Perform commands over ssh with Python

Question

I m writing a script to automate some command line commands in Python  At the moment I m doing calls thus   cmd    some unix command  retcode   subprocess call cmd shell True    However I need to run some commands on a remote machine  Manually  I would log in using ssh and then run the commands  How would I automate this in Python  I need to log in with a  known  password to the remote machine  so I can t just use cmd   ssh user remotehost  I m wondering if there s a module I should be using

User · Accepted Answer

I will refer you to paramiko

see this question

ssh = paramiko.SSHClient()
ssh.connect(server, username=username, password=password)
ssh_stdin, ssh_stdout, ssh_stderr = ssh.exec_command(cmd_to_execute)

User · Answer

The accepted answer didn t work for me  here s what I used instead  import paramiko import os  ssh   paramiko SSHClient   ssh set missing host key policy paramiko AutoAddPolicy      ssh load system host keys   ssh load host keys os path expanduser     ssh known hosts    ssh connect  quot d d d d quot   username  quot user quot   password  quot pass quot   port 22222   ssh stdin  ssh stdout  ssh stderr   ssh exec command  quot ls -alrt quot   exit code   ssh stdout channel recv exit status     handles async exit error   for line in ssh stdout      print line strip      total 44 -rw-r--r--   1 root root  129 Dec 28  2013  tcshrc -rw-r--r--   1 root root  100 Dec 28  2013  cshrc -rw-r--r--   1 root root  176 Dec 28  2013  bashrc       Alternatively  you can use sshpass  import subprocess cmd    quot  quot  quot  sshpass -p  quot myPas  quot  ssh user d d d d -p 22222  my command  exit   quot  quot  quot  print  subprocess getoutput cmd      References   https   github com onyxfish relay issues 11 https   stackoverflow com a 61016663 797495   Notes   Just make sure to connect manually at least one time to the remote system via ssh   ssh root ip  and accept the public key  this is many times the reason from not being able connect using paramiko or other automated ssh scripts

User · Answer

Keep it simple  No libraries required   import subprocess  subprocess Popen  ssh  user   host   cmd   format user user  host host  cmd  ls -l    shell True  stdout subprocess PIPE  stderr subprocess PIPE  communicate

User · Answer

paramiko finally worked for me after adding additional line  which is really important one  line 3    import paramiko  p   paramiko SSHClient   p set missing host key policy paramiko AutoAddPolicy        This script doesn t work for me unless this line is added  p connect  server   port 22  username  username   password  password   stdin  stdout  stderr   p exec command  your command   opt   stdout readlines   opt      join opt  print opt    Make sure that paramiko package is installed  Original source of the solution  Source

User · Answer

Asking User to enter the command as per the device they are logging in  The below code is validated by PEP8online com   import paramiko import xlrd import time  ssh   paramiko SSHClient   ssh set missing host key policy paramiko AutoAddPolicy    loc      Users harshgow Documents PYTHON WORK labcred xlsx   wo   xlrd open workbook loc  sheet   wo sheet by index 0  Host   sheet cell value 0  1  Port   int sheet cell value 3  1   User   sheet cell value 1  1  Pass   sheet cell value 2  1   def details Host  Port  User  Pass       time sleep 2      ssh connect Host  Port  User  Pass      print  connected to ip    Host      stdin  stdout  stderr   ssh exec command         x   input  Enter the command        stdin write x      stdin write   n       print  success    details Host  Port  User  Pass

