fetch_build_files

#!/bin/bash

# make bash behave
set -euo pipefail
IFS=$'\n\t'

# constants
stdout=1
stderr=2
success=0
failure=1
badusage=64
noinput=66

packagingurl='https://github.com/citusdata/packaging'
download=$(mktemp)

# outputs usage message on specified device before exiting with provided status
usage() {
    cat << 'E_O_USAGE' >&"$1"
usage: fetch_build_files project format target_directory

    project : 'citus', 'enterprise', 'hll', or 'rebalancer'
    format : 'deb', 'rpm', or 'pgxn'

fetch_build_files fetches files needed to package a specified Citus project for
a specified software packaging system.
E_O_USAGE

    exit "${2}";
}

if [ "$#" -eq 1 ] && [ "${1}" = '-h' ]; then
    usage $stdout $success
fi

if [ "$#" -ne 3 ]; then
    usage $stderr $badusage
fi

case "${1}" in
    citus|enterprise|hll|rebalancer)
        project=${1}
        ;;
    *)
        echo "$0: unknown project -- ${1}" >&2
        usage $stderr $badusage
        ;;
esac

case "${2}" in
    deb)
        format='debian'
        ;;
    rpm)
        format='redhat'
        ;;
    pgxn)
        format='pgxn'
        ;;
    *)
        echo "$0: unknown format -- ${2}" >&2
        usage $stderr $badusage
        ;;
esac

targetdir=$3
# validate inputs
if ! [ -d "${targetdir}" ]; then
    echo "$0: ${targetdir}: Is not a directory" >&2
    exit $noinput
elif [ ! -e "${targetdir}" ]; then
    echo "$0: ${targetdir}: No such file" >&2
    exit $noinput
elif [ ! -r "${targetdir}" ]; then
    echo "$0: ${targetdir}: Permission denied" >&2
    exit $noinput
fi

downloadurl="${packagingurl}/archive/${format}-${project}.tar.gz"

# download a tarball of the build files
httpcode=$(curl -sL "${downloadurl}" -w "%{http_code}" -o "${download}")

if [ "${httpcode}" -ne 200 ]; then
    echo "$0: could not fetch build tarball from ${downloadurl}" >&2
    echo "$0: HTTP code was: ${httpcode}" >&2
    exit $failure
fi

# expand them directly into the target directory
tar xf "${download}" -C "${targetdir}" --strip-components 1