Scan a Terraform module for dependencies that can be upgraded.

scan-versions.sh

#!/usr/bin/env bash

set -euo pipefail

modules=($(grep -r --exclude-dir={examples,.terraform} --include '*.tf' '\"git@github.com:' | cut -d ":" -f3 | cut -d "\"" -f1 | sort -u))

declare -A latest_versions needs_upgrade

for module in ${modules[@]}; do
    if [[ $module =~ ([^\/]+)\/([^\.]+)[^?]+\?ref=(.+) ]]; then
        repo="${BASH_REMATCH[1]}/${BASH_REMATCH[2]}"
        version=${BASH_REMATCH[3]}

        if [[ -z ${latest_versions["${repo}"]:-} ]]; then
            latest_versions["${repo}"]=$(
                git ls-remote --refs --tags "git@github.com:${repo}.git" | cut --delimiter='/' --fields=3 |
                    tr '-' '~' | sort --version-sort | tail --lines=1
            )
        fi

        latest=${latest_versions["${repo}"]}
        [[ "${version}" != "${latest}" ]] && needs_upgrade["${repo} ${version}"]=${latest}
    fi
done

IFS=$'\n'
for old in ${!needs_upgrade[@]}; do
    echo -e "${old} needs upgrade to ${needs_upgrade["${old}"]}"
done
unset IFS