I am having issues passing responses to a bash script on a remote server over SSH.
I am writing a program in Python 3.6.5 that will SSH to a remote Linux server.
On this remote Linux server there is a bash script that I am running which requires user input to fill in. For whatever reason I cannot pass a user input from my original python program over SSH and have it fill in the bash script user input questions.
main.py
from tkinter import *
import SSH
hostname = 'xxx'
username = 'xxx'
password = 'xxx'
class Connect:
def module(self):
name = input()
connection = SSH.SSH(hostname, username, password)
connection.sendCommand(
'cd xx/{}/xxxxx/ && source .cshrc && ./xxx/xxxx/xxxx/xxxxx'.format(path))
SSH.py
from paramiko import client
class SSH:
client = None
def __init__(self, address, username, password):
print("Login info sent.")
print("Connecting to server.")
self.client = client.SSHClient() # Create a new SSH client
self.client.set_missing_host_key_policy(client.AutoAddPolicy())
self.client.connect(
address, username=username, password=password, look_for_keys=False) # connect
def sendCommand(self, command):
print("Sending your command")
# Check if connection is made previously
if (self.client):
stdin, stdout, stderr = self.client.exec_command(command)
while not stdout.channel.exit_status_ready():
# Print stdout data when available
if stdout.channel.recv_ready():
# Retrieve the first 1024 bytes
alldata = stdout.channel.recv(1024)
while stdout.channel.recv_ready():
# Retrieve the next 1024 bytes
alldata += stdout.channel.recv(1024)
# Print as string with utf8 encoding
print(str(alldata, "utf8"))
else:
print("Connection not opened.")
The final /xxxxxx in class Connect is the remote script that is launched.
It will open a text response awaiting a format such as
What is your name:
and I cannot seem to find a way to properly pass the response to the script from my main.py file within the class Connect.
Every way I have tried to pass name as an argument or a variable the answer seems to just disappear (likely since it is trying to print it at the Linux prompt and not within the bash script)
I think using the read_until function to look for the : at the end of the question may work.
Suggestions?
Write the input that your command needs to the stdin:
stdin, stdout, stderr = self.client.exec_command(command)
stdin.write(name + '\n')
stdin.flush()
(You will of course need to propagate the name variable from module to sendCommand, but I assume you know how to do that part).
I'm trying to run a remote Python script using Paramiko and have it forward anything Python prints back to the client in realtime (i.e. continuous stdout). I connect to my server by calling my class with the following:
class SSH:
client = None
def __init__(self, address, username, password):
self.client = client.SSHClient()
self.client.set_missing_host_key_policy(client.AutoAddPolicy())
self.client.connect(address, username=username, password=password, look_for_keys=False)
I then send commands to the server through my send_command function:
def send_command(self, command):
if(self.client):
stdin, stdout, stderr = self.client.exec_command(command)
for i in range(5): # just print 5 bytes
print(stdout.channel.recv(1))
time.sleep(0.1)
else:
print("Connection not opened.")
Normally, this would work with any continuous/looping command that fills the buffer on stdout as it loops. My problem is that for some reason stdout is filled only when the Python script finishes running, and anything that Python would output comes up only AFTER the script finishes. I want it to print while the script is running. This is the test script I'm using:
from time import sleep
print("Test.")
sleep(1)
print("Test again.")
sleep(2)
print("Final test.")
Is there a way around this or am I doing anything wrong? Thanks in advance.
Problem solved. The solution was actually very simple. I had to request a psuedo-terminal from the server when running a Python script (command = 'python3.6 test.py'). This is done in Paramiko by simply setting the get_pty bool flag to True. See below (note the get_pty in exec_command):
class SSH:
client = None
def __init__(self, address, username, password):
self.client = client.SSHClient()
self.client.set_missing_host_key_policy(client.AutoAddPolicy())
self.client.connect(address, username=username, password=password, look_for_keys=False)
def send_command(self, command):
if(self.client):
stdin, stdout, stderr = self.client.exec_command(command, get_pty=True)
while not stdout.channel.exit_status_ready():
OUT = stdout.channel.recv(1024)
print(OUT)
else:
print("Connection not opened.")
I'm now successfully continuously printing the output of the Python script in real-time.
I am having issues passing responses to a bash script on a remote server over SSH.
I am writing a program in Python 3.6.5 that will SSH to a remote Linux server.
