perf: cache base image pull only, rebuild all our layers

ARG CACHE_BUST placed immediately after FROM so only the base image layer is served from GHA cache. All RUN/ENV/COPY layers are rebuilt every build via CACHE_BUST=$GITHUB_SHA. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-03-03 16:51:22 +00:00
parent d5338ab836
commit 01d5ebbdb8
3 changed files with 9 additions and 2 deletions
@@ -1,5 +1,8 @@
 FROM jlesage/baseimage-gui:ubuntu-22.04-v4

+# Bust cache for all layers below (base image pull is still cached)
+ARG CACHE_BUST
+
 # Set environment variables
 ENV APP_NAME="Dev Container" \
    KEEP_APP_RUNNING=1 \