User · Answer

First  I m surprised that no one has mentioned fabric yet  Second  For exactly those requirements you describe I ve implemented an own python module named jk simpleexec  It s purpose  Making running commands easy  Let me explain a little bit about it for you  The  executing a command locally  problem My python module jk simpleexec provides a function named runCmd     that can execute a shell     command locally or remotely  This is very simple  Here is an example for local execution of a command  import jk simpleexec  cmdResult   jk simpleexec runCmd None   quot cd     ls -la quot    NOTE  Be aware that the returned data is trimmed automatically by default to remove excessive empty lines from STDOUT and STDERR   Of course this behavior can be deactivated  but for the purpose you ve in mind exactly that behavior is what you will want   The  processing the result  problem What you will receive is an object that contains the return code  STDOUT and STDERR  Therefore it s very easy to process the result  And this is what you want to do as the command you execute might exist and is launched but might fail in doing what it is intended to do  In the most simple case where you re not interested in STDOUT and STDERR your code will likely look something like this  cmdResult raiseExceptionOnError  quot Something went wrong  quot   bDumpStatusOnError True   For debugging purposes you want to output the result to STDOUT at some time  so for this you can do just this  cmdResult dump    If you would want to process STDOUT it s simple as well  Example  for line in cmdResult stdOutLines      print line   The  executing a command remotely  problem Now of course we might want to execute this command remotely on another system  For this we can use the same function runCmd     in exactly the same way but we need to specify a fabric connection object first  This can be done like this  from fabric import Connection  REMOTE HOST    quot myhost quot  REMOTE PORT   22 REMOTE LOGIN    quot mylogin quot  REMOTE PASSWORD    quot mypwd quot  c   Connection host REMOTE HOST  user REMOTE LOGIN  port REMOTE PORT  connect kwargs   quot password quot   REMOTE PASSWORD    cmdResult   jk simpleexec runCmd c   quot cd     ls -la quot          process the result stored in cmdResult      c close    Everything remains exactly the same  but this time we run this command on another host  This is intended  I wanted to have a uniform API where there are no modifications required in the software if you at some time decide to move from the local host to another host  The password input problem Now of course there is the password problem  This has been mentioned above by some users  We might want to ask the user executing this python code for a password  For this problem I have created an own module quite some time ago  jk pwdinput  The difference to regular password input is that jk pwdinput will output some stars instead of just printing nothing  So for every password character you type you will see a star  This way it s more easy for you to enter a password  Here is the code  import jk pwdinput        define other  constants  such as REMOTE LOGIN  REMOTE HOST      REMOTE PASSWORD   jk pwdinput readpwd  quot Password for  quot    REMOTE LOGIN    quot   quot    REMOTE HOST    quot    quot     For completeness  If readpwd     returned None the user canceled the password input with Ctrl C  In a real world scenario you might want to act on this appropriately   Full example Here is a full example  import jk simpleexec import jk pwdinput from fabric import Connection  REMOTE HOST    quot myhost quot  REMOTE PORT   22 REMOTE LOGIN    quot mylogin quot  REMOTE PASSWORD   jk pwdinput readpwd  quot Password for  quot    REMOTE LOGIN    quot   quot    REMOTE HOST    quot    quot   c   Connection host REMOTE HOST  user REMOTE LOGIN  port REMOTE PORT  connect kwargs   quot password quot   REMOTE PASSWORD    cmdResult   jk simpleexec runCmd      c   c      command    quot cd     ls -la quot    cmdResult raiseExceptionOnError  quot Something went wrong  quot   bDumpStatusOnError True   c close    Final notes So we have the full set   Executing a command  executing that command remotely via the same API  creating the connection in an easy and secure way with password input   The code above solves the problem quite well for me  and hopefully for you as well   And everything is open source  Fabric is BSD-2-Clause  and my own modules are provided under Apache-2  Modules used   fabric   http   www fabfile org  jk pwdinput   https   github com jkpubsrc python-module-jk-pwdinput jk simplexec   https   github com jkpubsrc python-module-jk-simpleexec  Happy coding   -

