Re: [dpdk-dev] [PATCH 3/4] devtools/test-meson-builds: add testing of pkg-config file

[Luca Boccassi <bluca@debian.org>]

On Fri, 2019-04-26 at 15:56 +0100, Bruce Richardson wrote:
> On Wed, Apr 24, 2019 at 02:37:58PM +0100, Luca Boccassi wrote:
> > On Wed, 2019-04-24 at 13:31 +0100, Bruce Richardson wrote:
> > > On Wed, Apr 24, 2019 at 12:02:24PM +0100, Luca Boccassi wrote:
> > > > On Wed, 2019-04-24 at 11:41 +0100, Bruce Richardson wrote:
> > > > > On Wed, Apr 24, 2019 at 10:22:04AM +0100, Luca Boccassi
> > > > > wrote:
> > > > > > On Tue, 2019-04-23 at 23:06 +0100, Bruce Richardson wrote:
> > > > > > > The pkg-config file generated as part of the build of
> > > > > > > DPDK
> > > > > > > should
> > > > > > > allow
> > > > > > > applications to be built with an installed DPDK. We can
> > > > > > > test
> > > > > > > this
> > > > > > > as
> > > > > > > part of the build by doing an install of DPDK to a
> > > > > > > temporary
> > > > > > > directory
> > > > > > > within the build folder, and by then compiling up a few
> > > > > > > sample
> > > > > > > apps
> > > > > > > using make working off that directory.
> > > > > > > 
> > > > > > > Signed-off-by: Bruce Richardson < 
> > > > > > > bruce.richardson@intel.com
> > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > --- devtools/test-meson-builds.sh | 17 +++++++++++++++++
> > > > > > > 1
> > > > > > > file
> > > > > > > changed, 17 insertions(+)
> > > > > > > 
> > > > > > > diff --git a/devtools/test-meson-builds.sh
> > > > > > > b/devtools/test-
> > > > > > > meson-
> > > > > > > builds.sh index 630a1a6fe..dfba2a782 100755 ---
> > > > > > > a/devtools/test-meson-builds.sh +++ b/devtools/test-
> > > > > > > meson-
> > > > > > > builds.sh @@
> > > > > > > -90,3 +90,20 @@ if command -v $c >/dev/null 2>&1 ; then
> > > > > > > $use_shared
> > > > > > > --cross-file $f done fi + +############## +# Test
> > > > > > > installation of
> > > > > > > the
> > > > > > > x86-default target, to be used for checking +# the sample
> > > > > > > apps
> > > > > > > build
> > > > > > > using the pkg-config file for cflags and libs
> > > > > > > +###############
> > > > > > > +build_path=build-x86-default
> > > > > > > +DESTDIR=`pwd`/$build_path/install-
> > > > > > > root ;
> > > > > > > export DESTDIR
> > > > > > > +PKG_CONFIG_PATH=$DESTDIR/usr/local/lib64/pkgconfig ;
> > > > > > > export PKG_CONFIG_PATH +$ninja_cmd -C $build_path install
> > > > > > > +
> > > > > > > +#
> > > > > > > rather
> > > > > > > than hacking our environment, just edit the .pc file
> > > > > > > prefix
> > > > > > > value
> > > > > > > +sed
> > > > > > > -i "s|prefix=|prefix=$DESTDIR|"
> > > > > > > $PKG_CONFIG_PATH/libdpdk.pc
> > > > > > 
> > > > > > What about just using meson's prefix option instead? Which
> > > > > > is
> > > > > > how
> > > > > > it
> > > > > > would be used in a real use case
> > > > > > 
> > > > > 
> > > > > I don't think that would fully work, as my understanding is
> > > > > that
> > > > > the
> > > > > prefix
> > > > > option would apply only to the /usr/local parts, but not to
> > > > > the
> > > > > kernel
> > > > > modules which would still try and install in /lib/.
> > > > > 
> > > > > /Bruce
> > > > 
> > > > What about doing a meson configure -Denable_kmods=false before
> > > > the
> > > > ninja install? The modules are not needed for that test anyway,
> > > > right?
> > > > Alternatively, the kernel src dir could be symlinked in the
> > > > build
> > > > path,
> > > > and the kernel_dir option could be used
> > > > 
> > > > I'm just worried that the test should be as "realistic" as
> > > > possible, to
> > > > avoid missing something
> > > > 
> > > 
> > > Yes, I did think of that too, but it does mean doing another
> > > configuration
> > > run in meson, and possibly a rebuild too if the
> > > rte_build_config.h
> > > file
> > > changes. Therefore I decided to use DESTDIR for the sake of speed
> > > here. I
> > > assumed there would be a pkg-config variable to adjust the output
> > > paths
> > > based on a sysroot, but couldn't find a suitable one.
> > > 
> > > In any case, I'll see about changing things as you suggest in V2
> > > -
> > > correctness is more important that speed here.
> > > 
> > > /Bruce
> > 
> > There actually is a pkg-config binary option, I just tried and it
> > works
> > (it seems to be disabled by default on Debian and derivatives): --
> > define-prefix
> > 
> 
> Any cmdline options to pkg-config don't solve the problem here as it
> means
> that the makefiles for any app need to be modified to use all those.
> 
> Also, I've been looking at the option you suggest of disabling the
> kernel
> modules for the install step - the problem that this brings is that
> it either:
> * disables them permanently for the default build, meaning subsequent
> runs
>   may fail to catch errors
> * causes us to constantly reconfigure the build directory
> with/without
>   the kmod setting, causing unnecessary work and slowdown in the
> script.
> 
> A third solution is to use a separate build folder for the pkg-config 
> test
> builds, but I think we have enough builds already in the setup
> without adding
> another one.
> 
> All-in-all, I feel at this point that the original solution of making
> a small
> change to the pkg-config file manually is the best solution for now.
> I don't
> see it as being terribly fragile, and it should catch 95% of problems
> with
> the pkg-config files. I suggest that any rework be looked at in a
> later set
> to improve things.
> 
> Regards,
> /Bruce

Makes sense, I had hoped it would be easier - thanks for giving it a
shot!

-- 
Kind regards,
Luca Boccassi