Auto-installer for CUDA Toolkit inside WSL2

bootstrap-cuda-toolkit.sh

#! /usr/bin/env bash
#
# Auto-installer for CUDA Toolkit inside Windows Subsystem for Linux.
#
if [ -z "${BASH_VERSINFO[0]}" ] || [ ${BASH_VERSINFO[0]} -lt 4 ]
then
    echo "ERROR: Only tested on Bourne-Again SHell v4/v5."
    exit 1
fi >&2

main() {
    installcuda
}

installcuda() {
    cudakeyring 1.0-1
    cudatoolkit 12-0
    # and some extra dev stuff suggested by deps above?
    #sudo apt install autoconf automake libtool flex bison gdb
}

cudakeyring() {
    local rev="$1"

    ! dpkg-query --list cuda-keyring ||return 0

    local ckrdeb="cuda-keyring_${rev}_all.deb"
    wget -N "https://developer.download.nvidia.com/compute/cuda/repos/wsl-ubuntu/x86_64/$ckrdeb"
    sudo dpkg --install "$ckrdeb"
    rm "$ckrdeb"
}

cudatoolkit() {
    local rev="$1"

    local repometa=(/var/lib/apt/lists/developer.download.nvidia.com_compute_cuda_repos_wsl-ubuntu_*)
    if [ "${#repometa[@]}" -eq 0 ]
    then sudo apt update
    fi

    #sudo apt install cuda
    # DANGER! do not install cuda pacakge as it contains driver that will break WSL2's stub libcuda.so

    # just the CUDA Toolkit and dependencies
    ! dpkg-query --list "cuda-toolkit-$rev" ||return 0

    sudo apt install "cuda-toolkit-$rev"
}

return 2>/dev/null ||:
shopt -s nullglob
set -ex
main
exit 0
# After reading all the crap on https://docs.nvidia.com/cuda/wsl-user-guide/index.html#cuda-support-for-wsl2
# I gave up on all the silly steps below and wrote the much smarter script above.

#wget -N https://developer.download.nvidia.com/compute/cuda/repos/wsl-ubuntu/x86_64/cuda-wsl-ubuntu.pin
#wget -N https://developer.download.nvidia.com/compute/cuda/repos/ubuntu2004/x86_64/cuda-ubuntu2004.pin
# both above are the same duh?

# why is this massive beast needed?
#wget -N https://developer.download.nvidia.com/compute/cuda/12.0.0/local_installers/cuda-repo-wsl-ubuntu-12-0-local_12.0.0-1_amd64.deb
#wget -N https://developer.download.nvidia.com/compute/cuda/12.0.0/local_installers/cuda_12.0.0_525.60.13_linux.run

#sudo mv cuda-wsl-ubuntu.pin /etc/apt/preferences.d/cuda-repository-pin-600