Collectives™ on Stack Overflow
Find centralized, trusted content and collaborate around the technologies you use most.
Learn more about Collectives
Teams
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
Learn more about Teams
I intend to run several commands on remote host using paramiko, but the ssh session closed after running a command.
The code listed below:
from paramiko import SSHClient
import paramiko
ssh = SSHClient()
ssh.load_system_host_keys()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(host, 22, user, passwd, timeout=3)
stdin, stdout, stderr = ssh.exec_command('uname -a')
So is there any way to stop the ssh session from closing? Or any alternatives for paramiko?
Update:
I was able to keeping calling exec_command on my Macbook when connected to a Linux server, but the ssh session closed automatically after exec_command once on a Linux server when connected to a switch and raised an
SSHException: paramiko.ssh_exception.SSHException: SSH session not active
>>> print ssh.get_transport()
>>> <paramiko.Transport at 0xf00216d0L (unconnected)>
>>> print ssh.get_transport().is_active()
>>> False
>>> print ssh.get_transport().is_authenticated()
>>> False
Is there any way to keep paramiko ssh session active all the time?
The paramiko debug mode info returned as following:
starting thread (client mode): 0x2657e10L
Connected (version 1.99, client Comware-5.20)
kex algos:[u'diffie-hellman-group-exchange-sha1', u'diffie-hellman- group14-sha1', u'diffie-hellman-group1-sha1'] server key:[u'ssh-rsa'] client encrypt:[u'aes128-cbc', u'3des-cbc', u'des-cbc'] server encrypt:[u'aes128-cbc', u'3des-cbc', u'des-cbc'] client mac:[u'hmac-sha1', u'hmac-sha1-96', u'hmac-md5', u'hmac-md5-96'] server mac:[u'hmac-sha1', u'hmac-sha1-96', u'hmac-md5', u'hmac-md5-96'] client compress:[u'none'] server compress:[u'none'] client lang:[u''] server lang:[u''] kex follows?False
Ciphers agreed: local=aes128-cbc, remote=aes128-cbc
using kex diffie-hellman-group14-sha1; server key type ssh-rsa; cipher: local aes128-cbc, remote aes128-cbc; mac: local hmac-sha1, remote hmac-sha1; compression: local none, remote none
Switch to new keys ...
userauth is OK
Authentication (password) successful!
[chan 0] Max packet in: 32768 bytes
[chan 1] Max packet in: 32768 bytes
[chan 0] Max packet out: 32496 bytes
Secsh channel 0 opened.
Secsh channel 2 open FAILED:
Resource shortage: Resource shortage
[chan 0] Sesch channel 0 request ok
[chan 0] EOF sent (0)
–
–
–
–
You can implement an interactive shell using paramiko, that way the channel is not closed after a command is executed on the remote shell.
import paramiko
import re
class ShellHandler:
def __init__(self, host, user, psw):
self.ssh = paramiko.SSHClient()
self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
self.ssh.connect(host, username=user, password=psw, port=22)
channel = self.ssh.invoke_shell()
self.stdin = channel.makefile('wb')
self.stdout = channel.makefile('r')
def __del__(self):
self.ssh.close()
@staticmethod
def _print_exec_out(cmd, out_buf, err_buf, exit_status):
print('command executed: {}'.format(cmd))
print('STDOUT:')
for line in out_buf:
print(line, end="")
print('end of STDOUT')
print('STDERR:')
for line in err_buf:
print(line, end="")
print('end of STDERR')
print('finished with exit status: {}'.format(exit_status))
print('------------------------------------')
def execute(self, cmd):
:param cmd: the command to be executed on the remote computer
:examples: execute('ls')
execute('finger')
execute('cd folder_name')
cmd = cmd.strip('\n')
self.stdin.write(cmd + '\n')
finish = 'end of stdOUT buffer. finished with exit status'
echo_cmd = 'echo {} $?'.format(finish)
self.stdin.write(echo_cmd + '\n')
shin = self.stdin
self.stdin.flush()
shout = []
sherr = []
exit_status = 0
for line in self.stdout:
if str(line).startswith(cmd) or str(line).startswith(echo_cmd):
# up for now filled with shell junk from stdin
shout = []
elif str(line).startswith(finish):
# our finish command ends with the exit status
exit_status = int(str(line).rsplit(maxsplit=1)[1])
if exit_status:
# stderr is combined with stdout.
# thus, swap sherr with shout in a case of failure.
sherr = shout
shout = []
break
else:
# get rid of 'coloring and formatting' special characters
shout.append(re.compile(r'(\x9B|\x1B\[)[0-?]*[ -/]*[@-~]').sub('', line).
replace('\b', '').replace('\r', ''))
# first and last lines of shout/sherr contain a prompt
if shout and echo_cmd in shout[-1]:
shout.pop()
if shout and cmd in shout[0]:
shout.pop(0)
if sherr and echo_cmd in sherr[-1]:
sherr.pop()
if sherr and cmd in sherr[0]:
sherr.pop(0)
self._print_exec_out(cmd=cmd, out_buf=shout, err_buf=sherr, exit_status=exit_status)
return shin, shout, sherr
I see you are using the timeout parameter in your connect call:
ssh.connect(host, 22, user, passwd, timeout=3)
From the documentation:
timeout (float) – an optional timeout (in seconds) for the TCP connect
In one of my scripts I simply do:
ssh = paramiko.SSHClient()
ssh.connect(host, username=settings.user)
which keeps the connection open until I call
ssh.close()
–
–
I found an answer on this link. You can use the command send instead of exec_command:
from paramiko import SSHClient
import paramiko
ssh = SSHClient()
ssh.load_system_host_keys()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(host, 22, user, passwd, timeout=3)
commands = ssh.invoke_shell()
commands.send("uname -a")
time.sleep(.5)
output = commands.recv(65535)
output = output.decode("utf-8")
print (output)
commands.send("ls -la")
time.sleep(.5)
output = commands.recv(65535)
output = output.decode("utf-8")
print (output)
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
