python使用paramiko模块实现ssh登录执行命令

#coding=utf8
import paramiko
import time
import logging

'''
if user root，can not login，must use user xx and then switch to root

not root ，then run

'''

def  _conn_root(ip,port,username,passwd,cmd):
s = paramiko.SSHClient()
s.load_system_host_keys()
s.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
#此处写入一个用于登录的用户
s.connect(hostname=ip, port=int(port), username='xx', password='xx')
except:
logging.info('err: can not conn %s ,pls check %s and password of xx',(ip,ip))

if username == 'root' or  'xx':
ssh = s.invoke_shell()
time.sleep(1)
if username=='xx':
ssh.send('su - xx\n')
else:
ssh.send('su -\n')
buff = ''
while not buff.endswith('Password: '):
resp = ssh.recv(2048)
buff += resp
ssh.send(passwd)
ssh.send('\n')
buff = ''
while not buff.endswith('# '):
resp = ssh.recv(2048)
buff += resp
ssh.send(cmd)
ssh.send('\n')
buff = ''
time.sleep(1)
resp = ssh.recv(2048)
resp = ''
while not buff.endswith('# '):
resp = ssh.recv(2048)
print resp
buff += resp
s.close()
result = buff
else:
stdin, stdout, stderr = s.exec_command(cmd)
result = stdout.read()
s.close()

return result

def _conn_nomal(ip,port,username,passwd,cmd):
s = paramiko.SSHClient()
s.load_system_host_keys()
s.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
s.connect(hostname=host, port=int(port), username=username, password=password)
except:
logging.info('err: can not connect %s ,pls check %s and user && password',(ip,ip))
#'get result'
stdin, stdout, stderr = s.exec_command(cmd)
result = stdout.read()
s.close()
return result

def Connect(ip,port=22,username='xx',passwd='xx',cmd='echo '):

if username=='root' or 'xx':
return _conn_root(ip,port,username,passwd,cmd)
else:
return _conn_nomal(ip,port,username,passwd,cmd)