feat: install most dependencies in cacheable layer, before adding main

Instead of requiring the whole stack to be reinstalled whenever a specific version (e.g. main) causes a cache fail, this aims to have stable default version with a second-stage installation of the potentially-modified versions of eicrecon and juggler. This should allow all builds to cache the first installation in virtually all cases, leading to faster builds.

containers/jug/dev.Dockerfile

@@ -129,13 +129,9 @@ EOF
 ## ========================================================================================
 FROM spack as builder
 
-## Setup our custom environment (secret mount for write-enabled mirror)
+## 1. Setup our default environment (secret mount for write-enabled mirror)
 COPY --from=spack-environment . /opt/spack-environment/
 ARG ENV=dev
-ARG JUGGLER_VERSION="main"
-ADD https://eicweb.phy.anl.gov/api/v4/projects/EIC%2Fjuggler/repository/tree?ref=${JUGGLER_VERSION} /tmp/juggler.json
-ARG EICRECON_VERSION="main"
-ADD https://api.github.com/repos/eic/eicrecon/commits/${EICRECON_VERSION} /tmp/eicrecon.json
 ENV SPACK_ENV=/opt/spack-environment/${ENV}
 RUN --mount=type=cache,target=/ccache,id=${TARGETPLATFORM}              \
     --mount=type=cache,target=/var/cache/spack                          \
@@ -146,8 +142,32 @@ export CCACHE_DIR=/ccache
 spack buildcache update-index local
 spack buildcache update-index eics3rw
 spack env activate --dir ${SPACK_ENV}
-spack add juggler@git.${JUGGLER_VERSION}
-spack add eicrecon@git.${EICRECON_VERSION}
+spack concretize --fresh --force --quiet
+make --jobs ${jobs} --keep-going --directory /opt/spack-environment SPACK_ENV=${SPACK_ENV} BUILDCACHE_MIRROR="local eics3rw"
+ccache --show-stats
+ccache --zero-stats
+EOF
+
+## 2. Setup our environment with custom versions (on top of cached layer)
+ARG JUGGLER_VERSION=""
+ARG EICRECON_VERSION=""
+ADD https://eicweb.phy.anl.gov/api/v4/projects/EIC%2Fjuggler/repository/tree?ref=${JUGGLER_VERSION} /tmp/juggler.json
+ADD https://api.github.com/repos/eic/eicrecon/commits/${EICRECON_VERSION} /tmp/eicrecon.json
+RUN --mount=type=cache,target=/ccache,id=${TARGETPLATFORM}              \
+    --mount=type=cache,target=/var/cache/spack                          \
+    --mount=type=secret,id=mirrors,target=/opt/spack/etc/spack/mirrors.yaml \
+    <<EOF
+source $SPACK_ROOT/share/spack/setup-env.sh
+export CCACHE_DIR=/ccache
+spack buildcache update-index local
+spack buildcache update-index eics3rw
+spack env activate --dir ${SPACK_ENV}
+if [ -n ${JUGGLER_VERSION} ] ; then
+  spack config add "packages:juggler::require:['@git.${JUGGLER_VERSION}']"
+fi
+if [ -n ${EICRECON_VERSION} ] ; then
+  spack config add "packages:eicrecon::require:['@git.${EICRECON_VERSION}']"
+fi
 spack concretize --fresh --force --quiet
 make --jobs ${jobs} --keep-going --directory /opt/spack-environment SPACK_ENV=${SPACK_ENV} BUILDCACHE_MIRROR="local eics3rw"
 ccache --show-stats