#!/bin/bash

##############################################################################
# Copyright 2018 EuropeanSoftwareMarketingLtd.
# ===================================================================
#  Licensed under the ApacheLicense, Version2.0 (the"License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#  http://www.apache.org/licenses/LICENSE-2.0
#
# software distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under
# the License
##############################################################################
# vnftest comment: this is a modified copy of
# yardstick/tools/vnftest-img-lxd-modify

# vnftest-img-lxd-modify - download and modify a Ubuntu cloud image
#
# The actual customization is done by a script passed with an absolute path as
# the only single argument. The command needs to be invoked as sudo
#
# Example invocation:
# vnftest-img-lxd-modify /home/vnftest/tools/ubuntu-server-cloudimg-modify.sh
#
# Warning: the script will create files by default in:
#   /tmp/workspace/vnftest
# the files will be owned by root!
#
# TODO: image resize is needed if the base image is too small
#

set -e
set -x

die() {
    echo "error: $1" >&2
    exit 1
}

test $# -eq 1 -o $# -eq 2 || die "no image specific script as argument"
test $(id -u) -eq 0 || die "should invoke using sudo"

cmd=$1
RELEASE=$2
test -x $cmd
mountdir="/mnt/vnftest"
workspace=${WORKSPACE:-"/tmp/workspace/vnftest"}
host=${HOST:-"cloud-images.ubuntu.com"}
release=${RELEASE:-"xenial"}
image_path="${release}/current/${release}-server-cloudimg-amd64-root.tar.gz"
image_url=${IMAGE_URL:-"https://${host}/${image_path}"}
sha256sums_path="${release}/current/SHA256SUMS"
sha256sums_url=${SHA256SUMS_URL:-"https://${host}/${sha256sums_path}"}

imgfile="${workspace}/vnftest-image.tar.gz"
filename=$(basename $image_url)

# download and checksum base image, conditionally if local copy is outdated
download() {
    test -d $workspace || mkdir -p $workspace
    cd $workspace
    rm -f SHA256SUMS # always download the checksum file to a detect stale image
    wget $sha256sums_url
    test -e $filename || wget -nc --progress=dot:giga $image_url
    grep $filename SHA256SUMS | sha256sum -c ||
    if [ $? -ne 0 ]; then
        rm $filename
        wget -nc --progress=dot:giga $image_url
        grep $filename SHA256SUMS | sha256sum -c
    fi
    cd -
}

# extract files
setup() {
    mkdir -p $mountdir

    cp $cmd $mountdir/$(basename $cmd)

    cd $workspace
    tar zxvf $filename -C $mountdir
}

# modify image running a script using in a chrooted environment
modify() {
    # resolv.conf does not exist in base image, pass nameserver value from host
    nameserver_ip=$(grep -m 1 '^nameserver' \
        /etc/resolv.conf | awk '{ print $2 '})

    # prevent init scripts from running during install
    echo $'#!/bin/sh\nexit 101' >$mountdir/usr/sbin/policy-rc.d
    chmod a+x $mountdir/usr/sbin/policy-rc.d

    chroot $mountdir /$(basename $cmd) $nameserver_ip

    rm -rf $mountdir/usr/sbin/policy-rc.d

    tar zcvf $(basename $imgfile) $mountdir/
}

# cleanup the image
cleanup() {
    rm -rf $mountdir
}

exitcode=""
error_trap()
{
    local rc=$?

    set +e

    if [ -z "$exitcode" ]; then
        exitcode=$rc
    fi

    dmesg -T | tail -50

    cleanup

    echo "Image build failed with $exitcode"

    exit $exitcode
}

main() {
    cleanup

    trap "error_trap" EXIT SIGTERM

    download
    setup
    modify

    trap - EXIT SIGTERM
    cleanup

    echo "the modified image is found here: $imgfile"
}

main