This docker container has been created to allow us to easily crosscompile our c++ tools. The idea comes from multiarch/crossbuild, but that container unfortunately is outdated and the apt sources are no longer available.
The starting image is ubuntu:22.04. The starting image is only marginally important, since internally we use manually installed toolchains.
The toolchains are download from http://downloads.arduino.cc/tools/internal/toolchains.tar.gz . Inside that archive there are:
- gcc-arm-8.3-2019.03-x86_64-aarch64-linux-gnu toolchain to crosscompile for linux_arm64 (downloaded from here)
- gcc-arm-8.3-2019.03-x86_64-arm-linux-gnueabihf toolchain used to crosscompile for linux_arm (downloaded from here)
- i686-ubuntu16.04-linux-gnu toolchain to crosscompile for linux_386 (32bit)
- x86_64-ubuntu16.04-linux-gnu-gcc toolchain to crosscompile for linux_amd64
- osxcross toolchain to crosscompile for darwin_amd64. Inside
osxcross/tarballs/there is alreadyMacOSX10.15.sdk.tar.xz: the SDK required by macos to crosscompile (we tried with SDK version 10.09 but it was too old)
Regarding the two ubuntu toolchains: in the beginning we tried to use the ones shipped with 12.04 but they caused some build errors because they were too old, so we upgraded to 16.04 ones. They are created using crosstool-ng.
Apparently, osxcross does not have tags or version so we checkout a specific commit in order to have a pinned environment.
The last toolchain required to crosscompile for windows is mingw-w64 and it's installed through apt along with other useful packages.
Once the toolchains are installed in /opt we add the binaries to the PATH env variable, to easily use them in the CI.
As explained in the other README.md there are some libraries that needs to be compiled, in order to create static binaries. This is achieved by copying deps/ directory inside /opt/lib/ in the container and then by using build_libs.sh script here
To reduce the overall dimension of the docker image we used the multi-stage build. But the image still 8GB.
Usefull commands you can use:
-
docker build -t ghcr.io/arduino/crossbuild:<version> .to build the container -
docker push ghcr.io/arduino/crossbuild:<version>to push the image to github remote registry -
docker run -it --rm -e CROSS_COMPILE=<tool-chain> -v $PWD:/workdir ghcr.io/arduino/crossbuild:latestto get a shell inside the container with the selected toolchain. The image supports the following toolchain: -
x86_64-ubuntu16.04-linux-gnu
-
arm-linux-gnueabihf
-
aarch64-linux-gnu
-
i686-ubuntu16.04-linux-gnu
-
x86_64-apple-darwin13