On this remote Linux server there is a bash script that I am running which requires user input to fill in. For whatever reason I cannot pass a user input from my original python program over SSH and have it fill in the bash script user input questions.
main.py
from tkinter import *
import SSH
hostname = 'xxx'
username = 'xxx'
password = 'xxx'
class Connect:
def module(self):
name = input()
connection = SSH.SSH(hostname, username, password)
connection.sendCommand(
'cd xx/{}/xxxxx/ && source .cshrc && ./xxx/xxxx/xxxx/xxxxx'.format(path))
SSH.py
from paramiko import client
class SSH:
client = None
def __init__(self, address, username, password):
print("Login info sent.")
print("Connecting to server.")
self.client = client.SSHClient() # Create a new SSH client
self.client.set_missing_host_key_policy(client.AutoAddPolicy())
self.client.connect(
address, username=username, password=password, look_for_keys=False) # connect
def sendCommand(self, command):
print("Sending your command")
# Check if connection is made previously
if (self.client):
stdin, stdout, stderr = self.client.exec_command(command)
while not stdout.channel.exit_status_ready():
# Print stdout data when available
if stdout.channel.recv_ready():
# Retrieve the first 1024 bytes
alldata = stdout.channel.recv(1024)
while stdout.channel.recv_ready():
# Retrieve the next 1024 bytes
alldata += stdout.channel.recv(1024)
# Print as string with utf8 encoding
print(str(alldata, "utf8"))
else:
print("Connection not opened.")
The final /xxxxxx in class Connect is the remote script that is launched.
It will open a text response awaiting a format such as
What is your name:
and I cannot seem to find a way to properly pass the response to the script from my main.py file within the class Connect.
Every way I have tried to pass name as an argument or a variable the answer seems to just disappear (likely since it is trying to print it at the Linux prompt and not within the bash script)
I think using the read_until function to look for the : at the end of the question may work.
Suggestions?
Write the input that your command needs to the stdin:
stdin, stdout, stderr = self.client.exec_command(command)
stdin.write(name + '\n')
stdin.flush()
(You will of course need to propagate the name variable from module to sendCommand, but I assume you know how to do that part).
I am trying to build a Python script using Paramiko which should SSH Linux server and execute a command, some commands output is working for example df -f,netstat but some of them aren't for example onstat -,ifconfig. Need help solving this issue.
#!/usr/pkg/bin/python
#Importing modules
import paramiko
import time
#setting parameters like host IP, username, passwd and number of iterations to gather cmds
HOST = 'x.x.x.x'
USER = 'abc'
PASS = 'efg'
ITERATION = 3
client1=paramiko.SSHClient()
#Add missing client key
client1.set_missing_host_key_policy(paramiko.AutoAddPolicy())
#connect to CUCM
client1.connect(HOST,username=USER,password=PASS)
print("SSH connection to %s established" %HOST)
#Gather commands and read the output from stdout
stdin, stdout, stderr = client1.exec_command("onstat -")
time.sleep(2)
for line in stdout.readlines():
print(line)
client1.close()
print("Logged out of device %s" %HOST)
Any thought how to resolve this?
def exec_command(self, command, bufsize=-1):
#print "Executing Command: "+command
chan = self._transport.open_session()
chan.exec_command(command)
stdin = chan.makefile('wb', bufsize)
stdout = chan.makefile('rb', bufsize)
stderr = chan.makefile_stderr('rb', bufsize)
return stdin, stdout, stderr
When executing a command in paramiko, it always resets the session when you run exec_command.
I want to able to execute sudo or su and still have those privileges when I run another exec_command.
Another example would be trying to exec_command("cd /") and then run exec_command again and have it be in the root directory. I know you can do something like exec_command("cd /; ls -l"), but I need to do it in separate function calls.
Non-Interactive use cases
This is a non-interactive example... it sends cd tmp, ls and then exit.
import sys
sys.stderr = open('/dev/null') # Silence silly warnings from paramiko
import paramiko as pm
sys.stderr = sys.__stderr__
import os
class AllowAllKeys(pm.MissingHostKeyPolicy):
def missing_host_key(self, client, hostname, key):
return
HOST = '127.0.0.1'
USER = ''
PASSWORD = ''
client = pm.SSHClient()
client.load_system_host_keys()
client.load_host_keys(os.path.expanduser('~/.ssh/known_hosts'))
client.set_missing_host_key_policy(AllowAllKeys())
client.connect(HOST, username=USER, password=PASSWORD)
channel = client.invoke_shell()
stdin = channel.makefile('wb')
stdout = channel.makefile('rb')
stdin.write('''
cd tmp
ls
exit
''')
print stdout.read()
stdout.close()
stdin.close()
client.close()
Interactive use cases
If you have an interactive ssh use case, paramiko can handle it... I personally would drive interactive ssh sessions with scrapli.
