使用paramiko执行命令

Question

我正在写一个Python脚本，这个脚本可以在远程的Linux系统上执行命令。我查找了一下，发现了Paramiko这个库。我开发的脚本在执行像who、ps、ls这样的命令时运行得很好。但是，当我尝试执行top和ping命令时，脚本就失败了。请帮我解决这个问题。

import paramiko
import sys

class sampleParamiko:
    ssh = ""
    def __init__(self, host_ip, uname, passwd):
        try:
            self.ssh = paramiko.SSHClient()
            self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            self.ssh.connect(host_ip, username=uname, password=passwd)
            #print "In init function"
        except (paramiko.BadHostKeyException, paramiko.AuthenticationException, paramiko.SSHException) as e:
            print str(e)
            sys.exit(-1)

    def ececuteCmd(self,cmd):
        try:
            stdin, stdout, stderr = self.ssh.exec_command(cmd)
            out_put = stdout.readlines()
            for item in out_put:
                print item,
        except paramiko.SSHException as e:
            print str(e)
            sys.exit(-1)
host_ip = "10.27.207.62"
uname = "root"
password = "linux"
cmd = str(raw_input("Enter the command to execute in the host machine: "))
conn_obj = sampleParamiko(host_ip, uname, password)
conn_obj.ececuteCmd(cmd)

Answer 1

你可能想看看 paramiko.SSHClient 里的 invoke_shell() 方法。

根据你的代码，你可以这样做：

import paramiko
import sys

class sampleParamiko:
    ssh = ""
    def __init__(self, host_ip, uname, passwd):
        try:
            self.ssh = paramiko.SSHClient()
            self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            self.ssh.connect(host_ip, username=uname, password=passwd)
            #print "In init function"
        except (paramiko.BadHostKeyException, paramiko.AuthenticationException,     paramiko.SSHException) as e:
            print str(e)
            sys.exit(-1)

    def ececuteCmd(self,cmd):
        try:
            channel = self.ssh.invoke_shell()
            timeout = 60 # timeout is in seconds
            channel.settimeout(timeout)
            newline        = '\r'
            line_buffer    = ''
            channel_buffer = ''
            channel.send(cmd + ' ; exit ' + newline)
            while True:
                channel_buffer = channel.recv(1).decode('UTF-8')
                if len(channel_buffer) == 0:
                    break 
                channel_buffer  = channel_buffer.replace('\r', '')
                if channel_buffer != '\n':
                    line_buffer += channel_buffer
                else:
                    print line_buffer
                    line_buffer   = ''
        except paramiko.SSHException as e:
            print str(e)
            sys.exit(-1)
host_ip = "10.27.207.62"
uname = "root"
password = "linux"
cmd = str(raw_input("Enter the command to execute in the host machine: "))
conn_obj = sampleParamiko(host_ip, uname, password)
conn_obj.ececuteCmd(cmd)

输出结果是：

Jean@MyDesktop:~$ ./test_paramiko.py 
Enter the command to execute in the host machine: ping -c2 127.0.0.1
ping -c2 127.0.0.1 ; exit 
[root@myserver ~]# ping -c2 127.0.0.1 ; exit 
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.032 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.043 ms

--- 127.0.0.1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.032/0.037/0.043/0.008 ms
logout

但是你不能以交互的方式发送命令。所以如果你只是输入 ping 127.0.0.1，它会一直运行下去，直到你按下 [CTRL]+[C] 或者结束你的 Python 脚本。top 命令也是一样。

如果你想要一个交互式的命令行，可以看看 paramiko 自带的示例脚本。特别是 demos/demo.py 和 demos/interactive.py。