ci: forward SKIP_CAPACITY into docker builds invoking Skip toolchain

Dockerfile

@@ -11,6 +11,12 @@ RUN --mount=type=bind,source=./bin/apt-install.sh,target=/tmp/apt-install.sh \
 ENV CC=clang
 ENV CXX=clang++
 
+# Override at build time with --build-arg SKIP_CAPACITY=<value> to fit the
+# build host's memory budget. Empty (the default) preserves the runtime's
+# own 16 GB default for local dev builds.
+ARG SKIP_CAPACITY=
+ENV SKIP_CAPACITY=$SKIP_CAPACITY
+
 FROM skiplang-base AS bootstrap
 
 ARG STAGE=0

bin/docker_build.sh

@@ -22,6 +22,10 @@
 # Environment variables:
 #   STAGE              Compiler bootstrap stage (default: 0). Passed as STAGE
 #                      build arg to the root Dockerfile (skiplang/skip targets).
+#   SKIP_CAPACITY      If set, forwarded as SKIP_CAPACITY build arg to targets
+#                      that invoke the Skip toolchain at build time, capping
+#                      the runtime's mmap reservation. Required on hosts that
+#                      enforce virtual memory limits (e.g. gen2 CI builders).
 #   DOCKER_DEFAULT_ARCH  Default platform(s) when --arch is not given.
 #                        Supports same shorthands as --arch.
 #
@@ -198,6 +202,18 @@ if [[ -n "${STAGE:-}" ]]; then
     BAKE_ARGS+=(--set "skiplang.args.STAGE=$STAGE" --set "skip.args.STAGE=$STAGE")
 fi
 
+# Forward SKIP_CAPACITY to targets that invoke the Skip toolchain at build
+# time. Required on memory-constrained hosts (e.g. gen2 CircleCI builders)
+# where the runtime's 16 GB default mmap would fail.
+if [[ -n "${SKIP_CAPACITY:-}" ]]; then
+    BAKE_ARGS+=(
+        --set "skiplang.args.SKIP_CAPACITY=$SKIP_CAPACITY"
+        --set "skip.args.SKIP_CAPACITY=$SKIP_CAPACITY"
+        --set "skiplang-bin-builder.args.SKIP_CAPACITY=$SKIP_CAPACITY"
+        --set "skipruntime.args.SKIP_CAPACITY=$SKIP_CAPACITY"
+    )
+fi
+
 # Determine which bake targets to build
 BAKE_TARGETS=()
 

skiplang/Dockerfile

@@ -33,6 +33,12 @@ RUN --mount=type=cache,id=apt-cache-$TARGETARCH,target=/var/cache/apt,sharing=lo
 ENV CC=clang
 ENV CXX=clang++
 
+# Override at build time with --build-arg SKIP_CAPACITY=<value> to fit the
+# build host's memory budget. Empty (the default) preserves the runtime's
+# own 16 GB default for local dev builds.
+ARG SKIP_CAPACITY=
+ENV SKIP_CAPACITY=$SKIP_CAPACITY
+
 FROM base AS skiplang
 
 COPY ./skiplang /work/skiplang

skipruntime-ts/Dockerfile

@@ -3,6 +3,12 @@
 
 FROM skiplabs/skiplang-bin-builder AS build
 
+# Override at build time with --build-arg SKIP_CAPACITY=<value> to fit the
+# build host's memory budget. Empty (the default) preserves the runtime's
+# own 16 GB default for local dev builds.
+ARG SKIP_CAPACITY=
+ENV SKIP_CAPACITY=$SKIP_CAPACITY
+
 COPY ./skiplang /work/skiplang
 COPY ./skipruntime-ts /work/skipruntime-ts
 

skipruntime-ts/tests/native_addon/run.sh

@@ -5,5 +5,5 @@ set -euo pipefail
 # build, run, and remove the test container
 TEMP_FILE=$(mktemp)
 docker build --iidfile "$TEMP_FILE" .
-docker run --rm "$(cat "$TEMP_FILE")"
+docker run --rm -e SKIP_CAPACITY "$(cat "$TEMP_FILE")"
 rm "$TEMP_FILE"

skipruntime-ts/tests/native_addon_unreleased/run.sh

@@ -34,6 +34,6 @@ for arch in ${ARCH//,/ }; do
     echo "Testing linux/$arch..."
     TEMP_FILE=$(mktemp)
     docker build --platform="linux/$arch" --iidfile "$TEMP_FILE" .
-    docker run --rm "$(cat "$TEMP_FILE")"
+    docker run --rm -e SKIP_CAPACITY "$(cat "$TEMP_FILE")"
     rm "$TEMP_FILE"
 done