Listing all the ways I can think of to use paramiko interactively:
See nagabhushan's answer which uses paramiko interactively
By default, ansible paramiko usage is configurable
By default, exscript ssh uses paramiko
By default, netmiko ssh uses paramiko
By default, scrapli ssh uses paramiko
I might have missed some libraries that use paramiko, but it should be clear that paramiko is used quite extensively by python libraries that control ssh sessions.
Try creating a command string separated by \n character. It worked for me.
For. e.g. ssh.exec_command("command_1 \n command_2 \n command_3")
Strictly speaking, you can't. According to the ssh spec:
A session is a remote execution of a program. The program may be a
shell, an application, a system command, or some built-in subsystem.
This means that, once the command has executed, the session is finished. You cannot execute multiple commands in one session. What you CAN do, however, is starting a remote shell (== one command), and interact with that shell through stdin etc... (think of executing a python script vs. running the interactive interpreter)
You can do that by invoking shell on the client and sending commands. Please refer here
The page has code for python 3.5. I have modified the code a bit to work for pythin 2.7. Adding code here for reference
import threading, paramiko
strdata=''
fulldata=''
class ssh:
shell = None
client = None
transport = None
def __init__(self, address, username, password):
print("Connecting to server on ip", str(address) + ".")
self.client = paramiko.client.SSHClient()
self.client.set_missing_host_key_policy(paramiko.client.AutoAddPolicy())
self.client.connect(address, username=username, password=password, look_for_keys=False)
self.transport = paramiko.Transport((address, 22))
self.transport.connect(username=username, password=password)
thread = threading.Thread(target=self.process)
thread.daemon = True
thread.start()
def close_connection(self):
if(self.client != None):
self.client.close()
self.transport.close()
def open_shell(self):
self.shell = self.client.invoke_shell()
def send_shell(self, command):
if(self.shell):
self.shell.send(command + "\n")
else:
print("Shell not opened.")
def process(self):
global strdata, fulldata
while True:
# Print data when available
if self.shell is not None and self.shell.recv_ready():
alldata = self.shell.recv(1024)
while self.shell.recv_ready():
alldata += self.shell.recv(1024)
strdata = strdata + str(alldata)
fulldata = fulldata + str(alldata)
strdata = self.print_lines(strdata) # print all received data except last line
def print_lines(self, data):
last_line = data
if '\n' in data:
lines = data.splitlines()
for i in range(0, len(lines)-1):
print(lines[i])
last_line = lines[len(lines) - 1]
if data.endswith('\n'):
print(last_line)
last_line = ''
return last_line
sshUsername = "SSH USERNAME"
sshPassword = "SSH PASSWORD"
sshServer = "SSH SERVER ADDRESS"
connection = ssh(sshServer, sshUsername, sshPassword)
connection.open_shell()
connection.send_shell('cmd1')
connection.send_shell('cmd2')
connection.send_shell('cmd3')
time.sleep(10)
print(strdata) # print the last line of received data
print('==========================')
print(fulldata) # This contains the complete data received.
print('==========================')
connection.close_connection()
cmd = 'ls /home/dir'
self.ssh_stdin, self.ssh_stdout, self.ssh_stderr = self.ssh.exec_command(cmd)
print self.ssh_stdout.read()
cmd2 = 'cat /home/dir/test.log'
self.ssh_stdin2, self.ssh_stdout2, self.ssh_stderr2 = self.ssh.exec_command(cmd2)
print self.ssh_stdout2.read()
You can run multiple command using the below technique. Use semicolon to separate the Linux commands
Eg:
chan.exec_command("date;ls;free -m")
If you wish each command to have an effect on the next command you should use:
stdin, stdout, stderr = client.exec_command("command1;command2;command3")
but in some cases, I found that when ";" doesn't work, using "&&" does work.
stdin, stdout, stderr = client.exec_command("command1 && command2 && command3")
You can execute an entire BASH script file for better use, here is the code for that:
import paramiko
hostname = "192.168.1.101"
username = "test"
password = "abc123"
# initialize the SSH client
client = paramiko.SSHClient()
# add to known hosts
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
client.connect(hostname=hostname, username=username, password=password)
except:
print("[!] Cannot connect to the SSH Server")
exit()
# read the BASH script content from the file
bash_script = open("script.sh").read()
# execute the BASH script
stdin, stdout, stderr = client.exec_command(bash_script)
# read the standard output and print it
print(stdout.read().decode())
# print errors if there are any
err = stderr.read().decode()
if err:
print(err)
# close the connection
client.close()
This will execute the local script.sh file on the remote 192.168.1.101 Linux machine.
script.sh (just an example):
cd Desktop
mkdir test_folder
cd test_folder
echo "$PATH" > path.txt
This tutorial explains this in detail: How to Execute BASH Commands in a Remote Machine in Python.