Improve performance by using uncompressed snapshot and priming system (#27)

* .gitignore
  - Ignore all ./distro

* build-files/build-image.sh
  - Install additional packages (e.g. gcc)

* setup-build-env.sh
  - Create snapshot
  - Publish uncompressed snapshot
  - Prime filesystem by launching newly published image

Author: nealef

.gitignore

@@ -1,3 +1,4 @@
+distro/
 distro/*.tar.*
 distro/rootfs_almalinux_*
 distro/rootfs.squashfs

build-files/build-image.sh

@@ -15,7 +15,8 @@ msg() {
 update_fresh_container() {
     header "Upgrading and installing packages"
     sudo DEBIAN_FRONTEND=noninteractive apt-get -qq update -y >/dev/null
-    sudo DEBIAN_FRONTEND=noninteractive apt-get -qq install dotnet-sdk-8.0 -y >/dev/null
+    sudo DEBIAN_FRONTEND=noninteractive apt-get -qq install dotnet-sdk-8.0 make \
+        gcc g++ autoconf automake m4 libtool -y >/dev/null
 
     if [ $? -ne 0 ]; then
         exit 32

setup-build-env.sh

@@ -92,10 +92,17 @@ build_image_in_container() {
       lxc image delete ${IMAGE_ALIAS} 2>/dev/null
 
       msg "Runner build complete. Creating image snapshot."
-      lxc publish "${BUILD_CONTAINER}" -f --alias "${IMAGE_ALIAS}" description="GitHub Actions ${OS_NAME} ${OS_VERSION} Runner for ${ARCH}"
+      lxc snapshot "${BUILD_CONTAINER}" "build-snapshot"
+      lxc publish "${BUILD_CONTAINER}/build-snapshot" -f --alias "${IMAGE_ALIAS}" \
+            --compression none \
+            description="GitHub Actions ${OS_NAME} ${OS_VERSION} Runner for ${ARCH}"
 
       msg "Export the image to ${EXPORT} for use elsewhere"
       lxc image export "${IMAGE_ALIAS}" ${EXPORT}
+
+      msg "Priming the filesystem by launching the newly built container"
+      lxc launch "${IMAGE_ALIAS}" "primer"
+      lxc rm -f primer
   else
       msg "Build process failed with RC: $? - review log to determine cause of failure" >&2
   fi