python paramiko模块

1.介绍：

ssh是一个协议，OpenSSH是其中一个开源实现，paramiko是Python的一个库，实现了SSHv2协议(底层使用cryptography)。
有了Paramiko以后，我们就可以在Python代码中直接使用SSH协议对远程服务器执行操作，而不是通过ssh命令对远程服务器进行操作。
由于paramiko属于第三方库，所以需要使用如下命令先行安装：
pip install paramiko

2.paramiko介绍：

paramiko包含两个核心组件：SSHClient和SFTPClient。
SSHClient的作用类似于Linux的ssh命令，是对SSH会话的封装，该类封装了传输(Transport)，通道(Channel)及SFTPClient建立的方法(open_sftp)，通常用于执行远程命令。
SFTPClient的作用类似与Linux的sftp命令，是对SFTP客户端的封装，用以实现远程文件操作，如文件上传、下载、修改文件权限等操作。

转自Python模块学习 - Paramiko

3.实践：连接多个remote并实现上传下载和运行command

# -*- coding: utf-8 -*-

import paramiko
from paramiko import SSHClient as sc

import logging
import os

# 把接收的stdout转成generator，不然超过3k，程序会被hang住
class ReceiveGenerator(object):
    def __init__(self, stdout):
        self.output = stdout
        self.out_channel = stdout.channel

    def __iter__(self):
        return self

    def next(self):
        """
        python2 compatibly
        """
        return self.out_channel.recv(1024)

    def __next__(self):
        """
        python3 compatibly
        """
        return self.out_channel.recv(1024)

    def exit_code_ready(self):
        return self.out_channel.exit_status_ready()

    def exit_code(self):
        return self.out_channel.recv_exit_status()


class SSHClient(object):
    def __init__(self, transport, sftp, ssh):

        self.transport = transport
        self.sftp = sftp
        self.ssh = ssh
        self.hostname = None

    @staticmethod
    def connect(hostname, port, username, key_path):
        try:
            # 私钥的文件路径
            key = paramiko.RSAKey.from_private_key_file(key_path)
            # 创建transport通道
            transport = paramiko.Transport(hostname, port)
            transport.connect(username=username, pkey=key)

            # 创建sftp通道
            sftp = paramiko.SFTPClient.from_transport(transport)
            ssh = sc()
            ssh._transport = transport

            # logger.info('connection is succeed, hostname: %s', hostname)

            return SSHClient(transport, sftp, ssh)
        except:
            raise Exception('connection is failed')

    # 执行linux上的命令
    def ssh_command(self, command):

        stdin, stdout, stderr = self.ssh.exec_command(command)

        return stdin, stdout, stderr

     # 上传
    def sftp_upload(self, local_path, remote_path):

        self.sftp.put(localpath=local_path, remotepath=remote_path)

     # 下载
    def sftp_download(self, local_path, remote_path):

        self.sftp.get(localpath=local_path, remotepath=remote_path)

    def close(self):
        self.transport.close()

    def structure_output(self, command):
        stdin, stdout, stderr = self.ssh_command(command)

        # structure a generator class
        return ReceiveGenerator(stdout), stderr

    # 如果params是string的话直接上传至指定文件， 如果是路径直接上传并执行commamd
    def script(self, params, remote_path, command=None):
        if os.path.isfile(params):
            self.sftp_upload(params, remote_path)

            stdout_iterator, stderr = self.structure_output(command)
            out = ['']
            for i in stdout_iterator:
                # 返回长度为0通道关闭
                if not len(i):
                    break
                out[0] += i

            return {
                'stdout': out[0],
                'stderr': stderr.read().decode('utf-8'),
                'exitcode': stdout_iterator.exit_code()
            }

        ftp_file = self.sftp.file(remote_path, 'w', -1)
        ftp_file.write(params)
        ftp_file.flush()

        stdout_iterator, stderr = self.structure_output(command)

        return {
            'stdout': stdout_iterator,
            'stderr': stderr.read().decode('utf-8'),
            'exitcode': stdout_iterator.exit_code()
        }


if __name__ == '__main__':

    logger = logging.getLogger(__name__)
    logger.setLevel(level=logging.INFO)
    handler = logging.StreamHandler()
    logger.addHandler(handler)


    def main(hostname_list, port, username, pkey_path, input_params, remote_path, command):
        """
        :param hostname_list: list, of hostname
        :param port: int, port
        :param username: string
        :param pkey_path: string, path
        :param input_params: string, it can be path in local or string
        :param remote_path: string, path of remote
        :param command: string
        :return: a generator class
        """

        for hostname in hostname_list:
            ssh_client = SSHClient.connect(hostname, port, username, pkey_path)

            generator_outputs = ssh_client.script(params=input_params, remote_path=remote_path, command=command)
            yield generator_outputs

            ssh_client.close()


    test_hostname_list = ['52.82.7.121']
    test_port = 22
    test_username = 'ubuntu'
    test_pkey = '/home/python/Desktop/fastone-demo.pem'

    test_input_params = '/home/python/Desktop/cb-aws-vmtypes.json'
    test_remote_path = 'test.txt'
    test_command = 'cat test.txt'
    test_outputs_list = main(test_hostname_list,
                             test_port,
                             test_username,
                             test_pkey,
                             test_input_params,
                             test_remote_path,
                             test_command
                             )
    for outputs in test_outputs_list:
        for output in outputs:
            print('output : ', output)

这里不熟悉的朋友可以先把每个函数拆开实现，再抽象成类。
以上！

附带链接：
官方文档
python模块之 paramiko
Python模块学习 - Paramiko