ioc: reorder stages to improve portability.

Docker without BuildKit and Podman fail when an unused stage fails
before the defined target. As static build stage from the IOC image is
known to possibly fail, we now define all static build stages last.

Arguments have now been defined only in stages they are used. This is
required to support non-BuildKit builds, as they aren't inherited.

Dockerfile

@@ -3,9 +3,7 @@ ARG DEBIAN_VERSION=11.7
 
 FROM ghcr.io/cnpem/lnls-debian-11-epics-7:${BUILD_STAGE_VERSION} AS build-stage
 
-ARG JOBS=1
 ARG REPONAME
-ARG RUNDIR
 ARG BUILD_PACKAGES
 
 RUN if [ -n "$BUILD_PACKAGES" ]; then apt update && apt install $BUILD_PACKAGES; fi
@@ -17,21 +15,8 @@ COPY . .
 RUN cp /opt/epics/RELEASE configure/RELEASE
 
 
-FROM build-stage AS static-build
-
-RUN echo STATIC_BUILD=YES >> configure/CONFIG_SITE.local
-
-RUN make distclean && make -j ${JOBS} && make clean && make -C ${RUNDIR}
-
-
-FROM build-stage AS dynamic-build
-
-RUN make distclean && make -j ${JOBS} && make clean && make -C ${RUNDIR}
-
-
 FROM debian:${DEBIAN_VERSION}-slim as base
 
-ARG REPONAME
 ARG RUNDIR
 ARG ENTRYPOINT=/bin/bash
 ARG RUNTIME_PACKAGES
@@ -53,11 +38,31 @@ RUN ln -s ${ENTRYPOINT} ./entrypoint
 ENTRYPOINT ["./entrypoint"]
 
 
+FROM build-stage AS dynamic-build
+
+ARG JOBS=1
+ARG RUNDIR
+
+RUN make distclean && make -j ${JOBS} && make clean && make -C ${RUNDIR}
+
+
 FROM base AS dynamic-link
 
 COPY --from=dynamic-build /opt /opt
 
 
+FROM build-stage AS static-build
+
+ARG JOBS=1
+ARG RUNDIR
+
+RUN echo STATIC_BUILD=YES >> configure/CONFIG_SITE.local
+
+RUN make distclean && make -j ${JOBS} && make clean && make -C ${RUNDIR}
+
+
 FROM base AS static-link
 
+ARG REPONAME
+
 COPY --from=static-build /opt/${REPONAME} /opt/${REPONAME}

README.md

@@ -46,10 +46,10 @@ you **need** to link them dynamically, you must define the build target as
 dependencies will also be copied.
 
 Some Docker versions don't use
-[BuildKit](https://docs.docker.com/build/buildkit/) by default, and it is
-necessary to enable it, for instance, by exporting `DOCKER_BUILDKIT=1` when
-building the IOC image, because the classic builder goes through all stages
-even when they are not needed or are known to fail.
+[BuildKit](https://docs.docker.com/build/buildkit/) by default, and it can be
+more efficient to enable it, for instance, by exporting `DOCKER_BUILDKIT=1`
+when building the IOC image, because the classic builder goes through all
+stages even when they are not needed.
 
 Additional build and runtime packages to be installed can be listed in `args`,
 under the `BUILD_PACKAGES` and `RUNTIME_PACKAGES` keys, respectively. It is not