code: private static Tag uri(RequestLog requestLog) {
      int status = requestLog.statusCode();
      if (status > 299 && status < 400) return URI_REDIRECTION;
      if (status == 404) return URI_NOT_FOUND;
  
      String uri = getPathInfo(requestLog);
      if (uri.startsWith("/zipkin")) {
        if (uri.equals("/zipkin/") || uri.equals("/zipkin")
          || uri.startsWith("/zipkin/traces/")
          || uri.equals("/zipkin/dependency")
          || uri.equals("/zipkin/traceViewer")) {
          return URI_CROSSROADS; // single-page app route
        }
  
        // un-map UI's api route
        if (uri.startsWith("/zipkin/api")) {
          uri = uri.replaceFirst("/zipkin", "");
        }
      }
      // handle templated routes instead of exploding on trace ID cardinality
      if (uri.startsWith("/api/v2/trace/")) return URI_TRACE_V2;
      return Tag.of("uri", uri);
    }
docs: Ensure metrics cardinality doesn't blow up on variables