build-iso-image.sh

#!/usr/bin/env bash
# see also: https://nixos.mayflower.consulting/blog/2018/09/11/custom-images/

set -exuo pipefail

writeScripts() {
    local outDir="$1"
    local outFile="$2"
    cat <<EOF | tee "$outDir/dd.sh"
#!/usr/bin/env bash
set -ex
sdX="\$1"
sudo dd if="$outFile" of="\$sdX" bs=4M conv=sync
EOF
    chmod +x "$outDir/dd.sh"

    cat <<EOF | tee "$outDir/run-qemu.sh"
#!/usr/bin/env bash
set -ex
qemu-kvm -boot d -cdrom "$outFile" -m 32000 -cpu host -smp 6
EOF
    chmod +x "$outDir/run-qemu.sh"
}

getIsoFromOutLink() {
    local iso="$1"
    local outLink="$2"
    local outArr
    outArr=("$outLink/$iso/"*".iso")
    echo "$(readlink -f "${outArr[-1]}")"
}

build() {
    local iso="$1"
    local outDir="../$iso"
    local outLink="$outDir/result"

    time nix build --out-link "$outLink" --show-trace .#myconfig-"$iso"

    local out
    out="$(getIsoFromOutLink "$iso" "$outLink")"
    du -h "$out"

    writeScripts "$outDir" "$out"
}

iso="${1:-iso}"

cd "$(dirname "${BASH_SOURCE[0]}")"
[[ -d "$HOME/myconfig/priv" ]] && cd "$HOME/myconfig/priv"
nix flake update
build "$iso"
times