> On Fri, Aug 18, 2017 at 3:57 PM, Scott Moser <email address hidden> wrote:
> 
> > Review: Needs Information
> >
> > The distro can already override the default locale by simply providing
> > /etc/cloud/cloud.cfg.d/ entries with 'locale: C.UTF-8'.  So I don't know
> > that there is a reason to have the added complexity of looking this up in
> > the distro object.  Arguably we should support configuring locale under
> > "system_info" as it is OS configuration similar to "default_user".
> >
> 
> In general, I think default locale is something only the distro can
> provide; I don;t think it's something that should be in the datasource (the
> default value)

I agree that the datasource seems an odd place for this setting.
One example of it not being all that odd, though is if it came from the
metadata service.  Ie, it isn't that far fetched at all to consider
a China based cloud-provider to want to default to having a Chinese locale.

We're not doing anything dynamic with the locale currently, though.
So for now I have to agree.

> A distro can tell cloud-init what the current settings are:
> 
> (read LANG from env)

Well, not really.  LANG is just the LANG of the user running cloud-init.
Most of the time that would be the LANG that is set in the init system.
That definitely could contain 'LANG', but to my knowledge usually doesnt.
From my desktop:
  $ cat /etc/default/locale 
  LANG="en_US.UTF-8"

  $ sudo cat /proc/1/environ | tr '\0' '\n'
  HOME=/
  init=/sbin/init
  recovery=
  TERM=linux
  drop_caps=
  BOOT_IMAGE=/boot/vmlinuz-4.12.0-11-generic
  PATH=/sbin:/usr/sbin:/bin:/usr/bin
  PWD=/
  rootmnt=/root

Thats the environment that cloud-init would inherit when running in normal
boot, it does not have a LANG set.

> If anything, it would be better to remove the "Default" value from
> Datasource base-class and leave it to the distro (to determine default).

Yes, you've convinced me of this.  But your 'get_locale' method that
you've added to distro should read /etc/default/locale on Debian/Ubuntu.
That way we read the "correct" place for such a definition and the
image-builder does not have to repeat themselves or patch cloud-init
to get that change done.

Basically, get_locale should do
   
   if //etc/default/locale has value: 
       return that
   else
       return 'en_US.UTF-8'

That would make cloud-init respect the wishes of the image builder
and also allow the cloud-images team to make the change if they so
choose.
The only issue I see with this is that they wont' necessarily think that
through, and a bug will be opened against cloud-init for behavioral change...

> > The bigger issue with this is that it changes the default locale for any
> > instance with cloud-initnit from en_US.UTF-8 to C.UTF_8.  That is a
> > behavior change that we'd then have to revert in Ubuntu stable releases.
> > Admittedly, I'm not sure of the real-world affect of that change other than
> > having 'locale' mention it, but I think that change was generally not
> > intended or thought out.
> >
> Yes, that's true;  I don't think we can change this in previous stable
> releases.

I'm willing to push that burden off onto to the cloud-images team if they
agree.

> > The one other comment I have is that it'd be best if we chose to not
> > regenerate any locale that was already generated.  Currently what we do is
> > simply not generate (or regenerate) the locale if it is configured to be
> > the system default locale.
> >
> 
> Yes, I was hoping to avoid more exec'ing but with some thought, I probably
> makes sense to

If these 'exec' end up causing 9M of read, and thus a similar slowdown
in boot to what we were trying to avoid, we could shortcut them.

> 1) determine the current LANG setting

see above.

> 2) check if there's a system configured LANG setting (/etc/default/locale)

We're doing this already.

> 3) check what's available (locale -a)
> 
> compare that to what's being requested
> 
> And only locale-gen if the requested locale isn't already available (1, 2)

that seems sane.

> If the requested locale is available (whether we regen or not) we should
> update the system_conf file with the requested locale.
> 
> Does that make sense?

Yep. I think the change to reading the setting from the distro makes
this complete.