use multiarch/crossbuild and multiarch/alpine docker images for linux build

reduce the number of dockerfiles

Author: arturcic

.github/workflows/ci.yml

@@ -31,6 +31,10 @@ jobs:
             name: linux-musl-x64
           - os: ubuntu-20.04
             name: linux-arm64
+          - os: ubuntu-20.04
+            name: linux-musl-arm
+          - os: ubuntu-20.04
+            name: linux-musl-arm64
           - os: ubuntu-20.04
             name: linux-arm
           - os: macos-10.15
@@ -49,6 +53,9 @@ jobs:
       - name: Build macOS
         if: runner.os == 'macOS'
         run: ./build.libgit2.sh
+      - name: Setup QEMU
+        run: docker run --rm --privileged multiarch/qemu-user-static:register --reset
+        if: matrix.name == 'linux-musl-arm' || matrix.name == 'linux-musl-arm64'
       - name: Build Linux
         if: runner.os == 'Linux'
         run: ./dockerbuild.sh

CMakeLists.arm.txt

@@ -0,0 +1,9 @@
+FROM multiarch/crossbuild
+ARG ARCH='amd64'
+ENV CROSS_TRIPLE=${ARCH}
+RUN apt update && apt -y install pkg-config
+
+WORKDIR /nativebinaries
+COPY . /nativebinaries/
+
+CMD ["/bin/bash", "-c", "./build.libgit2.sh"]

CMakeLists.arm64.txt

@@ -0,0 +1,8 @@
+ARG ARCH='amd64'
+FROM multiarch/alpine:${ARCH}-v3.12
+RUN apk add --no-cache bash build-base cmake
+
+WORKDIR /nativebinaries
+COPY . /nativebinaries/
+
+CMD ["/bin/bash", "-c", "./build.libgit2.sh"]

Dockerfile.linux

@@ -11,7 +11,7 @@ the following platforms:
 
  - Windows (x86, x64, arm64)
  - macOS (x64, arm64)
- - Linux (arm, arm64, x64)
+ - Linux (arm, arm64, x64, musl-x64, linux-musl-arm, linux-musl-arm64)
 
  [lg2s-nb]: https://www.nuget.org/packages/LibGit2Sharp.NativeBinaries
  [lg2]: https://libgit2.github.com/

Dockerfile.linux-arm

@@ -5,7 +5,6 @@ set -e
 LIBGIT2SHA=`cat ./nuget.package/libgit2/libgit2_hash.txt`
 SHORTSHA=${LIBGIT2SHA:0:7}
 OS=`uname`
-ARCH=`uname -m`
 PACKAGEPATH="nuget.package/runtimes"
 OSXARCHITECTURE="x86_64"
 
@@ -22,18 +21,6 @@ rm -rf libgit2/build
 mkdir libgit2/build
 pushd libgit2/build
 
-export _BINPATH=`pwd`
-
-if [[ $RID == *arm ]]; then
-	export TOOLCHAIN_FILE=/nativebinaries/CMakeLists.arm.txt
-fi
-
-if [[ $RID == *arm64 ]]; then
-	if [[ $OS != "Darwin" ]]; then
-		export TOOLCHAIN_FILE=/nativebinaries/CMakeLists.arm64.txt
-	fi
-fi
-
 cmake -DCMAKE_BUILD_TYPE:STRING=Release \
       -DBUILD_CLAR:BOOL=OFF \
       -DUSE_SSH=OFF \
@@ -42,7 +29,6 @@ cmake -DCMAKE_BUILD_TYPE:STRING=Release \
       -DCMAKE_OSX_ARCHITECTURES=$OSXARCHITECTURE \
       -DUSE_HTTPS=$USEHTTPS \
       -DUSE_BUNDLED_ZLIB=ON \
-      -DCMAKE_TOOLCHAIN_FILE=${TOOLCHAIN_FILE} \
       ..
 cmake --build .
 

Dockerfile.linux-arm64

@@ -1,8 +1,23 @@
 #!/bin/bash
 
 set -e
+echo "building for $RID"
 
-docker build -t $RID -f Dockerfile.$RID .
+if [[ $RID =~ arm64 ]]; then
+  arch="arm64"
+elif [[ $RID =~ arm ]]; then
+  arch="armhf"
+else
+  arch="amd64"
+fi
+
+if [[ $RID == linux-musl* ]]; then
+    dockerfile="Dockerfile.linux-musl"
+else
+    dockerfile="Dockerfile.linux"
+fi
+
+docker buildx build -t $RID -f $dockerfile --build-arg ARCH=$arch .
 
 docker run -t -e RID=$RID --name=$RID $RID