Re: [PATCH v5 03/13] meta: cache deb srcs as part of postprocessing

["vijaikumar....@gmail.com" <vijaikumar.kanagarajan@gmail.com>]

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Ping

On Thursday, June 11, 2020 at 5:14:38 PM UTC+5:30 vijaikumar....@gmail.com 
wrote:

> Hi Henning,
>
> Did you get a chance to review the rest of the series?
>
> Thanks,
> Vijai Kumar K
>
> On Fri, May 8, 2020 at 11:14 AM vijai kumar
> <vijaikumar....@gmail.com> wrote:
> >
> >
> >
> > On Monday, May 4, 2020 at 2:12:38 PM UTC+5:30, vijai kumar wrote:
> >>
> >>
> >>
> >> On Wednesday, April 29, 2020 at 11:49:41 AM UTC+5:30, Henning Schild 
> wrote:
> >>>
> >>> Am Wed, 22 Apr 2020 02:57:13 -0700 (PDT)
> >>> schrieb vijai kumar <vijaikumar...@gmail.com>:
> >>>
> >>> > On Wednesday, April 22, 2020 at 12:36:42 PM UTC+5:30, Henning Schild
> >>> > wrote:
> >>> > >
> >>> > > On Fri, 17 Apr 2020 15:00:30 +0530
> >>> > > Vijai Kumar K <vijaikumar...@gmail.com <javascript:>> wrote:
> >>> > >
> >>> > > > Collect the deb sources of the corresponding deb binaries cached
> >>> > > > in DEBDIR as part of image postprocess.
> >>> > > >
> >>> > > > Signed-off-by: Vijai Kumar K <Vijaikumar_...@mentor.com
> >>> > > > <javascript:>> ---
> >>> > > > meta/classes/deb-dl-dir.bbclass | 39
> >>> > > > +++++++++++++++++++++++++++++++++ meta/classes/image.bbclass
> >>> > > > | 2 +- meta/classes/rootfs.bbclass | 8 +++++++
> >>> > > > 3 files changed, 48 insertions(+), 1 deletion(-)
> >>> > > >
> >>> > > > diff --git a/meta/classes/deb-dl-dir.bbclass
> >>> > > > b/meta/classes/deb-dl-dir.bbclass index 29a3d67..472b9fe 100644
> >>> > > > --- a/meta/classes/deb-dl-dir.bbclass
> >>> > > > +++ b/meta/classes/deb-dl-dir.bbclass
> >>> > > > @@ -5,6 +5,45 @@
> >>> > > >
> >>> > > > inherit repository
> >>> > > >
> >>> > > > +debsrc_download() {
> >>> > > > + export rootfs="$1"
> >>> > > > + export rootfs_distro="$2"
> >>> > > > + mkdir -p "${DEBSRCDIR}"/"${rootfs_distro}"
> >>> > > > + ( flock 9
> >>> > >
> >>> > > I think you can grab that lock only for the actual writes, and keep
> >>> > > the generation of the list out of the critical section.
> >>> > >
> >>> >
> >>> > To note, this lock also guards the mount part.
> >>>
> >>> Any why does that need to be under the lock? What is the essence of the
> >>> lock anyways?
> >>
> >>
> >> We are mounting DEBSRCDIR onto the image rootfs and then downloading
> >> the deb srcs on-to that. Once that is done, we are unmounting it. The 
> lock
> >> makes sure that there is no race condition between mounts and unmounts.
> >> Not seen such races but there could be a situation where in the first 
> builds unmount
> >> is called after the second builds mount check.
> >
> >
> > Looking back, I don't think there will ever be a case like this for 
> image rootfs.
> > The lock may not be needed for mounts.
> >
> >>
> >> On an alternate way, we could just mount DL_DIR in rootfs_do_mounts and 
> take care
> >> of the cleanup in rootfs_finalize. That way we can avoid this 
> additional mount.
> >>
> >>
> >>> As far as i understand there are multiple writers potentially creating
> >>> the same files in DEBSRCDIR. If that is a problem we also need locking
> >>> in do_apt_fetch. While one multiconfig image is in your postprocess,
> >>> another might still be fetching that same sources.
