[OE-core] [RFC][PATCH 6/6] local.conf.sample: make debug-tweaks depend on IMAGE_MODE

[Khem Raj]

On Mon, May 15, 2017 at 12:47 PM, Patrick Ohly <patrick.ohly at intel.com> wrote:
> On Mon, 2017-05-15 at 12:34 -0700, Khem Raj wrote:
>> On Mon, May 15, 2017 at 12:18 PM, Patrick Ohly <patrick.ohly at intel.com> wrote:
>> > On Mon, 2017-05-15 at 08:50 -0700, Khem Raj wrote:
>> >> On Mon, May 15, 2017 at 6:27 AM, Patrick Ohly <patrick.ohly at intel.com> wrote:
>> >> > Enabling "debug-tweaks" unconditionally, even if it is only in the
>> >> > local.conf.sample file, runs the risk of that getting used in
>> >> > production images.
>> >> >
>> >> > By checking the per-image IMAGE_MODE, the debug tweaks only get
>> >> > enabled for images not meant for production.
>> >> >
>> >> > Signed-off-by: Patrick Ohly <patrick.ohly at intel.com>
>> >> > ---
>> >> >  meta/conf/local.conf.sample | 5 +++--
>> >> >  1 file changed, 3 insertions(+), 2 deletions(-)
>> >> >
>> >> > diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample
>> >> > index 85c5e21..edadbb7 100644
>> >> > --- a/meta/conf/local.conf.sample
>> >> > +++ b/meta/conf/local.conf.sample
>> >> > @@ -114,8 +114,9 @@ PACKAGE_CLASSES ?= "package_ipk"
>> >> >  #                     e.g. ssh root access has a blank password
>> >> >  # There are other application targets that can be used here too, see
>> >> >  # meta/classes/image.bbclass and meta/classes/core-image.bbclass for more details.
>> >> > -# We default to enabling the debugging tweaks.
>> >> > -EXTRA_IMAGE_FEATURES ?= "debug-tweaks"
>> >> > +# We default to enabling the debugging tweaks unless an image is explicitly
>> >> > +# requested to be built for production.
>> >> > +EXTRA_IMAGE_FEATURES ?= "${@ '' if 'production' == d.getVar('IMAGE_MODE') else 'debug-tweaks'}"
>> >>
>> >> is IMAGE_MODE defined per image recipe ?
>> >
>> > Conceptually it is, although I guess it might get set globally in
>> > practice.
>> >
>> > The class just defines the empty string (= no specific mode) as ??=
>> > default. Then a distro's local.conf sample can define a weak ?= default,
>> > probably "development" (similar to the current practice of enabling
>> > debug-tweaks in local.conf.sample). Finally, specific image recipes
>> > (like a core-image-minimal-development.bb which includes
>> > core-image-minimal.bb) can force a fixed mode with
>> > IMAGE_MODE_forcevariable = "development".
>>
>> People use same distro with two different images for production and
>> devcelopment and conrols are inserted via IMAGE_FEATURES
>> with this change once effectively needs two different distros for prod and dev
>
> Why that?
>
> The production image recipe "foobar-image-production.bb" can use
> IMAGE_MODE_forcevariable = "production"
> and the development image recipe "foobar-image-development.bb" can use
> IMAGE_MODE_forcevariable = "development".
>
> Then whatever the user might configure in local.conf is ignored in favor
> of the fixed recipe values. If there's a concern about using
> _forcevariable: that could be addressed by configuring a global
> IMAGE_MODE_DEFAULT ??= "" and an IMAGE_MODE ??= "${IMAGE_MODE_DEFAULT}"
> in image-mode.bbclass and changing IMAGE_MODE_DEFAULT in distro or local
> conf. Then individual recipes can set IMAGE_MODE =
> "development/production" without having to fall back to _forcevariable.
>
> Or do you mean that there's just one image .bb and traditionally
> IMAGE_FEATURES were changed to switch back and forth? The same works
> with IMAGE_MODE. The advantage over enabling or disabling dangerous
> IMAGE_FEATURES is that users of a distro don't need to know about them.
> They get the guarantee that (for a responsible distro) the dangerous
> once will not get enabled by default for IMAGE_MODE=development.
>

IMAGE_MODE is a distro settings not image setting is that correct ?