Dockerfile to build a buildroot-based cross-compile environment for v…

…zlogger

vzlogger_buildroot_builder.Dockerfile

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+# Dockerfile to build a buildroot-based cross-compile environment for vzlogger
+
+# the OS version used here is largely irrelevant,
+# as buildroot compiles it's own toolchain
+FROM	debian:buster as builder
+
+LABEL	maintainer="Thorben T. <r00t@constancy.org>"
+
+# don't inherit upstream labels
+LABEL	org.label-schema.build-date=null
+LABEL	org.label-schema.license=null
+LABEL	org.label-schema.name=null
+LABEL	org.label-schema.schema-version=null
+LABEL	org.label-schema.vendor=null
+
+# update host-OS and install required host packages
+# (we should optimize by using a base image that already contains this.)
+RUN	set -xe ; \
+	apt-get update ; \
+	apt-get -y --force-yes upgrade ; \
+	apt-get -y --force-yes install \
+		# https://buildroot.org/downloads/manual/manual.html#requirement
+		make gcc g++ \
+		patch \
+		bzip2 \
+		cpio \
+		unzip \
+		rsync \
+		file \
+		bc \
+		#libncurses-dev \
+		wget \
+		git \
+	; \
+	apt-get purge ; \
+	rm -fr /var/lib/apt/lists
+
+WORKDIR	/buildroot
+
+RUN \
+	set -xe ; \
+	\
+	# download and unpack buildroot
+	wget --progress=dot:mega https://buildroot.org/downloads/buildroot-2021.02.1.tar.bz2 ; \
+	tar xj --strip-components=1 <buildroot-2021.02.1.tar.bz2 ; \
+	rm buildroot-2021.02.1.tar.bz2 ; \
+	\
+	# create vzlogger package configuration
+	mkdir -p package/vzlogger ; \
+	echo 'config BR2_PACKAGE_VZLOGGER' >>package/vzlogger/Config.in ; \
+	echo 'bool "vzlogger"' >>package/vzlogger/Config.in ; \
+	echo 'help' >>package/vzlogger/Config.in ; \
+	echo '    vzlogger' >>package/vzlogger/Config.in ; \
+	# have the package pull in vzlogger's deps
+	echo 'select BR2_TOOLCHAIN_BUILDROOT_CXX' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_UTIL_LINUX' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_UTIL_LINUX_LIBUUID' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_OPENSSL' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_ZLIB' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_LIBZLIB' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_LIBOPENSSL' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_LIBCURL' >>package/vzlogger/Config.in ; \
+	echo 'select BR2_PACKAGE_LIBCURL_OPENSSL' >>package/vzlogger/Config.in ; \
+	\
+	echo 'VZLOGGER_SITE = https://github.com/volkszaehler/vzlogger.git' >>package/vzlogger/vzlogger.mk ; \
+	echo 'VZLOGGER_SITE_METHOD = git' >>package/vzlogger/vzlogger.mk ; \
+	echo 'VZLOGGER_GIT_SUBMODULES = NO' >>package/vzlogger/vzlogger.mk ; \
+	# this is a hack, it only works if we delete the cache in dl/vzlogger/git before building,
+	echo 'VZLOGGER_VERSION = origin/master' >>package/vzlogger/vzlogger.mk ; \
+	echo 'VZLOGGER_DEPENDENCIES = libgcrypt libunistring json-c libmicrohttpd util-linux libcurl' >>package/vzlogger/vzlogger.mk ; \
+	echo 'VZLOGGER_CONF_OPTS = -DENABLE_SML=Off -DENABLE_OMS=Off' >>package/vzlogger/vzlogger.mk ; \
+	echo '$(eval $(cmake-package))' >>package/vzlogger/vzlogger.mk ; \
+	\
+	# add vzlogger package to buildroot
+	sed -i '1a        source "package/vzlogger/Config.in"' package/Config.in ; \
+	\