> >>
> >>
> >>
> >> As I see, there are only two writers who write to DEBSRCDIR.
> >> 1. The post process caching function from this series.
> >> 2. Fetch case using SRC_URI=apt://
> >>
> >> Most of the package sources are fetched via postprocess. And with lock 
> in
> >> place no two deb-src caching takes place at the same time.
> >>
> >> For fetch case using SRC_URI=apt://, say Package X.
> >>
> >> Assume there are two multiconfig images A and B both include
> >> the recipe which provides Package X. In that case when image A is in 
> postprocess
> >> deb-src caching, Package X source would already be available in 
> DEBSRCDIR.
> >> If multiconfig image B is fetching package X when image A is in 
> postprocess
> >> accessing it, there would be no issue, since apt-get source 
> download-only does not
> >> re-download the package.
> >>
> >>
> >>>
> >>>
> >>> > > Note that i played with this "flock 9" syntax instead of what is
> >>> > > used in deb-dl-dir, it did not work as expected. Probably because
> >>> > > it will be many shells and 9 is a different fd in all of them.
> >>> > >
> >>> >
> >>> > Interesting. Works as expected here. If we still need to switch the
> >>> > syntax to be sure, we could.
> >>>
> >>> So you did try multiconfig and two or more writers never ran at the
> >>> same time?
> >>
> >>
> >> Yes.
> >>
> >>>
> >>> In deb-dl-dir there is exclusive writer locking and shared reader
> >>> locking, maybe that is why i decided against "flock 9".
> >>>
> >>> > > + set -e
> >>> > > > + printenv | grep -q BB_VERBOSE_LOGS && set -x
> >>> > > > + sudo -E -s <<'EOSUDO'
> >>> > > > + mkdir -p "${rootfs}/deb-src"
> >>> > > > + mountpoint -q "${rootfs}/deb-src" || \
> >>> > > > + mount --bind "${DEBSRCDIR}" "${rootfs}/deb-src"
> >>> > > > +EOSUDO
> >>> > > > + find "${rootfs}/var/cache/apt/archives/" -maxdepth 1 -type f
> >>> > > > -iname '*\.deb' | while read package; do
> >>> > > > + local src="$( dpkg-deb --show --showformat '${Source}'
> >>> > > > "${package}" )"
> >>> > > > + # If the binary package version and source package
> >>> > > > version are different, then the
> >>> > > > + # source package version will be present inside "()" of
> >>> > > > the Source field.
> >>> > >
> >>> > > dpkg-query(1)
> >>> > >
> >>> > > dpkg-deb --show --showformat '${source:Version}'
> >>> > > dpkg-deb --show --showformat '${source:Upstream-Version}'
> >>> > >
> >>> > > might help to write this cleaner.
> >>> > >
> >>> >
> >>> > Thanks. Will use this.
> >>> >
> >>> >
> >>> > >
> >>> > > > + local version="$( echo "$src" | cut -sd "(" -f2 | cut
> >>> > > > -sd ")" -f1 )"
> >>> > > > + if [ -z ${version} ]; then
> >>> > > > + version="$( dpkg-deb --show --showformat
> >>> > > > '${Version}' "${package}" )"
> >>> > > > + fi
> >>> > > > + # Now strip any version information that might be
> >>> > > > available.
> >>> > > > + src="$( echo "$src" | cut -d' ' -f1 )"
> >>> > > > + # If there is no source field, then the source package
> >>> > > > has the same name as the
> >>> > > > + # binary package.
> >>> > > > + if [ -z "${src}" ];then
> >>> > > > + src="$( dpkg-deb --show --showformat '${Package}'
> >>> > > > "${package}" )"
> >>> > > > + fi
> >>> > >
> >>> > > I still could not find those proxies that all downloading functions
> >>> > > need in their env.
> >>> > >
> >>> >
> >>> > From what I see, the rootfs class from where this is called, already
> >>> > takes care of this
> >>> >
> >>> > 
> https://github.com/ilbers/isar/blob/next/meta/classes/rootfs.bbclass#L22
> >>>
> >>> I see. It might be a good idea to run a local test with BB_NO_NETWORK.
