Pass TERM variable to application's environment if appropriate

[mpasternacki]

Currently, $TERM is always unset, which is problematic when one attempts to work interactively within a container. Since runtime is responsible for providing stdin/stdout/stderr to the app, it should also set $TERM if application runs on a terminal device.

[mpasternacki]

bump?

[philips]

/cc @eyakubovich

[philips]

Err, /cc @vcaputo

[vcaputo]

@mpasternacki Seems reasonable to me, as long as it can be unset for non-interactive containers.

Things quickly get muddy in the context of pods though, are we placing a requirement on the ACE to provide a pty per application for interactive containers having multiple apps? (think screen/tmux) They can't all share a pty if they do termio, and caring about the TERM variable implies termio is happening.

[philips]

@mpasternacki Yes, can you give an example of what you would like to do? Do you want a container with just a single process and attach it to the current TERM?

[philips]

Ping.

[vbatts]

detecting tty/pty is not impossible, but can be tricky. Though, $TERM is something I would expect to pass to a container...

[vbatts]

Is seems almost more sane to just have a default $TERM like screen(1) does, and allow users to override it.