+	# create a minimal buildroot system configuration
+	head --lines 6 configs/raspberrypi2_defconfig >.config ; \
+	# WCHAR support is needed at least for libunistring
+	echo BR2_TOOLCHAIN_BUILDROOT_WCHAR=y >>.config ; \
+	# we can disable these as we never build an OS image
+	echo BR2_INIT_NONE=y >>.config ; \
+	echo BR2_SYSTEM_BIN_SH_NONE=y >>.config ; \
+	echo "# BR2_TARGET_ROOTFS_TAR is not set" >>.config ; \
+	\
+	# enable our vzlogger package
+	echo BR2_PACKAGE_VZLOGGER=y >>.config ; \
+	\
+	# calculate full config based on above settings
+	make olddefconfig ; \
+	\
+	# sanity check to ensure config was applied correcly
+	grep -q BR2_PACKAGE_VZLOGGER=y .config ; \
+	grep -q BR2_TOOLCHAIN_BUILDROOT_WCHAR=y .config
+
+# install a helper for neatly formatted build output
+RUN \
+	set -xe ; \
+	( \
+	echo '#!/bin/bash' ;\
+	echo 'f=/tmp/br_make_wrapper.$$' ; \
+	echo 'trap "rm -f $f" EXIT' ; \
+	echo 'echo "=== make $@ ===" >&2' ; \
+	echo 'make "$@" &> >(tee "$f" | grep --line-buffered ">>>") || {' ; \
+        echo '    e=$?' ; \
+        echo '    cat "$f" >&2' ; \
+        echo '    exit $e' ; \
+	echo '}' ; \
+	) >br_make_wrapper.bash ; \
+	chmod +x br_make_wrapper.bash
+
+# download required sources
+RUN	./br_make_wrapper.bash source
+
+# build toolchain
+RUN	./br_make_wrapper.bash toolchain
+
+# WIP: we could package the toolchain, but seems pointless with docker
+#RUN	./br_make_wrapper.bash sdk
+#RUN	ls -l buildroot/output/images/*_sdk-buildroot.tar.gz
+
+# build deps of vzlogger
+# (this will also download vzlogger source, which we delete again)
+RUN	./br_make_wrapper.bash vzlogger-depends && rm -fr dl/vzlogger output/build/vzlogger-*
+
+# this stuff is not needed anymore
+# (but we need to keep the .stamp files inside the directories)
+RUN	rm -fr dl output/build/*/* && du -chx . | sort -h | tail -n 30 ; ( du -sh / 2>/dev/null || true )
+
+# ensure build works
+#RUN \
+#	set -xe ; \
+#	./br_make_wrapper.bash vzlogger-build ;\
+#	file output/build/vzlogger-*/src/vzlogger ; \
+#	ls -l output/build/vzlogger-*/src/vzlogger ; \
+#	rm -fr dl/vzlogger output/build/vzlogger-*
+
+FROM	debian:buster
+
+COPY	--from=builder /buildroot /buildroot
+
+WORKDIR	/buildroot
+
+# disable buildroot's dependency check
+# we install a minimal set of host-software that works for building vzlogger,
+# other buildroot operations will be broken, but we don't need them
+RUN	ln -sf /bin/true support/dependencies/dependencies.sh
+
+# docker-COPY-ing the buildroot tree clobbers some timestamp,
+# making buildroot want to run `make syncconfig`, which would requite gcc.
+# this prevents this
+RUN	touch output/build/buildroot-config/auto.conf
+
+RUN	set -xe ; \
+	apt-get update ; \
+#	apt-get -y --force-yes upgrade ; \
+	apt-get -y --force-yes install \
+		# these are required to run a vzlogger build
+		make \
+		rsync \
+		git \
+		# only for showing the type of the binary below
+		file \
+	; \
+	apt-get purge ; \
+	rm -fr /var/lib/apt/lists
+
+# ensure build works (also usage example for final image)
+RUN \
+	set -xe ; \
+	./br_make_wrapper.bash vzlogger-build ;\
+	file output/build/vzlogger-*/src/vzlogger ; \
+	ls -l output/build/vzlogger-*/src/vzlogger ; \
+	rm -fr dl/vzlogger output/build/vzlogger-*
+