Delete old deployed versions on Google App Engine

cleanupOldAppEngineVersions.sh

#!/bin/bash
# vim: set ts=4 sw=4 noet fileencoding=utf-8:

readonly SERVICE=${1-api}
readonly versions=$(gcloud app versions list --service=$SERVICE \
                    --sort-by=~version.createTime \
                    --format='table[no-heading](id)')
declare -i KEEP_LAST=${KEEP_LAST-5}

declare -i c=0
for version in $versions; do
	((++c))
	if [[ $c -gt $KEEP_LAST ]]; then
		gcloud versions delete --service $SERVICE --version $version
	fi
done