[RFC PATCH 1/3] meta/isar-bootstrap-helper+dpkg.bbclass: bind mount /var/cache/apt/archives

[claudius.heine.ext@siemens.com]

From: Claudius Heine <ch@denx.de>

Bind mount the /var/cache/apt/archives directory to the original
isar-bootstrap root file system, so that the cache is shared between all
images based on it. Central package cache is the first step of
reproducible builds.

This should allow faster execution of subsequent builds.

Signed-off-by: Claudius Heine <ch@denx.de>
---
 meta/classes/dpkg.bbclass                  | 5 +++++
 meta/classes/isar-bootstrap-helper.bbclass | 9 ++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/meta/classes/dpkg.bbclass b/meta/classes/dpkg.bbclass
index c8d4ac5..5422b9a 100644
--- a/meta/classes/dpkg.bbclass
+++ b/meta/classes/dpkg.bbclass
@@ -5,6 +5,11 @@ inherit dpkg-base
 
 # Build package from sources using build script
 dpkg_runbuild() {
+    DEBOOTSTRAP_DIR="${DEPLOY_DIR_IMAGE}/isar-bootstrap-${DISTRO}-${DISTRO_ARCH}/"
     E="${@ bb.utils.export_proxies(d)}"
+    mountpoint -q "${BUILDCHROOT_DIR}/var/cache/apt/archives" || \
+        sudo mount --bind \
+            "$DEBOOTSTRAP_DIR/var/cache/apt/archives" \
+            "${BUILDCHROOT_DIR}/var/cache/apt/archives"
     sudo -E chroot ${BUILDCHROOT_DIR} /build.sh ${PP}/${PPS}
 }
diff --git a/meta/classes/isar-bootstrap-helper.bbclass b/meta/classes/isar-bootstrap-helper.bbclass
index 76e20f6..fa68a9f 100644
--- a/meta/classes/isar-bootstrap-helper.bbclass
+++ b/meta/classes/isar-bootstrap-helper.bbclass
@@ -17,8 +17,10 @@ setup_root_file_system() {
               -o Debug::pkgProblemResolver=yes"
     CLEAN_FILES="${ROOTFSDIR}/etc/hostname ${ROOTFSDIR}/etc/resolv.conf"
 
+    DEBOOTSTRAP_DIR="${DEPLOY_DIR_IMAGE}/isar-bootstrap-${DISTRO}-${DISTRO_ARCH}/"
+
     sudo cp -Trpfx \
-        "${DEPLOY_DIR_IMAGE}/isar-bootstrap-${DISTRO}-${DISTRO_ARCH}/" \
+        "$DEBOOTSTRAP_DIR" \
         "$ROOTFSDIR"
 
     echo "deb file:///isar-apt ${DEBDISTRONAME} main" | \
@@ -27,6 +29,10 @@ setup_root_file_system() {
     echo "Package: *\nPin: release n=${DEBDISTRONAME}\nPin-Priority: 1000" | \
         sudo tee "$ROOTFSDIR/etc/apt/preferences.d/isar" >/dev/null
 
+    sudo mount --bind \
+        "$DEBOOTSTRAP_DIR/var/cache/apt/archives" \
+        "$ROOTFSDIR/var/cache/apt/archives"
+
     sudo mount --bind ${DEPLOY_DIR_APT}/${DISTRO} $ROOTFSDIR/isar-apt
     sudo mount -t devtmpfs -o mode=0755,nosuid devtmpfs $ROOTFSDIR/dev
     sudo mount -t proc none $ROOTFSDIR/proc
@@ -55,6 +61,7 @@ setup_root_file_system() {
             /usr/bin/apt-get purge -y ${IMAGE_CFG_PACKAGE}
     fi
     if [ "clean" = ${CLEAN} ]; then
+        sudo umount -l "$ROOTFSDIR/var/cache/apt/archives"
         sudo -E chroot "$ROOTFSDIR" \
             /usr/bin/apt-get autoremove --purge -y
         sudo -E chroot "$ROOTFSDIR" \
-- 
2.17.0