Paramiko help - processing multiple commands

[Noah Dain]

On Wed, Jun 24, 2009 at 8:35 PM, Frank Ruiz<frank.ruiz at gmail.com> wrote:
> Hi Jon,
>
> Thanks for the reply. So there are no errors. Essentially everything
> runs as planned. Sorry for being ignorant, but I am not sure if there
> is another way for providing trace data. I will look into what other
> debugging I can provide.
>
> Essentially what happens is that only the second command gets
> processed and the first is ignored.
>
> As far as the global variables are concerned, I am not too sure what
> the best way is to allow my variables to be seen by another sub. In
> the script I am using optparse, however in order for the variables to
> make any sense to my storagessh sub, I have to declare them as global,
> since all the variables within my options sub have a local scope.
>
> I am not too sure of a better way to do this. I don't like it much
> either. Hopefully you can help me shed some light on this in terms of
> best practice.
>
> Normally I declare variable scope outside of my subroutines where required.
>
> However since variable scope is local within a subroutine, seems like
> I have to declare them global in order for the other subs to see it.
>
> Anyhow.. your feedback has been much appreciated.. The script is still
> a work in progress, so I plan to do so more cosmetic enhancements once
> I review it a few more times.
>
> Thanks!
>
> On Wed, Jun 24, 2009 at 4:34 PM, Jon Clements<joncle at googlemail.com> wrote:
>> On Jun 24, 11:22 pm, Frank Ruiz <frank.r... at gmail.com> wrote:
>>> Greetings,
>>>
>>> I am trying to process multiple commands using paramiko. I have
>>> searched other threads, and I think my use case is a little different.
>>> I am trying to login to a storage node that has a special shell, and
>>> as such I cant execute a script on the storage node side.
>>>
>>> I am also trying to avoid using pexpect because I hate making system
>>> calls.. hence my leaning towards paramiko.
>>>
>>> Was hoping someone could help me identify a way to process multiple
>>> commands using paramiko.
>>>
>>> I have two commands listed below, however only one is getting processed.
>>>
>>> Any help is much appreciated.
>>>
>>> Thanks!
>>>
>>> Here is my script:
>>>
>>> #!/usr/bin/env python
>>>
>>> #-Modules---------------------------------------------------------------------
>>> import optparse
>>> import sys
>>> import paramiko
>>>
>>> #-Variables-------------------------------------------------------------------
>>> plog = 'storagessh.log'
>>> suser = 'root'
>>>
>>> #-Config----------------------------------------------------------------------
>>>
>>> #-Subs-Defined----------------------------------------------------------------
>>> def options():
>>>     global hostname
>>>     global goldenimage
>>>     global lunclone
>>>     global sshport
>>>
>>>     usage = "usage: %prog [options] -n <nodename> -g <goldenimage> -l <lun>"
>>>
>>>     parser = optparse.OptionParser(usage)
>>>
>>>     parser.add_option("-n", "--node",
>>>                       dest="hostname",
>>>                       help="Name of storage node you are connecting to.")
>>>     parser.add_option("-g", "--gold",
>>>                       dest="goldenimage",
>>>                       help="Name of goldenimage to clone.")
>>>     parser.add_option("-l", "--lun",
>>>                       dest="lunclone",
>>>                       help="Name of lun to create.")
>>>     parser.add_option("-p", "--port",
>>>                       dest="sshport",
>>>                       default=22,
>>>                       help="SSH port number.")
>>>     options, args = parser.parse_args()
>>>
>>>     if not options.hostname:
>>>         parser.error("Missing hostname argument.")
>>>         exit
>>>     elif not options.goldenimage:
>>>         parser.error("Missing goldenimage argument.")
>>>         exit
>>>     elif not options.lunclone:
>>>         parser.error("Missing lun argument.")
>>>         exit
>>>
>>>     hostname = options.hostname
>>>     goldenimage = options.goldenimage
>>>     lunclone = options.lunclone
>>>     sshport = options.sshport
>>>
>>> def storagessh():
>>>     paramiko.util.log_to_file(plog)
>>>     client = paramiko.SSHClient()
>>>     client.load_system_host_keys()
>>>     client.connect(hostname, sshport, suser)
>>>     stdin, stdout, stderr = client.exec_command('show')
>>>     stdin, stdout, stderr = client.exec_command('help')
>>>     print stdout.read()
>>>     client.close()
>>>
>>> #--Initialization-------------------------------------------------------------
>>> if __name__ == "__main__":
>>>     options()
>>>     storagessh()
>>
>> Again, as you were asked on the original post -- full tracebacks and
>> explain "what is not working".
>>
>> The use of global variables scares me -- why are those needed?
>> --
>> http://mail.python.org/mailman/listinfo/python-list
>>
> --
> http://mail.python.org/mailman/listinfo/python-list
>

this works for me:

def storagessh():
    paramiko.util.log_to_file(plog)
    client = paramiko.SSHClient()
    client.load_system_host_keys()
    client.connect(hostname, sshport, suser)
    stdin, stdout, stderr = client.exec_command('ps')
    print stdout.read()
    stdin, stdout, stderr = client.exec_command('help')
    print stdout.read()
    client.close()

1) you reassign stdin, stdout, stderr so with your code you will never
see the stdout of the first command ('show')
2) the 'show' command did not exist on my system, so no output.  I
substituted 'ps' and added the print statement

also, using user 'root' for dev code is a Bad Thing.

-- 
Noah Dain