[Tutor] Passing arguments to & running a python script on a remote machine from a python script on local machine .

[eryksun]

On Wed, Sep 19, 2012 at 6:13 PM, eryksun <eryksun at gmail.com> wrote:
>
>     cmd = 'python remote.py "%s" "%s" "%s"' % (arg1, arg2, arg3)
>
>     try:
>         out = subprocess.check_output(['ssh', '%s@%s' % (user, hostname), cmd])

I forgot you need to escape special characters in the arguments. You
can add quoting and escape special characters at the same time with
the undocumented function pipes.quote:

    import pipes

    args = tuple(pipes.quote(arg) for arg in (arg1, arg2, arg3))
    cmd = 'python test.py %s %s %s' % args

Notice there are no longer quotes around each %s in cmd. Python 3.3
will have shlex.quote:

http://docs.python.org/dev/library/shlex.html#shlex.quote


Also, if you don't care about the output, use subprocess.check_call()
instead. However, the connection still waits for the remote shell's
stdout to close. If remote.py is long-running, redirect its stdout to
a log file or /dev/null and start the process in the background (&).
For example:

    cmd = 'python remote.py %s %s %s >/dev/null &' % args

With this command remote.py is put in the background, stdout closes,
the forked sshd daemon on the server exits, and ssh on the client
immediately returns.