reorganize build script

gemcompiler.sh

@@ -1,16 +1,30 @@
 #!/bin/sh
+set -e
 
-export PATH=usr/lib/ccache/bin:$PATH
-PLATFORM=`ruby -e "puts RbConfig::CONFIG['arch']"`
+# CCache
+export PATH=/usr/lib/ccache/bin:$PATH
 
-cd /srv/gems
+source /etc/os-release
+alpine_version="${VERSION_ID%.*}"
+platform="`ruby -e "puts RbConfig::CONFIG['arch']"`"
+gems_dir="${GEMS_DIR:-/srv/gems}"
+cache_dir="${gems_dir}/cache"
+release_dir="${RELEASE_DIR:-${gems_dir}/${alpine_version}}"
 
-test -f ${GEM}-${VERSION}.gem \
-  || gem fetch --source=https://${SUTTY} --platform=ruby \
-               --version ${VERSION} ${GEM}
+mkdir -p "${cache_dir}" "${release_dir}"
 
-test -f ${GEM}-${VERSION}-${PLATFORM}.gem \
-  || gem compile -V --prune --strip "strip --strip-unneeded" ${GEM}-${VERSION}.gem
+gem="${GEM}-${VERSION}.gem"
+release="${GEM}-${VERSION}-${platform}.gem"
 
-gem inabox -o ${GEM}-${VERSION}-${PLATFORM}.gem \
-  --host https://${HTTP_BASIC_USER}:${HTTP_BASIC_PASSWORD}@gems.${SUTTY}
+if ! test -f "${cache_dir}/${gem}" ; then
+  cd "${cache_dir}"
+  gem fetch --source=https://gems.${SUTTY} --platform=ruby --version ${VERSION} ${GEM}
+fi
+
+if ! test -f "${release_dir}/${release}"; then
+  cd "${release_dir}"
+  gem compile -V --prune --strip "strip --strip-unneeded" "${cache_dir}/${gem}"
+fi
+
+test -f "${release_dir}/${release}" \
+  && gem inabox -o "${release_dir}/${release}" --host https://${HTTP_BASIC_USER}:${HTTP_BASIC_PASSWORD}@gems.${SUTTY}