#!/usr/bin/env bash
set -eu

if [[ -n ${SOURCE_DATE_EPOCH:-} ]]; then
   snapshot=$(date -u -d @"$SOURCE_DATE_EPOCH" +%Y%m%dT%H%M%SZ)
else
   snapshot=$(date -u +%Y%m%dT%H%M%SZ)
fi

env SNAPSHOT_ISO8601="$snapshot" envsubst < "$1" > "$2"
