Switch to scratch based libgit2 container image

This moves the `libgit2` compilation to the image, to ensure it
can be build on builders that aren't backed by AMD64.

The image is structured in such a way that e.g. running nightly
builds targeting a different Go version, or targeting a different
OS vendor would be possible in the future via build arguments.

Signed-off-by: Hidde Beydals <[email protected]>

.github/workflows/e2e.yaml

@@ -44,7 +44,7 @@ jobs:
             exit 1
           fi
       - name: Build container image
-        run: make docker-build IMG=test/source-controller TAG=latest
+        run: make docker-build IMG=test/source-controller TAG=latest BUILD_PLATFORMS=linux/amd64 BUILD_ARGS=--load
       - name: Load test image
         run: kind load docker-image test/source-controller:latest
       - name: Deploy controller

Dockerfile

@@ -1,6 +1,37 @@
-ARG BASE_IMG=ghcr.io/fluxcd/golang-with-libgit2
-ARG BASE_TAG=1.16.8-bullseye-libgit2-1.1.1-1
-FROM ${BASE_IMG}:${BASE_TAG} AS build
+ARG BASE_VARIANT=bullseye
+ARG GO_VERSION=1.16.8
+ARG XX_VERSION=1.0.0-rc.2
+
+ARG LIBGIT2_IMG=ghcr.io/fluxcd/golang-with-libgit2
+ARG LIBGIT2_TAG=libgit2-1.1.1
+
+FROM --platform=$BUILDPLATFORM tonistiigi/xx:${XX_VERSION} AS xx
+FROM ${LIBGIT2_IMG}:${LIBGIT2_TAG} as libgit2
+
+FROM --platform=$BUILDPLATFORM golang:${GO_VERSION}-${BASE_VARIANT} as gostable
+FROM --platform=$BUILDPLATFORM golang:1.17rc1-${BASE_VARIANT} AS golatest
+
+FROM gostable AS go-linux
+
+FROM go-${TARGETOS} AS build-base-bullseye
+
+# Copy the build utiltiies
+COPY --from=xx / /
+COPY --from=libgit2 /Makefile /libgit2/
+
+# Install the libgit2 build dependencies
+RUN make -C /libgit2 cmake
+
+ARG TARGETPLATFORM
+RUN make -C /libgit2 dependencies
+
+FROM build-base-${BASE_VARIANT} as libgit2-bullseye
+
+# Compile and install libgit2
+ARG TARGETPLATFORM
+RUN FLAGS=$(xx-clang --print-cmake-defines) make -C /libgit2 libgit2
+
+FROM libgit2-${BASE_VARIANT} as build-bullseye
 
 # Configure workspace
 WORKDIR /workspace
@@ -27,7 +58,16 @@ ARG TARGETPLATFORM
 RUN xx-go build -o source-controller -trimpath \
     main.go
 
-FROM debian:bullseye-slim as controller
+FROM build-${BASE_VARIANT} as prepare-bullseye
+
+# Move libgit2 lib to generic and predictable location
+ARG TARGETPLATFORM
+RUN mkdir -p /libgit2/lib/ \
+    && cp -d /usr/lib/$(xx-info triple)/libgit2.so* /libgit2/lib/
+
+FROM prepare-${BASE_VARIANT} as build
+
+FROM debian:${BASE_VARIANT}-slim as controller
 
 # Link repo to the GitHub Container Registry image
 LABEL org.opencontainers.image.source="https://github.com/fluxcd/source-controller"

Makefile

@@ -3,14 +3,14 @@ IMG ?= fluxcd/source-controller
 TAG ?= latest
 
 # Base image used to build the Go binary
-BASE_IMG ?= ghcr.io/fluxcd/golang-with-libgit2
-BASE_TAG ?= 1.16.8-bullseye-libgit2-1.1.1-1
+LIBGIT2_IMG ?= ghcr.io/fluxcd/golang-with-libgit2
+LIBGIT2_TAG ?= libgit2-1.1.1
 
 # Allows for defining additional Docker buildx arguments,
 # e.g. '--push'.
-BUILDX_ARGS ?=
+BUILD_ARGS ?=
 # Architectures to build images for
-BUILDX_PLATFORMS ?= linux/amd64,linux/arm64,linux/arm/v7
+BUILD_PLATFORMS ?= linux/amd64,linux/arm64,linux/arm/v7
 
 # Produce CRDs that work back to Kubernetes 1.16
 CRD_OPTIONS ?= crd:crdVersions=v1
@@ -110,18 +110,12 @@ generate: controller-gen  ## Generate API code
 	cd api; $(CONTROLLER_GEN) object:headerFile="../hack/boilerplate.go.txt" paths="./..."
 
 docker-build:  ## Build the Docker image
-	docker build \
-		--build-arg BASE_IMG=$(BASE_IMG) \
-		--build-arg BASE_TAG=$(BASE_TAG) \
-		-t $(IMG):$(TAG) .
-
-docker-buildx:  ## Build the cross-platform Docker image
 	docker buildx build \
-		--build-arg BASE_IMG=$(BASE_IMG) \
-		--build-arg BASE_TAG=$(BASE_TAG) \
-		--platform=$(BUILDX_PLATFORMS) \
+		--build-arg LIBGIT2_IMG=$(LIBGIT2_IMG) \
+		--build-arg LIBGIT2_TAG=$(LIBGIT2_TAG) \
+		--platform=$(BUILD_PLATFORMS) \
 		-t $(IMG):$(TAG) \
-		$(BUILDX_ARGS) .
+		$(BUILD_ARGS) .
 
 docker-push:  ## Push Docker image
 	docker push $(IMG):$(TAG)
@@ -178,7 +172,7 @@ ifeq (1, $(LIBGIT2_FORCE))
 	@{ \
 	set -e; \
 	mkdir -p $(LIBGIT2_PATH); \
-	docker cp $(shell docker create --rm $(BASE_IMG):$(BASE_TAG)):/libgit2/Makefile $(LIBGIT2_PATH); \
+	docker cp $(shell docker create --rm $(LIBGIT2_IMG):$(LIBGIT2_TAG)):/Makefile $(LIBGIT2_PATH); \
 	INSTALL_PREFIX=$(LIBGIT2_PATH) make -C $(LIBGIT2_PATH); \
 	}
 endif