test-build: port dep cache, namespaced by image digest

1 files changed, 86 insertions, 0 deletions

diff --git a/.extras/test-build b/.extras/test-build
index a7e796e..1f7920c 100755
--- a/.extras/test-build
+++ b/.extras/test-build
@@ -286,6 +286,92 @@ apply_overrides_to_order() {
   RESOLVED_ORDER=("${keep[@]:-}")
 }
 
+# =============================================================================
+# Dependency cache. Layout: $CACHE_ROOT/<cat>/<prog>/<prog>-<ver>-...txz where
+# CACHE_ROOT = $PKG_CACHE/<image-digest> (set per run by resolve_cache_root).
+# Key is prog+version. --no-cache (USE_CACHE=0) or empty PKG_CACHE disables.
+# =============================================================================
+CACHE_ROOT=""   # set by resolve_cache_root once the image digest is known
+
+# True when the cache is usable this run.
+_cache_on() { [[ $USE_CACHE -eq 1 && -n "$PKG_CACHE" && -n "$CACHE_ROOT" ]]; }
+
+_cache_ver_of() {
+  local prog="$1" base="$2"
+  base="${base#"$prog"-}"
+  echo "${base%%-*}"
+}
+
+# cache_decision <cat> <prog> <version> -> cached | bump:OLD:NEW | new
+cache_decision() {
+  local cat="$1" prog="$2" version="$3"
+  _cache_on || { echo new; return; }
+  local dir="$CACHE_ROOT/$cat/$prog"
+  local f newest=""
+  for f in "$dir/$prog"-*.t?z; do
+    [[ -e "$f" ]] || continue
+    [[ -z "$newest" || "$f" -nt "$newest" ]] && newest="$f"
+  done
+  [[ -z "$newest" ]] && { echo new; return; }
+  local have; have="$(_cache_ver_of "$prog" "$(basename "$newest")")"
+  if [[ "$have" == "$version" ]]; then echo cached; else echo "bump:$have:$version"; fi
+}
+
+cache_path() {
+  local cat="$1" prog="$2" version="$3"
+  _cache_on || return
+  local dir="$CACHE_ROOT/$cat/$prog"
+  local f newest=""
+  for f in "$dir/$prog"-*.t?z; do
+    [[ -e "$f" ]] || continue
+    [[ -z "$newest" || "$f" -nt "$newest" ]] && newest="$f"
+  done
+  [[ -z "$newest" ]] && return
+  [[ "$(_cache_ver_of "$prog" "$(basename "$newest")")" == "$version" ]] && echo "$newest"
+}
+
+cache_store() {
+  local cat="$1" prog="$2" src="$3"
+  _cache_on || return
+  local dir="$CACHE_ROOT/$cat/$prog"
+  mkdir -p "$dir"
+  rm -f "$dir"/*.t?z
+  cp -a "$src" "$dir/"
+}
+
+cache_label() {
+  local dir="$1" is_target="$2"
+  local cat prog ver dec
+  cat="$(category_of "$dir")"; prog="$(basename "$dir")"; ver="$(version_of "$dir")"
+  dec="$(cache_decision "$cat" "$prog" "$ver")"
+  local label
+  case "$dec" in
+    cached)   label="cached ($ver)" ;;
+    bump:*)   label="rebuild: ${dec#bump:}"; label="${label/:/ -> }" ;;
+    *)        label="build (new)" ;;
+  esac
+  if [[ "$is_target" == "1" ]]; then
+    case "$dec" in
+      cached) label="build (cached $ver, rebuilt as target)" ;;
+    esac
+    echo "target, $label"
+  else
+    echo "$label"
+  fi
+}
+
+# Compute CACHE_ROOT from the image's digest. Falls back to the tag if the
+# digest cannot be read (still isolates per image reference).
+resolve_cache_root() {
+  [[ -z "$PKG_CACHE" ]] && { CACHE_ROOT=""; return; }
+  local digest
+  digest="$(docker image inspect --format '{{index .Id}}' "$ACTIVE_IMAGE" 2>/dev/null)"
+  [[ -z "$digest" ]] && digest="tag-${ACTIVE_IMAGE//[^a-zA-Z0-9._-]/_}"
+  digest="${digest//[^a-zA-Z0-9._-]/_}"
+  CACHE_ROOT="$PKG_CACHE/$digest"
+  mkdir -p "$CACHE_ROOT"
+}
+
 main() {
   parse_args "$@"
   init_color