update.sh

#!/bin/bash
set -xeo pipefail

# A POSIX variable
OPTIND=1 # Reset in case getopts has been used previously in the shell.

while getopts "v:u:d:" opt; do
    case "$opt" in
    v)  VERSION=$OPTARG
        ;;
    u)  QEMU_VER=$OPTARG
        ;;
    d)  DOCKER_REPO=$OPTARG
        ;;
    esac
done

cd "$(readlink -f "$(dirname "$BASH_SOURCE")")"

versions=""
if [ "${VERSION}" != "" ]; then
    versions="${VERSION}"
elif [ ${#} -gt 0 ]; then
    versions=( "$@" )
else
    versions=( */ )
fi

get_part() {
    dir="$1"
    shift
    part="$1"
    shift
    if [ -f "$dir/$part" ]; then
        cat "$dir/$part"
        return 0
    fi
    if [ -f "$part" ]; then
        cat "$part"
        return 0
    fi
    if [ $# -gt 0 ]; then
        echo "$1"
        return 0
    fi
    return 1
}

for version in "${versions[@]}"; do
    version="${version%/}"
    dir="$(readlink -f "$version")"
    url="$(get_part "$dir" url)"
    tags="$(get_part "$dir" tags)"
    centos_version="$(get_part "$dir" version)"
    arch="$(get_part "$dir" arch)"
    qemu_arch="$(get_part "$dir" qemu_arch "")"
    scw_arch="$(get_part "$dir" scw_arch "$arch")"
    cd "$dir"

    # fetch image
    wget -N $url

    mkdir -p iso-slim

    # create rootfs.tar
    # Minimaize used sudo scope.
    # virt-tar-out and guestfish outputs below meesage without sudo.
    # "*stdin*:1: libguestfs: error: /usr/bin/supermin exited with error status 1"
    # https://bugzilla.redhat.com/show_bug.cgi?id=1591617
    # That's a bug of Ubuntu kernel. This does not happen on Fedora.
    # https://bugs.launchpad.net/ubuntu/+source/linux/+bug/759725
    if [[ $url =~ \.(img|raw)\.xz$ ]]; then
        imgxzfilename="$(basename $url)"
        imgfilename="${imgxzfilename%.xz}"

        if [ ! -f "${imgfilename}" ]; then
            cat "${imgxzfilename}" | unxz > "${imgfilename}"
        fi
        if [ ! -f iso-slim/rootfs.tar ]; then
            sudo virt-tar-out -a "${imgfilename}" / iso-slim/rootfs.tar
            user_name=$(id -un)
            group_name=$(id -gn)
            sudo chown ${user_name}:${group_name} iso-slim/rootfs.tar
        fi
    fi
    if [[ $url =~ \.tar\.xz$ ]]; then
        xzfilename="$(basename $url)"
        if [ ! -f iso-slim/rootfs.tar ]; then
            cat "${xzfilename}" | unxz > iso-slim/rootfs.tar
        fi
    fi
    if [[ $url =~ \.qcow2$ ]]; then
        filename="$(basename $url)"
        if [ ! -f iso-slim/rootfs.tar ]; then
            sudo virt-tar-out -a "${filename}" / iso-slim/rootfs.tar
            user_name=$(id -un)
            group_name=$(id -gn)
            sudo chown ${user_name}:${group_name} iso-slim/rootfs.tar
        fi
    fi
    if [[ $url =~ \.iso$ ]]; then
        filename="$(basename $url)"
        if [ ! -f iso-slim/rootfs.tar ]; then
            # Use guestfish directly because of virt-tar-out issue for iso file.
            # https://github.com/libguestfs/libguestfs/issues/37
            # https://www.redhat.com/archives/libguestfs/2019-May/msg00019.html
            file_system=$(
                sudo guestfish -a ${filename} --ro <<EOF | cut -d: -f 1
                run
                list-filesystems
EOF
)
            sudo guestfish --ro -a "${filename}" -m "${file_system}" tar-out / iso-slim/rootfs.tar
            user_name=$(id -un)
            group_name=$(id -gn)
            sudo chown ${user_name}:${group_name} iso-slim/rootfs.tar
        fi
    fi

