[yocto] Good example of bbclass customization? maintainer

[Darcy Watkins]

On Thu, 2017-12-07 at 11:08 -0600, Marcelo E. Magallon wrote:
--snip!--
> My concern right now is a *different* case, where your goal is to modify
> the class in order to affect all the recipes already inheriting from it.
> For example, where there's a modification to a function in the class.
>
> Is there a good example out there as to how to implement such a thing?

In my case I needed to override behaviour of RPMs being installed on
the target.  We would download all files, reboot, run the RPM
transaction during startup, then reboot again.  The default behaviour
to stop and restart services while upgrading the RPM packages was
incompatible with our scheme (since we run the transaction with the
services offline and then reboot into a new startup sequence anyway).

So I cloned the update-rc.d.bbclass and commented a few lines out to
not stop and restart the services, and placed this in our layer.  For
this to properly work, make sure that your layer priorities (and/or
ordering) gives priority to your layer.

Using this approach means you have to repeat this mod whenever you
upgrade to a newer Yocto version (merge/carry forward your change to
the new one then pop that in place of your old one).



Regards,
 
Darcy
 
Darcy Watkins ::  Senior Staff Engineer, Firmware
 
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