User · Answer

All have already stated  recommended  using paramiko and I am just sharing a python code  API one may say  that will allow you to execute multiple commands in one go   to execute commands on different node use   Commands   run cmd host ip  list of commands      You will see one TODO  which I have kept to stop the execution if any of the commands fails to execute  I don t know how to do it  please share your knowledge      usr bin python  import os import sys import select import paramiko import time   class Commands      def   init   self  retry time 0           self retry time   retry time         pass      def run cmd self  host ip  cmd list           i   0         while True            print  Trying to connect to  s   i  i      self host  i  self retry time           try              ssh   paramiko SSHClient               ssh set missing host key policy paramiko AutoAddPolicy                ssh connect host ip              break         except paramiko AuthenticationException              print  Authentication failed when connecting to  s    host ip              sys exit 1          except              print  Could not SSH to  s  waiting for it to start    host ip              i    1             time sleep 2             If we could not connect within time limit         if i  gt   self retry time              print  Could not connect to  s  Giving up    host ip              sys exit 1            After connection is successful           Send the command         for command in cmd list                print command             print   gt      command               execute commands             stdin  stdout  stderr   ssh exec command command                TODO     if an error is thrown  stop further rules and revert back changes               Wait for the command to terminate             while not stdout channel exit status ready                      Only print data if there is data to read in the channel                 if stdout channel recv ready                        rl  wl  xl   select select   stdout channel              0 0                      if len rl   gt  0                          tmp   stdout channel recv 1024                          output   tmp decode                           print output            Close SSH connection         ssh close           return  def main args None       if args is None          print  arguments expected      else            args      lt ip address gt     lt list of commands gt           mytest   Commands           mytest run cmd host ip args 0   cmd list args 1       return   if   name         main         main sys argv 1      Thank you

User · Answer

I found paramiko to be a bit too low-level  and Fabric not especially well-suited to being used as a library  so I put together my own library called spur that uses paramiko to implement a slightly nicer interface   import spur  shell   spur SshShell hostname  localhost   username  bob   password  password1   result   shell run   echo    -n    hello    print result output   prints hello   If you need to run inside a shell   shell run   sh    -c    echo -n hello

User · Answer

I have used paramiko a bunch  nice  and pxssh  also nice    I would recommend either   They work a little differently but have a relatively large overlap in usage

User · Answer

Works Perfectly    import paramiko import time  ssh   paramiko SSHClient    ssh load system host keys   ssh set missing host key policy paramiko AutoAddPolicy    ssh connect  10 106 104 24   port 22  username  admin   password      time sleep 5  print  connected   stdin  stdout  stderr   ssh exec command  quot   quot    def execute           stdin write  xcommand SystemUnit Boot Action  Restart n          print  success    execute

User · Answer

Reading the Host username password port from excel file import paramiko  import xlrd  ssh   paramiko SSHClient   ssh set missing host key policy paramiko AutoAddPolicy     loc      Users harshgow Documents PYTHON WORK labcred xlsx   wo   xlrd open workbook loc  sheet   wo sheet by index 0  Host   sheet cell value 0 1  Port   int sheet cell value 3 1   User   sheet cell value 1 1  Pass   sheet cell value 2 1   def details Host Port User Pass       ssh connect Host  Port  User  Pass      print  connected to ip   Host      stdin  stdout  stderr   ssh exec command         stdin write  xcommand SystemUnit Boot Action  Restart n       print  success    details Host Port User Pass

User · Answer

You can use any of these commands  this will help you to give a password also  cmd   subprocess run   quot sshpass -p  password  ssh -o StrictHostKeyChecking no -o UserKnownHostsFile  dev null root domain com ps   grep minicom quot    shell True  stdout subprocess PIPE  stderr subprocess STDOUT  print cmd stdout  OR cmd   subprocess getoutput  quot sshpass -p  password  ssh -o StrictHostKeyChecking no -o UserKnownHostsFile  dev null root domain com ps   grep minicom quot   print cmd

User · Answer

Have a look at spurplus  a wrapper we developed around spur that provides type annotations and some minor gimmicks  reconnecting SFTP  md5 etc    https   pypi org project spurplus

User · Answer

Below example  incase if you want user inputs for hostname username password and port no     import paramiko    ssh   paramiko SSHClient      ssh set missing host key policy paramiko AutoAddPolicy         def details       Host   input  Enter the Hostname        Port   input  Enter the Port        User   input  Enter the Username        Pass   input  Enter the Password        ssh connect Host  Port  User  Pass  timeout 2     print  connected      stdin  stdout  stderr   ssh exec command        stdin write  xcommand SystemUnit Boot Action  Restart n      print  success      details

User · Answer

Or you can just use commands getstatusoutput      commands getstatusoutput  ssh machine 1  your script      I used it extensively and it works great   In Python 2 6   use subprocess check output

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