// get the prefix of the metric to delete if its specified. Prefixes can only be done at the entity level,
// meaning the entire string within a '.'. For example, for metic store.bytes, 'store' as a prefix will match
// 'store.bytes', but 'stor' as a prefix will not match.
private String getMetricPrefixFromRequest(HttpRequest request) {
Map<String, List<String>> queryParams = new QueryStringDecoder(request.getUri()).getParameters();
List<String> prefixEntity = queryParams.get("prefixEntity");
// shouldn't be in params more than once, but if it is, just take any one
return (prefixEntity == null || prefixEntity.isEmpty()) ? null : prefixEntity.get(0);
}