    # create iso-slim dockerfile
    cat > iso-slim/Dockerfile <<EOF
FROM scratch
ADD rootfs.tar /
ENV ARCH=${scw_arch} CENTOS_VERSION=${centos_version} DOCKER_REPO=${DOCKER_REPO} CENTOS_IMAGE_URL=${url} QEMU_ARCH=${qemu_arch}

EOF

    ## build iso-slim image
    docker build -t ${DOCKER_REPO}:$version-iso-slim iso-slim
    for tag in $tags; do
        docker tag ${DOCKER_REPO}:$version-iso-slim ${DOCKER_REPO}:$tag-iso-slim
    done

    # create iso dockerfile
    mkdir -p iso
    if [ -n "${qemu_arch}" -a ! -f "iso/qemu-${qemu_arch}-static" ]; then
        wget https://github.com/multiarch/qemu-user-static/releases/download/${QEMU_VER}/qemu-${qemu_arch}-static -O "iso/qemu-${qemu_arch}-static"
        chmod +x "iso/qemu-${qemu_arch}-static"
    fi
    if [ -n "${qemu_arch}" ]; then
        cat > iso/Dockerfile <<EOF
FROM ${DOCKER_REPO}:$version-iso-slim
ADD qemu-${qemu_arch}-static /usr/bin
EOF
    else
        cat > iso/Dockerfile <<EOF
FROM ${DOCKER_REPO}:$version-iso-slim
EOF
    fi
    docker build -t ${DOCKER_REPO}:$version-iso iso
    for tag in $tags; do
        docker tag ${DOCKER_REPO}:$version-iso ${DOCKER_REPO}:$tag-iso
    done

    docker run -it --rm ${DOCKER_REPO}:$version-iso bash -xc '
        uname -a
        echo
        cat /etc/os-release 2>/dev/null
        echo
        cat /etc/redhat-release 2>/dev/null
        true
    '

    # build iso-cleanup image
    mkdir -p iso-clean
    cat > iso-clean/Dockerfile <<EOF
FROM ${DOCKER_REPO}:$version-iso
RUN yum remove -y \
      kernel-* *-firmware grub* centos-logos mariadb*       \
      postfix btrfs* mozjs17 xfsprogs cloud-init pciutils*  \
      libsoup* libgudev* python-prettytable                 \
      python-setuptools python-boto yum-utils               \
      libsysfs* glib-networking libproxy plymouth*          \
      libdrm wpa_supplicant *-desktop-*                     \
      perl gcc cpp doxygen emacs-nox || true
RUN rm -rf /boot
EOF
    docker build -t tmp-${DOCKER_REPO}:$version-iso-cleaner iso-clean
    tmpname=export-$(openssl rand -base64 10 | sed 's@[=/+]@@g')
    docker run --name="$tmpname" --entrypoint=/does/not/exist tmp-${DOCKER_REPO}:$version-iso-cleaner 2>/dev/null || true
    docker export "$tmpname" | \
        docker import \
           -c "ENV ARCH=${scw_arch} CENTOS_VERSION=${centos_version} DOCKER_REPO=${DOCKER_REPO} CENTOS_IMAGE_URL=${url} QEMU_ARCH=${qemu_arch}" \
           - "${DOCKER_REPO}:$version-clean"
    docker rm "$tmpname"
    for tag in $tags; do
        docker tag ${DOCKER_REPO}:$version-clean ${DOCKER_REPO}:$tag-clean
    done
    docker run -it --rm ${DOCKER_REPO}:$version-clean bash -xc '
        uname -a
        echo
        cat /etc/os-release 2>/dev/null
        echo
        cat /etc/redhat-release 2>/dev/null
        true
    '
done