SSH connection not persistent

Question

I have the following script which SSH's into a network server and executes some commands, for some reason the SSH connection opens but by the time the commands are executed it closes (I think), as a result the commands are failing with below error? Can anyone provide info how to make the SSH connection persistent?

#!/usr/bin/python
import os
import sys
import json
import fileinput
import pwd
from subprocess import Popen, PIPE, STDOUT
import re
import paramiko
import MySQLdb

resource = r'qca-cdit-01'
ssh = paramiko.SSHClient()
ssh.load_system_host_keys()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(resource, username='username', password='passwordname')
#chan = ssh.get_transport().open_session()
chan = ssh.invoke_shell()
chan.get_pty()

commandstringlist = \
    ['/local/mnt/workspace/LA_host_builds/AU_LINUX_ANDROID_LA.BF64.1.2.1_RB2.05.01.01.081.031_msm8992',
     'cd frameworks/base',
     'git fetch ssh://[email protected]:29418/platform/frameworks/base refs/changes/21/1260821/2 && git cherry-pick FETCH_HEAD']
for cmd_val in commandstringlist:
    #chan.exec_command(cmd_val)
    chan.send(cmd_val)
    print(chan.recv(1024))

error:

Traceback (most recent call last):
  File "ssh_test.py", line 21, in <module>
    chan.get_pty()
  File "/usr/local/lib/python2.7/dist-packages/paramiko/channel.py", line 60, in _check
    return func(self, *args, **kwds)
  File "/usr/local/lib/python2.7/dist-packages/paramiko/channel.py", line 177, in get_pty
    self._wait_for_event()
  File "/usr/local/lib/python2.7/dist-packages/paramiko/channel.py", line 1086, in _wait_for_event
    raise e
paramiko.ssh_exception.SSHException: Channel closed

Answer 1

Every command you execute using exec_command has a channel of its own and therefore a context of its own. That context includes the working directory. You change the working directory in one context and then try to use it in another. Instead, use the same channel for all the commands. You can either open a channel and use it, or just issue all the commands at once.

commandstringlist = ['cd /local/mnt/workspace/test2 && cd data/log && git fetch ssh://[email protected]:29418/platform/data/log refs/changes/21/1260821/2 && git cherry-pick FETCH_HEAD']

Here are a few other questions that should explain this in more detail.

https://unix.stackexchange.com/questions/80821/why-does-cd-command-not-work-via-ssh https://superuser.com/questions/46851/keeping-working-directory-across-ssh https://stackoverflow.com/a/6770272/492773