Hacky script to build Salt packages for Debian with pbuilder and repo.saltstack.com packaging data

salt-pkg-builder.sh

#!/bin/bash -e

# The tag name (or branch) of whatever you want to package.
declare -r tag="${1-v2017.7.5}"
declare -r pbuilder_target="${2-stretch}"

declare -r git_dir=./salt

# This makes no sense to me. Why are these different?
declare -r salt_upstream_version="${tag:1}"
declare -r pkg_upstream_version="${tag:1}+ds"

declare -r sitepoint_revision="sp1"

# Nothing below this point should normally require touching unless
# adding support for new distributions, compression formats or
# repository structure.

declare -r changelog_root='http://metadata.ftp-master.debian.org/changelogs/main/s/salt'
declare -r salt_repo='http://repo.saltstack.com/apt'
declare -r major_minor_ver="$(echo ${tag} | tr -d 'v' | cut -d '.' -f 1-2)"

declare -i download_changelog=1
declare distro
declare pbuilder_target_num

case "${pbuilder_target}" in
    "jessie" )
        distro=debian
        pbuilder_target_num=8
        ;;
    "stretch" )
        distro=debian
        pbuilder_target_num=9
        ;;
    "trusty" )
        distro=ubuntu
        pbuilder_target_num=14.04
        ;;
    "xenial" )
        distro=ubuntu
        pbuilder_target_num=16.04
        ;;
esac

declare -r repo_base_url="${salt_repo}/${distro}/${pbuilder_target_num}/amd64/${major_minor_ver}"

if [ -d "${salt_upstream_version}" ]
then
    echo "Error: Output directory '${salt_upstream_version}' already exists."
    exit 1
fi

declare changelog_file
declare compression_type
declare compression_ext

if wget --spider \
    "${repo_base_url}/salt_${pkg_upstream_version}-1.debian.tar.xz" \
    2>/dev/null ||
    [ -f "salt_${pkg_upstream_version}-1.debian.tar.xz" ]
then
    compression_ext=.xz
    tar_compression_arg=J
    if [ -f "salt_${pkg_upstream_version}-1.debian.tar.xz" ]
    then
        download_changelog=0
        mkdir -p ${salt_upstream_version}
        cp -f "salt_${pkg_upstream_version}-1.debian.tar.xz" \
            "${salt_upstream_version}/salt_${pkg_upstream_version}-1.debian.tar.xz"
    fi
elif wget --spider \
    "${repo_base_url}/salt_${pkg_upstream_version}-1.debian.tar.gz" \
    2>/dev/null
then
    compression_ext=.gz
    tar_compression_arg=z
elif wget --spider \
    "${repo_base_url}/salt_${pkg_upstream_version}-1.debian.tar" \
    2>/dev/null
then
    compression_ext=''
    tar_compression_arg=''
else
    echo "Failed to locate salt_${pkg_upstream_version}-1.debian.tar." 1>&2
    exit 1
fi

if [ ! -d "${git_dir}" ]
then
    git clone https://github.com/saltstack/salt.git "${git_dir}"
fi

cd ${git_dir}

git fetch
git checkout ${tag}
git clean -fdx
git reset --hard

# Generates a modified tarball. For details see:
# https://github.com/saltstack/salt/issues/36360
python setup.py sdist

mkdir -p ../${salt_upstream_version}

# Note the use of '-' instead of a '+'. This is unconventional but
# required due to a well-known bug in S3.
mv dist/salt-${salt_upstream_version}.tar.gz \
    ../${salt_upstream_version}/salt_${pkg_upstream_version}.orig.tar.gz

cd ../${salt_upstream_version}/

# Fetch, verify and extract the debian packaging files.
if [ ${download_changelog} -eq 1 ]
then
    wget "${repo_base_url}/salt_${pkg_upstream_version}-1.debian.tar${compression_ext}"
    wget "${repo_base_url}/salt_${pkg_upstream_version}-1.dsc"

    # Checksum verification
    gpg --verify salt_${pkg_upstream_version}-1.dsc
    grep -A2 '^Checksums-Sha256:' salt_${pkg_upstream_version}-1.dsc |
        grep '.debian.tar' |
        sed 's/\s*\([^[:space:]]*\).*[[:space:]]\([^[:space:]]*\)$/\1  \2/' |
        sha256sum -c -
fi

tar zxf salt_${pkg_upstream_version}.orig.tar.gz

cd salt-${salt_upstream_version}
tar ${tar_compression_arg}xf \
    ../salt_${pkg_upstream_version}-1.debian.tar${compression_ext}

# Fetch the changelog for the most recent Salt package in Debian
# (which is almost certainly not up to date). Unfortunately, the Salt
# repos do not provide a changelog file.
changelog_file="$(w3m -dump "${changelog_root}/" |
    grep -E '^\[TXT\]\s+.*salt_.*(ds|dfsg1)-[0-9]+_changelog\s+.*' |
    sort -V | tail -n 1 | sed 's/^\[TXT\]\s\+\([^\ ]*\).*/\1/')"

# Update the local changelog.
echo >> debian/changelog
wget -q -O - "${changelog_root}/${changelog_file}" \
    >> debian/changelog
debchange -v ${pkg_upstream_version}-${sitepoint_revision} -D stable \
    'New upstream release.'

# Use a clean pbuilder environment. I know these aren't the typical
# branch names, but there is no practical difference.
DIST=${pbuilder_target} pdebuild

echo "Look under /var/cache/pbuilder for build results."