use shared folders (downloads and sstate) in yocto build

base-image/Dockerfile

@@ -21,18 +21,14 @@ RUN apt-get update \
 		sudo \
 	&& rm -rf /var/lib/apt/lists/*
 
-RUN useradd -m builder \
-	&& mkdir /dest \
-	&& chown builder /dest
-
 RUN locale-gen en_US.UTF-8
 ENV LANG en_US.UTF-8
 ENV LC_ALL en_US.UTF-8
 
-USER builder
-
 ENV SOURCE_DIR /source
 ENV DEST_DIR /dest
+ENV SHARED_DOWNLOADS /yocto/shared-downloads
+ENV SHARED_SSTATE /yocto/shared-sstate
 
 COPY build.sh /
 CMD bash -ex build.sh

base-image/automation/jenkins-build.sh

@@ -4,6 +4,8 @@ set -o errexit
 set -o pipefail
 
 date=$(date +'%Y%m%d' -u)
+JENKINS_PERSISTENT_WORKDIR=${1:-/var/lib/yocto}
+DL_DIR="$JENKINS_PERSISTENT_WORKDIR/shared-downloads"
 # MACHINE_LIST: generic-x86-64 generic-x86 generic-armv6 generic-armv7hf generic-armv5
 # MACHINE_LIST should be set in jenkins config
 
@@ -30,9 +32,18 @@ for machine in $MACHINE_LIST; do
 		REPO='resin/armel-supervisor-base'
 	;;
 	esac
+	SSTATE_DIR="$JENKINS_PERSISTENT_WORKDIR/$machine/sstate"
+	# Make sure shared directories are in place
+	mkdir -p $DL_DIR
+	mkdir -p $SSTATE_DIR
+
 	docker run --rm \
 		-e TARGET_MACHINE=$machine \
+		-e BUILDER_UID=$(id -u) \
+		-e BUILDER_GID=$(id -g) \
 		-v `pwd`:/source \
+		-v $DL_DIR:/yocto/shared-downloads \
+		-v $SSTATE_DIR:/yocto/shared-sstate \
 		-v `pwd`/dest:/dest \
 		supervisor-base-builder
 	if [ -f dest/rootfs.tar.gz ]; then

base-image/build.sh

@@ -3,10 +3,11 @@
 set -o errexit
 
 BUILD_DIR='/home/builder/tmp'
-
-mkdir -p $BUILD_DIR
-cp -r $SOURCE_DIR/* $BUILD_DIR/
-cd $BUILD_DIR
-source oe-core/oe-init-build-env build bitbake
-MACHINE=$TARGET_MACHINE bitbake core-image-minimal
-cp --dereference tmp-glibc/deploy/images/$TARGET_MACHINE/core-image-minimal-$TARGET_MACHINE.tar.gz  $DEST_DIR/rootfs.tar.gz
+groupadd -g $BUILDER_GID builder
+useradd -m -u $BUILDER_UID -g $BUILDER_GID builder
+sudo -H -u builder /bin/bash -c "mkdir -p $BUILD_DIR \
+	&& cp -r $SOURCE_DIR/* $BUILD_DIR/ \
+	&& cd $BUILD_DIR \
+	&& source oe-core/oe-init-build-env build bitbake \
+	&& DL_DIR=$SHARED_DOWNLOADS SSTATE_DIR=$SHARED_SSTATE MACHINE=$TARGET_MACHINE $BUILD_DIR/bitbake/bin/bitbake core-image-minimal"
+cp --dereference $BUILD_DIR/build/tmp-glibc/deploy/images/$TARGET_MACHINE/core-image-minimal-$TARGET_MACHINE.tar.gz  $DEST_DIR/rootfs.tar.gz