[PATCH v2 3/3] Changes for a faster build using less disk space

[Uladzimir Bely <ubely@ilbers.de>]

From: "Roberto A. Foglietta" <roberto.foglietta@gmail.com>

Faster build for larger projects with a lot of debian packages

This patch leverages few ways to accomplish the task to optimise
the large buildings.

Put a CACHEDIR.TAG file in each cache folder in such a way every
tar that uses the option --exclude-caches could be avoided
to include debian packages saving a lot of time and disk space.

Signed-off-by: Roberto A. Foglietta <roberto.foglietta@gmail.com>
Signed-off-by: Uladzimir Bely <ubely@ilbers.de>
---
 meta/classes/deb-dl-dir.bbclass                     | 2 +-
 meta/classes/rootfs.bbclass                         | 3 ++-
 meta/recipes-core/isar-bootstrap/isar-bootstrap.inc | 7 ++++++-
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/meta/classes/deb-dl-dir.bbclass b/meta/classes/deb-dl-dir.bbclass
index 7db25251..3afad4e8 100644
--- a/meta/classes/deb-dl-dir.bbclass
+++ b/meta/classes/deb-dl-dir.bbclass
@@ -102,7 +102,7 @@ deb_dl_dir_export() {
             -maxdepth 1 -type f -iname '*\.deb' |\
         while read p; do
             # skip files from a previous export
-            [ -f "${pc}/${p##*/}" ] && continue
+            [ -e "${pc}/${p##*/}" ] && continue
             # can not reuse bitbake function here, this is basically
             # "repo_contains_package"
             package=$(find "${REPO_ISAR_DIR}"/"${DISTRO}" -name ${p##*/})
diff --git a/meta/classes/rootfs.bbclass b/meta/classes/rootfs.bbclass
index 786682d9..f274443d 100644
--- a/meta/classes/rootfs.bbclass
+++ b/meta/classes/rootfs.bbclass
@@ -308,7 +308,8 @@ rootfs_install_sstate_prepare() {
     # so we use some mount magic to prevent that
     mkdir -p ${WORKDIR}/mnt/rootfs
     sudo mount --bind ${WORKDIR}/rootfs ${WORKDIR}/mnt/rootfs -o ro
-    sudo tar -C ${WORKDIR}/mnt -cpSf rootfs.tar --one-file-system rootfs
+    lopts="--one-file-system --exclude-caches"
+    sudo tar -C ${WORKDIR}/mnt -cpSf rootfs.tar $lopts rootfs
     sudo umount ${WORKDIR}/mnt/rootfs
     sudo chown $(id -u):$(id -g) rootfs.tar
 }
diff --git a/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc b/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc
index cb0079ec..44019f95 100644
--- a/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc
+++ b/meta/recipes-core/isar-bootstrap/isar-bootstrap.inc
@@ -395,6 +395,10 @@ EOSUDO
 
     # Cleanup apt cache
     sudo -Es chroot "${ROOTFSDIR}" /usr/bin/apt-get -y clean
+
+    # Don't include apt cache into sstate cache by marking the directory
+    # with a CACHEDIR.TAG file with a special signature
+    sudo -Es sh -c "echo Signature: 8a477f597d28d172789f06886806bc55 > ${ROOTFSDIR}/var/cache/apt/archives/CACHEDIR.TAG"
 }
 
 addtask bootstrap before do_build after do_generate_keyrings
@@ -405,7 +409,8 @@ SSTATEPOSTINSTFUNCS += "bootstrap_sstate_finalize"
 
 bootstrap_sstate_prepare() {
     # this runs in SSTATE_BUILDDIR, which will be deleted automatically
-    sudo tar -C $(dirname "${ROOTFSDIR}") -cpSf bootstrap.tar --one-file-system $(basename "${ROOTFSDIR}")
+    lopts="--one-file-system --exclude-caches"
+    sudo tar -C $(dirname "${ROOTFSDIR}") -cpSf bootstrap.tar $lopts $(basename "${ROOTFSDIR}")
     sudo chown $(id -u):$(id -g) bootstrap.tar
 }
 
-- 
2.20.1