko模块

	import paramiko

2. 建立SSHClient对象

	ssh = paramiko.SSHClient()

3. 设置可信任，将主机加到host_allow列表

	ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())

4. 创建连接

    ssh.connect("150.158.16.123", 22, "wuyanping", "2022")

5. 创建命令，发送并获取响应结果

    stdin, stdout, stderr = ssh.exec_command("ls /home")
    print(stdout.read().decode("utf-8"))

6. 关闭连接

    ssh.close()

3.执行多个命令

# 执行多条命令,注意传入的参数有个list
def execMultiCmd(host, user, psw, cmds: list, port=22) -> (str, str):
    with paramiko.SSHClient() as ssh_client:
        ssh_client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        ssh_client.connect(hostname=host, port=port, username=user, password=psw)
        cmd = ";".join(cmds)
        _, stdout, stderr = ssh_client.exec_command(cmd, get_pty=True)
        result = stdout.read().decode('utf-8')
        err = stderr.read().decode('utf-8')
    return result, err


if __name__ == '__main__':
    cmdList = ["cd /home", "ls"]
    print(execMultiCmd("192.168.220.128", "root", "root", cmdList))

4.SFTPClient下载文件

方法封装：

def down_file(host, user, psw, local_file, remote_file, port=22):
    with paramiko.Transport((host, port)) as transport:
        # 连接服务
        transport.connect(username=user, password=psw)
        # 获取SFTP示例
        sftp = paramiko.SFTPClient.from_transport(transport)
        # 下载
        sftp.get(remote_file, local_file)
        transport.close()

问题：（错误)

if __name__ == '__main__':
    down_file(my_linux.host, my_linux.user, my_linux.psw, "D:\\ssh_download", "/home/test.txt")

Traceback (most recent call last):
  File "D:\MyCode2\py-1\ssh\download.py", line 17, in <module>
    down_file("192.168.220.128", "root", "root", "D:\\ssh_download", "/home/test.txt")
  File "D:\MyCode2\py-1\ssh\download.py", line 11, in down_file
    sftp.get(remote_file, local_file)
  File "D:\MyCode2\py-1\venv\lib\site-packages\paramiko\sftp_client.py", line 810, in get
    with open(localpath, "wb") as fl:
PermissionError: [Errno 13] Permission denied: 'D:\\ssh_download'

正确使用

要指定下载的文件名，不能只是一个目录

if __name__ == '__main__':
    down_file(my_linux.host, my_linux.user, my_linux.psw, "D:\\ssh_download\\test.txt", "/home/test.txt")

5.上传文件

def upload_file(host, user, psw, local_file, remote_file, port=22):
    with paramiko.Transport((host, port)) as transport:
        # 连接服务
        transport.connect(username=user, password=psw)
        # 获取SFTP示例
        sftp = paramiko.SFTPClient.from_transport(transport)
        sftp.put(local_file, remote_file)
        transport.close()

测试同下载，特别要注意路径问题。如

if __name__ == '__main__':
    upload_file(my_linux.host, my_linux.user, my_linux.psw, "D:\\ssh_download\\test123.txt", "/home/test/test123.txt")

6.ssh工具封装

import os

import paramiko


class SSHTool():
    def __init__(self, ip, port, user, psw):
        """
        初始化
        :param ip:
        :param port:
        :param user:
        :param psw:
        """
        self.ip = ip
        self.port = port
        self.user = user
        self.psw = psw

    def connect_ssh(self):
        """
        创建连接
        :return:
        """
        try:
            self.ssh = paramiko.SSHClient()
            self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            self.ssh.connect(
                hostname=self.ip,
                port=self.port,
                username=self.user,
                password=self.psw
            )
        except Exception as e:
            print(e)
        return self.ssh

    def close_ssh(self):
        """
        关闭连接
        :return:
        """
        try:
            self.ssh.close()
        except Exception as e:
            print(e)

    def exec_shell(self, shell):
        ssh = self.connect_ssh()
        try:
            stdin, stdout, stderr = ssh.exec_command(shell)
            return stdin, stdout, stderr
        except Exception as e:
            print(e)

    def sftp_put_file(self, file, local_dir, remote_dir):
        try:
            t = paramiko.Transport((self.ip, self.port))
            t.connect(username=self.user, password=self.psw)
            sftp = paramiko.SFTPClient.from_transport(t)
            sftp.put(os.path.join(local_dir, file), remote_dir)
            t.close()
        except Exception:
            print("connect error!")

    def sftp_get_file(self, file, local_dir, remote_dir):
        try:
            t = paramiko.Transport((self.ip, self.port))
            t.connect(username=self.user, password=self.psw)
            sftp = paramiko.SFTPClient.from_transport(t)
            sftp.get(remote_dir, os.path.join(local_dir, file))
            t.close()
        except Exception:
            print("connect error!")

补充

• 获取当前文件路径：os.getcwd()

  import os
  
  if __name__ == '__main__':
      print(os.getcwd())  # D:\MyCode2\py-1\ssh
  

• python函数返回多个参数

  def get_strs() -> (str, str):
      return "hello", "word"
  if __name__ == '__main__':
      # 返回值为元祖的形式
      print(get_strs())  # ('hello', 'word')
      # 获取元祖的个数
      print(len(get_strs()))  # 2
      # 通过下标获取元祖的某一个值
      print(get_strs().__getitem__(1))  # word
      # 通过元祖的某个元素定位对应的下标
      print(get_strs().index("hello"))  # 0
  

• with … as …使用

  为了更好地避免此类问题，不同的编程语言都引入了不同的机制。在 Python 中，对应的解决方式是使用 with as 语句操作上下文管理器（context manager），它能够帮助我们自动分配并且释放资源。简单的理解，同时包含 enter() 和 exit() 方法的对象就是上下文管理器。

  格式：

  with 表达式 [as target]：
      代码块
  

学习参考

• Python]远程SSH库Paramiko简介_alwaysrun的博客-CSDN博客_python ssh库
• Python with as用法详解 (biancheng.net)
• Python中的with-as用法 - 简书 (jianshu.com)

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