[lxc-devel] [PATCH] console API improvements

[Dwight Engen]

On Mon, 10 Jun 2013 15:49:07 -0500
Serge Hallyn <serge.hallyn at ubuntu.com> wrote:

> Quoting Dwight Engen (dwight.engen at oracle.com):
> > On Mon, 10 Jun 2013 14:55:08 -0500
> > Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> > 
> > > Quoting Dwight Engen (dwight.engen at oracle.com):
> > > > Add a higher level console API that opens a tty/console and
> > > > runs the mainloop as well. Rename existing API to
> > > > console_getfd(). Use these in the python binding.
> > > > 
> > > > Allow attaching a console peer after container bootup,
> > > > including if the container was launched with -d. This is made
> > > > possible by allocation of a "proxy" pty as the peer when the
> > > > console is attached to.
> > > > 
> > > > Improve handling of SIGWINCH, the pty size will be correctly
> > > > set at the beginning of a session and future changes when using
> > > > the lxc_console() API will be propagated to it as well.
> > > 
> > > Hi,
> > > 
> > > we're hitting on black magic here as far as I'm concerned - but I
> > > can verify that with this patch, 'sudo lxc-console -n container
> > > -t 0' gives me the right size (per stty -a) on console which
> > > never happened before. However, if I then resize my xterm, I have
> > > to disconnect and reconnect the console to get the new size.  Is
> > > that expected?
> > 
> > Hmm, its supposed to work when you resize as well. It does in my
> > (xfce) Terminal session (both stty -a and the shell updated $LINES
> > and $COLUMNS). It also worked from the simple python around vte
> > exmaple, that was in the patch, but that is pretty much the same as
> > Terminal (or gnome-terminal I would think) since they are all based
> > on vte.
> > 
> > When you say xterm do you literally mean xterm or some other newer
> > Terminal emulator? Just wondering so I could look at it, I wonder if
> > SIGWINCH isn't getting there.
> 
> Weeeell, it was screen in mosh in gnome-terminal :)  But outside of
> the container stty -a was getting updated information.  I tried it
> both with lxc-console and python console API.  I can test natively
> inside an xterm tonight if it helps.

I couldn't reproduce it here: as root I ran gnome-terminal, then at the
prompt I did (mosh didn't like my LANG=C):

LANG=en_US.UTF-8
screen mosh <ip of container>
<login as root in container>
stty -a
<resize window>
stty -a

And the resize showed up for me. Not sure why its not working for you,
I'm guessing you are running it some other way because you mentioned
lxc-console and I'm a bit confused though as to the relationship between mosh and
lxc-console in your scenario :)

mosh is going to ssh into the container and get its own pty
(ls /proc/self/fd will show /dev/pts/1), lxc-console is a different
matter and will allocate one of the ptys that lxc sets up as /dev/tty
or (with -t0) /dev/console.

> > I'll also check into the escape thing from your next message, its
> > supposed to default to 'a' just like lxc-console would. Thanks.
> 
> Great, thanks.
> 
> (Frankly I prefer ctrl-`, as it doesn't conflict with any of my
> regular nested screen/tmux escape codes, but I don't think we can
> really change it for lxc-console now)
> 
> -serge