(FACT-3023) xen command: avoid xen-toolstack warning

[lollipopman]

xen-toolstack is deprecated and so on Puppet runs in Debian buster you
receive this nettlesome message:

warning: something called deprecated script /usr/lib/xen-common/bin/xen-toolstack

Prior to this change we used xen-toolstack if it is present, but that is
only necessary if more than one stack is installed. Instead check if we
have multiple tool stacks and if we do use xen-toolstack if it is
present.

[puppetlabs-jenkins]

Can one of the admins verify this patch?

[GabrielNagy]

Hi @lollipopman, thanks for the contribution! 🎉

I have a couple of questions, and I don't have much experience with Xen (and no hypervisor VM on hand), so please bear with me:

• Is this warning shown on stdout/stderr when executing Facter without --debug? Normally, the execution API should redirect all external command output to debug.
• I was able to find some context on this -- a thread on bugs.debian.org which mentions that:

The xm toolstack is long gone now, and xl is the only choice.

Initially I wanted to ask if there was an accepted way of getting the toolstack in case of multiple stacks, but from what I understand there's only xl now?

It would be good to update https://github.com/puppetlabs/facter/blob/main/lib/schema/facter.yaml#L1897 to reflect the new behavior.

Also, I opened FACT-3023 to track the work on this. Can you amend your commit title to include the ticket ID instead of maint?

Thanks again for your contribution!

[lollipopman]

• Is this warning shown on stdout/stderr when executing Facter without --debug? Normally, the execution API should redirect all external command output to debug.

The output goes to stderr, the full text of the script is:

#!/bin/sh
set -e
echo >&2 "warning: something called deprecated script $0"
exec xl "$@"

• I was able to find some context on this -- a thread on bugs.debian.org which mentions that:

The xm toolstack is long gone now, and xl is the only choice.

This is mostly true, but it was still available in Debian Jessie, which has long term support until June of 2022, [1].

Initially I wanted to ask if there was an accepted way of getting the toolstack in case of multiple stacks, but from what I understand there's only xl now?

That is true now, but I assumed we wanted to be backward compatible, what are the compatibility guarantees for facter?

It would be good to update https://github.com/puppetlabs/facter/blob/main/lib/schema/facter.yaml#L1897 to reflect the new behavior.

Will do, once we agree upon the behavior

Also, I opened FACT-3023 to track the work on this. Can you amend your commit title to include the ticket ID instead of maint?

done!

Thanks again for your contribution!

Thank you!

[GabrielNagy]

Yep @lollipopman I agree we should keep this backwards-compatible. The current approach of executing xen-toolstack only if multiple stacks are available seems fine to me.

[lollipopman]

thanks @GabrielNagy updated with your feedback, let me know if you want any other changes!