It's arguably both – Fabric's run() (and similar things, like `ssh hostname somecommand`) can't return control to Python until the remote program exits, and spawning an interactive shell (which `su` does, unless you give it `-c`) by definition expects to sit around in the foreground until the user manually quits it.
Fabric should be linking up your local stdin/out/err to the remote end by default, so technically you can type `exit` or Ctrl-D to quit that internal shell, and you'd see the `run()` end up finishing and continuing. That's just...not very useful for something intended to be a noninteractive script :) thus, why `su -c` or `sudo` are preferable. Best, Jeff On Sat, Dec 29, 2018 at 5:21 AM Mateusz <mglowinsk...@gmail.com> wrote: > Hi Jeff, > > thank you for answer. You are right, executing "su -c 'command'" is > working fine:) > > This is not exactly what i needed, but it is enough for now. > > I would like to clarify one thing. You mentioned that "su" spawns a new > shell. Is that a reason why "run" command gets stuck while executing "su"? > Or is that because no exit code is being returned? > > Regards > > Mateusz Glowinski > On 28.12.2018 23:49, Jeff Forcier wrote: > > Hi Mateusz, > > The problem with `su` is that it spawns a new interactive shell, expecting > a human user to continue interacting with that shell during a single > overall SSH session. Tools like Fabric spawn a new session for every new > `run()` or similar, as described in this FAQ: > > > http://www.fabfile.org/faq.html#my-cd-workon-export-etc-calls-don-t-seem-to-work > > Going by my local `man su` it looks like `su` can take a `-c` argument to > run its subshell that way (same as directly running the user's login shell > with `-c`, which usually means "run this one interpreted string and exit"). > > So at a basic level you should be able to solve this by replacing: > > dss.run("su", watchers=[...]) > dss.run("whoami") > > with: > > dss.run("su -c whoami", watchers=[...]) > > though you'd necessarily need to have ALL subsequent commands mixing in > the `su -c` and `watchers=` bits; possibly a good spot for a subroutine or > subclass method. > > We've got a `prefix` context manager that works well for commands that can > be strung together with `&&`, but we don't yet have an equivalent for this > sort of use case. We'll probably get one eventually! > > Best, > Jeff > > > On Fri, Dec 28, 2018 at 5:17 PM Mateusz <mglowinsk...@gmail.com> wrote: > >> Hi There, >> >> I'm trying to use fabric library to control subprocesson on linux device. >> I've prepared a piece of code, which intention is to log as a root user. >> I can't use "sudo" method because that is not existing on the system that >> i want to control. Also logging directly as "root" is impossible. My idea >> is to log as a "admin" user and then use "su" command to switch to "root" >> user. >> >> Code: >> >> from fabric import Connection >> from invoke import Responder >> >> sudopass = Responder(pattern=r'Password:', response='adminPassword\n') >> >> with Connection('192.168.0.106', user="admin", port=22, >> connect_kwargs={"password": "admin"}) as dss: >> command = "uname -s" >> print("Response on {} is: {}".format(command, dss.run(command))) >> command = "whoami" >> print("Response on {} is: {}".format(command, dss.run(command))) >> command = "su" >> print("Response on {} is after executing su command: {}".format(command, >> >> dss.run(command, pty=True, watchers=[sudopass]))) >> command = "whoami" >> print("Response on {} is: {}".format(command, dss.run(command))) >> print("Script end") >> >> Output: >> >> Linux >> Response on uname -s is: Command exited with status 0. >> === stdout === >> Linux >> >> (no stderr) >> dssadmin >> Response on whoami is: Command exited with status 0. >> === stdout === >> dssadmin >> >> (no stderr) >> Password: >> /home/dssadmin # >> >> As you can see script got stuck after sending "su" command. Any ideas how >> to solve that? >> >> I'm using: >> Python 3.7 >> Fabric 2.4.0 >> >> >> Thanks in advance >> >> Mateusz Glowinski >> _______________________________________________ >> Fab-user mailing list >> Fab-user@nongnu.org >> https://lists.nongnu.org/mailman/listinfo/fab-user >> > > > -- > Jeff Forcier > Unix sysadmin; Python engineer > http://bitprophet.org > > -- Jeff Forcier Unix sysadmin; Python engineer http://bitprophet.org
_______________________________________________ Fab-user mailing list Fab-user@nongnu.org https://lists.nongnu.org/mailman/listinfo/fab-user
