Docker volume prune with until workaround (filter for --until isn't supported)

docker-volume-prune.sh

#!/usr/bin/env bash

set -euo pipefail

volumes=$(docker volume ls --filter dangling=true --quiet)
if [[ -z "$volumes" ]]; then
  echo "No dangling volumes found"
  exit 0
fi

for volume in $volumes; do
  if [[ -z "$volume" ]]; then
    continue
  fi

  echo "Checking creation date for $volume"
  created_at=$(docker inspect "$volume" --format '{{.CreatedAt}}')
  seconds_since_created=$(($(date +%s) - $(date -d"$created_at" +%s)))
  echo "Created $seconds_since_created ago"
  if [[ "$seconds_since_created" -gt "3600" ]]; then
    echo "Deleting volume $volume"
    docker volume rm "$volume" --force
  fi
done