Re: [ptxdist] [PATCH 2/5] RAUC: add option to enable streaming support

[Michael Olbrich <m.olbrich@pengutronix.de>]

On Fri, Jun 17, 2022 at 01:47:14PM +0200, Enrico Jörns wrote:
> Am Freitag, dem 17.06.2022 um 12:48 +0200 schrieb Michael Olbrich:
> > On Fri, Jun 17, 2022 at 12:27:50PM +0200, Michael Olbrich wrote:
> > > On Fri, Jun 17, 2022 at 11:47:19AM +0200, Enrico Jörns wrote:
> > > > Am Freitag, dem 17.06.2022 um 08:28 +0200 schrieb Michael Olbrich:
> > > > > On Wed, Jun 15, 2022 at 04:22:14PM +0200, Enrico Jorns wrote:
> > > > > > Enable it by default so that default installation can benefit from this.
> > > > > > Can be deactivated for saving space or for deactivating network
> > > > > > functionality.
> > > > > > Web server must support HTTP range requests for this and NBD support
> > > > > > must be enabled in kernel.
> > > > > > 
> > > > > > Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
> > > > > > ---
> > > > > >  rules/rauc.in   | 11 +++++++++++
> > > > > >  rules/rauc.make |  1 +
> > > > > >  2 files changed, 12 insertions(+)
> > > > > > 
> > > > > > diff --git a/rules/rauc.in b/rules/rauc.in
> > > > > > index aee162b83..832967b44 100644
> > > > > > --- a/rules/rauc.in
> > > > > > +++ b/rules/rauc.in
> > > > > > @@ -13,6 +13,7 @@ menuconfig RAUC
> > > > > >  	select BUSYBOX_FEATURE_SEAMLESS_GZ	if BUSYBOX_TAR
> > > > > >  	select DBUS				if RAUC_SERVICE
> > > > > >  	select LIBCURL				if RAUC_NETWORK
> > > > > > +	select LIBNL3				if RAUC_STREAMING
> > > > > >  	select JSON_GLIB			if RAUC_JSON
> > > > > >  	select UTIL_LINUX_NG_LIBFDISK		if RAUC_GPT
> > > > > >  	select SQUASHFS_TOOLS			if RUNTIME
> > > > > > @@ -44,6 +45,16 @@ config RAUC_NETWORK
> > > > > >  	  Note that network is primarily designed to be used for RAUC'S casync
> > > > > >  	  capabilities, not for fetching full bundles.
> > > > > >  
> > > > > > +config RAUC_STREAMING
> > > > > > +	bool
> > > > > > +	prompt "Enable streaming support"
> > > > > > +	default y
> > > > > 
> > > > > Why 'default y'? I think most users won't need this.
> > > > 
> > > > I am not convinced that streaming is not required for most users. I guess that
> > > > being able to download bundles form HTTP directly is a use case that is more and
> > > > more common. With network and streaming enabled, one can download bundles only
> > > > externally or install from USB sticks etc.
> > > > 
> > > > In Yocto we have this enabled by default, too. If it's ptxdist's philosophy to
> > > > ship as little features as possible by default (i.e. focus on small size), we
> > > > can also make this default n.
> > > 
> > > The thing is, nobody changes the defaults unless they notice something is
> > > not working as expected. And enabling things in PTXdist is easy.
> 
> Indeed.
> 
> > > How does this work anyways? If I call 'rauc install <some-url>', will this
> > > use streaming implicitly or does it require an explicit option?
> 
> No explicit option required. Streaming will be used by default. But required NBD
> support to be enabled in the kernel.
> 
> Without streaming enabled (only network enabled), the download size of RAUC is
> limited by default to allow only casync bundles that do not have any image
> inside (only index files).
> 
> > > How about 'default RAUC_NETWORK'? This way those that use networking also
> > > get streaming by default.
> > 
> > Grr, kconfig does not allow that. So it'll be disabled by default.
> > 
> > Hmmm, or maybe just use the same option? What would the consequences be?
> 
> As up to now the use case for RAUC_NETWORK was primarily casync support, I would
> assume that most of these existing users do not require/benefit from built-in
> streaming.
> 
> Thus maybe just make it 'n' then.
> 
> Note that I have to rebase this series anyway in case the other rauc series I
> sent (for pinning configure options) is applied.

Not needed. It applies just fine on-top of that. No need for a resent.
Btw, 'default n' is the default, so need to add that (I've removed it in
one of the patches).

Michael

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