Re: [yocto-patches] [meta-rockchip][PATCH] user-selectable wic format

[Trevor Woerner <twoerner@gmail.com>]

On Tue 2024-06-11 @ 05:28:42 PM, Quentin Schulz via lists.yoctoproject.org wrote:
> Hi Trevor,
> 
> On 6/11/24 5:13 PM, Trevor Woerner via lists.yoctoproject.org wrote:
> > On Tue 2024-06-11 @ 04:31:26 PM, Quentin Schulz via lists.yoctoproject.org wrote:
> > > Hi Trevor,
> > > 
> > > On 6/11/24 4:15 PM, Trevor Woerner via lists.yoctoproject.org wrote:
> > > > Allow the user to choose their preferred wic image format.
> > > > 
> > > 
> > > Can you provide some use case for this?
> > 
> > In order to build a wic.xz image the build has to first create a wic image,
> > then compress it as an extra step. On a slow machine this extra step takes
> > a noticeable amount of time.
> > 
> > On my local, slow build machine I prefer wic images since it saves build time
> > not having to do the compression and since everything is local, there's no
> > over-the-internet xfer time to consider.
> > 
> > When I build using some remote, fast build machine, the extra time spent doing
> > the extra step of compressing is recuperated by the savings in transfer time
> > retrieving the image from the remote. Therefore I prefer to make wic.xz
> > images. Building wic images on remote machines would lead to very long xfer
> > times to download the image artifact.
> > 
> > If I simply do:
> > 
> > 	IMAGE_FSTYPES += "wic.xz"
> > 
> > in my conf/local.conf then MACHINEs that don't normally build wic images will
> > fail. So the only way to build wic.xz images on remote builds is to tweak the
> > meta-rockchip:conf/machine/include/rockchip-wic.inc file. So I'm always
> > carrying this tweak for every remote build that I do.
> > 
> > So I could simply modify conf/machine/includes/rockchip-wic.inc to set it to
> > wic.xz but that wouldn't suit my use-case since I could then have to tweak it
> > again for any local builds. Besides, I could never guess what preferred wic
> > version others would prefer and I don't want to be changing it every other
> > week.
> > 
> > So this patch maintains the existing behaviour completely, and when I do a
> > build on a remote machine I can simply set
> > 
> > 	WIC_FSTYPE = "wic.xz"
> > 
> > in my conf/local.conf without having to tweak the layer.
> > 
> > And if others want compression but would prefer bz2 or gzip (or whatever) then
> > then can specify it however they wish.
> > 
> > > > Signed-off-by: Trevor Woerner <twoerner@gmail.com>
> > > > ---
> > > >    conf/machine/include/rockchip-wic.inc | 3 ++-
> > > >    1 file changed, 2 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/conf/machine/include/rockchip-wic.inc b/conf/machine/include/rockchip-wic.inc
> > > > index dab61d83ed2c..eb895cd0b4ad 100644
> > > > --- a/conf/machine/include/rockchip-wic.inc
> > > > +++ b/conf/machine/include/rockchip-wic.inc
> > > > @@ -5,7 +5,8 @@ require conf/machine/include/rockchip-rk-u-boot-env.inc
> > > >    SPL_BINARY ?= "idbloader.img"
> > > > -IMAGE_FSTYPES += "wic wic.bmap"
> > > > +WIC_FSTYPE ?= "wic"
> > > > +IMAGE_FSTYPES += "${WIC_FSTYPE} wic.bmap"
> > > 
> > > Would this be a way to NOT have wic in IMAGE_FSTYPES? What are we trying to
> > > achieve here?
> > > 
> > > If so, shouldn't we also not build wic.bmap there?
> > 
> > The goal isn't to not build a wic image, the point is to allow the user to
> > specify which type of wic image (i.e. with or without compression and if with
> > compression, which one?).
> > 
> > I guess I could do:
> > 
> > 	WIC_COMPRESSION ?= ""
> > 	IMAGE_FSTYPES += "wic${WIC_COMPRESSION} wic.bmap"
> > 
> > And then specify:
> > 
> > 	WIC_COMPRESSION = ".xz"
> > 
> > in my conf/local.conf?
> > 
> 
> Thanks for taking the time to explain your use case :)
> 
> I was about to suggest this :)
> 
> Should we allow multiple values in WIC_COMPRESSION?
> 
> Also maybe it should be named "EXTENSION" instead since we have the dot in
> there?

Sounds good.

> Additionally, I don't see wic.xz in IMAGE_TYPES in https://git.openembedded.org/openembedded-core/tree/meta/classes-recipe/image_types.bbclass,
> is xz really working?

I have been using "wic.xz" in IMAGE_FSTYPES for years. Works with bmaptool
too.

> If so, why do we need to specify wic.gz and all the
> others in IMAGE_TYPES? Maybe we do not?

I guess that's for others to answer/investigate.