Re: [PATCH 5/6] meta/dpkg: add dpkg-custom class

[Claudius Heine <claudius.heine.ext@siemens.com>]

Hi Jan,

On 08/31/2017 10:42 AM, Jan Kiszka wrote:
> On 2017-08-31 10:38, [ext] Claudius Heine wrote:
>> Hi
>>
>> On 08/30/2017 09:03 PM, [ext] Henning Schild wrote:
>>> Issues:
>>> 1. full customizations of the images is hard to impossible to
>>> realize in a layer without touching Isar
>>> 1.1. there is no easy way to just copy a file into the image
>>> 1.2. configuration (passwords, groups, cfg-files changes) can not be
>>> done in a layer, there is no way too hook into multistrap or the
>>> configure-script
>>>
>>> Change:
>>> Introduce a class that lets users create custom debian packages on the
>>> fly, without having to create a /debian directory and actually building.
>>> That allows you to pull in debian-dependencies, you could have a
>>> package that has no content and is just there to install what you need
>>> for a feature of your product.
>>> Using package hooks (preinst, postinst ..) you can configure pretty much
>>> all you want when installing the package.
>>> The package can contain actual payload as well, basically any files that
>>> come from "somewhere else". Say binary data like wallpapers, sound files
>>> or application binaries.
>>>
>>> Impact:
>>> This patch addresses the metioned issue in a way that uses debian
>>> mechanism. All the customizations will enjoy features like
>>> - collission protection (multiple packages providing the same file)
>>> - config file protection
>>> - versioning and the ability to deploy your changes in an updateable way
>>>
>>> This patch introduces a major new feature to Isar.
>>>
>>> This class introduces a new class for building debian packages on the
>>> fly. They can basically contain anything from random sources, where
>>> building happens outside of Isar. It also allows to create meta-packages
>>> that contain nothing but pull in dependencies, once all our packets come
>>> in via multistrap that will come in handy.
>>> For rootfs configuration you would use post- and pre- scripts just like
>>> regular debian packages do.
>>>
>>> Signed-off-by: Henning Schild <henning.schild@siemens.com>
>>> ---
>>>    meta/classes/dpkg-custom.bbclass | 57
>>> ++++++++++++++++++++++++++++++++++++++++
>>>    1 file changed, 57 insertions(+)
>>>    create mode 100644 meta/classes/dpkg-custom.bbclass
>>
>> Also not a big fan of this name. 'custom' is a bit too unspecific for
>> what it does. I get that your idea that those packages are *custom*
>> made, but at the same time, so are all the packages that are directly
>> created within isar.
>>
>> I liked the old 'dpkg-bin' name more, but maybe even this is a bit to
>> unspecific. How about 'dpkg-plain'? That describes better that those
>> packages are very simple, created impromptu without much to it, IMO.
> 
> How about dpkg-wrap, because this wraps existing stuff as-is into debian
> package?

I would still be slightly in favor of 'dpkg-plain', because as a recipe 
writer you inherit from dpkg-plain, because you want to create a very 
simple debian package. With 'dpkg-wrap' I would think about a wrapper 
around dpkg packages of around the dpkg tool.

But here we are in the subjective area.

So generally its about describing what it does 'dpkg-wrap' comparing 
with describing what it provides 'dpkg-plain'.

I would still prefer the latter. But would be ok with both.

Cheers,
Claudius

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-54 Fax: (+49)-8142-66989-80 Email: ch@denx.de