Remove MUSL and enable threadless libgit2 support

Use of MUSL was a temporary solution to mitigate cross-platform
issues while building openssl and libssh2. Since Unmanaged transport has
been deprecated, openssl and libssh2 dependencies are no longer required
and by extension MUSL.

Enables libgit2 threadless support and provides a regression assurance
for fluxcd#339.

Signed-off-by: Paulo Gomes <[email protected]>

Dockerfile

@@ -1,9 +1,9 @@
 ARG BASE_VARIANT=alpine
 ARG GO_VERSION=1.18
-ARG XX_VERSION=1.1.0
+ARG XX_VERSION=1.1.2
 
-ARG LIBGIT2_IMG=ghcr.io/fluxcd/golang-with-libgit2-all
-ARG LIBGIT2_TAG=v0.1.2
+ARG LIBGIT2_IMG=ghcr.io/fluxcd/golang-with-libgit2-only
+ARG LIBGIT2_TAG=v0.2.0
 
 FROM ${LIBGIT2_IMG}:${LIBGIT2_TAG} AS libgit2-libs
 
@@ -17,7 +17,7 @@ FROM gostable AS go-linux
 # These will be used at current arch to yield execute the cross compilations.
 FROM go-${TARGETOS} AS build-base
 
-RUN apk add --no-cache clang lld pkgconfig
+RUN apk add clang lld pkgconfig
 
 COPY --from=xx / /
 
@@ -37,23 +37,6 @@ COPY go.sum go.sum
 # Cache modules
 RUN go mod download
 
-# The musl-tool-chain layer is an adhoc solution
-# for the problem in which xx gets confused during compilation
-# and a) looks for gold linker and then b) cannot find musl's dynamic linker.
-FROM --platform=$BUILDPLATFORM alpine as musl-tool-chain
-
-COPY --from=xx / /
-
-RUN apk add bash curl tar
-
-WORKDIR /workspace
-COPY hack/download-musl.sh .
-
-ARG TARGETPLATFORM
-ARG TARGETARCH
-RUN ROOT_DIR="$(pwd)" TARGET_ARCH="$(xx-info alpine-arch)" ENV_FILE=true \
-        ./download-musl.sh
-
 # Build stage install per target platform
 # dependency and effectively cross compile the application.
 FROM build-go-mod as build
@@ -64,7 +47,7 @@ COPY --from=libgit2-libs /usr/local/ /usr/local/
 
 # Some dependencies have to installed
 # for the target platform: https://github.com/tonistiigi/xx#go--cgo
-RUN xx-apk add musl-dev gcc lld
+RUN xx-apk add musl-dev gcc clang lld
 
 WORKDIR /workspace
 
@@ -74,20 +57,14 @@ COPY controllers/ controllers/
 COPY pkg/ pkg/
 COPY internal/ internal/
 
-COPY --from=musl-tool-chain /workspace/build /workspace/build
-
 ARG TARGETPLATFORM
 ARG TARGETARCH
 ENV CGO_ENABLED=1
 
-# Performance related changes:
-# - Use read-only bind instead of copying go source files.
-# - Cache go packages.
-RUN export $(cat build/musl/$(xx-info alpine-arch).env | xargs) && \
-    export LIBRARY_PATH="/usr/local/$(xx-info triple):/usr/local/$(xx-info triple)/lib64" && \
-    export PKG_CONFIG_PATH="/usr/local/$(xx-info triple)/lib/pkgconfig:/usr/local/$(xx-info triple)/lib64/pkgconfig" && \
-    export CGO_LDFLAGS="$(pkg-config --static --libs --cflags libssh2 openssl libgit2) -static" && \
-    GOARCH=$TARGETARCH go build  \
+RUN export LIBRARY_PATH="/usr/local/$(xx-info triple)" && \
+    export PKG_CONFIG_PATH="/usr/local/$(xx-info triple)/lib/pkgconfig" && \
+    export CGO_LDFLAGS="$(pkg-config --static --libs --cflags libgit2) -static -fuse-ld=lld" && \
+    xx-go build  \
         -ldflags "-s -w" \
         -tags 'netgo,osusergo,static_build' \
         -o /image-automation-controller -trimpath main.go;

Makefile

@@ -7,8 +7,8 @@ TAG ?= latest
 CRD_OPTIONS ?= crd:crdVersions=v1
 
 # Base image used to build the Go binary
-LIBGIT2_IMG ?= ghcr.io/fluxcd/golang-with-libgit2-all
-LIBGIT2_TAG ?= v0.1.2
+LIBGIT2_IMG ?= ghcr.io/fluxcd/golang-with-libgit2-only
+LIBGIT2_TAG ?= v0.2.0
 
 # Allows for defining additional Docker buildx arguments,
 # e.g. '--push'.
@@ -42,37 +42,20 @@ LIBGIT2_PATH := $(BUILD_DIR)/libgit2/$(LIBGIT2_TAG)
 LIBGIT2_LIB_PATH := $(LIBGIT2_PATH)/lib
 LIBGIT2_LIB64_PATH := $(LIBGIT2_PATH)/lib64
 LIBGIT2 := $(LIBGIT2_LIB_PATH)/libgit2.a
-MUSL-CC =
 
 export CGO_ENABLED=1
 export PKG_CONFIG_PATH=$(LIBGIT2_LIB_PATH)/pkgconfig
 export LIBRARY_PATH=$(LIBGIT2_LIB_PATH)
 export CGO_CFLAGS=-I$(LIBGIT2_PATH)/include -I$(LIBGIT2_PATH)/include/openssl
-
+export CGO_LDFLAGS=$(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --libs --static --cflags libgit2 2>/dev/null)
 
