```
docker service create --name="minio-service" \
  --secret="my_access_key" \
  --secret="my_secret_key" \
  --env="MINIO_ROOT_USER_FILE=my_access_key" \
  --env="MINIO_ROOT_PASSWORD_FILE=my_secret_key" \
  quay.io/minio/minio server /data
```

 * </p>
 *
 * <p>
 * The handler relies on environment variables for configuration:
 * </p>
 * <ul>
 *   <li>{@code S3_ENDPOINT}: The endpoint URL of the S3 service.</li>
 *   <li>{@code S3_ACCESS_KEY}: The access key for authentication.</li>
 *   <li>{@code S3_SECRET_KEY}: The secret key for authentication.</li>
 *   <li>{@code S3_REGION}: The region of the S3 service (default: us-east-1).</li>
 * </ul>
 *
 * <p>

        if (StringUtil.isBlank(accessKey)) {
            throw new CrawlingAccessException(
                    "S3 access key is blank. Please set the S3_ACCESS_KEY environment variable or accessKey parameter.");
        }
        final String secretKey = getInitParameter("secretKey", null, String.class);
        if (StringUtil.isBlank(secretKey)) {

	// Construct the final presigned URL.
	return nil
}

// preSignV2 - presign the request in following style.
// https://${S3_BUCKET}.s3.amazonaws.com/${S3_OBJECT}?AWSAccessKeyId=${S3_ACCESS_KEY}&Expires=${TIMESTAMP}&Signature=${SIGNATURE}.
func preSignV2(req *http.Request, accessKeyID, secretAccessKey string, expires int64) error {
	// Presign is not needed for anonymous credentials.