goreleaser-cross

Docker container to turn CGO cross-compilation pain into a pleasure. It tested on variety of platforms. Custom sysroots also can be used.

Tip! Should you wish to see working examples instead of reading

Credits

This project is rather a cookbook combining various projects into one. Special thanks to osxcross for an amazing cross-compile environment for OSX.

Docker

Docker images are available on both GitHub and Docker hub. The image's tag version follows Golang release so if you use 1.19.4, you are effectively compiling your Go code using Golang at version 1.19.4. The actual version of the other tools installed within the Docker image like goreleaser can be found in the latest releases.

Images from version v1.17.4 are multi-arch. Supported hosts are listed in the table below.

Host	Supported	CC is set to	CXX is set to
amd64	✅	x86_64-linux-gnu-gcc	x86_64-linux-gnu-g++
arm64 (aka aarch64)	✅	aarch64-linux-gnu-gcc	aarch64-linux-gnu-gcc

Below are additional environment variables to set when cross compiling with CGO.

Env variable	Value	Required	Notes
CGO_ENABLED	1	Yes	Instead of specifying it in each build it can be set globally during docker run -e CGO_ENABLED=1
CC	see targets	Optional
CXX	see targets	Optional
PKG_CONFIG_SYSROOT_DIR		Required if sysroot is present
PKG_CONFIG_PATH		Optional	List of directories containing pkg-config files

• PKG_CONFIG_SYSROOT_DIR modifies -I and -L to use the directories located in target's sysroot.
• The value of PKG_CONFIG_SYSROOT_DIR is prefixed to -I and -L. For instance -I/usr/include/libfoo becomes -I/var/target/usr/include/libfoo with a PKG_CONFIG_SYSROOT_DIR set to /var/target (same rule apply to -L)
• PKG_CONFIG_PATH - A colon-separated list of directories to search for .pc files.

Supported toolchains/platforms

Platform	Arch	CC	CXX	Verified
Darwin	amd64	o64-clang	o64-clang++	✅
Darwin (M1/M2)	arm64	oa64-clang	oa64-clang++	✅
Linux	amd64	x86_64-linux-gnu-gcc	x86_64-linux-gnu-g++	✅
Linux	arm64	aarch64-linux-gnu-gcc	aarch64-linux-gnu-g++	✅
Linux	armhf (GOARM=5)	arm-linux-gnueabihf-gcc	arm-linux-gnueabihf-g++	Verification required
Linux	armhf (GOARM=6)	arm-linux-gnueabihf-gcc	arm-linux-gnueabihf-g++	Verification required
Linux	armhf (GOARM=7)	arm-linux-gnueabihf-gcc	arm-linux-gnueabihf-g++	✅
Linux	s390x	s390x-linux-gnu-gcc	s390x-linux-gnu-g++	✅
Windows	amd64	x86_64-w64-mingw32-gcc	x86_64-w64-mingw32-g++	✅
Windows	arm64	/llvm-mingw/bin/aarch64-w64-mingw32-gcc	/llvm-mingw/bin/aarch64-w64-mingw32-g++	✅

Docker

Environment variables

• Goreleaser variables
• GPG_KEY (optional) - defaults to /secrets/key.gpg. ignored if file not found
• DOCKER_CREDS_FILE (optional) - path to JSON file with docker login credentials. Useful when push to multiple docker registries required
• DOCKER_FAIL_ON_LOGIN_ERROR (optional) - fail on docker login error

Login to registry

Github Actions

Use docker login to auth to repos and mount docker config file. For example:

docker run -v $(HOME)/.docker/config.json:/root/.docker/config.json ...

Docker Creds file

To login from within goreleaser-cross container create creds file.

{
    "registries": [
        {
            "user": "<username>",
            "pass": "<password>",
            "registry": "<registry url>" // for example ghcr.io
        }
    ]
}

Sysroot howto

Most reasonable way to make a sysroot seem to be rsync and the example is using it. You may want to use the script to create sysroot for your desired setup. Lets consider creating sysroot for Raspberry Pi 4 running Debian Buster.

• install all required dev packages. for this example we will install libftdi1-dev, libusb-1.0-0-dev and opencv4

  ./sysroot-rsync.sh pi@<ipaddress> <local destination>

sshfs

Though sshfs is a good way to test sysroot before running rsync it introduces cons. Some packages are creating absolute links and thus pointing to wrong files when mounted ( or appear as broken). For example RPI4 running Debian Buster the library /usr/lib/x86_x64-gnu-linux/libpthread.so is symlink to /lib/x86_x64-gnu-linux/libpthread.so instead of ../../../lib/x86_x64-gnu-linux/libpthread.so.

Contributing

Any contribution helping to make this project is welcome

Examples

• Example described in this tutorial

Projects using

• Akash