> >>> That will show whether the proxies really "arrive" and you will learn
> >>> how you feature and that switch work together.
> >>
> >>
> >> I did an offline build(with BB_NO_NETWORK set) with this series and it 
> seems
> >> to work fine.
> >>
> >> Thanks,
> >> Vijai Kumar K
> >>
> >>>
> >>> Henning
> >>>
> >>> >
> >>> > >
> >>> > > Henning
> >>> > >
> >>> > > > + sudo -E chroot --userspec=$( id -u ):$( id -g )
> >>> > > > ${rootfs} \
> >>> > > > + sh -c ' mkdir -p "/deb-src/${1}/${2}" && cd
> >>> > > > "/deb-src/${1}/${2}" && apt-get -y --download-only --only-source
> >>> > > > source "$2"="$3" ' download-src "${rootfs_distro}" "${src}"
> >>> > > > "${version}"
> >>> > > > + done
> >>> > > > + sudo -E -s <<'EOSUDO'
> >>> > > > + mountpoint -q "${rootfs}/deb-src" && \
> >>> > > > + umount -l "${rootfs}/deb-src"
> >>> > > > + rm -rf "${rootfs}/deb-src"
> >>> > > > +EOSUDO
> >>> > > > + ) 9>"${DEBSRCDIR}/${rootfs_distro}.lock"
> >>> > > > +}
> >>> > > > +
> >>> > > > deb_dl_dir_import() {
> >>> > > > export pc="${DEBDIR}/${2}"
> >>> > > > export rootfs="${1}"
> >>> > > > diff --git a/meta/classes/image.bbclass
> >>> > > > b/meta/classes/image.bbclass index 6b04c0a..fcaebd6 100644
> >>> > > > --- a/meta/classes/image.bbclass
> >>> > > > +++ b/meta/classes/image.bbclass
> >>> > > > @@ -63,7 +63,7 @@ image_do_mounts() {
> >>> > > > }
> >>> > > >
> >>> > > > ROOTFSDIR = "${IMAGE_ROOTFS}"
> >>> > > > -ROOTFS_FEATURES += "clean-package-cache generate-manifest"
> >>> > > > +ROOTFS_FEATURES += "clean-package-cache generate-manifest
> >>> > > > cach-deb-src" ROOTFS_PACKAGES += "${IMAGE_PREINSTALL}
> >>> > > > ${IMAGE_INSTALL}" ROOTFS_MANIFEST_DEPLOY_DIR ?=
> >>> > > > "${DEPLOY_DIR_IMAGE}"
> >>> > > > diff --git a/meta/classes/rootfs.bbclass
> >>> > > > b/meta/classes/rootfs.bbclass index cee358c..ee57989 100644
> >>> > > > --- a/meta/classes/rootfs.bbclass
> >>> > > > +++ b/meta/classes/rootfs.bbclass
> >>> > > > @@ -185,6 +185,14 @@ python do_rootfs_install() {
> >>> > > > }
> >>> > > > addtask rootfs_install before do_rootfs_postprocess after
> >>> > > > do_unpack
> >>> > > > +ROOTFS_POSTPROCESS_COMMAND +=
> >>> > > > "${@bb.utils.contains('ROOTFS_FEATURES', 'cache-deb-src',
> >>> > > > 'cache_deb_src', '', d)}" +cache_deb_src() {
> >>> > > > + rootfs_install_resolvconf
> >>> > > > + deb_dl_dir_import ${ROOTFSDIR} ${ROOTFS_DISTRO}
> >>> > > > + debsrc_download ${ROOTFSDIR} ${ROOTFS_DISTRO}
> >>> > > > + rootfs_install_clean_files
> >>> > > > +}
> >>> > > > +
> >>> > > > ROOTFS_POSTPROCESS_COMMAND +=
> >>> > > > "${@bb.utils.contains('ROOTFS_FEATURES', 'clean-package-cache',
> >>> > > > 'rootfs_postprocess_clean_package_cache', '', d)}"
> >>> > > > rootfs_postprocess_clean_package_cache() { sudo -E chroot
> >>> > > > '${ROOTFSDIR}' \
> >>> > >
> >>> > >
> >>> >
> >>>
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