 # The pkg-config command will yield warning messages until libgit2 is downloaded.
 ifeq ($(shell uname -s),Darwin)
-export CGO_LDFLAGS=$(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --libs --static --cflags libssh2 openssl libgit2 2>/dev/null)
 GO_STATIC_FLAGS=-ldflags "-s -w" -tags 'netgo,osusergo,static_build'
-else
-export PKG_CONFIG_PATH:=$(PKG_CONFIG_PATH):$(LIBGIT2_LIB64_PATH)/pkgconfig
-export LIBRARY_PATH:=$(LIBRARY_PATH):$(LIBGIT2_LIB64_PATH)
-export CGO_LDFLAGS=$(shell PKG_CONFIG_PATH=$(PKG_CONFIG_PATH) pkg-config --libs --static --cflags libssh2 openssl libgit2 2>/dev/null)
 endif
 
 ifeq ($(shell uname -s),Linux)
-ifeq ($(shell uname -m),x86_64)
-# Linux x86_64 seem to be able to cope with the static libraries
-# by having only musl-dev installed, without the need of using musl toolchain.
 	GO_STATIC_FLAGS=-ldflags "-s -w" -tags 'netgo,osusergo,static_build'
-else
-	MUSL-PREFIX=$(BUILD_DIR)/musl/$(shell uname -m)-linux-musl-native/bin/$(shell uname -m)-linux-musl
-	MUSL-CC=$(MUSL-PREFIX)-gcc
-	export CC=$(MUSL-PREFIX)-gcc
-	export CXX=$(MUSL-PREFIX)-g++
-	export AR=$(MUSL-PREFIX)-ar
-	GO_STATIC_FLAGS=-ldflags "-s -w -extldflags \"-static\"" -tags 'netgo,osusergo,static_build'
-endif
 endif
 
 # API (doc) generation utilities
@@ -213,16 +196,11 @@ controller-gen: ## Download controller-gen locally if necessary.
 libgit2: $(LIBGIT2)  ## Detect or download libgit2 library
 
 COSIGN = $(GOBIN)/cosign
-$(LIBGIT2): $(MUSL-CC)
+$(LIBGIT2):
 	$(call go-install-tool,$(COSIGN),github.com/sigstore/cosign/cmd/cosign@latest)
 
 	IMG=$(LIBGIT2_IMG) TAG=$(LIBGIT2_TAG) PATH=$(PATH):$(GOBIN) ./hack/install-libraries.sh
 
-$(MUSL-CC):
-ifneq ($(shell uname -s),Darwin)
-	./hack/download-musl.sh
-endif
-
 # Find or download gen-crd-api-reference-docs
 GEN_CRD_API_REFERENCE_DOCS = $(GOBIN)/gen-crd-api-reference-docs
 .PHONY: gen-crd-api-reference-docs

controllers/suite_test.go

@@ -24,6 +24,7 @@ import (
 	"testing"
 	"time"
 
+	git2go "github.com/libgit2/git2go/v33"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/client-go/kubernetes/scheme"
 	ctrl "sigs.k8s.io/controller-runtime"
@@ -53,6 +54,8 @@ func init() {
 }
 
 func TestMain(m *testing.M) {
+	mustHaveNoThreadSupport()
+
 	utilruntime.Must(imagev1_reflect.AddToScheme(scheme.Scheme))
 	utilruntime.Must(sourcev1.AddToScheme(scheme.Scheme))
 	utilruntime.Must(imagev1.AddToScheme(scheme.Scheme))
@@ -90,3 +93,22 @@ func TestMain(m *testing.M) {
 
 	os.Exit(code)
 }
+
+// This provides a regression assurance for image-automation-controller/#339.
+// Validates that:
+// - libgit2 was built with no support for threads.
+// - git2go accepts libgit2 built with no support for threads.
+//
+// The logic below does the validation of the former, whilst
+// referring to git2go forces its init() execution, which is
+// where any validation to that effect resides.
+//
+// git2go does not support threadless libgit2 by default,
+// hence a fork is being used which disables such validation.
+//
+// TODO: extract logic into pkg.
+func mustHaveNoThreadSupport() {
+	if git2go.Features()&git2go.FeatureThreads != 0 {
+		panic("libgit2 must not be build with thread support")
+	}
+}

hack/install-libraries.sh

@@ -136,11 +136,11 @@ install_libraries(){
         fi
     fi
 
-    FILE_NAME="linux-$(uname -m)-all-libs.tar.gz"
-    DIR="libgit2-linux-all-libs"
+    FILE_NAME="linux-$(uname -m)-libgit2-only.tar.gz"
+    DIR="linux-libgit2-only"
     if [[ $OSTYPE == 'darwin'* ]]; then
-        FILE_NAME="darwin-all-libs.tar.gz"
-        DIR="darwin-all-libs"
+        FILE_NAME="darwin-libgit2-only.tar.gz"
+        DIR="darwin-libgit2-only"
     fi
 
     download_files "${FILE_NAME}"

tests/fuzz/oss_fuzz_build.sh

@@ -16,7 +16,7 @@
 
 set -euxo pipefail
 
-LIBGIT2_TAG="${LIBGIT2_TAG:-v0.1.2}"
+LIBGIT2_TAG="${LIBGIT2_TAG:-v0.2.0}"
 GOPATH="${GOPATH:-/root/go}"
 GO_SRC="${GOPATH}/src"
 PROJECT_PATH="github.com/fluxcd/image-automation-controller"