Merge branch 'master' into better_base

containers/Dockerfile.centos7-GCC-9.3.0

@@ -1,5 +1,15 @@
 FROM easybuilders/base:centos7-eb4.2.1
-# install software & accompanying modules
+# CPU_ARCH is expected to be defined in the "docker build" command,
+# for example: docker build --build-arg CPU_ARCH=haswell
+ARG CPU_ARCH
+# make sure CPU_ARCH is defined
+RUN test -n "${CPU_ARCH}" || (echo "\$CPU_ARCH undefined, use 'docker build --build-arg CPU_ARCH=...'" && exit 1)
+# verify provided CPU_ARCH value, should match with what archspec produces
+RUN export HOST_CPU_ARCH=$(python3 -c 'import archspec.cpu; print(archspec.cpu.host())') && \
+  (test "${CPU_ARCH}" == "$HOST_CPU_ARCH" || (echo "Host CPU arch '${HOST_CPU_ARCH}' doesn't match specified CPU arch '${CPU_ARCH}'!" && exit 1))
+# use $CPU_ARCH to define label and set it as environment variable (to use in subsequent builds
+LABEL cpu_arch=${CPU_ARCH}
+ENV CPU_ARCH=${CPU_ARCH}
 # use /easybuild for everything that should persist in the container (software, modules and sources)
 # everything else goes in /scratch, which will be cleaned out
 RUN eb --prefix /scratch --installpath /easybuild GCC-9.3.0.eb --robot --trace \