Re: Run-time discovery of machine for image compatibility check

["Eystein Måløy Stenberg" <eystein@mender.io>]

Virgil,

Thank you for pointing this out, I've updated the post to override the
variable instead!

On 11/11/15 08:50, Smith, Virgil wrote:
> The recommendations on your blog suggest modifying image-buildinfo.bbclass to change IMAGE_BUILDINFO_VARS.
> You /should/ be able to avoid this by simply adding something like
> 
> IMAGE_BUILDINFO_VARS_append = " MACHINE DEVICE_MODEL DEVICE_TYPE"
> or
> IMAGE_BUILDINFO_VARS = "DISTRO DISTRO_VERSION MACHINE DEVICE_MODEL DEVICE_TYPE"
> to local.conf.
> 
> The first version should extend the value whereas the second should completely replace it.
> This should work because image-buildinfo.bbclass used the ?= operator to set the variable.
> For the same reason you should NOT use += to extend the variable, but should use _append instead.
> 
> This should be easier to maintain when updating your 'version of yocto'.
> 
> 
> NOTE: In /extreme/ summary this would mean
> 
> Add the following to  local.conf
>    INHERIT += "image-buildinfo"
>    DEVICE_MODEL = "some-extra-identifying-details"
>    IMAGE_BUILDINFO_VARS_append = " MACHINE DEVICE_MODEL"
> 
> to get a /etc/build file in your resulting image with information similar to the build configuration summary bitbake outputs during a build.
> 
> 
> 
>> -----Original Message-----
>> From: yocto-bounces@yoctoproject.org [mailto:yocto-
>> bounces@yoctoproject.org] On Behalf Of Eystein Måløy Stenberg
>> Sent: Tuesday, November 10, 2015 8:29 PM
>> To: Khem Raj
>> Cc: yocto@yoctoproject.org
>> Subject: Re: [yocto] Run-time discovery of machine for image compatibility
>> check
>>
>> Thanks to everyone on the input on this issue. I eventually solved it by using an
>> image feature called "buildinfo".
>>
>> In case someone come across a similar need in the future I've created these two
>> blog post to advertise buildinfo it a bit more and show how to use it:
>>
>> * https://www.mender.io/blog/build-info-yocto-1
>> * https://www.mender.io/blog/build-info-yocto-2
>>
>> On 30/09/15 17:45, Khem Raj wrote:
>>>
>>>> On Sep 30, 2015, at 2:31 PM, Eystein Måløy Stenberg <eystein@mender.io>
>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Before starting a bitbake build, we input the MACHINE variable in
>>>> local.conf (e.g. MACHINE ?= beaglebone).
>>>>
>>>> Is there a way to detect this variable at run-time? I.e. if I have
>>>> built the image, written it to a device, and I'm now logged in to it.
>>>
>>> There is no standard bill of materials that you will find on images.
>>> Everyone produces it per own needs. The reason is that we do not have
>>> a one OTA mechanism recommended or preferred in OpenEmbedded or
>>> maintained by yocto project. May be this could be a thing to consider
>>> come future right now, there were other big fish to fry around workflow. OTA
>> firmware upgrade, could be big thing for next release or there after.
>>>
>>> I don’t have a better answer for you at the moment. You have to work
>>> with device firmware manufacturer and see if they have put some image info
>> into the image in some form.
>>>
>>>>
>>>> The reason I want this is that I'm working on a project to deploy
>>>> image updates (remotely), and I only want to write the image if the
>>>> device is compatible with the image file. So I need to know both the
>>>> hardware/board type and what the image target is (assuming this is
>>>> the MACHINE variable alone). Then I will only write the image if they
>>>> are the same.
>>>>
>>>> Also, do you think using the MACHINE variable is the right approach
>>>> for this problem? Maybe someone has had a similar problem?
>>>>
>>>> I'm new to Yocto, sorry if I'm asking something obvious (but I could
>>>> not find an answer in the docs).
>>>>
>>>> Thanks!
>>>>
>>>> --
>>>>
>>>> Eystein
>>>> --
>>>> _______________________________________________
>>>> yocto mailing list
>>>> yocto@yoctoproject.org
>>>> https://lists.yoctoproject.org/listinfo/yocto
>>>
>>
>> --
>>
>> Eystein
>> --
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-- 

Eystein