Cache Spack for GH Actions (#1619)

- make spack ci run use arbor version information
- Cache Spack for GH Actions

.github/workflows/spack.yml

@@ -3,6 +3,8 @@ name: Spack
 on:
   push:
     branches: [ master ]
+  pull_request:
+    branches: [ master ]
 
 jobs:
   build:
@@ -16,5 +18,13 @@ jobs:
         uses: actions/checkout@v2
         with:
             path: arbor
+
+      - name: Spack cache
+        uses: actions/cache@v2
+        with:
+          path: ~/.spack-cache
+          key: cache-${{ github.sha }}
+          restore-keys: cache-
+
       - name: Build Arbor's Spack package against the develop branch
         run: arbor/scripts/build_spack_package.sh arbor develop

scripts/build_spack_package.sh

@@ -46,12 +46,20 @@ case $SPACK_VERSION in
         echo "SPACK_VERSION" must be \"latest_release\" or \"develop\"
         exit 1
 esac
+
+mkdir ~/.spack
+cp $ARBOR_DIR/spack/config.yaml ~/.spack
+
 source $SPACK_DIR/share/spack/setup-env.sh
 spack repo create $SPACK_CUSTOM_REPO
 
 mkdir -p $SPACK_CUSTOM_REPO/packages/arbor
 spack repo add $SPACK_CUSTOM_REPO
 
+# to make use of the cached installations
+spack reindex
+
 cp $ARBOR_DIR/spack/package.py $SPACK_CUSTOM_REPO/packages/arbor
 cd $ARBOR_DIR
-spack dev-build arbor@with-package-from-repo
+ARBOR_VERSION=$(cat "$ARBOR_DIR/VERSION")
+spack dev-build arbor@${ARBOR_VERSION}

spack/config.yaml

+config:
+  source_cache: ~/.spack-cache/source_cache
+  misc_cache: ~/.spack-cache/misc_cache
+  test_cache: ~/.spack-cache/test_cache
+  install_tree:
+    root: ~/.spack-cache/install